Killing the Holy Cows of Renewable Energy

"the blame [for bad movies and poorly performing sports teams] can be laid at the feet of the people of South Asia, whose tolerance of mediocrity knows no bounds." - Chan Akya

"Leadership is not just charisma or showmanship. It means consistency, being forthright, having no tolerance for mediocrity, and not compromising integrity." - Rahul Bajaj

Chan Akya an Indian writer pointed out the consequences of a lack of critical standards. If people are tolerant of mediocrity, mediocrity is what they will get. When I began to read discussions of renewable energy sources as couple of years ago, I noticed that these discussions invariably left important questions unanswered. Pro-renewable environmentalists like David Roberts basically wrote public relations copy for the renewables industries. Needless to say they left many questions unanswered. I started to look for answers, and the answers I found, the things that Robers, Romm and others were trying to sweep under the rug, were disturbing.

The basic question with renewables is how much is is it going to cost. Other questions include where is the power going to come from if the wind does not blow and the sun goes down. Renewables advocates seldom provide satisfactory answers to these questions. Indeed they seemed to sweep these very real questions under the rug. Or offer answer that said in effect, "Don't worry, every thing will turn out oK." Eventually I began to find answers that were less comforting. For example, I discovered the question of summer wind. At first I found a reference to the problem in California, then New England. Senator Lemar Alexander was upset because wind generators only provide electricity 7% of the time during August in Tennessee. Texas has a summer wind problem too, including windy Amarillo, and so do the Northern Great Planes and Ontario. Nowhere in North America seemed safe from the summer wind scourge.

So there was a wind reliability problem even when during the summer. There are other issues. The cost of windmills has been going up. Yet none of the windbags seemed to be talking about that, There is a disconect, because the cost of reactors have been going up and all of the windbags seem to be talking about that.

We have similar issues with solar. While solar generators have the potential of generating electricity for up to 8 hours a day, But depending on where you live, and that includes 75% of the United States, it could be 5 to 6 hours a day. So what do you do for electricity for the other 18 to 19 hours a day. Solar advocates will talk about various storage schemes, none of which have been demonstrated to be practical and cost effective on a massive scale. When I examined the costs of storage schemes such as giant batteries, and pump storage facilities, they turn out to be as least as expensive as nuclear plants. Why build storage facilities that do not produce electricity when for the same amount of money you can build a nuclear plant that does produce electricity?

I have been posting recently on the cost of solar power. I have not based those cost estimates on information found in glossy handouts written by PR people, but on information from people who are actually building or paying for solar generating facilities. i am not trying to make the solar industry look bad. I am not cherry picking data. The information I have found, does not look as good as the information from the glossy handouts.

Tuesday I wrote about the costs of BrightSource solar facilities:
"A further consideration would be that BrightSources own estimated cost estimates falls within the cost range of current cost estimates for nuclear power plants costs. For the basically the same price as a 1 GW BrightSource generating facility PG&E could buy a 1 GW reactor that would generate power day and night, rain or shine with 3 times the daily electrical output of the BrightSource facility."

No one has disputed my calculations or conclusions. Yet in a comment posted on "Energy from Thorium", sam j demanded to know, "Why denigrate renewables?" Sam followed, of course, with the tired anti-nuclear line that we are running out of uranium and there is of course no other possible reactor fuel - I wonder what he thinks the "Energy from Thorium" title is about. Sam appears to believe that the problems of Renewables should be swept under the rug.

Jesse Ausubel has raised questions about the land use requirements of renewables. (Also see here, here, here, here Ausubel is a conservationist in the traditional sense, but not a green, and not a Amory Lovins clone. (also see here)  Jesse Ausubel is the Director of Rockefeller University's human environment program.  He looked at how much energy a given unit of land produced through different technologies.  His conclusion was that hydroelectric power made the least efficient use of land.  

Ausubel argued if the entire provence of Ontario Canada was surrounded by a 60 foot high dam, and the water behind the dam were used to produce electricity, the amount of electricity generated would only equal 80% of the electricity generated by Canada's nuclear 25 power plants.  

If American energy needs were meet by wind power, Ausubel argued that an area the size of Texas, would need to be covered with windmills.

To power New York City by electricity from solar cells, an area the size of the entire state of Connecticut would have to be covered by the solar array. 

Ausubel has argued that:

* renewables are not green
* nuclear is green

Needless to say, Ausubel's argument has driven the supposedly pro-environmental, anti-nuclear greens crazy, and no one went crazier than Joe Romm.  

