How do you heat a passive house?

Some people may think the answer is "you don't," but Passive houses do need some heating. 

The real answer is that you don't need very much, so it's not so important how you heat it. 

A comprehensive discussion can be found here from Zehnder Passive House, listing the pros and cons of each approach.

My personal favourites at the moment are underfloor heating and air-source heat pumps, athough I have not always thought so, and cannot guarantee that as a final answer. 

I wrote about underfloor heating before, highlighting the advantages: saving space, evenly distributing heat and increasing thermal mass; and also warning of the problems that can come from incorrect design and installation. One disadvantage that I forgot to mention is that it's very difficult to get to the underfloor pipes if something goes wrong with them, although they are just pipes and it's very unlikely that anything will go wrong.

Air conditioning units are becoming standard installations in Japanese houses, and their COP is getting better all the time. As well as cooling, they can reverse the circuit to heat air. In a regular house using these for heating can be uncomfortable since they are only heating the air, while the building itself stays cold and the temperature is not balanced. In addition, the hot air can rise giving you cold feet and a hot head when you stand up. This may also be an expensive way of heating your house, and it may even be both uncomfortable and expensive. 

Since a passive house has such low heating demands, modest air conditioning units can easily provide the heating needs of a building. The peak heating load of a Passive house should be around around 10 Watts per square metre, so for a 100-square-metre house, you need 1 kW. Units are typically rated at several times this, so one air conditioner can produce all the heating or cooling you will need for a whole house, although you may have to think carefully about where to put it. It can go on a wall or ceiling so, similar to underfloor heating, it won't take up any floor space. 

An additional advantage of an air conditioning unit is that it can also cool the house, and may also have a dehumidifier. The units are stand-alone, rather than incorporated into the ventilation system, so they may be less complicated. And depending on where you are, you may get something that comes with a guarantee, and can be easily be maintained or replaced.  

And by the way, if you're in Japan trying to work out how to read the symbols on the remote control so you can use the air conditioner this post from Surviving Japan may be useful.

Or the missing piece may be turning Power into Gas

Another interesting idea for smoothing out the inevitable irregularity of renewable energy is to convert excess power into gas, as espoused by Chris Goodall in Carbon Commentary. He starts with some figures for Germany showing the live generation over a week, and points out that at times there is more supply than demand, which means the cost of electricity is zero. The prices are the wavy lines at the bottom, which you can see dipping to zero and beyond.

Converting electricity into hydrogen is usually expensive, and hydrogen is usually produced from methane. If the power is free, then the economics change, at least according to the article. The hydrogen can be converted into methane, which is the main ingredient of natural gas. 

Gas has the advantage over batteries that it can be stored, so for example gas generated in the summer could be stored for winter use. It can also be transported and there is already an infrastructure for using gas as a fuel, from power stations and vehicles to domestic heaters and cookers. If renewable energy is being used to generate gas, and taking carbon dioxide out of the air in the process, then this could replace fossil fuel gas and help our carbon accountancy. 

This idea may come unstuck when you look at energy returns on energy invested (EROI) and how much extra energy you need to make the infrastructure to convert the power to gas. Also we have to be very careful that we don't get an unvirtuos non-cycle of the electricity being converted to hydrogen, then the hydrogen to methane, then the methane leaking into the atmosphere, since methane is much more powerful as a greenhouse gas. 

On the other hand, if something like this doesn't start happening, then the power prices that have been driven down by renewables are going to have interesting economic consequences. Lower prices may mean that investments in energy become financially unviable. 

Reasons to be skeptical about climate change - or not

Six months ago when I was collecting suggestions for debate proposals in a class of second-year university science students, I had to politely reject one about global warming being caused by humans. I asked the class for a show of hands, and nobody was against this. "We can't really debate this," I had to tell them. "Nobody disagrees that global warming is caused by humans."

  

Since then, the climate change debate has reared its ugly head again. But it's not so much about whether climate change is true, or what can be done about it. It's more like a punch up between the protagonists in Fight Club. On one side the argument is that the science is irrelevant. On the other side, it is that politicians don't understand science. Debate is not really happening because the two sides are not engaging. One side is attacking "climate deniers" and the other is attacking "climate warmists". Nobody identifies themselves with these titles. 

Below are a few of the kinds of arguments that you'll hear, and what is wrong with them. 

