Two dangerous assumptions

First is the belief that a few well-meaning individuals can make a difference.

Turning a few lights off is not going to stop global warming. Turning a power station off could. Reducing your own consumption of oil by a few litres is not going to make a big difference. Reducing a country's imports or reducing a company's output by a few million barrels is. Throwing a few tins into the recycling is not going to save the world. It's just a tiny drop, and the drop is probably of molten melted in an oil-fired crucible.

The second, much more dangerous assumption is that a few well-meaning individuals won't make a difference. Most of the critical decisions that could affect our survival are going to be taken by individuals. The important actions are going to be made by individuals. Leaders of businesses, heads of governments and representatives of organisations are all individuals. Every policy and paper starts from the pen of one person. The only people who can make a difference are well-meaning individuals. You may be one of them. Somebody you know may be one of them. Somebody who happens to see one of your trivial deeds may be one of them.

Human actions are influenced in many ways, and it's not always clear why things happen. This is why people can get advanced degrees and influential jobs in economics and still sound like complete idiots.

But just when I was worrying about my own actions making no difference at all. Just as I was settling into the realisation that the main results of my noble attempts to change the world through building a house had all long since gone in and out of the bank accounts of various agents in the industry, who are now back to their inevitable unecological tricks. Just when I thought it was all a waste of time, the water bill came. Nothing unusual about that, but on it was a piece of advice. It said something like this: to avoid your pipes freezing, be sure to put some insulation, for example expanded polystyrene, around the main tap.

Now I know this is a small thing, and it would be a lot more useful if the invoice for heating bills suggested you insulate your whole house, but that may be like expecting the people in the hamburger shop recommending you drink water rather than a large container of brown fizzy sugar, or saying "are you sure you want fries with that?"

But it's a positive thing. It's much better than the usual solution, which is wrapping pipes with an electrical heating element that comes on whenever the temperature gets anywhere near zero. I'm sure it does not directly result from my building project, but somebody out there is making some sensible suggestions, and I'm not a lone crazy voice shouting into a wilderness.

Shovelling snow and suffering pain

Winter is here, and that means sooner or late it's going to snow. And that means sooner or later having to shovel some of it. Not only does this seem a largely futile activity since you can walk over snow while it's there, and if you leave it, it's all going to melt before too long. Also, it tends to result in back pain, either chronic, acute or both. 

I've always assumed this is because snow appears to be light and fluffy, but is in fact much heavier, so the body is unprepared for the amount of work and the strain each lifting will take. 

I think there may be more to it than that. Snow also has air in it. This does not make it any heavier, but does make it more massive. The extra air is not going to make a difference to the weight, since the snow is already floating in air, but it is going to affect the mass since you have to move all that air as well as the snow. 

Japanese science-hero Denjiro-sensei performed a really good experiment to show the difference between weight and mass. He took a large balloon, something over a metre in diameter. First, he threw it uninflated across the stage at a foldable chair, which had little impact. Next he threw an inflated balloon at the same chair, causing it to fly across the stage. You could probably repeat this experiment in your own living room using a regular balloon and something like a pet bottle. 

So back to shovelling snow, not only does snow look much lighter and fluffier than it actually weighs, so we are not fully prepared for the strain of the lift. It is also more massive than it is heavy, so we need more strength to move it around, changing its inertia, than we would guess just from holding up a shovelful.

When did we turn the heating on last year?

Ask the slab. 

We have ten thermometers in the slab, recording and logging the temperature every few minutes. There are five buried at the bottom of the foundation, one near each corner and one in the middle, and another five in the screed, hopefully a safe distance from the underfloor heating pipes so that they are measuring the temperature of the floor and not just the pipes. They should give us an idea of when the heating went on though.

The best one to look at is probably the thermometer in the middle of the floor. Before the heating went on, it was nicely cycling day to day with the temperature at its lowest mid-morning, then rising from 10 or 11 am, as the heat of the sun found its way into the slab. The heat either does this directly by hitting the floor and conducting through the tiles and concrete, or indirectly by heating the air in the house, and the air heating the floor. My instinct is that solar radiation is going to have more effect heating the floor than ambient air, probably because I've been indoctrinated into the mantra of hot air rising, and the consequence that not much heat will be going down from the air into the floor. 

The data is a bit grainy, since we only have precision to a tenth of a degree while  James Joule reckoned he could measure the temperature of his beer vats to 1/200 of a degree Farenheit. Making the best of our 21st century tools, the floor seems to stop warming around 3.30, which is about when the sun stops reaching it directly. The room temperature is still a couple of degrees warmer at this point, but can be five or six degrees warmer around noon. Hopefully you can see this in the first chart, where the green line is the room temperature, the red line the temperature just under the floor, and the blue line the temperature at the bottom of the slab. Of course a bigger temperature difference means more heat would be conducted from air to floor, and in fact the ambient thermometer is half way up the wall on the south side of the house, so it's possible that the air temperature at the floor is only above the floor temperature until 3:30. Anyway, this is not strictly relevant to my question. 

On 5th December, we must have switched the heating on from around 5:30 am because the slab started to heat up then. From then, depending on the weather, there's a double peak effect when the morning injection of heat starts wearing off and the solar gain hasn't kicked in yet. 

On some days there was obviously no solar gain, and the temperature just falls after the morning boost. This happened on December 8th, 9th and 10th when there was a fair bit of snow. 

Then from 12 December we get a triple peak effect when the heating was also on from 7:30 or 8 pm for half an hour. This only lasted for a couple of days, perhaps until my Yorkshire genes got the better of me. 

The triple peak starts up again from 19th December, this time the heating going on from 10 pm for half an hour. 

We went away from 22nd December for 2 weeks, leaving the heating off. The screed went back to the diurnal cycle, with the temperature at the bottom of the foundation plumetting to an all-time low of 19.2 degrees centigrade. The lowest trough in the screed was 18.7 degrees. 

The heating went back on again in the mornings from 3rd January, and I can't tell exactly when it went on in the evenings. There is a rise in screed temperature around 8pm on 7th, 24th to 26th and 30th Janary, and 2nd, 3rd and 8th February. On other days there is a slight plateauing of temperature around that time, before the fall over the night, so I guess night time heating was on at least until 16th February. There are a couple of days when the heat went on around 10:30 pm.

We turned the morning heating off on 8th March, and just turned it on again 12th December. Instinct once again tugs at my coat tails, urging me to switch on the heating so the house doesn't lose too much heat making it more difficult later. Knowledge of thermodynamics suggests that making the house warmer is just going to mean losing more heat, so if we can survive the temperature, we should be OK. Experience also shows that it's not going to get that cold. It was still above 18 degrees in the middle of the slab with no heating on for two weeks at the end of December. Also, experience of the underfloor heating is that the response is not so bad, and while it doesn't give the instant blast of hot air you get from a fan heater or air conditioner, it feels warm within ten or fifteen minutes of switching it on. And if things get really desparate we can switch on the air conditioner, or do something really drastic like put socks on.

Whether to turn it on in the mornings or evenings is another question for another day.

If NEDO had been done

I should write about the plan of the man who wanted to supply heat but not much light.

We had had reservations about his system from early on. During discussions about the chances of actually receiving the NEDO grant, I asked their boss and the builder's boss whether they would cover the grant amount in the event that we didn't get it because they hadn't built our house within the deadline. I think they thought this was funny. Evidently there was no concept of a penalty for not meeting a deadline. The Supplier of Heat but Not much Light suggested a place where I could get a loan to cover the cost. 