Romm seems willing to sacrifice every tree in the forrest, if it means that we don't rely on nuclear power.    In his attack on Ausubel, Romm engaging in spin doctoring, worthy of an Exxon employed climate change skeptic. He accuses Ausubel on not mentioning climate change in a speech he gave in which he sumerized his findings. He accuses Ausubel of thinking that "if decarbonization is all but inevitable, then global warming will mostly take care of itself. He doesn't come out and say this, but his talk never discusses the threat of climate change, which is much more likely to rape nature than renewables."

Say what?

If we decarbonize society, that is we stop using carbon based fuels. then we stop adding greenhouse gases to the atmosphere. Once this happens the processes that lead to anthropogenic global warming are interrupted, and eventually the climate change will no longer be driven by increasing levels of greenhous gases. So it would seem that there is no problem with this assumption. It is tasit in Ausubel's thinking. Ausubel is addressing the issue of how much land would be required to impliment various post-carbon energy schemes. We understand the reasons for wanting to do this. Romm is not pushing a weak case against Ausubel. He has no case at all, and simply substitutes words for statements containing substance.

Romm quibbles about land requirements for various renewable options. He argues, for example, that Windmills only occupie 5% of the land on which they are placed. The other 95%, the rest of the land could have alternative uses, Rumm argues. The issue is not just the question of competing land use, each installed wind generator must be connected by a service road and a power line. Thus an area larger than Texas must be densely packed with wind generating towers, service roads and electrical lines. This would represent an enormous investment for what is at best intermittant electrical service. But for windmills, roads and electrical lines, vegitation must be cut back, and maintance must be given, The impact on the environment will be considerable, and as yet largely unacknowledged by Greens like Romm. 

Renewable Energy: Wasted Days and Empty Nights

One of the I had to learn when I began to read discussions of renewable sources of electricity is the vocabulary of power. Generators of electricity can be divided into three different types. There are base power generators, these are the units that can be counted on to generate electricity, all the time, except during periods of maintance. A base power unit can be counted on to generate electricity 60% to 95% of the time. Examples of base electrical generators include coal and natural gase fired electrical generating plants, nuclear power plants, geothermal power plants, hydroelectric power generators.

Peak power generators represent a second class of generators. Peak power generators can provide electricity when demand is high. Usually peak demand is during the day time, when stores, offices and factories are using electrical energy for their operation. In the North peak demand may occure on winter nights, when cold waves drive demand for electrical heating. The popularity of lighted Christmas displays is another source of winter night time peak demand. In the South peak demand is associated with summer use of air conditing. Although the absolute peaks of air conditioning driven summer demand are in day time, the air may remain hot at night, bringing about elevated demand for electricity after dark. Sources of peak demand electricity may include pump storage facilities, as well as reserve conventional electrical generators.

Supplemental power is a third category of electrical generator. Supplemental power cannot be counted on to be avaliable on demand. Some renewable sources of energy like wind powered generators cannot be counted on on to provide electricity on demand. Wind power is avaliable when the wind is blowing. Other supplemental generators, for example solar voltaic panels, are only avaliable at spacific times of the day. Since the "fuel" for wind generation is free, and they do not generate greenhouse gases, the use of supplemental renewable power sources, may be desirable to replace base power when the supplementals electricity is avaliable.

Electricity from variable renewable energy sources has to be ballanced, Electrical demand stays constant whether the sun is shining or behind a cloud. For a simple solar or wind generating system a battery might do. Feed the electricity into the battery and then draw it out when you need powet. pump storage facilities are sort of super batteries. You can pump water up a mouintain when the sun is shining, or the wind is blowing, and then let it flow down the mountain through a generating turbine, when consumers want electricity. A more common way to ballance variable renewable power is by using power from a generating source that can quickly be drawn on as the wind drops, or clouds cover the sun. Denmark draws on electricity generated at Norwegian dams to ballance its wind generated electricity.

Electrical generation has to be able to come on line quickly in order to ballance the variations of wind generated electricity. If you have access to hydroelectric power and plenty of water, that will do fine. but California does not have enough hydroelectrical power to ballance its wind generators. Balancing power usually come then from convintional fossil fuel powered electrical generators. These are called back up generators. In order to be able to supply power quickly, the back up fossil fuel generators must be kept running all the time. Power companies call running back up generators "spinning" them. Of course when you run a back up generator, when you spin it, you are burning fossel fuel, and you are producing geenhouse gas.

