Wednesday, December 3, 2008

Solar Thermal Power

This is a good survey article on solar energy with lot of handy links.

Direct solar conversion to electricity has been getting all the recent attention, but it must be said that converging solar energy into usable heat is also a good working strategy that is very easy to integrate into the power grid. Some of the systems are now very attractive.

Converting solar energy into a hot working fluid is then easily converted into grid power with conventional power equipment. I assume that the working fluid is water and that during the daytime operations can produce a large inventory of high grade steam that can be stored into the night. An additional energy source during the night is to take the spent steam and use it to drive a reverse Rankin cycle generator that drops the spent water from boiling temperature to the ambient nighttime temperature and produces seventy five percent brake horsepower.

Cheap solar cells are very good for static applications not needing high voltages. That means that it works well for buildings and the Eden machines. Not so well if you need a source of high power and you do not want to tie up a farm next door.

Giant solar collector fields can be built out in the desert and the energy easily converted into high voltage grid power for industrial use. The possibility of using spent water at night to provide a base load during the off peak period is actually attractive.

Posted in earth 4 energy by: stevaxx
November 30th, 2008

According to this link Europe uses 4,000 terawatts of energy but in the normally unusable deserts of North Africa and the Middle East 630,000 terawatts fall unused. If solar thermal plants covered the desert about the size of Austria it could power the whole entire world. The technology is cheap and includes an ability to store the energy for nighttime needs. If all this is possible why on Earth are we not employing this clean, cheap, abundent source of energy?

Solar thermal could do just that at affordable costs. Solar thermal can now produce electricity at as low as 8 cents a watt, and that would be improved by the economy of scale of mass production of the solar plant components.

1% of the Sahara desert could power the whole world.

1% of the deserts in the American southwest could power the whole country.

And solar photovoltaic efficiencey is not stuck at 10% as someone answered. It is closer to 20%.

And that efficiency is rapidly improving and the cost of making solar panels is falling just as rapidly.
Solar panel industry experts say they are just a few years away from being at grid parity with coal and gas power plants.

In fact, Nanosolar is already there, being able to produce solar panel complete systems for less money than it takes to build a coal power plant.

And then there is the cost of the coal and the pollution from it.

"Nanosolar’s founder and chief executive, Martin Roscheisen, claims to be the first solar panel manufacturer to be able to profitably sell solar panels for less than $1 a watt. That is the price at which solar energy becomes less expensive than coal.With a $1-per-watt panel,” he said, “it is possible to build $2-per-watt systems.

According to the Energy Department, building a new coal plant costs about $2.1 a watt, plus the cost of fuel and emissions, he said."

Concentrating solar photovoltaic power plants and solar thermal power plants in the southwest should be a large part of our future energy system.

Scientific American A Solar Grand Plan

Shows how we could have 69% solar power in the U.S, by 2050, spending less in taxpayer dollars than we spent building the internet and high speed information highway, and in about the same 35 year time frame.

And by spending about 1/8 as much annually over those years as we now give oil companies in subsidies.

Some solar thermal companies.

"I'd put my money on the sun & solar energy. What a source of power! I hope we don't have to wait until oil and coal run out before we tackle that." Thomas Edison, 1931

Solar thermal plants can store heat, which will generate steam driven electricity at night.

"Solar thermal power plants such as Ausra's generate electricity by driving steam turbines with sunshine. Ausra's solar concentrators boil water with focused sunlight, and produce electricity at prices directly competitive with gas- and coal-fired electric power."

"All of America's needs for electric power – the entire US grid, night and day – can be generated with Ausra's current technology using a square parcel of land 92 miles on a side. For comparison, this is less than 1% of America's deserts, less land than currently in use in the U.S. for coal mines."

Some of the arguments against wind and solar just don't make sense, like the argument that they are too intermittent, or not constant.

"There are areas in Denmark and Germany who use more than 40 percent of their electricity from wind. From what I have read, they are less concerned about the intermittency than we are in the United States even though we aren't at 1 pecent yet. Why? Because we are told by the fossil fuel guys, hey, can't use wind, can't use solar, what about the intermittency. If wind gets up to 40 percent of the electricity we use and solar gets up to 40 of the electricity we use, the other percents of electricity we need can be made up from the fossil fuel plants that are still there. If they are run less at full power, they can last a long time. That can be your electricity `battery.'"

"Using mirrors to focus the sun's heat on one of any various heat-to-electricity converters seems to have separated itself out as being the cheapest form of solar power."

"Solar energy is the great leveler (unlike oil, which has been the great divider) between the haves and the have nots). No one owns the sun. It can't be drilled or mined or tied up in financial derivatives."

(See Here Comes the Sun, February 17, 2007, Commentary,

Green Wombat has several articles about solar thermal plants in California and Arizona. California has 9 small pilot plants that were built in the 80s and 90s. They produce 355 megawatts. Two larger plants have been approved for the Mojave Desert at 355 and 500 megawatts. Another is to be built near San Luis Obispo at 175 megawatts. Two or three others are in proposal stage, at up to 800 and 900 megawatts, for two of them.

from the Scientific American article:

"The greatest obstacle to implementing a renewable U.S. energy system is not technology or money, however. It is the lack of public awareness that solar power is a practical alternative—and one that can fuel transportation as well. Forward-looking thinkers should try to inspire U.S. citizens, and their political and scientific leaders, about solar power’s incredible potential. Once Americans realize that potential, we believe the desire for energy self-sufficiency and the need to reduce carbon dioxide emissions will prompt them to adopt a national solar plan"

"The huge reduction in imported oil would lower trade balance payments by $300 billion a year, assuming a crude oil price of $60 a barrel (average prices were higher in 2007). "

Together with Wind and other renewable, we can go to clean energy, while ultimately improving our economy as well.

A Blueprint For U.S. Energy Security

From the SetAmerican free document above.

The total of all oil-related external or “hidden” costs of $825 billion per year. Thistotal is nearly twice the figure authorized for the Department of Defense in 2006.To put the figure in further perspective, it is equivalent to adding $8.35 to the priceof a gallon of gasoline refined from Persian Gulf oil. This would raise that figure to$10.73, making the cost of filling the gasoline tank of a sedan $214.60, and of anSUV $321.90.

And then there's the $300 billion oil adds to our trade imbalance annually.

You think that makes for a good economy?

There is an unbelievable amount of disinformation about the potential of renewable energy.

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