The radical part of it was a solar thermal system, providing hot water in the summer, and heating in the winter. 

Most people assume the problem with a solar thermal system is what to do on days when there isn't enough sun, but in fact that is a fairly simple problem. You need a back-up heating system. There are any number of ways to heat water from gas or oil burners, to a heating element from a kettle in the boiler. You don't see them so often but it's certainly possible to have an electrical heating element at the tap. A low-tech solution would be an electrical shower unit, which may be expensive to use but if you only need it a few days every year, then the total cost would not be so much.

The biggest problem with solar thermal systems is failure in the face of too much solar heat going in and not enough hot water going out. 

My simple question about the system was, what if the refrigerant boiled? This seemed likely to happen sooner or later. The behaviour of liquids heating up is quite predictable. As the liquid gets warmer it expands slightly. Then it starts to boil. The amount of gas steadily increases, with the pressure rising. When all the liquid in the solar collector turns to gas it will probably stop circulating and the system will stagnate. Gas tends to have a low thermal capacity so it won't take much more heat, and low conductivity so very little heat will get into the rest of the system, and the liquid in the circuit beyond the solar collector will not start boiling. The gas will reach some temperature at which there is an equilibrium between the solar heat getting in and heat radiating out. 

If the system survives this high pressure and high temperature, the next challenge is what to do as it cools down.

The gas will start to condense into liquid, and the collector must fill up again, so that it can continue to flow and get heat where it is needed.

A robust system should probably be able to cope with this. The Victorians were using steam systems for heating, so the pressure should not be a problem. 

In the plan of the man providing heat but little light, the solar elements used vacuum tubes, with a refrigerant pumped through them all the time. The pump was served by a dedicated solar panel, ensuring that the refrigerant would not stop, which would lead to disaster. This was his answer: it's not going to happen. 

That was one worry about the system.

In discussions around the same time as I found that penalties for not meeting deadlines were from an alien world, I asked what kind of guarantee they had on the solar thermal system, having heard that many solar thermal systems fail within about five years. He could only offer a one-year guarantee.  This did not reduce my worry.

Another minor worry, which I would have lived with, was that the back-up heating system used paraffin oil. Having spent too many winters lugging tanks of the stuff to my house, syphoning it into the small tanks and ferrying them to the heaters inside, and spilling several litres of it in the process, I really didn't want the stuff anywhere near my house. 

I know that in terms of environmental impact directly using fossil fuels is less wasteful than getting electricity off the grid that has come from gas-fired power stations, but given a choice I didn't want to build a house that took any fossil fuels. 

The delays meant that we were no longer going to get the 2.7 million yen NEDO grant, but once we had established this, it also meant we were no longer bound to this elaborate and expensive system that was included in the grant application. 

This system was certainly going to cost us at least an extra million yen, but if we had been able to get the grant, we probably would have been financially better off.

But, I suspect that if we had gone for the grant and followed their plan, by now we may have been stuck with a system that didn't work properly, and seeing a lot of their repair men, so it's probably a good thing that we got out of the grant.

Or perhaps if we hadn't even thought about applying for the NEDO grant in the first place, we may have bashed the plans around a bit more, changed the windows on the south side from triple to double and got some curtains for them, or given up on the concertina window, and found ways to save a great deal more than the 2.7 million of grant that we would have got.

And then it may have taken another year to build, and we would have paid another million in rent and bills on the old house. 

As it is, we have a great house where the good points far outweigh the bad points, so there is not much to complain about, and it doesn't help much to wonder what might have been.

NEDO - No Deal

So the discussion of the NEDO grant started early in 2010, dangled in front of us like a piece of bait to lure the client into the contractor's trap.

We got the applications in to the Suppliers of Heat but Not much Light, and they sent them in to NEDO in May. The approval came back in July. 

From May their plan had been pretty much part of our plan, at least as far as I was concerned, and from the arrival of the piece of paper bearing the red government seal, their plan was a fixed in ours. This set the project completion date before January, since that was one of the conditions of the NEDO grant. In fact January 2011 was already a lot later than October 2010, which had been the completion date in earlier plans. I had hoped to be moving out of the old house before the winter of 2010, but January became March, and then seemed more like it would be May 2011. In the end everyone was rushing around like blue-arsed flies because I was holding the site foreman to his promise that we would be in by Christmas 2011. 

In order to meet the deadline of January 2011, we needed the windows to arrive by November 2010, so they had to be ordered pretty quickly to be assembled and delivered from Germany in time. Although we'd basically decided what windows we wanted when they made the semi-fictitious invoice for them for the NEDO application, it took a while to specify the exact details, including which way they opened, the style of the handles and whether they needed mosquito screens. Then we had to send this order to the importer, and at this point we learnt that the hinge of a window is indicated in opposite ways on Japanese and European drawings. So the order went back and forth a couple of times as we checked various things before it could be sent to Germany.

We were then rushed to hold the ground breaking ceremony in September. This is a Shinto ceremony that basically clears the way with the local spirits　for building the house. I'm not a particularly religious person, but I am quite superstitious. This is partly because other people are, and they may be upset if you don't follow their superstitions. It's also partly because however unlikely it is, there's a chance of a grain of truth in superstition, and taking Pascal's wager, the stake of following the superstition is relatively small compared to the potential cost of not following it. So it's worth getting a couple of bottles of sake and a pineapple, and putting a bit of cash in an envelope if there's a chance it will stop your house being swallowed up by an earthquake, even if there is no obvious scientific connection. Or who knows, maybe the local shrines are in league with the local mafia. 

From the ground breaking ceremony for another couple of months, nothing seemed to move, except the steady realisation that the January deadline and the NEDO grant were impossible, and that there had been absolutely no hurry at all to hold the ceremony. I'd started taking pictures of the plot everyday, and this period is a little boring. A piece of string appeared in the middle of December, then a digger was there until the end of the month. Then the hole sat there until March. 

In October, we still hadn't signed the contract with the builders, although they had been at the ground breaking ceremony and there was a spoken understanding that they would be building the house. With hindsight I think a few things were happening: The builders wanted precise plans to work out a price. The architect didn't have precise plans and the price he'd promised us was not going to be the same as the price the builders were going to come up with. I wanted a price to be fixed and expected some teamwork between the architects, the builders, the passive house lady and me to work out the exact details to proceed, so we could get on and start pouring the foundation before we decided what colour the bath taps were going to be. Also the architect was probably busy on another project and his next invoice, and not paying full attention to ours. 

This was another point at which we should probably have sacked the architect. The first time was when he said that calculating the energy efficiency of a building was too much like hard work. By this time I think we were suffering from Stockholm Syndrome. In a very real way, the architect was holding us hostage in our own house, except it hadn't been built yet. We'd already ordered the windows and felt we needed him to have a house to put them in. We should probably have told him to give us the pretty pictures and leave us and the builders to work them out. This had not been offered to us as an option, but in life we often don't understand our options until it's too late.

Walking to an eco house?