Cherry picking of data 

"My grandfather smoked 20 cigarettes a day, drank, ate meat and lived to 95"

Ok, maybe he did, but my grandfather smoked, drank, ate meat and died at the age of 46. Neither of these proves anything about the connection between lifestyle and longevity, any more than rolling a dice once and getting a 1 will tell you what is on the other sides, how many sides the dice has, whether it's loaded, or what will happen on the next roll.

Climate science requires long and broad sets of data to find whether it's getting warmer or not. One swallow does not make a summer, and one snowball does not mean that global warming is a lie. The butterfly you saw in February is not proof that the world is getting warmer, but it is evidence, and taken with all the other evidence, it becomes very difficult to deny. See this list of climate monitoring groups that say the world is not getting warmer. 

Expecting scientists to be 100% sure

"There's a big black bear coming to kill you!"

"No, I think you'll find it's just a really dark shade of brown"

The reality with science is that nobody is ever 100% sure. Scientists often show how sure they are with a "p" followed by a percentage. That percentage is the probability that the results they saw were the result of a coincidence. Predictions should always have ranges, and in fact one problem between the media and the scientists who have tried to communicate with media is that these ranges are often left out.

So for example you get stories like Heat-related deaths will rise 257% by 2050 because of climate change. Not 256%, not 258%, but 257%! The original paper says "around 257%" in the abstract, and the actual paper no doubt gives margins of error. Unfortunately the actual science is protected by a pay wall, so we can't easily get it. We can get this headline, which will almost certainly be wrong, and access will be completely free to blog posts saying that scientists got it wrong again. 

Next time, please write something like: "Heat-related deaths to increase two and a half times by 2050...".   

There's an article here from the Max Planck institute saying there is a 1.7±0.5 mm per year rise in sea levels over the 20th century. That's a huge margin of error, but note that even the lower level means the sea rose over 120 mm in a hundred years. In their wildest dreams the sea level did not fall. 

Turning arguments against you

"No you're a big fat idiot"

People seeking to attack the climate science will often turn arguments around. 

For example:

Oil companies have been accused of a conspiracy to cover up global warming -> Scientists are accused of a conspiracy by the renewable energy industry to create climate science

The media were accused of taking information out of context from Climategate emails immediately before Copenhagen Climate Talks that helped sink any agreement there -> NOAA scientists were recently accused of speeding global warming data to publication immediately before Paris Climate Talks to create agreement

Right wing politicians have political objections to climate change and have attacked the science ->  Scientists are accused of politicising the science.  

Strategically what is happening here is a takeover of the rhetoric. The intention is that when we hear "climate change" and "conspiracy", instead of thinking of the well-documented conspiracies by oil executives to promote junk science, people will be duped into imagining some a group of communists who have got together to create climate science.

Accusations of hypocrisy

"If you ... you cannot be an environmentalist"

Where the "..." could be any of a number of things that have an impact on the environment, for example have children, drive a car, fly, use a computer, cook food, or breathe.

This is first of all an ad hominem attack, where things have turned from attacking arguments to attacking the person arguing. These kinds of attacks happen on both sides of tribal conflicts, and do not help. The establishment loves accusing idealists of hypocrisy, although ironically they often fail to see hypocrisy in themselves.

This kind of argument puts excessive restraints on who can be classified an environmentalist, which gives an excuse for many people to do nothing. It also seeks to create a gap between environmentalists and everyone else, making it more difficult for people to take environmental positions.

And these arguments often miss the point of environmentalism. For all but a lunatic fringe, environmentalism is not really about saving the planet. It is about making sure the planet can save us. For example, it is an admirable choice to not have children since population is a multiplier of environmental damage, but the whole point of environmentalism is to make a planet where our children, and their children can survive. 

Environmentalists are not all soppy romantics desperate to save cute furry animals and to hug trees. They are pragmatists who appreciate that all our food, fresh water and clean air come from complex ecosystems that have developed over millions of years, and that may not be able to survive the sudden changes we are imposing. The people who tell us everything will be fine are the wishy-washy idealists.

The reality is that we are a complex species living in a complex environment, and there are no simple solutions, but the first step is being honest. 

Economics as Thermodynamics

We tend to think of human activity as something altogether different to thermodynamics, but James Lovelock looked at the amount of energy that people have used and noticed that things start to get culturally interesting when we use more than one watt per square metre. As I wrote before, he linked human activity to the reynolds number, which is a measure of turbulence. 

Tim Garrett of Utah State calculated total human wealth is proportional to the amount of primary energy we consume. One 1990 US dollar is approximately 10 milliwatts.  

