Not so Green Solar Energy

You think solar electrical generation is going to save you or the Planet? Think again.

While it is true that photovoltaic solar panels do not pollute while they are producing electricity -- what about the manufacturing process? What happens when these panels reach the end of their projected lifecycle in twenty-five years? (This is, by the way, an optimistic view of their useful life.)

Those questions are addressed in a study by the watchdog group Silicon Valley Toxics Coalition.

"Green Power" is being hyped as the "Safe Solution." It is anything but safe -- when all factors are considered.

Here is a partial list (eight of fifty) of chemicals associated with solar photovoltaic (PV) manufacturing and disposal:

Someting that I have always wondered about solar panel arrays- they are just as land intensive as say, a strip mine.

Wind, solar, and even hydro power is most likely more land intensive than coal and nuclear.

A strip mine can be reclaimed.

Ash landfill space can be reclaimed.

Millions and millions of acres devoted to windfarms and solar panels will be permanently used for that purpose. Add in ALL the extra wires that will occupy space and I believe you have more land per MW capacity used than conventional and nuclear.

The truth is, the true green movement doesn't even want us to use wind and solar. It's an issue they use to get us to commit energy suicide and shut down coal, oil, and nuclear power. They lie and tell us "renewables" have to be rushed into service, we need to shut down the conventional power sources, and conserve for the "energy gap" (which is HUGE). Once that is done, they will shut off the wind/solar energy too. They want humans to just go away.

Tower-based solar thermal with huge underground thermal storage reservoirs to level load a secondary working-fluid system for actual power generation makes a lot of sense for electric generation.

Locate it in vast areas of the desert southwest, and couple it with a new advanced high voltage direct current backbone across the continent to move the electricity across the country and into the existing AC grids.

Call it a 20 year project and this is a workable technology.

I am in the oil industry, and the only long-term substitutes for liquid hydrocarbons (most likely bio-engineered algaes) will take time also to come into place.

Fortunately there are actually huge amounts of oil and natural gas still in place, and accessible at rational prices that the economy can afford. Land and offshore drilling technology has been developed to the point that aversion to drilling has no truly substantive / fact-based underpinnings or justification. It is all emotion/”taste” driven (nimby bs). These are still factors - not adult ones, but childish ones.

So we have time for a 30-50 year transition for much electric generation and alternative liquid fuel technology to be developed.

Then we are talking about energy sufficient for a robust economy virtually without limits - plenty to get us to the next unstoppable nature-driven ice-age, Yellowstone-caldera eruption, or NEO asteroid or Oort-cloud comet impact - when all bets are then off.

Maybe we can get a colony with long-term viability on Mars before then, as a back-up plan.

It may be workable but it does not sound economically viable. I am not sure about the cost of the solar thermal systems themselves but the DC backbone will be cost prohibitive unless cost is no object. We will have dramatically higher electricity rates if that backbone is constructed. In addition, their is no nation wide grid. There will be a huge cost to expand the electric grid across the country. Have you objectively looked at the economics of your proposal?

OK - some calculations

US electric generation 2006 was about 4 terawatt-hrs. (70% of this is hydrocarbon based.) Lets say we want to convert 2 terawatt-hrs of this to be solar thermal. On a daily basis this means we need to generate 5.48 gigawatt-hrs per day.

Arizona averages 6 kwh/day per m^2. (Peak rate is 1 kw-hr/hr).

AT 66% actually captured = 4 kw-hr/day/m^2 - this means 1.37 billion m^2. At 1,000,000 m^2/km^2 = 1,370 km^2. Also Phoenix averages 300 sunny days per year. Factoring this in means we need 1,667 km^2.

Let's say net conversion efficiency given thermal storage - working fluid system - actual generation - etc. is 25% = 4X = 6,668 km^2 actual footprint (81.66 km sq)(50.75 mile square = 2575 sq.mi.)

Discount for actual physical layout (roads - infrastructure - greenspace (desertspace)) that we actual use 3x land needed = 20,000 km^2.

THIS MEANS that our “solar district” can be a single square land parcel of 141.42 km on a side (87.87 miles on a side - call it 88 miles or 7,744 sq.mi.).

Arizona is 114,000 sq miles, so we are talking about using only 6.8% of Arizona's land area for this program... and this from the hot deserty parts not otherwise heavily used. Arizona is 82% owned by governmental agencies and Indian reservations - only 18% of Arizona is owned in the “normal” way by private entities.

Also, there are plenty of agricultural areas of much greater physical extent than this, where almost nothing but a single “crop” - corn or wheat or cotton or etc. - is raised and almost all land is given to this crop.

Or 77 distributed 10-mile-square (100 square mile) solar farms scattered across the desert southwest.

Molten-salt storage can hold 1 weeks worth of thermal energy. A small number of times a year certain areas might go more than 1 week with cloudy skies (65 days a year total in Phoenix as noted above). One could consider having secondary heating with natural gas to maintain the molten salt reservoir temperature as a backup on those few instances of long periods of cloudiness that might occur.

We are talking a lot of money for infrastructure build.

But thereafter we are talking 2 terawatt/hrs each year of electricity for maintenance costs. Using heat that otherwise would just make the sand hot during the day and then would be lost at night.

NOW we are talking about building almost 11 square miles of actual facility per month to do this as a twenty-year project once POC and clearances are obtained. SO maybe this is a 30 or 40 year project...

BUT it is still something that is doable.

IMHO

Well here is the deal...

Firstly, we are going to be building new electrical infrastructure to convert energy use to renewable, as a matter of public policy.

Secondly - A DC backbone with spurs to tie to the existing grid would only be a fraction of the length of all high-tension transmission lines already in place. Some of them are actually convertable from hi-voltage AC to HVDC and would not need complete new construction. If we could afford to build what is already there over the years, we can afford to add another 15% or maybe less (note that HVDC has much lower loss of power - 3% vs 8% for existing power transmission).

Finally, yes is is not economically viable at 6 cents per kh-hr. BUT as an identified national priority for energy independence and solar-based renewable energy source, over a 20 or 30 year program life, it is actually no big deal.

The National Renewable Energy Lab of the DOE is actually looking at aspects of electical infrastructure build-out as a fifty-year infrastructure program.

http://www.nrel.gov/analysis/analysis_tools_tech_infra.html

http://www.netl.doe.gov/moderngrid/

http://www.theoildrum.com/node/4918

We have to do something to modernize and redesign the grid. Combining this solar thermal concept with a new grid design and backbone, gets us to a good place by the time our grand-kids will need it.

And is probably a better place to spend money than some of the places the most recent trillion dollars got spent by the government... < grin >

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