A colleague recently asked where I parked. Parking is very draconian where I work, and a big issue for drivers. I told him I didn't drive to work, but came by bicycle, bus or on foot. This surprised him as he knew I had an eco house, and assumed it was somewhere in the mountains.
There seems to be a perception that eco houses should be deep in nature, perhaps in primeval rain forest, and accessible only by Tarzan swing or four-wheel drive. My house is a ten-minute walk from the city station and a twenty-minute bike ride to work. And I suppose eco houses have the image of being off-grid and self-sufficient, but why be off grid if there's a chance of supporting a smart grid? Urban living has less impact on the planet than rural living, if you look at it per capita.
Probably.
There is a sense that The System is destroying the planet, so in order to stop destroying the planet you need to get out of The System. But you're still going going to have an impact on the planet if you leave the system, and we stand a much better chance of survival working together than seven billion people, and counting, going off on their own.
Anyway, I don't really understand how it would be an eco house if I had to drive to work each day from it. Back to carbon accountancy and walking to work, if I was to drive the 4km to and from work each day, something like 250 days a year, and with my car doing 10 km to the litre, that would use about 200 litres of petrol per year, emitting half a tonne of CO2. That's already over half of my share of the 2.7 tonnes the house emits a year. Build an eco house in the wilderness and you risk blowing all the benefits commuting from it to work.
I know it's not a terribly efficient car, but it was second hand, and I reasoned that since we drive so little, it was much better for us to get an inefficient car than for somebody who was going to be driving it every day to buy it. I'm not exactly sure my logic is sound here, but anyway, I'm not going out to buy the latest super-efficient hybrid just to write this post.
According to some websites, walking and riding a bicycle produce no carbon at all, but once again it's not so simple. If you walk to work, you're using your body as a machine, and the fuel going in is the food you eat. If you were to grow all your own food, use local, natural fertilisers, and pick it by hand, then you'd be carbon neutral.
In fact the production of food is not at all carbon neutral. From preparing the ground to harvesting crops and from sowing seeds to stacking the packaging on the shelves, energy is being used. The industrial production of ammonia and its use as a fertiliser are now an essential part of the supply of food to our growing and greedy population, and we probably could no longer survive without it. Our dependence on oil is so great that we are virtually eating it. You can see more details here on shrinkthatfootprint.com about the carbon footprint of different diets, and some in depth comparisons here on www.pacinst.org. On a very rough average, every calorie of food we eat has used a calorie of oil to produce. So the calorific content of food is not just the number of calories inside it, that are organic in the chemical sense that they are based on life, and carbon-free in the climatological sense that they have a net zero effect on CO2 levels.
It also depends what you have for breakfast. If you're eating food flown half way around the world, or your diet consists of large amounts of beef, walking or riding a bicycle could actually be producing more carbon than driving.
Bicycles are much more efficient at turning our energy into food than walking, so on the surface that's going to be low carbon. We have to think about the cost of the bicycle itself though, even though I have a bike anyway, and it's not going to make much difference whether I use it or not. But we do need to factor in the capital cost of the technology into the running cost of the calories in our food.
Which reminds me, if you're going to treat your food as carbon neutral, you shouldn't be using any iron tools either.
Of course you could argue that you'd be eating all that food anyway, and you shouldn't be looking at it as an extra environmental cost, and it's certainly true there are plenty of people sitting in cars who eat as much as cyclists. Some of them are even driving to the gym to burn off all those calories in an oil-heated pool or on an electrically-driven treadmill. This may be a rather ridiculous exercise, but I think any attempt to assess our impact on the planet is worthwhile
And sometimes I get the bus. I'm not exactly sure how to calculate the carbon for that. I could take the view that the bus is moving anyway, so it's just the extra carbon used to carry my weight. This may be close to the truth when it's packed and I'm standing at the back, but sometimes I'm the only person on the bus. In that case, it's going to be doing a lot less than 10 km to the litre and I'd be better off driving my own car.
I'd really like to find a definitive answer to how much carbon each of these transport options produces, but I've already spent enough carbon surfing the web without an answer, so I think the definitive answer is that there isn't one. Just, rather obviously:

• walking and cycling are better than driving
• if you're going to drive, living close to where you work could make a bigger difference than building an eco house
• if you're concerned about the environment avoid eating beef.

Also, if any bus companies are reading, you should consider providing taxis instead of buses for off-peak routes, since it would reduce carbon and your bottom line.

If you are want to know more about the carbon coming out of your food, you may be interested that in 2007 the Guardian reported Tesco's plan to label all their products with a quantified carbon footprint, only to report in 2012 that  they had dropped the plans. www.carbontrust.com is still working on it though. 

Three things we didn't mention

There were three things we didn't mention when they came around for the one-year-and-four-months inspection. It should have been the one-year inspection, but it was a little late. We did mention several issues, and one was addressed quickly, when the electrician came shortly afterwards and quickly switched the sensor light in the pantry, then drilled a hole in the cover for the light in the under-floor storage so we can use that. Most of the other issues took a couple of months, and we're still waiting for others.

One of the things we didn't mention was the lights above the kitchen sink. They shine down in a perfect direction, but unfortunately the sink below them is about 20 cm too far forward, so the front of our kitchen top is not adequately illuminated. At the time, we had to put the lights in that position to fit the shelves in the cupboards above the sink, which cleverly can be pulled down and allow the space to be used. I suppose it's possible we could do something about their angle. It would be quite easy to fit a lens, if we had one.

Another thing we didn't mention was the trip-wire functionality of anything plugged into the power sockets at the top of our staircases. This is a design issue that we can't do a lot about now.

The other thing is the width of the wardrobes. This is another design issue, and it would also cause some upheaval to fix it now. Wardrobes need to be an adequate width to ward the robes inside them, so that the doors will shut properly and not hit the jackets and shirts hanging on their hangers, even if the doors slide rather than open outwards. I think the problem is that the architect was doing his usual calculation from the centre of the pillars in the wall to the centre of the pillars of the wardrobe door frames, forgetting that there is an extra 60 mm of insulation on the inside of our walls. I worry that the solution to this design problem may have been to remove the insulation.

This problem manifests itself most in broken buttons on the cuffs of my jackets. The first time this happened, it seemed like one of those bits of wear and tear that just seems to happen to things. When a bit of broken button dropped off another suit, it struck me as a little strange. Then when I saw the button that had been replaced on the first sleeve broken again, I realised there was some systematic problem here. It can take over a year to realise some of these problems.

Carbon accountancy

In Energy cost, energy use and carbon I wrote that the new house emits about half the carbon of our old house. At first sight this doesn't seem so impressive, but it's important to note that the whole of the new house stays warm throughout the winter and relatively cool through the summer, while the old house was literally freezing in many places for some of the winter, and although cooler than a lot of other modern buildings, was not coping with the record temperatures of the decade we lived there.

Having noted this, I should still re-emphasise that we were only using twice the energy in the old house, so while the efficiency of our new house may be many times better, the actual carbon emissions have only halved. This is an example of the Jevons paradox, and the old adage: a little energy efficiency is a dangerous thing. We would probably emit a lot less carbon if we lived in a tent, but I'm not sure whether I'd still have a job and a family. 

Also I should note that the calculation of our carbon emissions did not consider the electricity we produce, which may substantially change the equation.

The electricity we use from the grid was probably turned from burnt fossil fuel, with all the inefficiency involved in the burning process and the turning of turbines and generators. Then it's been stepped up, sent hundreds of kilometres and stepped down again, wasting little energy on the way, but more in the stepping processes, and then some more in the wires on the way to your house. So by the time you get one kWh to your electrical appliances, you've used something like 2.7 kWh of fossil fuel. Each kilowatt hour of domesticated electricity is going to release around half a kg of carbon dioxide, and its equivalents, into the atmosphere. 

