Wednesday, October 1, 2008

Still no Solar

A few days ago I watched the CEO of Skypoint Solar give a presentation on solar power. It pretty much convinced me solar will not matter for at least a decade, probably two, if then. The following two figures from his presentation pretty much make the case:

(you can click on the first image to get a larger one if you cannot read it)

Solar electricity has been one of the favorite energy topics for researchers for quite some time. The first working prototypes were decades ago. In all of this time solar has only managed to hit .034% of world electricity production. Three hundredths of a percent. Compare that to wind, and geothermal. As best as I can tell have been comparatively ignored by governments yet produce ten times, and twenty times as much electricity as solar respectively. Judging by the huge rates of growth in wind power for the past two years I suspect the numbers are even farther apart today.

That gets worse in the second slide. This figurelists what growth the solar electricity industry would need to maintain to produce 1% on the left, and 10% on the right of our electricity assuming energy use increases by either 175, or 450%. I am unaware of any industry maintaining 30% growth rates over a 17 year period. Yet that is exactly what would need to happen for solar to only produce 1% of the electricity the world uses in 2025! To actually put enough of a dent in coal to actually matter we would need 20-50% of our electricity from solar. Unless something changes in a big way that remains fifty years off. If we dramatically expand nuclear, geothermal, and wind power for the next two decades I don't actually see much remaining for solar to do. Most of our energy problems can be solved before this technology has a chance to get off the ground.

I actually dropped solar power as a field I am looking into on my resume. Once the industry manages to produce 1% of our electricity I will reconsider. The wind industry in America is already at that level, if the wind industry managed to get 30% growth rates over the same time period we would produce something like 50% of our electricity from wind(although practical concerns may limit that at about 20%). I would much rather be in an industry adding full percents to its market share than hundredths of a percent. Geothermal, and nuclear power are in a more similar position to wind than to solar, so those seem like reasonable technologies to work on. I gave up most hope on entering the nuclear power industry though when I looked at a map of where the nuclear power plants in America are located. Out of 104 plants, only 2 are in California and very few are elsewhere on the west coast.

There always is the chance of 40% efficiency solar cells at half the cost of current cells, and there has been 7 years of ~40% growth rates in the industry, so I haven't quite given up hope on the field, but in the next two decades don't expect anything out of it.


Anonymous said...

Have you seen the Nate Lewis (Cal Tech) work? Solar is the only sustainable energy source that could match current and future demand......

glmory said...

In the one thousand year plus time frame that is almost true. We have a lot of Thorium, and quite a bit of Uranium, certainly enough to fill demand for at least a thousand years. There is enough wind in America to supply all our current use, but probably not our future use, and even fulfilling current demand requires energy storage technology we do not have. After that thousand or so years than energy options do start looking pretty scarce.

From the year 3000 on, it is down to two energy sources, solar and nuclear fusion. I still hold out a lot of hope for nuclear fusion, the ITER is essentially a 500MW power plant. Despite all the pessimism in the field every successive tokamak has been a big improvement on the previous one. That can only continue so long in a world where fossil fuels keep getting more expensive before fusion hits economic viability. It really is just a race to see which of the two technologies takes over first. If we end up with 50% efficient solar cells for a tenth of the present cost it probably will be solar. That is at least a lot better than most of the schemes I hear to produce our energy. It certainly at least justifies more research money than it gets today.

In the short term though everything is flipped backward. Solar has little to offer in the next twenty years. The biggest reason, other than we have almost none of it, is probably just that it replaces peak power, not base load power. This means solar is competing mostly with natural gas, wind, and some hydro. If we were to produce 20% of our electricity from solar in twenty years, it would be unlikely to replace any coal power. That severely limits its ability to contribute to global warming. Compare that to geothermal power plants which fill the same role in the grid as coal, and can therefore immediately displace significant quantities of coal.