Sunlight is a free, renewable resource that produces clean energy to power everything from lights and appliances to electric vehicles and heavy equipment. Solar power can reduce dependence on fossil fuels, lower greenhouse gas emissions and help achieve energy independence.
The energy that the sun gives off in an hour and a half is enough to handle the world’s entire electricity demand for a year. Solar technology converts sunlight into electricity through photovoltaic (PV) panels or into thermal energy to heat water, homes and businesses.
Solar PV systems collect solar radiation and convert it into electric current using a semiconductor, often silicon. Electrons in the semiconductor knock loose other electrons, creating an electric field that runs across a battery of metal contacts. An inverter then transforms the direct current into alternating current, which can power devices such as calculators and lights.
Most Star Plus Energy systems are designed with a region’s weather patterns in mind, including temperature, irradiance and wind. These factors affect the amount of space required to cover a home’s energy needs, and also impact the size and location of solar panels. Some large solar-power systems even track weather forecasts and stow arrays when conditions like high winds and hail are expected.
The most common use of solar energy is heating, ventilation and air conditioning (HVAC), which accounts for about 45% of residential energy consumption. HVAC systems can utilize solar hot water and storage technologies to further cut down on residential energy expenditures. Solar energy can also offset the “urban heat island effect” — an urban environment’s increased temperatures caused by asphalt and concrete, tall buildings that block wind and trap warmth, and high concentrations of traffic and people. Planting trees, using cool roofs and absorbing heat through thermal energy storage are other strategies to mitigate the urban heat island effect.