But what about the electricity from our solar panels. That's green isn't it? Not completely green, but perhaps a lighter shade of grey. 

It's relatively straightforward to get a figure for the electricity we buy over the grid, making assumptions about the overall energy picture in Japan. Of course the exact carbon cost of electricity varies around the country, from region to region and even from house to house depending on whether you're next door to the stepping-down station, or up a valley at the end of a few kilometres of cable. Nagano prefecture has a lot of hydroelectric power, but most is owned by Tokyo Electric rather than Chubu Electric, which supplies our electricity.

The performance of each region's power company can be found here and here here at the department of environment's site. Chubu electric (which supplies power to Nagano) produced 518 grammes per kWh sold in 2011, and 473 g/kWh in 2009, when the nuclear power stations were running. Tokyo electric, with the help of the hydroelectric power stations they run in Nagano, produced 464 g/kWh in 2011 and 375 in 2009. They  had more nuclear power stations to switch off, as you may have heard. There improved carbon performance is possibly due to more urban consumers living within shorter cable lengths.

We also have to estimate the carbon emitted from the electricity we use from our own solar panels, which amounts to something like 10% of what we generate and 30% of what we use.

Our solar panels were made in China. They may be leading the green revolution on many fronts, most of which are invisible to a western media usually not even trying to understand what's happening behind the Great Wall, but they still use a fair bit of coal, so most of the electricity used to make the panels is from dirty fossil fuels. They make shoes for everyone, but walk barefoot.

The estimate here at EDF Energy, based on a 25-year life time of the panels, is that each kWh of solar electricity produces 72 grammes of carbon. This is around one seventh of the grid electricity, so as the site says, it's low carbon, not zero carbon. Nuclear power is similarly encumbered with carbon costs in the extraction, purification and transportation of radioactive materials, and windmills also need to be made out of something other than air. There's no such thing as a carbon free lunch.

Of course the estimate of kg carbon per kilowatt hour of solar power depends very much on the insolation, in other words how much sunshine you get. We perhaps get twice the sunlight to somewhere like Glasgow, so our 25 years are going to produce twice the electricity for the same embedded carbon costs, and our carbon per kWh would be half of theirs. We're also closer to China, so transportation costs are a little less, but they're still using those dirty coal power stations. Conservative estimate: 50 grammes of carbon per kWh.

So our consumption of electricity, both from the grid and from our own panels emits something like 2.7 tonnes of carbon per year.

Next, how do we account for the electricity we supply to the grid in calculating our carbon emissions?

In the simplest terms, we sell a little under 12,000 kWh to the grid per year. So instead of 12,000 kWh of fossil fuels being generated, at 500 g CO2/kWh, we're generating solar electricity at 50 g CO2/kWh. This is a saving of about 5.4 tonnes of CO2 per year. So we're in carbon credit.

This is simple, but almost certainly wrong. This assumes that the moment the electricity hits our meter it's going to be used by hungry consumers. In fact there is over ten metres of cable before it even gets to the next house, and the chances are that they'll be away at work while we're generously generating their power. Ten metres may not sound far, but my ballpark estimate inside the house was that we lose 1% of electricity every 5 metres.

In the worst-case estimate, the electricity from our panels is not going to make any difference at all. Chubu electric employees are not going to be sitting at the controls of their gas-fired power stations, looking at the weather forecast and turning down the volume because my house is putting out a couple of extra kilowatts.

We can perhaps split the difference and say that half of our solar electricity is going to be of use to someone, so the amount of dirty power is reduced by 6,000 kWh per annum, and we're saving 2.7 tonnes. This balances out the 2.7 tonnes we produce, so we're carbon neutral.

If you're interested in carbon, Sunearthtools.com's may be useful.

Talking to the taxman

Spent most of yesterday going back and forth getting documents for the tax office. At work the other day, I had to fill in some forms about tax, and among the documents they had asked for was something about mortgage rebates. I'd got a postcard from the bank a few days earlier showing how much I'd borrowed and how much I still owed, with the words shomeisho, beloved of bean counters, at the top. When I showed the postcard to the kind and long-suffering lady who deals with these things, she asked where the other form was. The one the tax office should have sent me.

When it comes to tax I'm deeply ambivalent. Not only in the literal sense of the word: that I have both a strong feeling that tax should be paid and a strong preference not to pay it myself. In the more widely used sense of the word, I really don't want to have to worry about it. I don't want to spend my time thinking about ways to avoid or reduce it, and I don't want to spend hours digging through documents and filling out forms. Take a slice of my money and I don't mind--it's just little bits of paper and bits of metal. But please don't take away my precious time.

Especially when it's a rainy day in November.

On my first visit to the tax office, I innocently asked whether they had my form, and it transpired that I had not applied for tax relief on my mortgage. On this journey I had taken as many documents as I thought I'd need. I had not brought enough. A kind young man gave me an envelope with a long list of items to check.

I went back home again, picked up what extra documents I could, and then some, and prepared myself for a journey to the city hall for a document proving my residence, then back to the tax office, with an option of having to go up the hill to the local legal affairs bureau in case the deeds I had to my house were not good enough. Often documents will only be accepted if they have been issued within three months.

When I got back to the tax office, another man began to process my papers. There was a bit of discussion about when exactly we moved in. They will give ten years of tax relief, so this becomes an important issue. We actually moved in on 22nd December, 2012, so our tax relief began in that year, and we received tax relief for the remaining week of it, even though our loan didn't start until 10th January 2014, so the tax relief was zero. I had some memory of deciding our official moving date, and wondered whether I had registered the actual change of address in January 2014. It turns out I'd registered our move in December. There may have been a good reason for doing this, but it was probably just my determination that I wanted to move within that year. In the event, it cost a year of tax relief.

Also he asked where the deeds for the land were. It turns out that if you buy land, then build on it within two years, your loan on the land is also eligible for tax rebate. We bought the land in November, 2010, two years and one month before we moved in. This is another cost of our delayed building.

He also asked about Eco points. Yes, we did get Eco points, and no, I don't have the documents for them, I have a huge drawer full of documents pertaining to the house and cannot bring all of them. I probably should put all the documents relating to money together. Anyway, I had to go back home again and get the document showing how many Eco points there were. I pointed out that we didn't actually get the Eco points, but they all went to the builders. He wanted some proof for this too.  

He kindly suggested I could come back Monday, but no, I have work on Monday, so I'd be back later. 

He also asked me to bring my bank book. This was a good sign since it meant they were likely to be paying me something!

A couple of hours later, he'd put all the data in, and was talking me through the printed-out form showing how everything was calculated. The lower amount of the cost of the house and the remaining unpaid loan was used for the rebate calculation, so in the end the eco points didn't make any difference. 

Filing returns is not compulsory in Japan, except for earnings over 200,000 yen. Ambivalence is fine as long as you know you're not breaking the law. I have had an issue with some money I get for translation work for the city's art gallery. This is less than I need to declare for my income tax, so for the past couple of years I haven't declared and have been leaving my tax returns to the place I work. The last time I did file, the difference was only a thousand yen, which didn't seem worth the hours I had put in. But the city notices that the amount they paid me is not on my income tax, which they base city tax on, and insist that I declare it to them.  

So, in the process of filing my tax returns, the translation work went back in, along with an estimate of the expenses to earn that. I think that put me into a higher tax bracket. Anyway, as he was going through each step of the calculation, I was beginning to wonder whether the punch-line would be that the tax I had already paid was almost the same as what I should pay, and they would be paying the difference of 53 yen. 