It's worth noting that this is talking about power and not energy. Wealth is not proportional to the amount of energy. It is proportional to the rate at which energy is used. So when there is inflation, and the amount of financial wealth increases, there is an increase in the rate we are using energy. In the fossil fuel paradigm, this means an increase in the rate we are using up resources. Inflation is compound, so the increase is exponential.

If we change to renewable sources of energy, we may be able to reduce the rate we are using up resources, but unless we have a zero-carbon economy, we will still be using up those finite resources. If you're heading towards a cliff, slowing down is not going to help: you need to stop or change direction. We don't need an economic paradigm where growth is used as the main metric, and lack of growth met by frowns on the faces of newscasters. 

Free market economics has been an interesting experiment, and we seem to be doing well at the moment, but in terms of experiments, it's a bit like an experiment with drugs. I once asked a friend what speed was like, and he said it was like riding a motorbike. But you had to walk back. The sooner we realise that free market economics, along with fossil fuel use, is an addiction, and that we too are going to have to walk back, the sooner we can start kicking the habit. 

When I talk about costs in terms of energy rather than in terms of money, I've been worrying that I'm just being an idealistic hippy. In fact, the reality may be precisely the opposite. Energy is the real metric, and money is just a loose approximation to it. Energy underlies the motions of the universe, not just in the shine of the sun and the orbits of the planets around it, but in the myriad human activities and their effects on a macroscopic level. It is people who don't see this who are living in a fantasy world. 

It's also worth going further into generalisation and thinking about the future. People spend a lot of time worrying about where to invest their money for the future. The Bible says that love of money is the root of all evil. Not the money itself. Rather than worrying about money, we should be thinking more about how we invest energy. It is now in great abundance, but there is no guarantee that it will be in the future. Money may lose most or all of its value, but energy will always have currency.  

Reference

Garrett, T. J.: No way out? The double-bind in seeking global prosperity alongside mitigated climate change, Earth Syst. Dynam., 3, 1-17, doi:10.5194/esd-3-1-2012, 2012.

Woodburning bad for climate

It turns out that burning lots of stuff is not good for the environment.

According to BBC News from 23rd February, 2017, converting coal power stations to burn wood that has been processed and shipped half way around the world has not reduced carbon emissions. In theory the carbon from trees is released when the wood is burned, and will be taken up by new growth. In practice a lot of forest is being clear cut to export from the US to the UK. This is not counted in the UK as a carbon emission because burning wood is considered carbon neutral, and the carbon is counted when the trees are harvested. In the US, on the other hand, carbon is not counted when the trees are harvested, so this carbon has vanished from the accounting system.

People who are against action on climate change will say, "I told you so", and hold this up as an example of the stupidity of environmentalists.

Environmentalists who have been saying that biofuels are not really the answer will also say, "I told you so", and hold this up as an example of commercial interests missing the point. 

Burning wood in power stations is not progress. This should be no surprise. If burning wood was so great, we would never have started burning coal.

Also there have been recent claims that poor air quality in London is due in part to the increase in wood burning stoves, so the evils of wood burning have become something of a meme.

The key is probably in moderation. Burning lots of stuff is not good for the environment, but wood can be part of a healthy calorie-controlled energy diet.    

It had to be yew

We finally got a yew hedge planted a couple of years ago, and I recently thinned them out, with the hope they will grow more like a hedge and less like a row of trees.

Just like the cut branches strewn on the ground, here are some links to websites about planting, growing and trimming yew.

Ashridge Trees.co.uk: How to plant yew hedges

Ashridge Trees.co.uk: Pruning yew hedge plants

Shumi no engei - (in Japanese)

Caring for Japanese yew

University of Arizona: Pruning hedges

University of New Hampshire: Pruning evergreens in the landscape

Japan's wind farm developers face wrong kind of gusts Nikkei Asian Review

The lack of wind power in Japan has always struck me as odd. 

Japan has wind, and quite a lot of it. Also it has some major turbine manufactures, including Hitachi, Japan Steel and Mitsubishi. Sometimes you hear that Japan has the wrong kind of wind; far too variable and much too strong in the typhoon season. But sixty years ago Mitsubishi made propellor planes faster than any hurricane.  

There is a story here in Nikkei Asian Review about Green Power Investment who have been planning a 40 billion yen project for a 200 MegaWatt wind farm in Iwate Prefecture, Tohoku (North eastern Japan).  

Unfortunately they have been told that it will take 10 years for the transmission capacity to be increased so they can connect the wind farm. 

