# 1.4 Making the calculations

Having defined the boundary and the scope, the next step is to add numbers to them. If there are accurate utility bills (including transport fuel records and employee travel claims), it is easy enough to put them on a spreadsheet, and to convert energy (or other emissions) into carbon dioxide equivalents. In the UK, DEFRA provides an annual update on emissions factors as part of its environmental reporting guidelines. There are even a few websites that will allow you to input the data and convert it automatically to tCO2e. However, you may want to apply more specific factors to your organisation: for example, you may have more accurate estimates of car fuel efficiencies based on the actual models driven by staff.

At the end of the process, you should end up with a figure for a carbon footprint, in terms of tonnes of CO2 equivalent. Although that may tell you what your contribution to global climate change has been, it is not very useful on its own. You will need to have something to measure this against: a baseline or a benchmark. A baseline is simply the same information for an earlier period of time – this is useful for monitoring your own performance, and how you are improving (or not). You will probably need to normalise the data to account for changes in the level of activities of your organisation. This can be done by converting the total CO2 figure to relative indicators – typical examples include CO2 per tonne of product manufactured, per square metre of office space occupied, per employee or per bed-night (for a hotel or a hospital). If the nature of your organisation’s activities has changed, it is sometimes necessary to convert the data to an indicator of carbon intensity – measuring CO2 per £ of turnover. You may also want to make adjustments for external factors such as weather compensation using a technique based on adjusting for ‘degree-days’.

Carbon indicators also allow comparison with other organisations through benchmarks. These may be publicly available, from the government or bodies such as the Chartered Institute of Building Services Engineers (CIBSE). Good benchmarks should take into account the type and function of the building you are occupying, or the industrial processes that are carried out. Sometimes benchmarks are calculated in energy use and will need converting to tCO2e.

## Web-based resources for calculating your carbon footprint

Web-based carbon calculators are available from:

• National Energy Foundation

• Carbon Trust

The Carbon Trust Standard includes a link to a free downloadable carbon footprint spreadsheet.

VESMA provides information about degree days and a whole host of other useful information about energy managemenmt in companies.

You can calculate your own degree days based on your local weather station.

The Energy Consumption Guide to Energy Use in Offices includes lots of information about benchmarks.

A summary document from Imperial College draws together the most commonly used building energy benchmarks.

### Activity 2

This section is possibly the most technical one in this unit, but it is necessary to be quite sure about what emissions your organisation is responsible for, before attempting to take action to reduce them.

Carbon calculations are increasingly driven by internationally set standards, as emissions – and the projected impacts of climate change – know no boundaries. Some were initially designed to permit carbon trading under the Kyoto Protocol, the so-called ‘clean development mechanism’, or under the EU Emissions Trading Scheme (ETS), but these tend to apply only to large companies with significant resources.

As over 95% of British businesses are small or medium enterprises (SMEs), do you think that enough is being done to help them tackle their carbon footprints?

Is it inevitable that much of the work appears to be driven by reporting needs, rather than a spontaneous interest in carbon saving?

Finally, Scope 3 asks companies to consider the carbon from energy use (or savings) of their products in practice. Try to list some products where energy in use exceeds (or is dwarfed by) energy used in their manufacturing.

1.3 What is to be measured – the scope

2 Taking action – energy management systems