Tech That Will Save Our Species - Solar Thermal Power

NoMoreCoal writes "Salon has up a story by Joe Romm, former undersecretary of energy during the Clinton administration, discussing a lesser-known alternative energy solution. It's a technology that (he claims) is ready to provide zero-carbon electric power big, fast, cheap and (most importantly) right now: solar thermal power. 'Improvements in manufacturing and design, along with the possibility of higher temperature operation, could easily bring the price down to 6 to 8 cents per kilowatt hour. CSP makes use of the most abundant and free fuel there is, sunlight, and key countries have a vast resource. Solar thermal plants covering the equivalent of a 92-by-92-mile square grid in the Southwest could generate electricity for the entire United States. Mexico has an equally enormous solar resource. China, India, southern Europe, North Africa, the Middle East and Australia also have huge resources.'" Interesting stuff, even if he does mention the Archimedes Death Ray.

Comments

Solar thermal power/solar photovoltaics

[jmpeax]

The difference between solar thermal power and more well-known solar photovoltaics.

Re:What about storage and transmission?

[xaxa]

Has anyone even read the summary? It says plants. That means more than one.

Solar thermal plants covering the equivalent of a 92-by-92-mile square grid

There are some pictures of the German plant here.

Re:And a related problem...

[B'Trey]

You know, sometimes it helps to RTFA. One of the specific advantages of this type of system is that the energy of the sun is not directly converted to electricity, as it is with solar cells. Rather, the energy is used in the form of heat, which in turn is used (via heating a fluid) to drive a generator. That means that you don't need to store electricity - you need to store heat so that the heat can be used to drive the generator during times when the sun is not available. The article specifically mentions using oil or molten salt to store the heat. Heat up oil or molten salt, store it in well insulated containers, and it will stay hot for a very long time. When you need it, you run the hot oil or salt through a heat exchanger, extract the heat and generate more electricity - all while the sun is on the other side of the planet.

Re:And a related problem...

[hador_nyc]

In other words, NYC is "solving" the "problem" of electricity wasted into heat (by resistance) by wasting a ton of electricity running a gigantic fucking A/C unit 24/7... which coincidentally, is just a heat pump. Is it just me, or is this really silly to start with? You might think so until you consider some details I didn't mention. The amount of energy wasted on cooling the superconductor is significantly less than the amount of energy lost in transmitting the power. Proper insulation does help, along with the fact that we are talking about a few limited, but VERY LARGE underground wires. In a single wire in your house, not that much power is wasted say heating up the wire that say supplies your tv with power. Touch it, it's not warm. The problem is when you try to send enough power for say Manhattan Island where you have roughly 10 million people at work during the day. Then you are sending A LOT of current, and it's the current that heats the wire. That same copper in your tv power cord ain't that good when you put a lot of power in it, and your transmission losses get huge. By cooling a special metal turning it into a superconductor, you eliminate those losses. Thus by spending a bit more energy on cooling, you save a lot more overall by using the material without resistance.

Read up on power losses on high power transmission lines and superconductors; then you'll understand how they make sense in limited installations.

Some issues I have with this topic.

[Masato]

Wow... Where to start with this topic. I'm by no means an expert in the subject of power, but I have been studying it for approximately a year now (as an electrical engineer) and know people who work in the industry, etc. After reading many of the comments, I just wanted to try and clear up a few of the possible issues I see with this new source of power.

Before I get into that though, I want to briefly discuss how power is produced today, since there seems to be a lot of misconceptions about how things seem to work.

Power utilities today have quite a few resources to generate power. The "base load" power that everyone seems to talk about these days comes from large generation units that maintain a continuous, rated power level 24/7. The reasons for this are usually economical, but can also be based out of safety concerns for things like nuclear power. Depending on the area, the remaining power is usually generated with generation units that are committed a few days in advance (although it is possible to get a generator started from a cold start in 1-2 hours) All generators have ramp rates (the maximum amount the power can change during a given period of time), so they are unable to change their power outputs instantly. In cases where the load demanded by the consumer starts to creep above that being generated by the power plants, peaking stations (normally natural gas based) can come online and are able to respond to the load change. Natural gas, while effective at being able to keep the power generation and load in balance, is expensive, so peaking plants normally don't operate unless power prices are high or it is necessary to use them.

If the load drops for any reason, power plants are capable of throttling down their power generation (again, subject to ramp rates) to approximately 10-20% of their rated output. Anything less than this and the unit will be forced offline (because a minimum level of stream production is necessary to turn the turbine, etc) Although this is one method of regulating power, generation units have a cost curve. The rated power is where the cost of generation is a minimum. Above and below that point, cost starts to rise, sometimes dramatically.

Alternative resources like wind are used, but not heavily due to the nature of their power production. With modern forecasting techniques, operators are able to predict fairly accurately what wind patterns will be doing 3-5 hours in advance. The major problem occurs when the wind stops blowing. Even though we know 3-5 hours in advance that we need to generate more power, it takes a lot of effort (and money) to commit a bunch of generators to make up the shortage on such short notice. Because of this, wind power tends to only make up a small percentage of total power - so only one or two generators need to come up to make up for any shortfall.

So what does this have to do with the current topic you ask? What the article seems to suggest is replacing the multitude of fossil fuel based generators with a few solar power generators. While this may look good on the surface, in reality there are many problems.

The first thing that comes to mind is reliability. People take for granted just how reliable the North American power grid is. In many countries of the world (such as India), power producers cannot meet demand and must make sacrifices to various areas (usually rural) to keep the load balanced. For most modern generators, it's not unreasonable to assume a 1-2% outage rate a year. With multiple smaller generation facilities, this isn't much of a problem, since it is easy to make up the shortage by bringing another generator online. Normally, the system has "reserve power" in the form of generators that are online but not producing power. These generators must be able to start producing power in 15 minutes or less. So, if a generator fails, another generator will be brought up in its place and within an hour should be producing the full amount of required power. In the ev