Playing around with the facts: Oil addiction

I found An America First Energy Plan on the new White House website and wondered what it would look like if they were talking about addictive drugs:

An America First Drugs Plan

Drugs are an essential part of American life and a staple of the world economy. The Trump Administration is committed to drug policies that lower costs for hardworking Americans and maximize the use of American resources, freeing us from dependence on foreign drugs.

For too long, we've been held back by burdensome regulations on our drug industry. President Trump is committed to eliminating harmful and unnecessary policies such as the Climate Action Plan and the Waters of the U.S. rule. Lifting these restrictions will greatly help American workers, increasing wages by more than $30 billion over the next 7 years.

Sound drug policy begins with the recognition that we have vast untapped domestic drug reserves right here in America. The Trump Administration will embrace the crack cocaine and crystal meth revolution to bring jobs and prosperity to millions of Americans. We must take advantage of the estimated $50 trillion in untapped grass and meth reserves, especially those on federal lands that the American people own. We will use the revenues from drug production to rebuild our roads, schools, bridges and public infrastructure. Less expensive drugs will be a big boost to American agriculture, as well.

The Trump Administration is also committed to clean heroin technology, and to reviving America's heroin industry, which has been hurting for too long.

In addition to being good for our economy, boosting domestic drug production is in America's national security interest. President Trump is committed to achieving drug independence from the Mexican cartels and any nations hostile to our interests. At the same time, we will work with our South American allies to develop a positive drug relationship as part of our anti-terrorism strategy.

Lastly, our need for drugs must go hand-in-hand with responsible stewardship of the environment. Protecting clean air and clean water, conserving our natural habitats, and preserving our natural reserves and resources will remain a high priority. President Trump will refocus the EPA on its essential mission of protecting our air and water.

A brighter future depends on drug policies that stimulate our economy, ensure our security, and protect our health. Under the Trump Administration's drug policies, that future can become a reality.

(I changed the following words: energy, coal, shale oil, natural gas, OPEC. Can you spot them?

Trends in the generation

With five years of data from my solar panels, it should be possible to find the answers to some interesting questions. Like are these panels producing any less electricity as they get older?

I'd probably need to compare the generation each month with the actual weather data to get a proper answer, but as a first approximation, I tried to calculate a normalised generation figure for each month. I did this by first finding the average generation for that month, dividing that by the average of the generation for the same month each year, then multiplying by the average generation for every month. 

While I was about it, and since it's really easy to copy spreadsheet functions into different columns, I did the same thing for the consumption.  

And here is what it looks like:
 

Google sheets does its magic and produces a trend line, assuming that each of the points is dancing around a linear trend. And if we can trust this, there is a downward trend. Generation has gone down a little under 5% in five years. At the risk of digressing into a discussion of logarithms, let's say that's about 1% per year. 

Interestingly, there is also a downward trend in the amount of electricity we use. This has gone down almost 10% in the last five years. There are spikes and troughs for the months of March and August when we have been away, so I should probably work out a way of ignoring these. Another factor that will slightly affect both graphs is the slight difference in each month, since I'm using the month of the electricity bill rather than the calendar month. 

The 1% per year loss of generation is in no way surprising. On the other hand, it is a surprise If we are on a trend to use 2% less electricity per year, and it is a pleasant surprise. I've always imagined that low energy houses are at their lowest energy levels when they are new, and as they age, lose efficiency, and acquire extra gadgets they steadily use more energy. That does not seem to be happening here yet. 

The other question I'm sure the data can answer is how big a battery I would need if I went off grid. 

As a bonus, here is a chart of the daily generation and consumption that is not at all normalised.

U Value Calculators: U is for useful or unilateral?

I realised my calculation for the heat saving of installed insulation for the lesson on economics was wrong. Instead of calculating how much heat the insulation stopped, I was just working out how much it let through. Of course to calculate how much less heat is going through a wall after you add insulation, you need to know how much was going through the wall before you added the insulation. So, I wondered, what's the U value of an uninsulated wall? 

Google will have the answer, I thought. 

But Google didn't have a simple answer. It did have several links to U value calculators. For example this one from British Gypsum

It works very well, and allows you to put in various wall structures, showing a nice diagram of what you are doing. You need to have one layer of Gyproc products, though.

Similarly, the innocently titled uvalue-calculator.co.uk is great for anything involving Kingspan products. No good for calculating a wall without insulation.

The best I could find was from Changeplan.co.uk. You can add as many layers as you like from a drop down list, or even add your own materials and put in thermal conductivities and thicknesses. When you add them to the wall, you can show what percentage of the wall they are covering, which is useful if you have insulation between pillars and studs.  

 

In the end I decided to just assume an original wall U value of 1 W/m²K, for the sake of easy calculation. 

One important thing to remember is that the more insulation you have, the less effective any extra layers will be. So the first 50 mm is worth a lot more than the last 50mm, although the cost may be no different. In fact as you add more it can sometimes become more expensive if you need extra materials to support the cladding. 

Ventilation Leak

Sam had an interesting issue with the mysterious appearance of water at his house in November. A narrow stream started appearing down a wall at the back of his house. Luckily it was on the outside. 

It came from the same place on the wall and seemed to be there all the time, although he could not confirm whether it was there while it was raining!

