Monday, September 12, 2011

Why There are No Solar Power Plants

   Isn't it time to quit relying on fossil fuels and switch to nice clean solar electricity?  Philosophically, it's the best possible scenario. There is an inexhaustible amount of energy from the sun, so why not try to harness it and use that to power our society.  Yet, there are no major solar power plants anywhere in the world.  Why is that?

   Power plants based on  natural gas, coal or oil can easily top 1000 Megawatts.  Solar power plants are usually in the range of 10 MW or less.  Mostly the reason why we have solar power plants at all is for a political show, and have no practical economic advantage.  

   For example, the largest power plant in the US east of Arizona is a 3 MW plant being built in Pennsylvania, occupying 16 acres at a cost of some $20 Million.   However, the plant doesn't produce 3 MW all the time.  Solar power won't work at night, works less well in the morning or late afternoon.  Cloudy days likewise limit the performance of solar systems. Also,there is less sunshine at higher latitudes than at the equator, and less well on cloudy days.  When you add it all up, the Solar power plant average power is 422 kilowatts (0.422 Megawatts), or 14% of the rated value.  

   So the capital cost (the amount that a utility company has to pay to build the plant) is $47000 per kilowatt. This is about 50 times more than a power plant built for natural gas (the only type of new power plant that can be realistically approved for construction in today's political environment in America).   Advocates claim that the government should throw money at the problem and soon it will become cheaper. Well, how much money should the government throw, and how much cheaper will it get?  Let's see some numbers, please.

   As another example, there are some interesting numbers posted on the web by the German organization Bundesverband Solarwirtschaft.  In this case the numbers are even more intimidating, the average power output of solar photovoltaics in Germany is less than 10% of their rated value. 
     A real plant---say 1000 MW average power---would cost the utility company some 47 billion dollars. That's more money than the entire gross domestic product of Bulgaria.  

     But wait a minute!  Isn't the operational cost of a solar plant going to be zero?  Well, no. First of all, you have to figure that the money you spent on the plant could have been invested in something else.  If the expected rate of return is a measly 5%, then that's $2.4 billion dollars per year that you need to earn from the sale of electricity.  It works out to some 27 cents per kilowatt-hour, or some 3 or 4 times the going rate for electricity.  That's just for the interest on the plant, assuming zero maintenance and zero electrical switching requirements (which is grossly optimistic). 

    But isn't it true that there is no environmental impact of solar power?  That also is blatantly false.   First of all let's consider the capital investment, which as you will recall is some 50 times higher than a natural gas plant.    The structure is made of metal, which requires consumption of coke made from petroleum and coal.  Are silicon semiconductors used?  That requires mining of silicon, and a significant amount of energy to melt and refine the silicon to create solar cells.   The energy is supplied mainly from fossil fuels (hint:  no plant that produces solar cells for profit could ever be powered by solar energy).  The capital cost must certainly be associated with consumption of raw materials.    
     We can argue about whether a solar photovoltaic plant has more or less environmental impact than some other, but there should be no question that all plants have some impact.   

    Proponents may argue that some other photovoltaic plants, notably in the American southwest where there is more access to sunshine, might have more favorable economics.  That's true to a limited extent, but the point remains that fossil fuels are far and away more economical than photovoltaics.  American industry could possibly remain competitive if they pay 10 or 20% extra for electric power, but 1000%, or 50000% is just unfathomable.   
    That is why solar energy continues to account for less than 1% of the total electrical energy produced in America.  

    Solar power, in its own way, is the subject of fantasies that are every bit as weird as, for example, the fantasy that President Obama has no birth certificate and is a secret agent of an Islamic group trying to take over the world.  But we're on to him!   Similary, solar power is highly economical, and that some massive conspiracy, usually led by the oil companies or defense industry, is preventing their use.  Well, the fact of the matter is that Obama may not be such a great president but he has a birth certificate, and solar power plants are unaffordable. 

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