In fact, I will get about 200,000 yen back, which should be arriving in my bank soon, so the day was not completely wasted. That was for last year, and a similar amount may come back for this year, and will not be taken out of my salary each month for the next seven years. Not bad for a day's work, and at the same time how terrible to think of it in those terms.

Energy cost, energy use and carbon emissions

While looking through the Nedo data, I decided to look at energy use for our old house. We used electricity, gas and paraffin. The electricity came from the mains. The gas was in tanks out the back, which would be replaced every month or two, usually before they ran out. Our house was not connected to town gas, and in fact it may be more sensible in an earthquake-prone country to deliver tanks to houses rather than pipe inflammable gas around. I used to fill 18 litre tanks of paraffin at petrol stations or hardware shops, and drive or sometimes cycle them home, remembering the Russian proverb: chop your own wood and it will warm you twice.

The paraffin heated the bath water year round, and was used in fan heaters in the winter. The gas heated the shower, the stove and the geyser that supplied hot water to the kitchen sink. We also used electricity for a kotatsu table heater and an electric carpet. And we had a futon heater that blew hot air between the sheets, which we have to consider part of our heating cost.  

This is what the energy costs were. I think we were away for part of February.

By comparison, this is the energy use, converting the gas and paraffin to kilowatt hours. Although the winter use of gas, electricity and paraffin were roughly the same cost, the paraffin was packing a lot more energy. 

Here's the kg of carbon released. An 18 litre tank of paraffin will release 53 kg of CO2. This seems to be defying the conservation of mass, but what is happening is that the paraffin provides the C, while the two Os come out of the air. It's difficult to understand whether that is a lot, but over the year, as a family we emitted something like thirty times our own weight, 4.6 tonnes. It seems a lot. On a very rough and conservative estimate we're emitting about half as much carbon in the new house, which is obviously better, but still fifteen times our own body weights.

The calculation of kWh per cubic meter of gas and per litre of paraffin came from rekauk.com.

The kilogrammes of carbon is fairly straightforward for the fossil fuels as it's chemistry, although you need to add a little bit to the amount of carbon dioxide released in burning to account for how much was used in its production and delivery. For electricity it gets a bit more complicated as you have to work out where the electricity came from. A whole new post of carbon accountancy is needed to go into this. For now I used data from carbonindependent.org, which I hope gives a roughly accurate answer. 

Mainstream media talking about the energy revolution

Well, the Huffington Post anyway.

Five things you can do for clean energy without having to buy your own micro power station.

huffpost.com: "5 Ways To Support Clean Energy If Solar Power's Out Of Reach"

And there's a story in the Guardian about a Passivhaus in Oldham.

theguardian.com: "Actively cutting energy bills in Oldham – welcome to the 'Passivhauses'" This shows that local councils can pay a little extra building houses but save much more by not having to pay out benefits and hospital bills. We just need to show them the way to Oldham.

NEDO

It's time to tell the tale of Nedo. 

In all areas of commerce we are besieged by offers of things for free, and must beware of spending all our money in their pursuit. The world of house building is no exception, and various bits of free were dangled in front of us, from the "ecopoints" that were eventually not given to us so that our house came close to our budget, to the offer of free insulation that ended up going cold. The Nedo grant was the biggest and most exciting.

Nedo is the New Energy and Industrial Development Organisation. It was set up in 1980, spurred by the oil shocks of the previous decade, and has been developing new energy since. They have an English language website with very different content to the Japanese website, and the organisation seems to function differently domestically and on the international stage. Anyone familiar with Japanese industry will have seen how the local market is used as a test bed full of guinea pigs, where products can be developed to generate income from markets abroad.

Their motives are perhaps more in long-term profits for industry than savings for consumers, but they offered us a grant of 2.7 million yen, which at the time seemed not only a boost to our finances, but an endorsement of what we were doing. The grant never materialised, but it remains as an endorsement of our attempt to solve the energy problem in our own little way, so I'll post it here, framed in cyberspace. 

From memory, one criterion for the grant was for energy savings over and above the the next generation energy standards. The initial cost to make those savings had to be less than 100 yen per kWh saved per year. The grant was for up to one third of those costs. A kWh can cost anything from over 40 yen in peak electricity to under 10 yen in paraffin, so this means a payback in the order of ten years.

Our situation was particularly attractive to the company that applied for the grant. One reason was that our old house was really very old and our gas, electricity and heating oil bills set a very high bench mark against which the energy savings would be measured. The other attractive feature was the windows we were planning on using. Their eyes lit up when they saw the U-values, and they did not even blink at the cost. These were people who understood the balance between initial costs of energy efficiency and running costs of heating bills, and knew which way the balance tipped. 

The fact that the windows were being imported was not an issue since NEDO is an internationally-minded organisation, actively seeking collaborations with other countries and cutting-edge technology. 

The fact that we were not going to be buying our windows through the company that was applying for the grant also did not seem to be a problem, and they were happy to forge an invoice. Perhaps I should have read this as a warning of lack of accountability.

The part the company were interested in was a solar thermal system that supplied domestic hot water in the summer, and heating in the winter. I think practically speaking, the windows made their sums much easier, and contributed more to the energy savings than their system, but I'll write more about that later. 

YKK zipping up the market, or closing windows on it?

Here's a breakdown of the kinds of windows used in different countries. The striking thing is the high proportion of aluminium windows used in Japan.  You may remember that aluminium has a thermal conductivity around a thousand times bigger than wood or PVC. In fact it would be difficult to find a material for window frames which would conduct more heat, and each time I see them, I shake my head in disbelief. As you can see from the chart, living in Japan I do a lot of head-shaking.

