A Road Map to the Decarbonization of the U.S. Energy Mix.

[jpak]

edit: this is a paper presented at the AAAS meeting last February. It was also published in this week's issue of the journal Science.

http://72.14.209.104/search?q=cache:XFBz-T3Wvc8J:www.nrel.gov/ncpv/thin_film/docs/decarbonization-02-24-06.doc+A+Road+Map+to+U.S.+Decarbonization+Reuel+Shinnar+and+Francesco+Citro&hl=en&gl=us&ct=clnk&cd=3

There's a PDF available too (google up the title).

A Road Map to the Decarbonization of the U.S. Energy Mix.

The Potential Impact of Solar Thermal Energy

Reuel Shinnar*, Francesco Citro

Today, 85% of the energy used in the U.S. comes from carbon-rich fossil fuels: oil, natural gas and coal (1). But, the demand throughout the world is increasing and there is little doubt that proven resources of oil and natural gas will peak in the next twenty to fifty years. It is not surprising that many leaders in Government and technology are calling for their replacement by alternative energy sources. Additional motivation for the decarbonization of the U.S. energy mix is the danger of global warming, which many attribute to the CO2 emissions that accompany the use of fossil fuels.

Any switch to alternative energy to be doable and affordable has to be done over a long period, at least 30 to 50 years. It is hardly too soon to develop a blueprint and timetable for achieving this goal.

In this paper we present a plan for the gradual replacement of 98% of our total fossil fuel needs with available and affordable technology (which would also reduce 97% of present total CO2 emissions). We show that the direct use of electricity produced from alternative sources can replace 72% of the fossil fuel we consume. Another 26% can be replaced by hydrocarbons produced from syngas, a mixture of carbon oxides produced by gasifying biomass and hydrogen generated by electrolysis powered by alternative energy sources. 50% of this goal could be achieved over thirty years, and 80-90% over about 50 years. We have limited the scope of this paper to a discussion of our technological options. A comprehensive plan would also focus on other critical problems such as priorities and costs, political and economic constraints, regulatory issues and government-mandated incentives without which the free market is not likely to reduce CO2 emissions or prepare for a distant, uncertain future. However, for society the penalty of strongly reduced oil and gas supplies would be catastrophic, unless we prepare in advance, as the timescale for achieving a substantial reduction is very large. Such a plan must be based on existing technologies, or at least on technologies that are available in a form which can be scaled up and implemented at a cost that can be estimated reliably. While research could and should lead to better technologies, and should be continued, we can never be sure which research will lead to useful results. In the 1970s, a worldwide research effort to produce H2 from nuclear reactors by thermochemical cycles was terminated with no results after approximately 40 billion (2005 dollars) dollars were spent (2). Further constraint on any such a plan is that the new technology should allow gradual phase in and preferably should use available distribution systems, which suggests wide use of electricity from alternative sources.

It is encouraging that proven technologies for decarbonizing our energy mix that use existing distribution systems already exist. The approach described in this paper is to a large part based on electricity from alternative sources, and the prime candidate is solar thermal energy with storage. Plants with 354 MWe installed capacity have been operating in California since the late 1980’s (3). This technology has been overlooked until now despite the fact that it probably has a larger potential than all other options. Our paper will compare its capabilities and costs with other available options. Before costs are taken into consideration, however, it must be acknowledged that technologies that achieve decarbonization by replacing power plants and other existing uses of fossil fuels cannot be competitive in the free market without some form of government incentive or subsidy. The only time when this is possible without incentives is either when the equipment becomes obsolete or the technology is no longer competitive or the fossil fuels costs become too expensive. We will show, however, that for new installations with specific applications a variety of alternative technologies are already competitive. Of these, solar thermal energy has applications on the broadest scale.

<much much more>

[Viking12]

1. Here's an important related article.

Solar Thermal Energy: The Forgotten Energy Source

http://www1.ccny.cuny.edu/ci/cleanfuels/upload/Solar%20Thermal%20Energy-10-20-05.pdf

[jpak]

2. Thanks - cool paper

They talk about how Luz got screwed by the CA tax code - just like wind power pioneer Kenetech.

IIRC it was California Republicans pulled the plug on these two companies...

[phantom power]

3. Unless oil and gas peak in the next 20-50 *months* ...

Which seems more realistic, if also more gloomy.