This seemed condensation-related, and evidently the cause was a problem with the seal on the exhaust vent meaning that instead of going outside, the exhaust air was going under the outer skin of the house. 

By November, it is usually colder outside than inside. The air is being cooled by the heat exchanger in the ventilation system as it leaves the house, and with at least a 10 degree temperature difference, and up to 50% relative humidity inside, this means the humidity of the exhaust air will usually reach 100% by the time it leaves. Since the ventilator does not have 100% efficiency, the exhaust air will always be a little warmer than the outside air, and have some moisture to deposit as soon as it hits something.

The something that was hit by the saturated and slightly warmer air seems to have been the inside of the siding, and the water found its way outside, where it dripped merrily away.

Bloomberg predicting solar will be cheaper than coal

You can read the article and listen to the story here: 

bloomberg.com

Do they know what they are talking about? Questions to ask your architect

Are you looking for someone to build a low energy house? Are you worried that they don't know what they are talking about. You probably should be! Here are some questions you can ask to find out. Check their answers with the handy key below, and find out whether you're in safe hands, or whether you should think twice about letting them build a kennel for your pet husky. 

1. I'm interested in Passive House. Can you build one?

a) I can build anything! 

b) Oh yes, passive solar. That's when you just use energy from the sun to heat the house.

c) I've heard of Passive House, but I'm not exactly sure what you need. I'll find out.

d) Yes, I'd really like to build a Passive House.

2. We're thinking about the layout of the house and wondering where to put the bathroom.

a) Oh, you can put it anywhere.

b) It should be on the South side of the house so the sun will get in through the windows and keep it warm.

c) It should be on the North side of the house because it'll be warm anyway and doesn't need south-facing windows.

d) The important thing is to keep hot water pipes as short as possible. You should try to keep the bathroom, kitchen and washing machine close to each other or in the room immediately above or below, and have the hot water source near. 

German scam!

3. These high performance windows seem really expensive, are they worth it? 

a) No, they're a German scam.

b) Yes [aside] I'm being paid by percentage.

c) No, you can just add more insulation in the walls.

d) I know they are expensive, but yes, they usually are worth it for the lower levels of heat loss and higher levels of comfort, unless you want to live in a cave!

4. For the ventilation system, which do you think is better, heat recovery ventilation or energy recovery ventilation? Heat recovery ventilation transfers the heat of outgoing air into the incoming air, while energy recovery ventilation also transfers the humidity.

a) Ventilation? What do you want that for? If you want fresh air, you can just open a window.

b) The best ones are made by the company we always use.

c) People here usually have energy recovery.

d) That's a good question. There are advantages and disadvantages to both. 

Yes, inside

5. I see a lot of houses around here with the hot water tank outside. Wouldn't it be better to put it inside? 

a) Boiler inside? Ha ha ha ha ha ha. That's a good one!

b) We always put the boiler outside. There's no space inside, and it will make the house too hot in the summer.

c) That's an interesting idea. Those things do lose a lot of heat, and it gets pretty cold here in the winter.

d) Yes, I know. I think that's because people are still following building practices from before the invention of air conditioning and insulation and hark back to a time when people didn't live long enough to die of cold in poorly-built houses. 

6. How much more expensive will it be to make a low energy house?

a) It'll be really expensive. We make really good houses already and there's no point in spending more money on this nonsense. 

b) It won't make any difference to the cost.

c) I'm not sure, we'd have to work out what extra time and materials are involved, then calculate the extra price. 

d) It'll probably put between 5 and 20 percent on your budget. Keeping costs down is a big challenge which the building trade really needs to work on. But the extra costs will pay for themselves within a few years in lower heating costs, and you'll have a more comfortable, healthier house that should last longer, so it's a price well worth paying. 

Answer key: 

Mostly a): Keep looking! The building trade is well known for its conservatism and you seem to have found a perfect example.

Mostly b): He (probably a he) doesn't really know what he's talking about, and probably doesn't realise. Or perhaps he assumes you know nothing, and is eagerly waiting to separate you and your money.

Mostly c): They don't have a lot of experience with low-energy building, but sound willing to find out and may be a good person to work with.

Mostly d): This sounds like a great person to build a low energy house. 

Five years of solar power!

Our Suntech display panel congratulated us the other morning on five years of generating solar power. We've made over 60 Megawatt hours. That would keep a 60 watt light bulb going for over a hundred years. But we don't have any 60 watt light bulbs, they're all low-power leds.

In the same period we've used under 30 Megawatt hours. Around 45% of what we have generated. We sold around 90% of the electricity we generated, and bought around 75% of the electricity we used. I'm not sure how much sense this makes in environmental terms or for overall energy usage, but economically it makes sense since we only pay 11 yen for off-peak electricity, and they have been paying us 48 yen per KiloWatt hour for our solar power, totaling over 3 million yen. 

Our contract lasts for another five years, and we will see what is available at the end of that. In the meantime I can start working on my plan to use the hot air under the panels for our atmospheric heat pump, rather than the frigid night air. I think it will take that long to find a brave enough heat pump engineer to tackle the project, or to learn enough about heat pumps to try it myself. 

(Corrected 10th January: originally said "Gigawatts", changed to "Megawatts". We're not a nuclear power station!)