Roundup: This Week’s Classics

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I surf across hundreds of articles a week as I learn more and more about green building, energy efficiency, and climate change. Most are interesting, but a few become touchstones that I end up talking about with others, and returning to again and again. Some candidates for that status that I found in the last week are below:

Zero Net Energy Homes Part 4 – Honda Accord Versus Solar Panels

El �ºltimo de los mohicanos
Money ('El Altimo de los Mohicanos' - photo by wakalani, CC 2.0 licensed)

One of the biggest problems for residential solar electricity generation is that it just costs too darn much to install those panels on your roof. Over the next five and ten years this will change significantly as new developments from the labs make it into large-scale production. Eventually houses will be generating all their own electricity using photovoltaics as a matter of course.

But is there a way to think about the cost today that makes the cost even seem reasonable?

Well, if you’re thinking about buying a new car, you should read on. Each year you don’t buy a new car and continue to drive the one that you’ve already paid for, you pays for another year of your solar panels. At the end of the loan period (seven years in my example below), you’re getting free electricity from a system that increases the value of your home and has another 20 years of life at the minimum. If you’d bought a car, in seven years you’d be driving a rapidly depreciating vehicle that you’d probably have to replace soon.

For my house, after rebates, putting up solar panels today would cost about $22,000. This would be a 4kw system, offsetting about 92% of my electric bill, according to the solar power calculator at Clean Power Estimator. With a $3,000 down payment, and using SunPower’s “Smart Financing” with a seven year term, my monthly net cost would be about $250, after subtracting out my electric bill.

So, $22,000 total cost, $3,000 down payment, $250 monthly – that sounds just about exactly like buying a new car, doesn’t it? In fact, if I go to carsdirect.com and price out a new Honda Accord EX, that comes out to $22,372. My current car, a 2000 Honda Accord, is worth $4,000. So I need to finance $18,000. With a four year loan, I’ll be paying about $420 per month.

Netting it out, for each year that I make the decision to buy solar panels versus a new car, I actually save about $170 per month. At the same time, according to the solar power calculator, I eliminate almost four tons of CO2 (worth an additional $320 at the currently accepted value of $80/ton). After seven years, all that electricity will be free to me, for at least the rated life of the panels. And I’ll get most or all of the cost of the panels back when I sell my house. When I sell the new Honda, I’ll get a lot less than I paid for it.

As an additional note, if you’re thinking about buying a new BMW, such as an M3. If you chose a BMW 335i with Sport Package instead, you could put up the solar panels with the difference in cost: 1 BMW M3 = 1 BMW 330i + Sport Package + solar panels. You’d get nearly the same performance – much more than you can effectively use anywhere in the U.S. except on a race track – and you’d offset all the CO2 you’d be generating with your new car.

Definitely let me know if I’ve convinced you to put up solar panels instead of buying a car this year! Or if you have any other comments on this topic – I’d love to hear from you.

High Fuel Prices Turn Out To Be A Good Incentive For Carpooling

Propaganda poster from the United States gover...Image via Wikipedia

It’s fun to see the articles and news reports on the upside of high gas prices – last night on the KTVU news was a report on how the air is getting a bit cleaner in the Bay Area because people are driving less.

Along these lines, Technology Review had an article the other day about technology-enabled car-pooling. On both general advertising sites like Craigslist and carpool-specific sites, drivers and riders are getting together to get together.

Although some people turned to these sites long ago to help reduce pollution or take advantage of faster, high-occupancy vehicle lanes that require at least two occupants, the pocketbook has been the largest influencer of all.

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Is this solar energy analysis is too simplistic?

According to this analysis from Clean Edge, (which I saw originally in the San Jose Mercury News, Solar energy cost may rival other forms soon, study says – SiliconValley.com):

Solar energy will cost the same as power produced by coal, natural gas and nuclear plants in about a decade, a report released Tuesday suggests. By then, the price parity could propel solar adoption so that it accounts for 10 percent of U.S. electricity generation by 2025

If you listen to this kind of thinking, solar energy (which is defined as what, by the way?) is still far more expensive than other kinds. But solar energy, even today, has a finite payback time – if I put solar collectors on my roof, for example, eventually they will pay for themselves.

So that’s one way it’s wrong.

Secondly, the study assumes that conventional energy prices will go up by 3% per year. That could be a slight underestimate. Didn’t we just experience a three month period where gas prices nearly doubled? (That’s 100%, folks!).

I can’t make any argument about the assumption that solar energy prices will come down 18% per year. That’s a lot, by one metric, but we’ve certainly seen large and faster price drops in high tech in the past. Even the iPhone last month, which dropped in price by almost 50% in less than a year. Sure, that was partly through some magic AT&T financial pixie dust, but to the user, it’s a clear 50% price cut. There’s no reason similar magic pixie dust, whether from the government or from the utilities themselves, won’t contribute to market price declines.

The claim that solar currently accounts for less than 1/10th of a percent of the U.S. energy supply today is fine. But the assumption that it will still be less than 1 percent in 2015 (seven years from now) is curious. If we start at .1 percent, and double our solar usage every year, we end up at 128 times as much – 12.8% of today’s total. This is the amazing power of Ray Kurzweil’s “Law of Accelerating Returns.” Even if it takes two years for each doubling, we’re still up a factor of 32x in seven years. That means 3.2% today’s usage. Our total energy usage may also go up (although there are very good reasons to think it may not go up much and and will be starting a downward trajectory), but for a 32x increase in solar supply to translate to 1% of our total energy use, total energy use would have to double. Not too likely in the U.S., where population growth has stopped, and SUVs are starting their long decline.

Finally, there’s good reason to believe that solar energy will actually have a much larger share of U.S. energy usage, due to the power of “negawatts” (as explained brilliantly by Amory Lovins in this series of talks at Stanford in 2007), in which efficiency turns out to be the most cost effective way to power industry and create profits. Oh, and by the way, it significantly reduces our energy usage, by as much as a factor of five to seven!

The article combines a couple of types of fallacious thinking – that technological progress is linear, for example, rather than geometric, and that other factors, such as the desire to reduce greenhouse gases or realizing the benefits of negawatts throughout the economy, don’t have an additional accelerating effect on technology changes.