For those reading in black and white, the charts are for (West to East) France, UK, Germany, Scandinavia, Korea, Japan, US. (No mention of India, China or Russia.) As for the colours, pink is aluminium, Yellow is wood, light blue is compound (for example aluminium with insulation), turquoise is PVC, which the site is promoting, showing in the table how Germany, the US and trendy neighbour South Korea use PVC in 60, 67 and a whopping 80% of their windows, while poor Japan only uses 7%. The red circle proclaims PVC is the global standard.
Looking more closely, for the Japan pie chart, yellow is marked aluminum compound, and wooden windows appear to be as unusual here as aluminium is in Scandinavia. And you thought wood was a traditional building material in Japan! I just checked the source data, where wooden windows make up less than 0.1%, so the data may in fact be completely ignoring wooden windows.
So why is this happening? Not so much the lack of wood or scarcity of PVC, but why so many aluminium windows?
Just a hypothesis, but what if the Japanese window manufacturing industry were controlled by the aluminium industry? The number one objective of the Japanese aluminium industry is to increase the use of aluminium. This is not surprising, and may not be sinister, unless you consider the prevalence of growth economics as an evil threat to our survival on the planet, which I for one do.
Protecting the environment is also an objective of the Japan Aluminium Association, so there may be a conflict of interest. For example, using aluminium in window frames will increase the use of aluminium. Using PVC or wood will reduce heating costs and be good for the environment. Increasing the use of aluminium is higher on the list of priorities, so we'd better do that!
If this hypothesis were true we would see the largest window manufacturers in Japan belonging to the Aluminium industry.
They may be better known around the world for the other part of their business, zips and zippers, where they have a massive global market share, but YKK also have a substantial architectural parts business, and make most of the window frames in Japan. YKK do belong to the Japan Aluminium Association.
However, if you look for YKK windows in English, you'll find information like this on their US plant, making and supplying vinyl windows. Not a mention of aluminium. Their Japanese website talks about the new windows they are making, with insulated aluminium frames. They don't seem to mention PVC frames for the domestic market. The mission statement and their fancy environment report talk about sustainability and energy efficiency, but when it comes to details, there's more emphasis on double glazing and low-e glass, but the care still aluminium. So more thermal bridges leading to condensation and while the aluminium frames aren't going to rot or rust, the wooden frames of the building they are fitted into may. Rather than replacing the windows, people will need to replace the building! So there is a different story for the English-speaking market, where "PVC is the standard" and domestic Japan, where there may still be some people who think that aluminium is a wonderful new product, and it's certainly seen as a normal way of fitting bits of glass into the walls of your wooden house.
Looking through the main shareholders of YKK, which is not listed on the stock exchange, there is no obvious link between YKK and the rest of the aluminium industry, and perhaps aluminium frames are just used because they are cheaper, and considered a normal part of a Japanese house. Momentum keeps the world turning. In some cases it keeps us hurling towards the abyss.
Or perhaps it is the power and inertia of YKK's president, Tadahiro Yoshida, son of the founder, who turned around the window business that was inherited from his uncle, and perhaps has the same view of windows as he did when he started managing the company in the 1970s.
The invention of the Sony Walkman is one example of how the strong ideas of a company leader can steer the company, but here is another about YKK, that I read on Forbes.com. I don't usually read Forbes magazine but it came up in one of my searches. Tadao Yoshida, founder and father, once announced that "golf will ruin Japan". He probably just meant that too much focus on playing golf would mean companies wasting money and Japan possibly taking its eye off the ball of business, but this lead to golf fans within the company keeping their habits a secret, until after Tadahiro, the son, had taken over and he announced one day that he was off to play golf. At this point the golfers could reveal their habit once again and many came out of the closet.
So who knows why aluminium is so prominent in Japanese windows, but the only way to change it is to raise awareness among consumers, and more importantly architects and builders, that there is an option.
Note: It was difficult to find precise information on the Japanese window industry. Although YKK seems to be the biggest producer, they do not mention "market share" once in their annual report. I kept getting google hits for a report on the global window and door market, but they were charging for it. It would be nice if information on windows were more transparent. 
Acknowledgement: The world window map is from Excel Shanon who seem to be making the best windows in Japan at the moment, although I think they are still somewhat limited by the thickness of glass that will fit in the standard frame size, so their triple glazed windows may not perform much worse if the middle glass layer were removed and they become double glazed.

YKK

Excel Shanon

Pazen

Mind the gap - A short history of double glazing

Commercially available double-glazed windows were first available in the US as Thermopane, patented by C. D. Haven in the 1930s, although he does not claim to have invented them, and mentions several previous patents, some of which had expired. Apparently the idea came from Victorian Scots, but double glazing did not take off in the UK until much later. In parts of the US through the prosperous 1950s Thermopane windows were the height of luxury. Meanwhile in the UK, double glazed windows were expensive and houses were heated with coal that was simply coming out of the ground, so the financial incentive was not there.

Double glazing hit Europe in the 1970s in the wake of the oil shock. The response to high oil prices was an attempt to increase energy efficiency of buildings. The same energy shock spurred the Japanese to make more efficient electrical goods. The main effects on US policy seem to have been a 55 mile per hour speed limit, and increased interest in Middle Eastern politics, although it undeniably increased awareness of environmental issues and possibilities for saving energy.

The first double glazing in the UK had a quarter-inch, 6 mm air gap. The extra air made a huge difference to the insulation, and people's heating bills, and double glazing salesmen trod the nation's doorsteps and appeared on off-peak TV advertising, no doubt late on those cold evenings of autumn and winter.

The double glazing sales teams were competing against each other, and sooner or later someone brought out panes with an 8 mm air gap. A bigger gap meant more insulation, but more importantly, a bigger number for salesmen to impress their marks with. They could also, perhaps, go back to old customers, and persuade them to upgrade to these new, improved models.  Next came a 12 mm gap, and half an inch became the standard. The insulation was significantly better, although the improvements were not as stark as the jump from single to double panes.

Science and engineering can reach optimum values, but sales and advertising always want more, and the windows continued to get thicker. Unfortunately, beyond 12 mm the increased insulation of the extra air has less and less effect because the air within the enclosure starts to circulate, air heating up on the inside pane, flowing up to the top as hot air rises, then losing that heat to the outside pane as it heads down the other side. 

So they could try bringing out windows with a bigger gap, sounding better, but they wouldn't perform any better.

According to  the window man, the introduction of argon filling was just a way to get thicker windows that could both sound better, and perform better. There is another story though.

Humidity pump

Another way of looking at humidity is in the pressure of the water vapour suspended in the air. In a wall, there is a temperature gradient between the inside temperature and the outside temperature. In the steady state this is going to be a straight line. If the insulation is glass fibre, air and moisture can pass with some freedom. If hot air from inside is passing all the way outside, as the temperature drops the humidity will rise so at some point the humidity will likely reach 100% and you will get condensation. To stop this, you need vapour barriers that will stop the air inside the house flowing through the wall structure. Then, the air will stop flowing, and in theory at least, you'll get constant humidity throughout the wall, even though the temperature is dropping and there is much less absolute moisture content in the air close to the outside than there is close to the inside.

In the summer, the temperature outside is higher, so you have the opposite situation and the danger of water condensing on the way in, as the temperature drops. The humidity inside the house is higher, so the walls may get too humid at some point.

Wufi software simulates the performance of a wall structure over time, and you can see an example below, although this is not for our house!

Just like insulation slowing down the heat rather than stopping it from escaping, vapour barriers and other kinds of waterproofing do not stop water, they just slow it down. Anyone who has stayed in the rain for long enough in waterproof clothes knows this. It's fine for a while, but eventually the rain will get through. I remember my Dad discovering how waterproof his boots were after a very rainy walk around Haweswater in the English Lake District--water had got into them but it took for ever to get out again. Cheap waterproofs can also be sweat proof, so sooner or later you're going to be wet inside anyway.

Essentially our house has a couple of rain coats on. On the outside is Tyvek sheet is made by Dupont, who also make Goretex rainwear, which is designed to stop precipitation from getting in while allowing perspiration to get out. We need the same thing in a house, so that moisture does not build up within the wall structure, leading to rot. Tyvek stops drops of water from getting through, but will let water vapour pass, so the walls can stay dry.

We used Intello inside the wall structure, which allows very little moisture through in the winter, preventing condensation and rotting walls. In the summer, it opens up and lets moisture through, which allows the walls to dry out.

You can see an interesting effect below of humidity going up with temperature, instead of going down as it usually does. The first chart is the normal situation, where the relative humidity gets lower as the temperature goes up, since the absolute humidity is the same, but the air's capacity for water vapour increases. The lines at the top are humidity, the higher one outside the house, and the lower inside the house. The temperature lines are below.

The next chart shows the humidity and temperature within the wall, when the sun is beating down outside, making the temperature just inside the Tyvek high. This makes the humidity low, and as a result, humidity starts flowing outwards through the wall. We're measuring temperature and humidity in the middle of the wall, so at some point it should be possible to test how the wall performs in real conditions.　After almost two years, the humidity seems to be staying in a safe range.

