About the Photovoltaic Array
The capacity of a PV system is rated in kilowatts of direct current power (kW DC). The systems we install are typically rated at 1 kW DC, meaning that under peak sun conditions (i.e. full sun, in cool weather, at noon in June), these arrays will produce 1,000 watts of electric power. Of course, the amount of power generated is proportional to the amount of sunlight hitting the array, the temperature of the photovoltaic cells, and the efficiency of the system. In addition to understanding the amount of power a system will produce under certain conditions, it is important to be able to estimate how much ENERGY the system will produce over the course of a year, which depends on a variety of factors.
(Photo taken by Jan Boutilier)
For instance, a small 1 kW system would consist of 6 photovoltaic modules (otherwise known as solar panels). Usually, each module is rated at 170 watts and is about 5 ft. by 2.5 ft., meaning that the entire system would be 5 ft. by 15 ft. or 10 ft. by 7.5 ft. Each module is roughly 37.5 lbs, and so six modules would weigh about 225 lbs. This weight estimate does not include racking. The physical size of the system will be directly proportional to it's DC capacity rating. For instance, a 2 kW array would have twice the physical dimensions of a 1 kW array. The standard system size for our school installations today is about 4 kW; larger installations may be possible with additional funding.
All of our photovoltaic arrays connect directly to the grid, meaning that they do not require any kind of storage or battery system. The array needs to be directly connected to an electrical panel in the facility. The project will also require an internet connection in order for the data monitoring system to work.
BEF has developed a thorough project management process, which ensures that every system that is installed as part of our program is properly designed, engineered, permitted and inspected. Prior to installation, each system design is reviewed by our technical staff. Upon completion, the project is commissioned by BEF staff. Ultimately, this means that schools we work with receive correctly installed PV systems that will reliably produce clean energy for many years to come.
Want to learn more about renewable energy? Check out our reading list for good books on solar, wind and other sources.
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More Links & Resources
Solar 4R Schools works with lots of organizations that specialize in renewable energy. Check our list and visit their sites for more information.