22 April 2008

Solar Thermal Kicking PV's Arse

Solar thermal energy plants have advantages over photovoltaics (PV) plants. Thermal energy is easier to store than electrical energy, for matching production to load. In addition, solar thermal is more efficient than PV. And, electricity from solar thermal plants can be produced by steam turbine driven generators, in three phase AC--just like in the most common form of electrical power systems. Eleven solar thermal companies are currently vying for desert space in the US Southwest.
California’s Mojave desert sure is getting crowded as more and more companies are raising money in an effort to build large solar power plants to harness the sun’s heat. Yesterday, eSolar said it had raised a massive $130 million from the likes of Google and Idealab for its small-scale solar thermal designs, while Stirling also said it had raised $100M from Irish renewable energy developer NTR for its SunCatcher solar thermal dishes. And this morning Infinia, which makes Stirling engines for solar thermal, said it had raised $57 million in a second round of funding. __Read more at earth2techfor information about 11 solar thermal companies
eSolar has been quite successful in raising funding, and has developed a modular design to match the power plant to the available land and required power loads.
Based on eSolar’s 33 MW pre-fab form-factor, the company’s modular design translates to minimal land requirements and are tailored to fit local resources and produce a low environmental footprint, favoring a straightforward sitting and permitting process. Various locations with multitude interconnection options mean that eSolar can deliver more clean, carbon free power where it is needed; close to the cities and towns where it is consumed.

“The eSolar power plant is based on mass manufactured components, and designed for rapid construction, uniform modularity, and unlimited scalability,” said Asif Ansari, CEO of eSolar. “Rather than over-engineering the solution, eSolar’s smart scalable solar architecture targets what we see as the four key business obstacles facing the sector: price, scalability, rapid deployment, and grid impact.”

eSolar’s approach to power plant design revolves around a tiered delivery model, beginning with a 25 MW base unit, called a module, consisting of several thermal receiver towers, each with a field of heliostats. These modules are replicated as many times as necessary to fit specific power requirements. ___ImpactLab
The rush is on to cash in on abundant solar energy in the desert regions of the US, in Spain, and soon the Persian Gulf countries. Solar thermal plants range from the 25 MW eSolar module up to 500 the MW installation being installed by Stirling Energy Systems, which can be expandable to over 850 MW eventually.

Someday, PV will be ready to compete with solar thermal. But that day will not appear within the next 15 or 20 years.

And if you need a lot of baseload energy--in the multi-GW range--nuclear is still your best bet for large scale baseload energy, other than coal.

The US is unfortunate in having what appears to be an incompetent US Congress at this time, on energy matters. The current US Congress seems determined to choke US energy sources and to create a large scale economic crisis in the US economy. I say the Congress "seems determined" to do this. If there is a better explanation for the extreme incompetence of the US Congress on energy matters, I am open to hearing it. Perhaps the Congress is simply stupid. That is possible. I prefer stupid over criminal.

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6 Comments:

Blogger Snake Oil Baron said...

I suppose that after a person or business has gotten great insulation (not just for those in cold climates) and the most efficient water heaters and appliances it might still make sense for those in laterally sprawled environments to have PVs on their roofs but the utility scale projects would seem to be better off going thermal.

As more of these projects dot desert landscapes there might be a need for water transport and conservation technologies as convenience stores and other service enterprises spring up to service the support staff. I have heard of a company that sells devices (personal or village size) which use refrigeration (solar powered) to condense water from the air - claiming that in even some fairly dry desert regions it can be a viable source of drinking water. I don't know if that idea would be economical but some sort of engineering could one day combine water management and desert reclamation techniques to create green belts throughout the arid regions of the world. The presence of energy and the people harvesting it might cause economies and ecologies to bootstrap each other. Maybe.

Wednesday, 23 April, 2008  
Blogger al fin said...

PV is fairly low voltage DC power (under 600 volts). You can easily invert DC to AC to power most appliances. So you are correct that for home-scale power, PV is great.

For large-scale power, you would have to boost the voltage into the tens or hundreds of thousands of volts for transmission--to avoid voltage drop and heavy power losses. You also want 3-phase AC for heavy industrial uses (large pump motors, industrial process motors etc.)

DC does not transform to high voltages and back down to low, so you must convert DC to AC first, then transform the voltage up or down, for transmission, distribution, or use.

You can easily make 3-phase power from DC using power electronics, but why would you bother if you can generate the 3 phase AC directly using steam turbine generators?

As for providing water in the desert, desalination from seawater and piping the freshwater inland makes the most sense to me, if you truly have an abundant solar energy supply (or a few good nukes). Of course, if some tribes or bedouins live along the pipeline who choose not to pay for the water they take, you may have pressure losses to deal with.

Wednesday, 23 April, 2008  
Blogger SensibleEnergy said...

DC can be converted low to high and vice versa using HVDC technology.

Wednesday, 23 April, 2008  
Blogger al fin said...

Yes, SE. But since you mention it, would you explain to the readers how low voltage DC is converted to high voltage DC for transmission? And how the HVDC is converted to low voltage for distribution?

You don't have to go through the entire power electronics solid state technical details, although that is interesting. Just the basics would be fine.

(You may note that I said that DC does not "transform" high to low and vice versa. I did not say that you cannot convert low voltage DC to high voltage DC for transmission.)

Wednesday, 23 April, 2008  
Blogger SensibleEnergy said...

Yes, of course you're right Al. I should know by now never to doubt you. I was just confused by the third paragraph. I had forgotten you made that HVDC post.

Wednesday, 23 April, 2008  
Blogger al fin said...

To tell you the truth, SE, I want people to contradict what I say. That's one of the best ways for me to learn something new.

I try to be careful when I post both articles and comments, but my lifestyle does not always allow the time or the sleep conducive to uniformly careful posting.

So, if you knock me down, I'll get up, dust myself off, try to learn something from the experience, and go on.
;-)

Wednesday, 23 April, 2008  

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