Opperating an electrical system that draws on wind generated electricity or solar pannel generation, requires generating back ups. This is called redundancy. How much redundancy do you need? That depends on how much electricity you are trying to get from your vaiable renewables. If you are just operating a few wind generators, you may need quite a lot. If you have a lot of wind, wind generators will produce a lot of electricity. Wind generators are rated by the mazimim amount of power they can generate on a very windy day. Unfortunately in most places the wind rarely blows that hard. In a light brieze, your wind generator may only produce 20% of its rated power. If you are commited to produce a certain percentage of your electricity by wind generation that may mean that you want to buy more wind generators to back up your generating capasity. Five wind generators operating in a light breeze will supply the same amout of power as one generator operating in a heavy wind. If you have light breezes 25% of the time, then you may need to buy five wind generators in order to provide the amount of wind generated electricity you want.

Now suppose no wind at all blows 25% of the time. How many wind generators do you need? Well no number of wind generators will get you what you need. So you will need 100% of your electricity from back up generators. How often do you need back up generators? How often have you been out in the wind, and saw a hard wind turn into a breeze, or even simply die away to nothing? You basically have to keep 100% of your back up capacity spinning all the time with wind. In desert environments the sun shines almost all the time, clouds are fairly predictable.

There is usually some warning if the sky is going to cloud over. So spinning back up is not nearly as critical with Solar power as it is with wind. You still need back up capacity with solar, and you need variable online power for ballancing, even if there are only a few clouds in the sky.

There sunlight is much more tricky than you might imagine. The problem of SV intermittency is discussed in "The Character of Power Output from Utility-Scale Photovoltaic Systems," by Aimee E. Curtright and Jay Apt, (Carnegie Mellon Electricity Industry Center Working Paper CEIC-07-05: http://wpweb2.tepper.cmu.edu/ceic/papers/ceic-07-05.asp). The paper is unfortunately password protected.

A quote from Curtright and Apt,
"The intermittency of large-scale PV power for four sites in the American southwest desert is significant, even during daylight hours. These data also imply that site diversity over a ~280 km range does not dampen PV intermittency sufficiently to eliminate the need for substantial firm power or dispatchable demand response. The high correlation between geographically dispersed arrays may indicate that high, widespread clouds are responsible for a portion of the intermittency. Observed rapid and deep fluctuations at time scales of 10 seconds to several minutes may indicate that a component of the intermittency is due to low, scattered clouds with significant opacity. We observe a number of examples of output power rising above nameplate capacity before and after deep drops in power. This may be due to focusing of sunlight around the edges of low clouds."

If the problem exists in the relatively cloudless southwest, how much worse is it going to be in the South East, when there can be a lot of clouds in the sky on "sunny" summer days?

The use of solar power for peak power is further complicated by demands for peak power at night and under adverse weather conditions. You also have to factor in the demand for peak electricity on cold, snowy winter days, and after dark in much of the country. Solar cells don't generate electricity when covered with snow. On hot summer days in Texas, AC demand continues all night. It is often in the upper 90's at midnight after hot Texas Summer days. We need peak power at night.

One other factor that can effect the reliability of solar power is air born dust. Dust can effect solar power both by blocking sunlight on dusty days, and by dust deposits both on solar panels, and on mirrors in Solar thermal mirror arrays. NASA has predicted a return to dust bowl conditions in the Southwest.

You need back up generators for the 12 hours a day the sun does not shine. Although advocates of solar power talk about night time backup systems, they require redundant generating capacity. Thus with stored solar back up, capital costs will be more than doubled. If you use none solar backup those generators will either burn fossil fuels, and thus they will emit CO2, or they will be nuclear powered. But why, if you built nuclear power plants, would you only want to run them at night? It would be cheaper to run them all the time and not worry about solar power.

Either a ST or an SV system ends up being expensive, vulnerable to clouds and dust storms, and is going to occupy a lot of territory, and damage a whole lot of vulnerable desert habitat. But hay, damaging the environment is no big deal to greens.

Building so much redundancy into the electrical generating system costs money. Taking land from other uses and committing it to renewable generated electrical power also has economic costs. Electrical grid systems that gather and transmits electrical energy from far flung renewable energy "farms" and transmits it to cities also costs money. And there is of course the cost of fuel to keep back up generators spinning. Is there a cheaper way to do thing?