Monday, November 07, 2005

Solar Heating Lowers Construction Costs

Solar Energy is a grim business. Usually, folks who decide to buy a solar system make some sort of projection about their fuel or electricity costs and then figure out how much the solar system is going to cost. The trouble is, these comparisons take thought, and are dependent on unknowns like the rising future cost of power, effective interest rates in the future, and structure depreciation. No wonder solar systems are a hard sell.

Well, things are changing in sunny California. Our Title 24 law sets energy efficiency standards for most buildings. A new revision of this law has come into effect as of October. Among other things, the law sets standards for window thermal resistance.

Essentially, California has mandated that you are going to save energy, relative costs be damned, but at least you get to pick how to do it. I could write a blog entry on how I feel about this kind of regulation versus simply changing the price of energy... but no. Today I want to talk about the solar industry.

The big news for the solar industry is that instead of comparing solar collectors to just burning fuel, people now get to compare solar collectors to better insulating windows. It's a much easier comparison, since you pay for both things when you build the house, and solar collectors come off looking very good in comparison. When the tract home developers figure this out, they're going to slap solar panels on any place they'll fit.

How's that? Well, consider a standard 4.5 foot by 3.5 foot sliding glass window.

A good aluminum-framed version will cost a few hundred dollars, and have a U-value of 0.61, which means that it leaks 0.61 BTUs an hour, per square foot, per degree F temperature difference. In San Francisco, where we have 3458 degree-days of heating each year, that's 797,345 BTUs a year -- about ten bucks.

As of October 1, California requires a U-value of 0.38 on most windows. These are pretty nice windows. To get that U value, you need double panes of low-E glass with argon fill, wood or vinyl frames, or high-end aluminum frames with thermal breaks. This window will cost a couple of hundred dollars more than the aluminum-framed window, and it'll leak about 300,000 BTUs a year less than the aluminum-framed version.

So here's the thing. A rooftop solar thermal system can supply those 300,000 BTUs a year for about $120. (That $4068 kit with 2 Gobi 408 collectors will pull down 80 to 120 therms a year.) And California will let you use inexpensive aluminum windows if you have a solar thermal collector to supply the extra heat.

Now some people are going to want the wood-framed window look, and so for those people this comparison doesn't much matter. But developers are the kind of folks (cheapskates, and I use that word endearingly) that will save a couple of bucks per house by using skinnier electrical wire. Saving $100 a window while being able to sell the resulting house as "green" is a fad they can embrace with enthusiasm.

But developers are also the kind of folks that prefer to suceed doing things they've seen other people succeed at. So, if you live in California and are building a new house, do your part and stick on a solar thermal collector. It won't take long to get the fad going.

Tuesday, November 01, 2005

Why Merlin?

My anonymous commentor is getting at a very interesting point. Why does SpaceX do their own engines when clearly better engines are available from Russia? The Russian engines have far better Isp, burn the same practical fuel mix, are available for known and probably reasonable amounts of money, and are known to work now (which takes a lot of schedule uncertainty out of SpaceX's plans).

Using Russian engines was Kistler's plan. Kistler spent five times as much money as SpaceX has without building a complete vehicle. Maybe it was their recovery system. Maybe it was their basing plan.

I suspect that using a Russian engine puts a big Chinese wall in the middle of the company, for both intellectual property and ITAR reasons. Enough of the vehicle design is tied to the engine design that what you end up with is a company that, to a noticeable extent, resells Russian launch services at the whim of international relations.

How big a deal can this be? The Atlas-V uses Russian engines, and is intended to be used by the military for sensitive launches. If Lockheed can do it, why not SpaceX?

According to Astronautix, Atlas V has launched 4 communication satellites, only one of which was a U.S. satellite, which was commercial. By comparison, Delta IV has launched 2 U.S. military commsats and a european commsat. My sense is that the U.S. military is averse to relying on a launcher using unsubstitutable components from a major overseas competitor, and funds the Atlas solely as a backup to the Delta.

I think SpaceX knows it will be dependent on launching U.S. military payloads, and knows it can't do that with Russian engines.

If SpaceX is sucessful, I expect an EELV, probably Atlas, to get cancelled by 2010. Delta will become the backup launcher, subsidized by the military and flying in very low numbers.

And seven years from now, I think the boost competition will not be United Space Alliance versus Ariane versus SpaceX. I think it will be SpaceX versus at least one Russian company (perhaps marketed by a western company e.g. SeaLaunch) versus the Chinese. SpaceX will get the U.S. military business by default. To win the international competition, SpaceX may need to figure out reuse.