[hunter]

4. It's all well and good...

... unless you are part of the finely tuned ecology getting bulldozed to build these blights.

Where there is water -- monocultural biomass. Where there is no water, solar thermal plants.

Gee, the future's so bright, I gotta wear shades!

I am certain that in terms of environmental damage, nuclear power would be a much better choice. Even a nuclear accident of the worst sort would do far less damage to the desert environment than these solar thermal plants do in their normal operation. To the extent that radioactive toxins excluded humans from the area, a nuclear accident might actually protect the natural environments of the desert. If you look at ariel photos of Hanford Washington those places where human beings are mostly excluded still exist in a somewhat natural state. Outside the "nuclear reservation," the natural environment has been utterly destroyed by agriculture.

Personally I think it is unwise and unethical to look at the deserts (or anything else) as simple "resources." As human beings that's how we always get into these messes -- rather than figuring out how we might better fit into the natural environment, we grab "natural" resources, and celebrate when we find and develop new ones. Solar-thermal will bring us new problems, just as the utilization of every other natural resource has. Clearly, one of these problems is the further destruction of desert environments.

Yet the consequences of burning fossil fuels might be even worse for the environment... widespread droughts, melting ice, rising sea levels are devastating to many natural environments worldwide, so maybe these plants are not so bad, at least to the extent they displace fossil fuels.

[Dead_Parrot]

5. Are there any particular porblems with solar thermal?

You'd need to give to give up a chunk of land for it, but we're going to have to get used to that anyway, I suspect. I was under the impression it was fairly "clean", as power generation goes...

[skids]

6. As long as it's a closed system, no.

All thermoelectrics have the associated problem of needing water supply if they are not an air-cooled closed system. And there was that cooling tower microbe issue posted last week. That problem is the same as for fossil and nuclear, though.

There's an environmental footprint associated with building anything in thematerials and construction costs, but again that applies to everything.

[hunter]

7. I suspect the "environmental footprint" for nuclear is much smaller.

All in all, and including mining and waste disposal.

The greatest advantage of solar thermal is that it's not nuclear, and this is entirely a matter of politics and public perceptions.

There's a nice picture of the Palo Verde Nuclear Power station here:

http://www.pbase.com/qleap/image/15808186

A solar thermal power plant of similar capacity would be considerably larger.

[skids]

8. Well, let's see about that...

The Palo Verde plant is 4000 acres, or about 16 million square meters.

When all the reactors are in working condition, it generates 3800 Megawatts.

So let's say about 1 acre per megawatt.

Nevada Solar One will be 400 Acres at 64MW, and let's assume 0.15 capacity loading, or 40 acres per megawatt. A factor of 40 in land use really isn't that awful.

Coincidentally, there are about 3 million acres of brownfields in the U.S. -- areas of land that have to be cleaned of toxins before they can be used, and are pretty much devoid of all but a few sick and dying weeds. Much of this cleanup is being left up to gradual recovery over time by natural processes. Good news -- you don't have to clean the toxins to put solar thermal plants on them, since you really don't have to do much of anything but put in a few post-holes.

At 40 acres per megawatt, solar could just about equal the current contribution of nuclear power using only brownfields.

[hunter]

9. They generally won't be built on "brownfields."

Nevada Solar One isn't. But we almost certainly need these solar plants simply as a matter of national security. I don't think we can count on natural gas imports as our foreign policy goes all to hell. We should probably be building these and nuclear power plants and some high capacity east-west HVDC lines if we expect to have any kind of soft landing as oil and natural gas prices increase.

What I really don't want to see is more coal development. That has been a far greater disaster. If you've ever been out to any of the big western coal developments, you know what I mean.



I am starting to miss the deserts of my youth, probably much the same way a lot of people felt as the prairies were plowed under.

[Dead_Parrot]

10. Well, here's a thought...

looking at the pic you posted up-tread, a lot of the Palo Verde site is, err, dirt :). If we say 2000 acres of it is free, that would allow (based on Solar One) an aditional 320MW of peak solar to go on the same site: The engineers and the grid are already there, no one loses any desert wilderness, and the output is a bit more responsive to the 24-hour cycle...

[4dsc]

11. Sadly we are not preparing for a future

with less energy as its business as usual in the good ole USA!!

Nice article but too bad most American's and Du'er don't believe we have a problem. that makes our weekend trips to the mall more guilt free.. Let's all drive, shop, and waste this weekend..