Alternative Energy

Increasingly, lifestyles are being defined in terms of the "carbon footprint" which results from the consumption of energy.  The intention of these pages is to profile some of the technologies available for home use in terms of cost, CO2 emission and lifestyle.  To maintain focus, transportation and indirect forms of energy consumption (e.g. cement manufacture) are not included.

It was clear when we started this exercise that it was not possible to rank technologies, for example, it is not possible to compare installing a wind turbine and doing the washing up in the sink rather than using the dish washer.  However, it was also clear that there are a lot of concepts competing for the hearts, minds and cash of people who want to determine the nature of their carbon footprint and possibly change it.  The situation is further complicated by the availability of government grants.

Sources of Energy for Home Use

The principal inputs of energy into the home are electricity and gas (methane).  Oil and coal are important in some locations.  The principal difference between electricity and gas is that gas is burned in the home, most commonly in a central heating boiler whilst electricity is the result of some form of conversion process which takes place in a coal, oil or gas fired power station or a nuclear plant.  The sources for electrical power are shown in the graphic below:

A high proportion of gas consumed in UK households comes from the UK's offshore oil and gas fields.  Offshore production has peaked an imports are expected to increase over the next decade.

Levels of Energy Consumption

The sales of gas and electricity for domestic use are shown in the table below, the average consumption/per household is based on 25 million households.

	Total (GWH)	Per Household (KWH)
Electricity	118,754	4,750
Gas	396,411	15,856

Energy consumption varies considerably with the nature of the property  and is proportional to the household income.  As disposable income increases, there is a disproportionate increase in energy consumption per household.

CO2 Production

The table below contains an estimate of the CO2 produced per kilowatt hour of energy consumption.

Per kWh	CO2 (kg)
Electricity	0.45
Gas	0.20

The higher value for electricity is due to the conversion process of converting nuclear and fossil fuel sources into electricity within power stations.  Typically, gas is burnt at the point of consumption, e.g. a central hearing boiler.

The Carbon Footprint of Domestic Energy Consumption

The table below is an estimate of the CO2 production as the result of domestic energy consumption.

CO2 (tonnes)	per Household	per Capita	Total
Electricity	2.1	0.9	52.5m
Gas	3.2	1.3	80.0m
Total	5.3	2.2	130.5m

The average per capita production of CO2 in the UK is approximately 10 tonnes, thus domestic consumption accounts for 20 to 25% of the total.

Domestic Use of Energy

The graph below is a rough estimate of domestic energy use, however, there are wide variations between properties.  A modern, well insulated town house with lots of appliances will have a lower proportion of heating costs and greater light and power consumption.  Whilst a detached, uninsulated Victorian villa will require a much larger amount of energy to maintain the same ambient temperature.

The approach to reducing the carbon footprint of a home will vary considerably between properties.  For an older property, upgrading (or installing) loft insulation and reducing the energy used for heating, whilst adding solar panels (for both water heating and electrical generation) to a modern property might be a move towards energy self-sufficiency.

Domestic Energy Prices

Energy prices in the UK have increased significantly over the past three years as shown in the graphs below.  the prices shown are typical prices for domestic consumption after some threshold has been consumed.

The mix of fuel sources used for electrical generation has softened the price rise relative to that for gas.

At the time of writing (1Q07) it looks probable the domestic energy prices will fall, but a long term upward trend is established, not least due to increased competition for energy resulting from strong economic growth in Asia.

Page Updated: 04-Mar-07

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