Bio-mass and Bio-fuel
Biomass is derived from plant material and animal wastes. It can be used to generate electricity and/or heat and to produce transport fuel known as bio-fuel. Examples include agricultural wastes, e.g. straw and other crop residues; crops grown specifically for energy production, e.g. willow, miscanthus, oil seed rape and wastes from a range of sources including food production.

Carbon Dioxide (CO2)
See Greenhouse Gases.

Carbon Offsetting
Carbon Offsetting is a way of compensating for carbon emissions produced from transport, buildings, manufacturing and various other activities, with an equivalent carbon dioxide saving. Offsetting works by investing funds in energy efficiency projects that absorb or prevent the release of CO 2 equivalent to an individual's Carbon Footprint. The process of Carbon offsetting involves a calculation of a carbon footprint, then buying 'carbon offset' credits from emission reduction projects which prevent or remove an equivalent amount of carbon dioxide elsewhere in the world.

CHP (Combined Heat and Power)
Combined Heat and Power (CHP) is the simultaneous generation of usable heat and power (usually electricity) in a single process. This is sometimes referred to as 'cogeneration'. CHP units recover the steam and hot water produced in generating electricity for other use in industrial processes or community and space heating. CHP uses a variety of fuels and technologies, although the majority of CHP plants is fuelled by natural gas. Micro-CHP units are also available for use in the home in place of a standard boiler.

Climate Change
Weather changes constantly. However, the average pattern of weather, the climate, changes gradually over longer periods, which life on Earth has usually been able to cope with. However, human activity in the last two centuries has had a significant impact on the climate with the burning of "fossil fuels" such as coal, oil and gas, causing it to warm at a faster rate than scientists predict would happen naturally . By burning fossil fuels we release carbon dioxide, a Greenhouse Gas, into the atmosphere. Through the greenhouse effect, this causes the temperature of the Earth's surface to increase.

Since the start of the Industrial Revolution in the early 1800s, the amount of carbon dioxide in the earth's atmosphere has increased by nearly 30%, whilst global temperature appears to have risen between 1° and 2°F. The result of this warmer climate is a change in weather patterns which can alter natural processes that we rely on with warmer and colder climates and changes to our landscapes and lives.

See Also Greenhouse Gases and Greenhouse Effect

Fossil Fuels
Fossil fuels include coal, oil and gas . These fuels contain carbon and burning them releases carbon dioxide gas into the atmosphere.

See also Climate Change

Global Warming
See Climate Change

Green Electricity
Green electricity is produced from sources which do not cause impact upon the environment, using the natural energy flows of the Earth. These are usually known as renewable energy sources, because they will never run out. See also Renewable Energy.

Greenhouse Effect
Solar radiation heats the Earth's surface and this heat is then re-emitted back up into the atmosphere. Greenhouse gases trap the heat and cause the surface of the Earth to warm. Without the Greenhouse Effect, the Earth would be uninhabitable.

Greenhouse Gases
Greenhouse gases occur naturally in Earth's atmosphere and by trapping heat from the Sun, they maintain the temperature required for life to exist.. There is a fine balance of these gases, which include carbon dioxide, oxygen, methane and others. When the balance of these gases change, alterations in the climate occur. Through the burning of fossil fuels, human activity is increasing the amount of greenhouse gases in the atmosphere.

Heat Pumps
There are two types of heat pump, ground source and air, though the latter is less well-developed. Ground Source Heat Pumps make use of ground heat, usually a few metres below our feet, to transfer underground heat into buildings to provide heating and in some cases, pre-heating domestic water. As the earth maintains a temperature of about 11-12°C throughout the year, ground source heat pumps can provide an energy efficient alternative for indoor heating. Air source heat pumps.

Hydro-power
Hydro power is produced when the energy of flowing water is converted into electricity by a turbine connected to an electricity generator. Small-scale schemes are making an increasing contribution towards new renewable energy installations in many regions of the world, especially in rural or remote regions where other conventional sources of power are less readily available.

Insulation
Insulation of a property usually means placing an extra layer between the walls and the outdoor bricks. An un-insulated property can lose around a third of its heat through the walls. Homeowners can make significant savings on energy bills by insulating the cavity between the walls or lofts, so much so that the payback on a relatively small investment is usually around 2 years, with the added bonus of saving on CO 2 emissions.

Micropower / Microgeneration
Micropower, or microgeneration as it is commonly known, is the small-scale production of heat and/or electricity, typically in households. Micropower technologies include wind turbines, solar electricity, solar hot water, heat pumps, biomass heating and hydro.

Nuclear Power
uclear energy is produced by a controlled nuclear chain reaction and creates heat, which is used to boil water, produce steam, and drive a steam turbine. The turbine can then be used for mechanical work and to generate electricity, one of the major sources of electricity.

Renewable Energy
Renewable energy is produced using energy from the natural environment, e.g. wind, solar, wave, hydro, biomass. In contrast to fossil fuels, of which there is only a limited supply in the world, renewable sources will not run out from continued use (although sources of biomass have to be replenished).

Solar PV (Solar Electricity)
The sun's energy can be converted directly into electricity using photovoltaic cells. PV cells can be used for applications as small as watches and calculators, to homes and businesses, to large national grid-connected panels. Solar PV can work even when overcast, a great attraction in the UK. The other great attraction of Solar PV is that it delivers electricity at the point of use, for example panels can be integrated into buildings to supply the buildings themselves. For example it can be cheaper to power parking meters with solar energy than power from the grid.

Solar Thermal (Solar Hot Water)
Solar thermal heating systems convert the sun's radiation into heat, primarily in domestic water heating and other low temperature heating applications such as swimming pools. Domestic water heating systems consist of solar collectors, a preheat tank, pump, control unit, connecting pipes, the normal hot water tank, and backup heat source such as gas or electric immersion heater. The collectors are mounted on the roof and heat the water tank via a fluid circulated between the collectors and the tank. The overall area of the panels is typically 3-4 square metres.

Sustainability
Sustainability is refers to how long ecological systems can be expected to be usefully productive, such as the planet's climate, agriculture, forestry, fisheries and human communities on which they depend. In the past, societies have died out, sometimes as a result of their own unsustainable growth and their impact on the environment. This means that modern industrial society, which continues to grow on an a vast scale and complexity, might be unsustainable and collapse.

Wind Turbines
Wind is renewable, clean and plentiful. Wind power has been harnessed for over 6000 years, powering boats, windmills and wind pumps, and now used for generating electricity using Wind Turbines. A wind turbine, which is installed on top of a building or tower, collects energy from the wind and converts it to electricity.

Watt-hour
A unit of energy equal to the power of one watt operating for one hour. One watt-hour equals 3600 joules. 1,000 watt-hours is equal to a kilowatt-hour, the most common way to measure electricity use.