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What’s at Stake for Solar in the Desert?

December 22, 2009

Senator Feinstein has expressed what a lot of people feel by making an effort to introduce a bill to protect a large area of the US Southwest from solar development (http://s.nyt.com/u/vqR and http://www.renewablesbiz.com/article/09/12/worlds-largest-solar-project-prompts-environmental-debate). There is also some indication that she is being sensitive to the need for solar development by indicating support for solar installations elsewhere, including in pre-arranged solar energy zones. It is quite possible that this represents a balanced, even productive approach to solar in the US Southwest. After all, we are talking about a major paradigm shift in how energy is made, so it’s not surprising that new laws are needed.

It’s important to be clear about why solar needs the desert lands. After all, one viewpoint is that there are plenty of roofs and otherwise disturbed land, so why bother with the desert?

For one kind of solar, based on using concentrated sunlight to boil water to make electricity, the desert is the only place cloudless enough for it to work. This is the kind of technology represented by BrightSource and the like (http://www.renewablesbiz.com/article/09/12/california-labor-unions-and-bechtel-construction-company-reach-agreement-build-solar-thermal-facility-0).

For photovoltaics (PV), which can work almost anywhere, the answer is lower cost in the desert:

1.  Solar electric prices are inversely proportional to sunlight. The more the sunlight, the more the output, and the lower the solar electric price, plain and simple. The US Southwest has about 50% more sunlight than most of the rest of the country, and that means that prices of solar electricity are 50% higher outside the Southwest. If solar electricity is 12 c/kWh in Arizona, it will be 18 c/kWh in Washington, DC, or New York City.

2.  Large systems are cheaper than small systems. Right now, residential systems are about 40% more expensive than larger, commercial rooftop systems; and those are another 25% more expensive than big (multi-MW) systems on the ground.

If you combine these two factors, you can get a factor of at least three between the price of solar electricity for a large system in the desert and a small system in the mid-Atlantic, and worse in really bad solar locations like off Lake Erie or near Seattle. So if PV electricity were to cost 12 c/kWh for a large system in Arizona or California, it might be 36 c/kWh on a house in DC, and 50 c/kWh on a house in Seattle.

In the future, we might expect the range between small and large systems to narrow as the markets mature, but we will likely always see at least a 10% difference between systems in the 1-10 kW range and those above 100 kW; and another similar gap from there to multi-MW systems. This means at least a factor of two between the desert and the majority of systems outside the desert, where sunlight is lower and system sizes more limited.

There are other factors that make this a bit more complex, but do not change the basic picture. Solar from the desert has to be transmitted elsewhere, adding cost. But it is also more dependable than solar in cloudier climates. The use of a smart grid will facilitate integrating either kind of solar, but each with a different set of components and costs.

It is important to note that once strip mining is included, solar uses no more land than coal mining. Solar is about 30 times less land intensive than hydroelectricity (where about 1% of US land is behind dams as artificial lakes), and about 50-100 times less than biomass production. It is our perception and our local preferences that drive these solar land conflicts, not national priorities about land use. Only wind uses land less intensively than solar per kWh.

It is clear that the resistance to large solar installations will be ubiquitous. It will be as bad or worse outside the sunny regions. No one is going to accept cutting down trees to build solar. Everyone will want it put only on roofs and parking lots and similar, and some will resist even that. We cannot solve global commons problems with local preferences.

Solar cannot afford the extra costs. What some may perceive as a small added permitting cost may in fact be fatal to large-scale solar development in the US, and this may already be showing up in cancellations (http://www.nytimes.com/external/venturebeat/2009/12/22/22venturebeat-new-report-is-first-solar-all-hat-no-cattle-55429.html). Solar may use no fuel, but it is only on during the day. Baseload plants are on 90% of the time. Thus, solar cannot defray added one-of-a-kind costs (like permitting and NIMBY delays) as easily as coal or nuclear can. It does not have as many annual kilowatt-hours to offset them with. Solar’s costs per kWh rise about four times faster for each dollar of initial cost.

We must not forget that what we don’t do in our back yard must be done in someone else’s. If we don’t have solar because we drive up its costs by segregating it from sunny regions, we will have coal, carbon dioxide, mountain top removal, and numerous health hazards. As a nation, we must decide. We have learned enough to know that if we are to have economic strength and avoid foreign energy dependence, we have to have something productive in our own backyards.

The combination of our preferences on cost, economic sustainability, and environmental protection will lead to the amount and mix of solar in the Southwest and elsewhere. But let us hope it is done at a national level and not haphazardly, based on local interests alone. For private lands, providing expedited environmental clearance, helping locals understand the value of their sacrifice for accepting big systems nearby, minimizing the impact of such big systems via prequalified acceptances (e.g., the BrightSource use of air instead of water cooling); and for public lands, similar rapid clearance and designated solar zones would go a long way towards balancing national (global) priorities with local ones.

Ken Zweibel

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2 Comments leave one →
  1. Ray Marshall permalink
    December 24, 2009 2:16 pm

    What seems to be missing in the solar PV message is that it equates to renewable energy, clean air, AND water conservation. Water conservation is especially critical in the Southwest states.

  2. joe1347 permalink
    January 1, 2010 3:34 pm

    Ken,

    Are you surprised that our Politicians don’t care about Solar? Why should they. There isn’t a well connected and well funded lobby to support solar energy – unlike you know what. The politically popular trend seems to be towards “make believe” carbon sequestration to keep the coal state senators happy. Sure solar will likely get a few million in tax breaks if any climate change legislation does pass, but it certainly looks like the mega billions will go to coal (for carbon sequestration projects). Granted carbon sequestration may not work and could result in a CO2 asphyxiation threat (for centuries) for anybody that lives near CO2 sequestration sites. The documentary ‘Heat’ on PBS’s Frontline was very illuminating on limitations associated with CO2 sequestration.

    http://www.pbs.org/wgbh/pages/frontline/heat/

    But, providing billions to coal seems to be the only way to pass any type of climate change legislation. So for now, our political leadership seems uninterested in solar and even surprisingly adversarial – given Senator Feinstein’s actions.

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