Main Types of Energy
Primary Energy TypeCoal
A sedimentary, combustable rock formed of residual plant matter and solidifying below rock strata. There are several types - brown coal, raw coal and hard coal. Nuclear fission Division of a heavy nucleus into two parts - this is usually accompanied by the emission of neutrons, gamma radiation and energy release. Natural gas Methane-rich gas found underground - it may contain water vapour, sulphur compounds and other non-hydrogren gases such as helium and nitrogen. Crude oil - petroleum Naturally occurring mineral oil consisting of many types of hydro-carbons. Ocean energy Energy harnessed by using either the physical characteristics of oceans - tidal movement, thermal gradients, ocean currents and wave motion. Solar energy Energy directly taken from solar radiation - its absorbed by a collector and converted into heat energy or into electricity by photovoltaic cells. Biomass Non-fossil, organic material with a biological origin. Rates of renewability differ. Wood is an example. Wind energy Related to solar activity which results in differences in atmospheric pressure and temperature. Turbines range from 600 kW to 5 MW of rated power. Hydrological energy Energy from the movement of water through lakes, rivers and dams. A 'head' of water is stored and then released to drive turbines and generate electricity. These hydrological systems can range in capacity from thousands of megawatts to smaller micro-hydro power schemes. Geothermal energy Comes from the rocks within the Earth and can be tapped in three ways - as hot rock energy, by conduction or as hot water or steam. |
ClassificationNon-renewable
Non-renewable - may be recyclable Non-renewable Non-renewable Renewable Renewable Recyclable Renewable Renewable and recyclable Renewable |
Energy Density (MJ kg-1)14 - 19
88,000,000 50 47 N/A N/A 6 - 17 N/A N/A N/A |
Key concerns/issuesWhen used it releases large amounts of carbon dioxide and pollutants into the atmosphere. Carbon-capture tech is used to remove carbon dioxide.
Health risks are associated with it - power plants (accidents like Chernobyl). Disposing of radioactive material raises safety issues - the long term risks of this are unknown. Lots of raw material is left on a global scale. Releases carbon dioxide on use. Costs and security of supply, especially for countries that are largely importers. Global supply concerns - they could have reached their peak, geopolitical tensions, security of supply and lack of alternatives, especially for transport. Carbon dioxide is released when its burnt. Only certain locations are suitable for offshore tidal generation - technology for large-scale generation is unproven.
Ocean sources have low energy densities - large devices are needed to harness this energy. Photovoltaic technology is expensive compared to fossil fuels. Distribution and availability varies. Relatively low energy densities - limited potential for large-scale electricity generation. Biomass acts as a carbon sink. Combustion releases stored carbon dioxide. Only certain locations have enough wind to be viable - wind energy is a variable source of power so its tough to manage the power supplies through a grid system without a back up energy source. Large-scale systems are costly to build. Dum-building has many impacts (environmentally, socially and politically) Smaller micro-hydro plants may not be economically viable. Geothermal heat in the outer 10km of Earth's crust is too diffuse to be exploitable. Availability is limited to a few locations eg Philippines or Iceland |