By Kathy Simpson
Solar power is booming in America. Annual solar installations have grown by over 1,600 percent since 2006, according to the Solar Energy Industries Association (SEIA). In the first quarter of 2015 alone, residential solar grew 76 percent over the first quarter of 2014. With government subsidies and improving technologies helping to lower costs, this trend is expected to continue as more people and businesses invest in this clean and abundant form of natural energy.
What is Solar Energy?
Solar energy harnesses the power of the sun to generate electricity, heat water for homes and businesses, and provide space heating and cooling for buildings. Unlike many other forms of energy, solar energy creates no waste or harmful emissions, and it’s available in limitless supply. The World Energy Assessment found that the sun’s annual potential is more than enough to satisfy the entire world’s energy needs of 2012.
How is Solar Energy Harnessed?
Solar energy may be collected in passive and active ways:
- Passive solar is generally a function of a building’s construction. Windows, walls and floors are designed to take advantage of the local climate by collecting solar heat in winter while rejecting it in summer. South-facing, thermal-paned windows that allow the sun’s rays in during the winter and provide shade in the summer are an example of a passive solar system.
- Active solar systems use mechanical and electrical devices to collect the sun’s radiant energy and convert it to usable energy. Active solar systems include solar electric, hot water, space heating and cooling, and concentrating solar power.
How Do Active Solar Systems Work?
Solar electric (photovoltaics). You’re probably already an experienced user of solar electricity generated by photovoltaics. This is the technology that powers pocket calculators, outdoor lighting and other “solarized” appliances by converting sunlight (photons) directly into electricity (voltage). Larger scale installations, which include roof- or ground-mounted panels with an AC converter, can deliver all or some of the power a home or business needs and also send electricity to the utility grid.
Solar hot water. This widely adopted form of green energy can provide hot water to homes and businesses throughout the year. Several types of solar hot water systems are available, but all generally include rooftop-installed solar collector panels, insulated piping and a hot water storage tank. The panels trap the sun’s heat and transfer it to heat potable water which flows to a storage tank from where it can be drawn as needed.
Solar air heating and cooling. While solar air heating and cooling technologies may not always be practical for residential use, they can save large commercial buildings on the cost of space heating, ventilation and cooling. Most systems have south-facing, wall-mounted panels to maximize collection of solar radiation during the winter months. Hot air taken off the top of the panel is ducted into the building. This same solar heat can serve as an energy source to cool the building in summer.
Concentrating solar power (CSP). CSP plants produce solar electricity on a large scale, similar to traditional power plants. The technology uses a system of mirrors to concentrate energy from the sun which then drives steam turbines that create electricity. The thermal energy can be stored and used as needed. There are currently seven CSP plants in the U.S., all located in open areas of California, Arizona and Nevada where solar radiation levels are high.
What Is the Future of Solar Technology?
The world’s energy demands continue to increase along with federal and state targets for new, clean energy sources that reduce carbon pollution and greenhouse gas emissions. Solar power can be a major contributor on both counts, and Americans’ demand for solar energy is at an all-time high, according to energy.gov.
The industry is working to increase solar technology production while making equipment and installation costs more affordable. Since 2007, all U.S. sectors have realized lower prices, in part due to federal, state and local incentives. For instance, prices for photovoltaic systems have dropped by 50 percent in recent years.
Several states also support community solar programs that allow multiple customers to share the cost and benefits of a ground-mounted solar installation. Panels can also be leased rather than purchased, another way to make installation more affordable.
One of the industry’s most recent developments is a home battery that Tesla Motors, the maker of a line of electrics cars, announced this spring. The new battery product is charged using electricity generated from solar panels. This allows homeowners to store their excess solar energy so it is available when they need it rather than sell it back to the grid.
Other potential solar innovations include:
- Bringing light to developing countries that otherwise rely on kerosene lamps and limited electricity
- Integrating photovoltaics into building materials such as roof shingles, facades and windows, thereby eliminating the need for separate panels
- Solar powered mobile devices
- Solar-powered transportation
Visit www.thehartford.com/renewable to view more renewable energy resources and insights.
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