Sunshine is free. Solar power is not.

By Michael W. Burnette

Mike-BurnettThe sun has been supplying energy on earth far longer than humans have been using energy. How long has the sun's energy made fuel that grows plants?

So why don't we convert the sun's energy to produce the electricity we need?

The fact is, we are using solar energy to produce solar power that helps us run our lives. In the past 40 years, technology has advanced remarkably to tap solar energy for use in homes, businesses and even vehicles. A now-common example is a rooftop solar panel assembly that heats water in a building's plumbing system.

Technology for converting solar energy into electricity has advanced as well, to the point where solar electric (photovoltaic) arrays on suitably exposed buildings can supply electricity to those buildings — when the sun shines. It's still expensive for homeowners and businesses to install photovoltaic systems, making the electricity they produce more costly than buying from a utility like an electric cooperative. But each kilowatt produced  — when the sun shines — is a kilowatt that a conventional power plant does not need to produce at that moment.

Similarly, solar electric technology is producing electric power on a large scale. Solar electric "farms" are generating electricity — when the sun shines — in many states, including North Carolina. The home shopping retailer QVC hosts an 18-acre solar electric farm at its distribution center near Rocky Mount on the system of the Edgecombe-Martin County EMC electric co-op. Duke Energy buys power from a 16-megawatt solar farm in Davidson County, enough power to supply about 2,600 homes — when the sun shines.

The key to understanding how solar-generated power fits into the overall U.S. electricity grid is to realize that when the sun does not shine, photovoltaic solar panels produce no electricity. To ensure an uninterrupted flow of electricity, utilities own an infrastructure, or "grid," of generating plants, substations and interconnected transmission and distribution lines and equipment that supply the exact amount of power consumers require 24 hours a day, seven days a week, rain or shine, day and night. The generating plants on the grid are fueled from a diverse fuel mix that includes natural gas, coal and nuclear power, available to run around-the-clock, as well as multi-megawatt solar farms and roof-top solar at small businesses and individual homes that generate electricity  — when the sun shines.

Planning, building and managing that grid is a very complex business. We all benefit from the grid, and we all must pay to keep it running.

Electric utilities, including North Carolina's electric cooperatives, are increasing their deployment of affordable, clean, renewable energy sources to generate electricity. Solar power is part of the mix, but unlike sunshine, it is not free.

About the Author

Mike Burnette is senior vice president and COO, Power Supply Division, for the North Carolina Electric Membership Corp. NCEMC is the power supply cooperative owned by the state’s electric cooperatives.

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