Solar Energy

Definition

Solar energy is the energy that comes to the earth through the sun’s rays. Sunlight is an abundant source of energy and can be advantageously used by converting it into other forms of energy. Solar energy can be used for heating (i.e. heating water in homes or swimming pools or for heating spaces like homes and greenhouses).

Solar energy can also be converted into electricity using photovoltaic (PV) devices and solar power plants. The PV systems directly convert sunlight into electricity whereas the solar power plants use solar collectors to trap the sun’s heat which is then used to power the generator.

Advantages & Disadvantages of Solar-generated Electricity

Distribution: The solar energy reaching the earth is not the same everywhere. The sun’s intensity depends on a number of factors including weather conditions, location, time of day, and season. In order to collect the sun’s energy, large surface area is required.

Renewable resource: Solar energy reaching the earth is vast and inexhaustible. The sunlight reaching the earth’s surface varies in intensity. The deserts receive the most sun, over 6KwH per day per square meter. With the increase in awareness about global warming and the contribution of fossil fuels to it, solar thermal plants are being viewed as renewable power sources.

Cost issues: Solar energy systems are expensive. It costs about $100,000 for a house to become energy independent. There are several reasons why the cost is so high. Solar energy alternatives like fossil fuel oil have been far less expensive. The Government has not taken leadership in promoting a sustainable culture. But with fossil fuel oil becoming expensive by the day, improvement in technology and Government’s initiative in promoting sustainable development, the cost of solar energy systems is expected to go down.

Supply and transport issues: Solar panels can be mounted on roof tops or erected on the ground. Unlike wind energy, solar energy can be collected and stored onsite. However, solar power plants operating in the desert where the solar potential is highest are not accessible to power grids, which creates transportation and supply problems.

Future of Solar Energy

Global demand for solar panels is growing at 50% annually. There has been a shortage of silicon, the raw material for solar panels. However, with more manufacturing plants coming online by 2009, the industry will produce three times what it did in 2006. According to Prometheus Institute of Sustainable Development in Cambridge, MA the price of solar panels will reduce by a third by 2010.

Reference

EERE Solar Energy Technologies Program
American Solar Energy Society
NREL Learning about Renewable Energy