Solar vs Coal: Who Wins?
Posted by Max Dunn Wed, 02 Jan 2008 00:09:00 GMT
A new solar power plant just opened up at Nellis Air Force Base in southern Nevada . Currently it is the largest solar photovoltaic system in North America with a capability of 14 megawatts (mW) of peak power, and producing about 25 million kilowatt-hours (kWh) of electricity per year .
However, it cost $100 million to build, which is about $7,000 per kilowatt (kW). This is a lot more than a coal-powered plants which costs about $3,000 per kW to build . But since the sun is free and coal-powered plants have to pay for the coal, shouldn’t this make up for the additional cost of solar systems?
It turns out, that it doesn’t. To see why, let’s look at the numbers.
A coal-fired power plant will cost about $3,000 per kW to build. The plant should last about 30 years and have a capacity factor of about 50%  . This means that each 1 kW of power capability will produce about 130,000 kilowatt hours (kWh) of energy over the life of the plant, which results in an amortization cost of $0.023 for each kWh of energy produced. For the fuel costs, one ton of coal costs about $50  and will produce about 2500 kilowatt hours (kWh)  of electricity so the cost of coal is just $0.02 per kWh, for a total cost of $0.043 per kWh.
These numbers make sense since wholesale electricity is sold for about $0.05 per kWh.
Now let’s look at the solar power. A tracking solar system will have a load capacity of approaching only 20% since the sun doesn’t shine brightly all the time. So in addition to being more expensive to build, solar systems also turn out less energy than coal plants. This means that for each kW of power capacity a photovoltaic system has, it will produce about 50,000 kWh of energy over it’s lifetime. Since it costs about $7,000 per kW of power for a photovoltaic system, it will cost $0.14 per kWh for the system.
So even though a solar photovoltaic system gets free energy from the sun, it still costs about $0.14 per kWh of energy produced versus $0.05 for coal-fired power plants.
Eventually, solar photovoltaic plants should be competitive with coal , but we are not there yet.
-  North America’s Largest Solar-Electric Plant Switched On
-  Largest U.S. Solar Photovoltaic System Begins Construction at Nellis Air Force Base
-  Price of new power plants rises sharply
-  Europe pays to ship U.S. coal as price sinks
-  How much coal is required
-  Utilization Rates of Coal-Fired Power Plants
-  Solar electricity to reach cost parity with coal-based power by 2010