Renewable energy I

Renewable energy I

1. Renewable sources of energy include solar, wind, hydropower, biomass, geothermal, wave and tidal. Advantages of using renewable energy compared to fossil fuel sources include: Improvements to local air quality, for example production of less primary pollutants such as particulates, SO2, NOx and secondary pollutants such as ozone. Reduced GHG emissions e.g. CO2.

   • The use of renewable energy although on the increase is relatively gradual. Factors which could accelerate growth include: Decline in fossil fuel reserves forcing prices up. Technological developments improving efficiency of renewable energy and capital cost. Governmental support through economic incentives e.g. subsidies. Increase awareness of environmental impact of using fossil fuels e.g. climate change. Need to meet agreed international targets e.g. reduction in carbon dioxide emissions.

2. Solar Power

   • The amount of solar radiation that reaches the planet surface depends on a range of factors including: Tilting of the earth reflecting the season e.g. highest radiation occurs during the summer months. Amount of cloud cover.
   • Two main types of solar panels include: Solar thermal panels used to heat water and buildings. Photovoltaic panels used to convert sunlight to electrical energy.
   • Solar thermal panels
     • These can be fitted onto the roof of buildings and can be used in a number of different ways: Air can be warmed and then passed back into the building.
     • Water can be heated and then either be: Stored until required (e.g. hot water for washing and bathing). Stored where it can transmit its heat (e.g internal wall). The heat from the water is gradually released during the night helping to maintain a more even room temperature.
   • Photovoltaic panels
     • The efficiency of photovoltaic panels typically ranges between 10 to 20%. Cost of production and installation is relatively high, although running costs are relatively low.
     • The manufacture of solar panels produce pollutants such as carbon dioxide but once set up and running there are no emissions. Panels called heliostat can track the movement of the sun, maximising the amount of electricity produced.

3. Wind power

   • Windmills have been used historically to pump water or drive mechanical machinery, such as for grinding grain to produce flour. Wind turbines that produce electricity are called aero-generators.
   • They usually have fewer blades than the traditional windmill and therefore require stronger winds to get started. In Northern hemisphere countries such as the UK, higher energy demand in the winter months is matched by greater number of windy days and higher wind speeds.
   • Offshore wind power
     • Wind farms can also be sited offshore where winds are often stronger than on land. Although noise becomes less of an issue at sea, other areas of concern include: Visual impact on the seascape, especially when sited near the coast. Corrosion of the aerogenerator. Potential impact of vibrations from the aerogenerator on sea life. Potential impact on seabirds. Disruption to shipping routes. Reduced fishing grounds for fishermen.

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