By Kevin Groenewold | For thousands of years humans have harnessed solar energy to accomplish daily tasks. From starting fires to heating water, the sun powers our society.
The latest wave of solar technology focuses on generating electricity. Some solar power systems span acres, while others are no bigger than a postage stamp. At the end of 2009, America’s cumulative solar capacity reached 2,108 megawatts, and in 2010 the top 10 utilities reported they added 561 megawatts of new solar capacity, an increase of 100 percent over 2009.
The nonprofit Solar Electric Power Association’s annual utility solar rankings report was recently released. According to SEPA, Westminster, Colo.-based Tri-State G&T and Kit Carson Electric Cooperative rank very prominently.
Kit Carson Electric, based in Taos, N.M., ranked second nationally among cooperatives with 22.2 watts per member of solar electric power. Among co-ops nationally, Kit Carson Electric ranked fourth in absolute production, with 620 kilowatts of solar electric power.
Tri-State’s Cimmaron Solar photovoltaic facility in New Mexico is the second largest operational facility of its kind in the country. The integration of 30 megawatts of solar power into the generation mix ranks Tri-State number six overall, but it also makes it the nation’s top electric cooperative in that category.
Under a 25-year agreement, Tri-State is the sole purchaser of the power produced at Cimarron. The photovoltaic facility consists of 500,000 modules, each measuring two feet by four feet, aligned on a 250-acre site within the service territory of a member system, Springer, N.M.-based Springer Electric Cooperative.
Although solar power remains more expensive and less reliable than more traditional forms of power generation, the technology’s potential is ever increasing. Solar power plants harness basic premises such as reflective heating to create steam, or use advanced materials to convert sunlight directly into electricity.
Whatever the method, all operate under one major condition: the sun must shine to make things work.
There are two primary methods of harnessing the sun: concentrating solar power (also known as solar thermal energy) and photovoltaic.
The earliest way to convert sunlight into power grew from the basic concept that if you can spin a turbine, you can generate electricity. As a result, solar energy focused to heat water and create steam does just that, creating a power plant that can, if properly operated, deliver electric power year-round. This high-temperature technology exists in a variety of forms.
Photovoltaic materials directly convert light into electrical energy without need for turbines, generators, or other mechanical assistance. When a PV system absorbs sunlight, energy passes on to electrons. The energized electrons break free and, in the right conditions, join an electric current—which can then power a member’s home.
Sunlight may then look like an easy way to generate electricity, particularly in remote areas without easy access to transmission lines, but there are drawbacks. The sun only shines for a set number of hours daily, and cloudy or overcast conditions can wreak havoc on solar power production. Without an effective way to store electricity for nighttime and cloudy day use, a solar system’s effectiveness remains limited.
But no matter the limitations, cooperatives will continue to find new and innovative ways to incorporate these evolving technologies into our supply of power. We will do so in an affordable manner. After all, we believe that is the leadership our members expect from us.
First published in Electric Co-op Today. Republished with author’s permission.