Renewable energy resources also include tidal power and hydroelectric power. Renewable tidal power stations use the kinetic energy of the flowing tide to drive a turbine, tides are created largely from the gravitational effect of the moon on the Earth's oceans. Renewable hydroelectric power stations use the kinetic energy of flowing water to drive a turbine, they are often associated with large scale dams. Millions of years age the Sun's energy was harnessed by photosynthesis and the carbon dioxide from the air was locked into plants and trees. Fossil fuels release energy when they are burned but they also release the carbon dioxide back into the atmosphere.
Carbon dioxide is the greenhouse gas that contributes most to global warming.
Biomass based renewable energy sources also release carbon dioxide back into the atmosphere. However the carbon dioxide given out is balanced by the carbon dioxide being mopped up from the atmosphere whilst the biomass is growing. Thus if the biomass crop is sustainable then there are no net carbon emissions over the time. The use of renewable energy source creates no net greenhouse gas emissions and Clarke Energy believes that the use of renewable energy is an important part of the world's response to the greenhouse effect.