We have tried to anticipate the questions you might have concerning the advice provided on this site.
What are the units of carbon emissions?
Both the science and policy worlds have settled on metric tonnes of carbon dioxide equivalent per year as the measure of emissions, shown as tCO2e/year. The word "equivalent" is in the unit because climate change is affected by six greenhouse gases, of which carbon dioxide (CO2) is the most prevalent. However, other gases are also important. For example, methane is about 21 times as powerful as CO2 in contributing to the greenhouse effect, so the release of 1 tonne of methane is "equivalent" to releasing about 21 tonnes of CO2.
What are the units of energy use?
Here, the answer depends on the kind of energy considered. Ideally, everyone would use one common unit such as kilowatt-hours (kWh). A kWh is an amount of energy equal to one kilowatt (1000 watts) consumed for one hour. This is the unit used in most electricity bills, and is the unit used on this site for both electricity and natural gas.
Natural gas bills might also show energy use in kWh. However, it is more common to show it in units of m3 (cubic metres) or BTUs (British Thermal Units). If your bills are in BTUs, multiply by 0.000293 to convert to kWh. If your bills are in m3, multiply by 10.35 to convert to kWh.
Other kinds of fuel, such as for vehicles, usually are sold in units of L (litres). This is the unit assumed on this site.
Where do I find the data I need?
Effective carbon management requires data on electricity use, natural gas use, use of "other" fuels for heat, and use of fuels by vehicles. For electricity and natural gas, your best source of the data is your bills from the energy provider, which should show the amount of energy purchased (in addition to what you paid for that energy).
Almost all energy providers have created a way for you to view your energy consumption through their website, and will even give you an estimate of your carbon emissions and allow you to track energy use over time. Simply contact them and ask how you access this information.
In regards to "other" heating fuels and fuels for vehicles, you will need to keep track of purchases. As with electricity and natural gas, the important bit of information is not the COST of the fuel (although there are obvious business reasons for wanting to know this as well), but rather the amount of fuel consumed. Since cost per litre (£/L) doesn't stay constant, you usually can't just divide the cost by a single value of the £/L to estimate the amount of fuel consumed.
Do I have a liability for carbon costs under the Carbon Reduction Commitment (CRC)?
The simplest answer is that you probably know if you do because you will have received a letter from Defra or DECC saying as much. But if you are not sure, the current guidelines are that (1) you must be on half-hourly metering and (2) have consumed 6,000,000 kWh or more of electricity during the period 1 January 2008 through 31 December 2008. This equates to roughly £1 million worth of electricity spend. The programme was set out in the Climate Change Act of 2008, begins officially in April 2010 and is administered by the Department of Energy and Climate Change. To learn more, visit the DECC site.
Is this SME website asking that I report my carbon emissions?
No. You may be part of a reporting scheme for some other reason, such as being within the Carbon Reduction Commitment or Carbon Disclosure Project, but this website was designed only to help you with reductions. There is no reporting requirement associated with its use.
Is there a commonly approved method for measuring and reporting greenhouse gas emissions from a company?
Yes, Defra have developed the Draft Guidance on How to Measure and Report Your Greenhouse Gas Emissions. This is the procedure we have used throughout this site. Annex 8 of that report provides examples of target intensity ratios, which is the amount of carbon dioxide equivalent released per unit of economic activity (tCO2e/£). You might take this as a rough guide in creating your own targets.
If I choose a method to reduce emissions, can I be sure to receive the promised reduction?
You need to be careful here. The amount of reduction in emissions may depend on very specific circumstances of your firm's assets and practices. For example, the Energy Saving Trust or Carbon Trust web sites provide useful information on how much reduction you might expect on average from specific measures such as installing double glazing.
The actual reduction you will see depends on many factors such as how heat is entering or leaving your buildings, the direction in which the windows face, how careful you are in installing them, etc. The best way to choose a reduction strategy is to have a formal energy audit by someone with an energy and engineering background.
What is an energy audit?
An energy audit determines where energy is being used (and carbon dioxide released) in an organisation; the purposes of that use; some measure of the efficiency of energy use; and where there are opportunities for reduction. It examines features such as the quality of the energy envelope-walls, roof, etc-in keeping heat in or out; the amount of thermal mass that can be used to store energy in the building; the efficiency of heating, cooling and ventilation systems; the efficiency of office appliances; etc.
A comprehensive energy audit can tell you not only where you are using energy, but where there are cost-effective opportunities to reduce energy use and carbon emissions. A web site such as the one by the Carbon Trust can provide a very good listing of candidate energy saving measures. Only a formal energy audit, however, will tell you which measure is right for your circumstances.