Useful terms
Biodiesel – a liquid fuel made by blending vegetable oil with solvents which can be used as a transport fuel. Biodiesel can be made from a variety of oils, some of which are from unsustainable sources such as coconut or palm oil. Biodiesel is different from using straight vegetable oil on its own. From 15 April this year all forecourt diesel has 2.5% biodiesel in it.
Biomass – any type of grown plant matter, ranging from logs, wood pellets and wood chip through to elephant grass and other materials. It can be combusted to produce heat or power.
Carbon emissions – carbon dioxide pollution from an activity that uses fossil fuel; for example, flying, heating a house with oil, gas or coal, driving a car that runs on petrol or diesel. Carbon dioxide is a greenhouse gas and is a major cause of climate change. Mains gas and electricity result in carbon emissions, with electricity producing over twice that of gas.
Ecological footprint – the amount of land it takes to support all our needs for resources, including water, food, fuels, materials and waste disposal.
Energy efficiency – the use of technology that requires less energy to perform the same function, for example using triple ‘A’ rated white goods or energy efficient light bulbs.
Evacuated tubes – a type of solar thermal unit, it is a pipe in a vacuum sealed tube that collects heat from the sun to produce hot water.
Ecohomes excellent – a standard by the Building Research Establishment (BRE) to rate a new-build house against a number of benchmarked ecological features. This has recently been replaced by the Code for Sustainable Homes, against which all new-build houses must be rated.
Greywater recycling – collecting waste water from sinks, showers and baths and reusing it for toilet flushing or watering the garden. Grey water is waste water that has not been mixed with sewage.
Photovoltaic (PV) panels – panels, usually mounted on a south facing roof, that use a technology that converts sunlight directly into electricity.
Passive solar design – a design form that uses less mains energy through taking advantage of natural elements; sun, wind, air and earth. It uses factors such as building orientation, solar gain, super insulation, thermal mass and passive ventilation to provide heating and cooling.
Rainwater harvesting – collecting water that falls on a roof and using it. A good way to reduce the amount of drinking-quality water used in a house by using rainwater for washing clothes, flushing a toilet or watering the garden.
Renewables – systems which produce energy and hot water in a way that doesn’t depend on fossil fuels such as gas and mains electricity. Examples include solar thermal units for hot water and photovoltaic panels or wind turbines for electricity
Solar thermal – using the sun’s energy to directly heat water. Can be a solar panel or evacuated tube.
Sustainable urban drainage – an outside surface that is porous to allow water to be absorbed by it, which is good for reducing flooding risk.
Zero carbon – a building/development that generates no total carbon emissions resulting from energy use from heating, hot water or electricity use. This is achieved by best practice in energy efficiency plus use of renewables.