Renewable energy technologies

Solar photovoltaics (PV) is a method of generating electrical power by converting solar radiation directly into electricity using semiconductors.

Solar thermal with storage or concentrating solar power uses mirrors to focus the sun’s rays onto a focal point. Heat is used to produce steam which powers a turbine to generate electricity. At night, or if the sun is blocked by clouds, the prior storage of heat (e.g. in molten salts) allows the power plant to keep operating.

Thanks to Greenpeace for these images and videos.

Wind power uses the prevailing wind resource and turns that kinetic energy into electrical power. Instead of driving a turbine using steam from burning fossil fuels, the turbine is spun from the rotation of the blades.

Geothermal energy uses underground heat to make high-temperature steam which drives a turbine just as in a conventional coal-fired plant. Geothermal resources worldwide are usually associated with volcanis activity but in Australia geothermal resources are associated with heat producing granites several kilmoetres beneath the earth’s surface. A geothermal energy rig consists of two to three wells that drill down to the hot rocks, and a turbine on the surface. Water is pumped down one well and once it reaches the hot rocks, the water heats up to create pressurised steam. The steam reaches the surface, spins the turbines to generate electricity, before being cooled back to water and recirculating down the well.

Bioenergy is energy that comes from organic matter (material derived from plants and animals). Bioenergy fuels include dedicated energy crops and many different types of waste, for example, sewage, food wastes and crop wastes. These fuels can be stored so bioenergy can directly replace coal- and gas-fired power plants.

Hydroelectricity currently supplies 6% of Australia’s electricity. There is limited capacity for growth of hydroelectricity in Australia.

Ocean power uses the oceans’ tides, currents or waves to produce electricity. Power comes from the water’s movement, i.e. either the changes in height of the tides or the ocean’s current. Different technologies adopt different methods for harnessing the ocean’s energy.