Energy Concepts

kWh

The Watt (W) is the unit of power. You will be familiar with watts from ordinary household light bulbs (40W, 60W, 100W etc.). A kW is one thousand watts, equal to ten 100W light bulbs. A kWh is the amount of power consumed over a period of one hour. For example, 10 x 100W common light bulbs left on for one hour consumes 1kWh , that is, 1kW x 1 hour = 1kWh.

Renewable energy

Effectively uses energy resources such as sunlight, wind, tides, wood, and hydropower which are naturally replenished.

Energy requirement

The minimum amount of energy required to achieve a desired output. The energy requirement relates to the issue of why a particular amount of energy is being used, and whether the output can be delivered in a different way that requires using less or no energy. Does the activity actually need energy? Is there another way of delivering the output?

Greenhouse gas

A greenhouse gas is a component of the atmosphere that contributes to the greenhouse effect. Without the greenhouse effect the Earth would be uninhabitable as temperatures would be much cooler. Greenhouse gases include in the order of relative abundance water vapour, carbon dioxide, methane, nitrous oxide, and ozone. Greenhouse gases come from natural sources and human activity. There is now scientific evidence that human activity through the production of C02 from burning fossil fuels for energy creation is having a significant impact on this greenhouse effect.

Energy performance indicator

A method of tracking energy use against known variables eg number of goods produced, external temperature, floor area, meals served etc. The development of appropriate Energy Performance Indictors allows companies to set goals for improvement and monitor progress.

Whole life cost

The total cost associated with the purchase and operation of a product, service or other item. Such costs will include energy and maintenance costs, but exclude costs associated with disposal. When purchasing energy items or equipment that consume energy, you should make your calculations on the basis of whole life cost and not just on the initial purchase cost of the item. This is because energy running costs may be a significant part of the whole life cost of the item. Let’s take an example of replacing a typical incandescent household lamp (GLS) with a compact fluorescent (CFL).