Cheyenne Botanic Gardens generates approximately 40 to 50% of its electricity from a photovoltaic solar energy system. It all begins with an array of solar electric cell modules that are the black rectangles located on the Cheyenne Botanic Gardens south facing roof.
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Cheyenne Botanic Gardens also has a solar powered gazebo that benefits from
having solar powered night and security lighting.
Solar electricity is the conversion of sunlight into electricity. It is the cleanest energy option available today. Solar electricity is nearly inexhaustible and depends upon two of the most plentiful resources on earth: sunshine and sand.
The Cheyenne Botanic Gardens solar electric system is made up of an array of
solar cells, system controller and inverter.
Solar cell. A solar cell has layers of very thin films of treated silicon (from sand). When sunlight strikes the solar electric cells placed on the Botanic Gardens roof, an electric current results between the films. The cells are wired together and encapsulated with glass (also derived from sand). Each bank of cells wired together is called a module. There are no moving parts involved in the generation of electricity.
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The solar array. The array is the term that describes all of the solar cells that are wired together on the roof. It is made up of 24 modules. These modules create a total of 2,040 watts. The power of this array varies in production according to weather and all of this power is wired to a bank of batteries where the power is stored. The batteries are located in the Cheyenne Botanic Gardens basement. |
The battery bank. The battery bank is made up of industrial grade, lead-acid solar batteries. The batteries store electricity generated by the array for use at night or on cloudy days. The batteries can store electricity from one to three days depending upon the electricity load. If the batteries run low on power they are automatically re-charged from the electric utility.
The system controller. The system controller is the brain of the solar power system. The controllers function is to regulate the voltage in the battery, distribute power to the battery and to transmit power from the battery to the inverter.
The inverter. Direct current power is the type of current the solar cells generate from the sun and store in the batteries. The job of the inverter is to change the nature of the electricity stored in the battery bank, which is ‘direct current’ (DC) power. The inverter changes it to ‘alternating current’ (AC) power. AC power is the type of electricity provided by our utility grid. AC is the power we use in our homes for running most everything. For instance, a refrigerator, computer or light bulb are all typically run on AC power. Cars and RV’s typically run on DC power.
The total effect. The Cheyenne Botanic Gardens photovoltaic system generates 30 to 50 percent of the Cheyenne Botanic Gardens electrical needs including the paddle fans, irrigation controls, many lights and all of the computers and office equipment in the building. The Cheyenne Botanic Gardens system has a total of 24 modules that produce 24 volts DC (which is converted to 110 volts AC. This creates 2,040 watts at 58.92 amps. The batteries store 1575 amps at a 100 hour discharge rate.
This system was funded by the State of Wyoming to educate the public on the many forms of energy generation. Because the price of solar electricity drops every year, perhaps someday it will be economical enough to power more home electrical needs. The advantages of a solar electric system include: low maintenance, non-polluting, inexhaustible and solar power reduces our need for foreign imports of energy sources. Solar electric technology is currently cost effective only for rural areas far from power lines. It will likely be an important energy source in the future, but it needs more people to urge governmental representatives to make research and implementation of renewable energy resources a top priority. The benefits to future generations is immeasurable. A skewed energy system that depends upon far away sources of production is partially to blame for world terrorism and international instability.
Find more information at The U.S. Department of Energy.
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