(I like to post news and thoughts on alternative energy, but I’m not the smartest guy when it comes to the hows and whats of practical applications. Mostly I just read, say, “that’s neat” or “that’s stupid”, and write about it like I know what I’m talking about. Luckily, I have very smart friends who explain to me how things actually work. One of those friends, Matt Patterson, has kindly offered to provide a science lesson.)

Hello there.

Just to get it out of the way, I’m not Dan. I’m a guy Dan knows. You may recall a while back, Dan posted an entry about the EU’s proposed Saharan Desert solar power generation plan.

I made some comments about why I thought this was a bad idea, and the long and short of it is that Dan said he would like for me to write a thing for his site about energy. So, here I am. I’m not a nuclear physicist, an electrical engineer, coal miner, oil geologist or wind farmer. What I am is a guy about to go back to school to get a degree in Environmental Science. A tree-hugging-dirty-fucking-hippie, if you will. Now that I’ve introduced myself, on with the show!

First, a few basic facts about the power grids that most industrialized nations use. These grids are massive, interconnected electrical circuits, with both generators and consumers of power. At any given moment, there is a certain constant load of power being used by the grid, which must be produced. This is your baseload. A grid that fails to produce the load required of it will fail, causing blackouts/brownouts, etc. On the other end of the scale is the peak usage of the grid, which is the maximum amount of power used. Obviously, the amount of power needed at any given moment is variable, and closely watched by utility companies. Certain types of power plants can change their power output more quickly than others; natural gas is pretty quick, coal slower, and nuclear varies by design. The great thing about these technologies is that they are fully under our control. You need more power? Fire up another turbine, and produce it. It’s also very easy to use them to produce the baseload constantly needed by the grid.

Now, lets talk about solar power. Solar power has great features, and holds a lot of promise. It generates power most effectively when demand is highest: During the middle of the day. Business are in full swing, people are running their air conditioners or furnaces, etc, etc. This is, as Martha would say, a good thing. The flip side of this issue is that solar power cannot generate power when the sun isn’t shining. On a cloudy day, power production can drop sharply. And it pretty much goes to zero once the sun goes down. This isn’t a big deal if we are talking about solar power as a secondary, supplemental power source for use during peak power consumption. But if we’re talking about solar power as a primary power producer, we have a serious problem. The grid needs a certain amount of power all the damn time. A giant photovoltaic power plant in the Sahara Desert generates juice like gangbusters during the day (provided that the weather is cooperative, no sandstorms, etc.) but once the sun goes down, the power supply to the grid will drop sharply. Which means that some sort of backup system is required for periods during which the sun is not shining.

There are a variety of ways to implement backup power. One is through energy storage. This can be thermal (storing the heat produced during the day to power turbines into the night, a system currently in use in the US at some solar power plants), or electrical (giant battery arrays), chemical (never seen it discussed, as it’s not very practical) or building backup generation capacity in the form of another power plant, be it natural gas, nuclear, biomass, or what have you.

Thermal storage is only useful for a short period of time, at most a couple of hours. Giant battery systems could be exceptionally costly, and they have a limited amount of storage capacity. What if the power plant is engulfed in one of the regular sandstorms, and can’t produce power for days at a time, even once the storm has passed, because repairs have to be made, the sand cleaned off the panels, and so on? To have days worth of backup batteries would be terribly costly, environmentally (look up nickel mining sometime) and economically.

This pretty much leaves “traditional” forms of power generation.

The good thing about solar is that, while we have no control over when the sun shines, we can predict it with pretty decent accuracy. That means we can guess pretty well when we’re going to need our backup power, and either limit our load, through some sort of load balancing scheme (like direct HVAC control) or through ramping up supplemental power production. Thus, every day, as dusk is falling, you fire up your natural gas plant, nuclear reactor, or whatever.

Wind power has the intermittency problem even worse than solar power, because wind is much more variable than the sun, and can change much more rapidly. Large scale wind power requires a significant investment in dynamic load balancing, and rapid response backup power production (both of which, in themselves, are things we need anyway).

The variable nature of both sun and wind means that we have to basically have the same amount of energy capacity in place, as a backup. That means that the cost of building a solar plant itself is not a clear indicator of the final cost of the project, as back-up generation may or may not be included in the estimate.

These facts suggest that solar and wind are extremely poor choices for primary power production. You have to site them very specifically and have extensive back up systems in place, and you have no control over when they actually generate power, or even the amount that they can generate. Both are great for use as supplemental, site produced power, and every building with a flat roof that gets decent sun during the day should probably have solar panels put on it in the near future. That doesn’t mean it’s a good idea to build vast solar plants in the desert, and then run thousands of miles power cables to the countries that want to use the power.

So what do we do?

We can’t, or shouldn’t use natural gas or coal. And nuclear power is a terrible idea, right?

Well… it doesn’t have to be a terrible idea.

In fact, I’d go so far as to say that nuclear power is the single best bet that humanity has for producing clean, safe, consistent power in the future.

If, and this is a big if, we’re smart.

How to be smart about nuclear power? That post will go up in a day or two, because this sucker is long enough as it stands.

(Dan again. To reiterate how little I have to contribute to a discussion about the potential for safe, consistent nuclear power, here is a link to an mp3 of Fred Kirby singing his country-western classic, “Atomic Power”:)

mp3 | Fred Kirby, “Atomic Power”