The Scottish problem

In the process of preparing a presentation about plus-energy housing, I noticed just how many Scots were involved in the whole business of thermodynamics. It's probably no exaggeration to say that James Watt invented global warming when he came up with the idea of burning coal to pump water out of mines so that you could get more coal out. The irony is that making a house more energy-efficient needs the same level of understanding of science that started the problems in the first place. Oh brave new world that has such people in it. 

James Clerk Maxwell was another Scot, discovering the demon better known as the second law of thermodynamics. This is the gambler's ruin theory of heat. And I didn't even get onto James Dewar, who invented the Thermos flask but unfortunately did not file a patent for it. 

It has been alleged that double glazing was invented in Scotland in Victorian times, although it was not commercialised until the 1930s in the US. The inventor of that was probably called James too. In fact another person involved with the whole business was James Joule, but he was a brewer from Manchester. Then there was Lord Kelvin who was not called James and may not have been born in Scotland, but did his work there. 

And he's not usually considered a scientist, but Billy Connolly's line about there being no such thing as bad weather, just the wrong clothes, belies a deep understanding of heat that would serve the building industry well: there's no such thing as a harsh climate, just inappropriate housing.

So given that global warming was all originally the fault of Scots, and since people in the United States are gradually starting to believe in it, it's only a matter of time before the lawyers get hold of the idea and they decide to sue. It therefore seems like a good idea for the English to support devolution. 

And I don't say that because I'm not British deep down. It's true that I usually tell people I'm English but that's more a matter of convenience since people where I live have usually heard of England, and use a similar name in their language, and it takes several minutes to explain that the country is not really England but the United Kingdom. It takes longer still to convince them that the first international football match was between England and Scotland, and that it was indeed an international match. At least they do appreciate the explanation of the Union Jack, until they start asking where the flag for Wales is. 

The point is, when those lawyers in Manhattan start suing Scotland, if it's a separate country from England, then at least some people in Britain will be unaffected. Of course this may come back to bite those south of the border since many of the insurance companies are in London. 

 

A random assortment of websites relating to solar power

Here are some links to sites about solar power with varying levels of relevance to each other and the real world. Actually a lot of the links are not even about solar power but at some point they seemed worth keeping, so it's just possible somebody else may find them useful. They are all working at the time of posting, although I had to throw a few out of the longer list I had before.

There's a slim chance that somebody who reads this may find one of these sites interesting, and I'm not sure whether to press the send button, or delete.

This is Chofu's Solar heater (in Japanese) http://www.chofu.co.jp/

Here are some water tanks (also in Japanese) http://www.fujitaka.com/

This is about heating in Passive Houses. http://www.passivhaustagung.de/Passive_House_E/

Not really connected to solar power, but here's a company in India supplying phase change materials: http://www.pcmenergy.com/

Here's a paper about using solar water heating with phase change materials, actually making the last link relevant. Anant Shuklaa, D. Buddhib, R. L. Sawhneya, (2009). Renewable and Sustainable Energy Reviews, 13(8), 2119–2125. linkinghub.elsevier.com

And another one from Atul Sharmaa, V. V. Tyagib, C. R. Chena, D. Buddhib, (2009). Renewable and Sustainable Energy Reviews, 13(2), 318–345 http://www.sciencedirect.com/science

The ideal solar thermal system

We ended up not choosing solar thermal, and just using photovoltaics which have no moving parts and nothing running through them that can freeze or boil. Below are some ideas from the planning phase of our building based on theory and various research.

The ideal solar thermal system stores heat in a single hot water tank which can collect heat from solar panels, add heat from a backup boiler or heater, provide hot water, and distribute heat to the radiators, underfloor heating or the ventilation system.

The problems and challenges facing solar thermal systems include overheating, chattering, hygiene and freezing. People often worry about not getting enough heat from their solar heaters, but apparently overheating is the biggest cause of failure for solar systems, and one reason why systems in Japan are usually under-sized, meeting demand only at maxiumum output. Overheating causes steam and high pressures, which can shorten the lifetime of elements within the system. It should be possible to design a system that can withstand a range of pressures and temperatures. After all, steam heating systems have been around for over a hundred years. Evidently they are not always designed for the pressures and temperatures that sooner or later they well reach, and solar systems often fail within five years.

Another problem is chattering. This happens when the hot water from the solar system is fluctuating around the level at which extra heat must be added. As with photovoltaics, sunny days are are no problem, as there is a large and constant amount of heat. Overcast or rainy days are not a problem, because there is a small and constant amount of heat. Partially cloudy days are a problem. Because solar systems cannot guarantee to supply enough heat all the time, there must be a backup system. If the solar heating is sufficient, the backup heater is not needed; if the solar heat is insufficient, for example on a snowy day, the backup must switch on. In certain weather conditions, the backup system may be switching on and off several times, rapidly wearing out motors and switches. A certain level of sophistication is needed in the control system. This problem should not be insurmountable, for example the backup system could only switch on after the sun has gone down.

Another issue is storage of water within the tank. The tank could most efficiently contain the same fluid used for the panels and for the domestic hot water. This is most efficient, however there may be issues with legionnaires disease, which thrives in the kind of temperatures that you will often get in a solar water system. In addition, tap water is liable to freeze, so any water left in the panels at night time could lead to problems, since freezing water expands and tends to burst pipes. Using a refrigerant within the solar circuit, and a heat exchanger for the domestic hot water also has advantages, for example in allowing higher pressure within the panels. Because of the heat exchanger it is, of course, less efficient.

One choice with solar systems is whether to use a drainback or continuous system. In the continuous system a refrigerant is used, and as soon as the water in the panels heats up, flow starts, transferring the heat from the panels outside into the tank inside. In the drainback system, water is sent to fill the panels in the morning, or at least when the panels start heating up. It is then returned either when the water has reached a certain temperature, or at the end of the day when it's got all the radiation it can get, before it starts cooling down. The advantages with this system are that overheating is avoided, since the hot water is sent into the house before it overheats. Tap water can be used, since there is no danger of the panels freezing as water will not be sent there if it is too cold, and will be sent into the house before the temperature drops.

Another issue is the performance of the hot water supply system. Ideally there should be time and volume settings so that the bath be filled to the desired volume and temperature. There should ideally be a means for re-heating the water within the tub, so that water may be saved as is customary in Japanese houses. Most commercially available hot water systems in Japan have all these functions ready fitted, although the controllers cannot necessarily be acquired separately. Designing your own system would be a challenge.

From the beginning solar thermal seemed very attractive as a way of reducing energy. Solar thermal panels turn over half the sun's energy into heat, and are three or four times more efficient that photovoltaics. In the end a major considerations for not choosing solar thermal were to keep the systems simple and the roof elegant. Thermally it may have made sense, but financially, in terms of initial cost and the relative costs of purchased and re-sold electricity, photovoltaics were the obvious choice. And if the solar thermal system was going to fail within five years, even the superior thermal efficiency of the system becomes doubtful. Another factor was our NEDO grant application, which I'll write more on later.

Free information and ecology

For several years now I've taken two things as self-evident. I'm also acutely aware that these are not at all evident to other people. 

The first is that the human race is treading on very thin ice when it comes to our relationship with the natural ecosystems of the planet. And the ice is about to melt, because that's the nature of thin ice.

The other is that intellectual property, and the notion of owning ideas and creations of a non-physical nature is just wrong. 