Wind turbine used as garnish for thermal power station

The local power company has not given any detailed explanation, but it may have something to do with a planned coal-fired power station in Akita. Yes, there really are plans for Japan to build a new coal-fired power station. 

In fact, according to Australian ABC news, it's going to build 45 new coal power stations, which the Guardian informs us will lead thousands of early deaths. It's also difficult to see how this will help Japan's commitment to reducing carbon emissions. Which country was Kyoto in? 

Another surprise from the Nikkei article is that power companies only pay 22 yen per kWh for wind-generated electricity, going down by 1 yen per year. They give me over twice that for my solar power. I know that the inflated tariffs for solar-generated electricity are partly subsidies for Japan's substantial solar industry, helping it to keep costs down and stay internationally competitive, but the same would apply to the manufacturers of wind turbines. 

Edit 15th March:
The feed-in tariff for household wind power is 59.4 yen. The tariff of 22 yen quoted in the Nikkei article applies to industrial wind (<20kw compare="" fair="" household="" it="" my="" not="" p="" really="" s="" so="" solar="" tariff.="" to="">

Nanosolar: Portable panels... a new toy

With a few kilowatts of generating power on my roof, I'm putting my money where my mouth is, and expecting to see it come back relatively quickly. But how about a solar charger for my phone when I'm out?

I've been looking at portable solar panels for a while, and saw one that would fold out over your backpack, or could be set up in a camp. At only a few hundred grammes it seemed appealing, although in one review it didn't score so well. The technology is still at the early-adopter phase, and if they were software, a lot of the products going on the market would be referred to as Beta, and given out for free

I did pick one up at a stall next to the park in Seoul's arty area of Hongdae. I'm sure if I'd gone to a bigger market or one of the digital areas there would have been a much wider range. I bargained him down from 15 to 13 thousand Won (knock the last nought off for Yen, the thousand for US dollars, or call it ten quid).

I checked the packaging and instructions and found no indication of a manufacturer or brand. Except that it was Made in China. The guy behind the stall was lamenting that nothing was made in Korea any more and all his wares were made in China. The world's biggest brand. I'm not sure whether the manufacturer name was missing because it was just designed to survive being purchased or because the manufacturers makes goods licensed for someone else and doesn't want to get caught by them.
Technically it's pretty simple. There's a one-watt panel on the front and a battery inside.  A red light comes on when it's charging. But, as the instructions warn, this will come on if there is any charge coming off the panels at all, and it really needs full sunlight to charge the batteries.

There is also a test button that lights a mini LED torch and shows the battery power with an array of LEDs. There are two USB sockets to charge devices, and a mini USB socket you can use to charge the internal battery from a computer.

The battery is rated at 2000 milli amp hours. Actually it's written 2000 MAh, and by convention a capital M is mega, so this would be 2 giga amp hours. That would take the array on my house about two month to charge! In fact this panel should fully charge the battery in two hours.

I was looking for an Israeli military device, which was a wire that connects to your knees, but instead I found a baton-shaped mechanical charger that you can put in your backpack and it will charge as you walk.
http://www.geo.tv/1-5-2011/76839.htm

(Written in 2012, and I've still hardly used this toy!)

David Mackay for science adviser!

The so-called president of the United States has been very slow to appoint a science adviser. This may simply be because he just doesn't care about science. His mission is in changing people's perception of America, not actually changing anything in the real world.

If this isn't worrying enough, a more sinister reason may be that it is difficult to find a credible science adviser who will deny the climate and keep the fossil fueled forces behind the White House happy. He seems to be looking at William Happer now, a physicist who apparently says climate change is great. It's difficult to imagine somebody more on-target.

The argument that climate change will bring more advantages than disadvantages is a bit difficult to maintain, although it may be tenable. He also claims that predictions of warming were exaggerated, although when you look at Jim Hansen's work from 1988, the predictions have been very close.

Happer also appears on this list of 300 "scientists" telling trump to burn the climate, carefully analysed by the Guardian's John Abraham.

I think David Mackay would make a great science adviser. Not only is he able to put things in simple terms, but he also has a good grasp of the reality of our energy problem, and realistic suggestions about what we can do.

Here is his TED talk:

UK Passivhaus case studies in Architects Data File

Architects Data file "Building Envelope" contains case studies of five recently completed UK Passivhaus projects. This includes The biggest UK Passivhaus building at Leicester University; Wilkinson Primary School in Bilston, West Midlands; a house at Landsdowne Drive, East London; Cre8 Barn at Stirley Community Farm in Honley, West Yorkshire and a terrace at Burnham Overy Staithe, Norfolk.