Solar energy systems convert sunlight into electricity or heat that can be used to meet energy needs.

Solar Thermal Systems: Otherwise known as solar water heaters, these systems convert sunlight into heat that can be used to warm water or buildings. This heat can even be converted into cooling using an absorption chiller. Learn how Solar Thermal Works at Office of Energy Efficiency & Renewable Energy, Department of Energy.

Solar Photovoltaic Systems: Convert sunlight into electricity that can offset energy generated from fossil fuels and distant power plants. Solar photovoltaic systems can be distributed on buildings, parking lots and open space. Learn more about how Solar Photovoltaics work at National Renewable Energy Laboratory.

Montgomery County Government facilities are using photovoltaic systems. We also are actively evaluating solar thermal systems.

A photovoltaic (PV) panel is usually made of silicon-based semiconducting material placed between two electrical contacts. Glass protects the panel’s components from the weather and wildlife.

To make sure PV panels have access to direct sunlight for most of the day, it is best to mount them on a sloping, south-facing roof or to mount them in a sloped, south-facing fashion on a flat roof or on the ground. Also, the semiconductor is coated in an antireflective substance to make sure it absorbs sunlight rather than scattering it away. As the panel absorbs sunlight, electrons are freed from the atoms that make up the semiconductor and an electrical current is created.

PV panels generate direct current, which is run through an inverter to change the electricity to alternating current so it can be used to power the building.

A utility meter measures how much electricity the solar panels are generating. During the day the solar panels often can produce more power than the facility needs, so excess power is sent to the electric grid to power homes and businesses. At night or on cloudy days, the facility uses power from the grid.