The Lewis Center utilizes a 60-kilowatt (60-kW) grid-connected photovoltaic (PV) system to produce a substantial fraction of its energy needs from a renewable source. The Ohio electricity grid is dominated by coal-fired power plants, which release particulate matter, mercury, radio nucleotides and other pollutants that are damaging to human health and the atmosphere. Coal power is also a primary cause of acid rain and global climate change.

How does it work? The PV system begins with 690 roof-mounted modules, which use semiconductors to convert solar energy into direct current (DC) electricity. Within the building inverters are used to convert DC power into the form of alternating current (AC). Now compatible with standard building devices, the energy enters the main distribution panel. Much like a breaker box in your own home, this panel distributes energy to various parts of the building. Unlike a breaker box, however, which typically divides circuits by areas ("kitchen," "living room," etc.), the panel separates electrical energy flow by end-use (e.g., "lights," "fans," etc.). Extensive energy monitoring equipment takes advantage of the panel's divisions to inform research and to enable optimization of the building's energy performance. Finally, when photovoltaic production exceeds the electrical consumption within the building, excess electricity reverses direction through the utility's billing meter and is sold back to the power company.

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