Since I believe both of these things, I don't usually think of them as separable, much less contradictory. However, I've been wondering recently whether intellectual property could actually be good for the environment. It's possible that freely allowing information to spread is going to lead to more consumerism and greater damage to the environment.

Then I think, no way, I must just be getting old and veering to the right. 

Cropping Energy

Or to visually compare our energy production and consumption with the financial income and expenses, see the graphs below. 

The wavy orange line is the simulated generation in the graph above, and in the graph below is the income we'd get if we sold all of that at 48 yen. The higher bars are the generation or income since January 2012, and the lower bars are the consumption or electricity bill.

I wish they all could be rechargeable

I saw some non-rechargeable batteries in the house. They were for a label printer that isn't used much and gets through one set of batteries in about five years. So it's not worth getting rechargeables. Or at least it seems intuitively like it's not worth it. At least it may not be worth it financially. 

In terms of environmental impact, it's probably always worth getting rechargeable batteries. Even if they are just going to sit in a device for ten years. At the end of the time, they can be taken out, recharged and reused somewhere else. 

I'm not really sure why they have to be so much more expensive than one-use dry cells. I'm sure a lot of the costs are the same. In fact I found with CR2s that I could get rechargeables online cheaper than the non-rechargeables in the local electric shop.

A battery has a metal case, which makes the anode. It has a rod down the middle, making the cathode. Between them is some chemical compound which can store and release current. The chemical compound is different, but it's only a few grammes. It's not like it's gold.

The costs are all wrapped up in economies of scale, and dry cell batteries are cheaper because more of them have been made for longer. Edison-style incandescent light bulbs aren't cheaper than LEDs because there are fewer resources, or because it's intrinsically easier to make vacuum-filled glass bulbs but because factories have been set up to make them, and the plant is all paid for. In fact once the plant is in place, LEDs are likely to be cheaper.

Also, the rechargeable batteries are more expensive because of supply and demand, since people are prepared to pay for more, and because the extra cost and the sale of battery chargers can mean more shop shelf space.

What would really make sense is solar-powered batteries. When they go flat, you could leave them somewhere in sunlight, like a windowsill. The tricky part would be to get the charging circuit to work with the battery characteristics to ensure effective charging without any memory effects, and without shortening the battery life. They may take a few days to charge, but batteries come in a few standard sizes, and you can get extras.

The solar panels would also need to be tough, since they represent the outer casing, so a next generation of solar cells is needed.

There, I've written about it, now I'm sure if I search the web for a few minutes I'll find somebody has made some. 

It takes four litres of water to make a one-litre bottle of water

Apparently. According to some people on a radio programme talking about a Stephen Emmot's book 10 billion.

I was just as shocked and horrified as you are. Then I started thinking about the alternatives.

Reusing a bottle is a great idea. Much better than buying a new one.  PET bottles are perfect for reuse. They're good for recycling too, but recycled PET goes to other uses rather than making bottles, since health and safety regulations prevent post-consumer recycled waste from being used on food and drink packaging. This is strange when you think that they've been using recycled glass for years, and they are quite happy to let us use recycled trees and recycled oil. Anyway, recycling is not going to reduce the amount of oil used to make new PET bottles. It could even use more energy by providing cheap resources to make other products we didn't know we didn't need, thrust onto the market with an eco label, because they are supporting recycling.

So reuse is definitely better than buying a new bottle. But back to the four litres of water, how many litres of water does it take to reuse a bottle? Remember you have to wash the bottle before refilling it. Who knows how many litres of water a trip to the doctor would take if you didn't, and somebody got sick as a result! Tap water flows at around 0.1 litres per second, so the litres quickly start clocking up. Don't forget to wash your hands too. And wring out the cloth you used to wipe the bottle.

Or you could just use a cup. Bottled water, at least in English-speaking countries, wasn't invented until the 1980s. Before then it was a quaint and derisable habit of continentals, whose primitive urban planners allegedly hadn't mastered plumbing. Then it was the preserve of yuppies and source of scorn to pour upon them. And now we are all buying water, left right and centre, and carrying it around wherever we go. So do we really need all this water? Has the world got more thirsty? Or is this just a result of beverage producers such as Coca Cola measuring their success by the percentage of human fluid consumption that they supply? Or is it part of a space programme, ensuring that there is a massive supply of water, ready and packed to send off in the escape pods?

Even using a cup is going to consume more than a litre per litre because you still have to wash it. Another thing we tend to do when getting water from the tap is to let it run for a while, and this is going to use more water too. I know you could be letting the water run while rinsing out the bottle, but the chances are you start filling the bottle after rinsing it, then realise that you didn't let the water run before that, so you need to rinse it out again.  A minute later the tap is still running, and that's six litres, mostly down the drain.

And the chances are that if you get a cup you could end up with a jug, which needs washing too, and if there's a jug people may start putting ice in it. And maybe a slice of lemon. 

So, it takes four litres of water to make a one-litre bottle of water, does it?

Well, that's not too bad. I wonder when they can reduce that to three litres?

A roof over our heads

We've now paid off the two-year loan for the solar panels. That means that we own the roof over our heads. This is a great thing. We still don't own the walls or the land beneath us, as those are long-term low-interest loans, but at least we own the roof.

Perhaps we should have put the panels in with the builder's contract, but it seemed to make the financing easier to pay some of this up front and get a separate loan for the rest of it. The rate was higher, but since we paid it back in two years rather than thirty-five, the total cost of the loan was a lot less. The first thing the bank advised us when we put the loan application in was to cut the costs by taking some of the panels off the roof. This is strange because it was about the same time they published this report in Japanese which seems positive towards domestic solar.

Over the year and a half of generation, we've earned 47,000 yen per month on average, and paid 7,500 yen for our electricity bill. We sold 89% of what we generated, so without our panels we would have paid another couple of thousand yen on the electricity bills. 

At this rate we'll pay back the investment on the panels in around eight and a half years. I'm not sure who else the bank is lending to, but a return on investments in under nine years seems fairly healthy, and I really don't know why they aren't insisting that all houses they finance put panels on the roof, even offering to fund them in return for the electricity companies paying directly to the bank to repay them. 

In terms of kWh we've generated an average 36 kWh per day, which is a little over twice the 16 kWH we use. In terms of the amount of electricity we are getting for each kilowatt of solar panel we have installed, that's 1450 kWh/kW per year or 4 kWh/kW per day. 

I'm not exactly sure how much of the cost we can attribute to the roof and how much to the panels. I have a back-of-the-envelope estimate from the architect, printed out on an undated piece of A4 with some of the figures to the nearest yen, and some to the nearest 10,000, which compares the option we took with a conventional roof and solar panels installed on top. It compares an older quote from Rooftech for an integrated roof system of 4.44 kW (actually written as kWh) which was around 3 million yen plus an estimate of 1.35 million for the roof work needed underneath their roof, which ends up as 4.35 million; 4.04 million after getting the grant. The other quote was 2.4 million for 4.81 kW of panels, with a roof estimated at 1.81 million coming to 4.21 million; 3.87 million after the grant.

In other words, the integrated roof and panel system was more expensive than installing panels on a conventional roof, but only about 3 or 4 percent. It should be added that this was for around half the roof area covered with solar panels, and it's not clear what kind of roof the alternative was. Anyway, we chose to go for the integrated roof because it seemed well worth the potentially slightly extra cost for the simpler design elegance.