Choose which environmental indicators to use
How to choose the key environmental performance indicators that will be most useful to your business.
Once you have collected and analysed your data you need to choose appropriate key environmental performance indicators (KEPIs) so that you can track your performance.
Your choice of KEPI will depend on the activities and processes that your business carries out, what data is available, what you can measure and the priorities for your business and its stakeholders.
Types of environmental indicators
Your environmental indicators may cover a number of areas including:
- resource use - eg water, oil, gas, metals and minerals
- emissions to air - eg greenhouse gases, dust and particles, and solvent emissions
- emissions to water - eg metals and organic pollutants
- emissions to land - eg pesticides, waste and metals
There are three types of KEPI that your business can use.
Absolute environmental indicators
This type of KEPI is a stand-alone indicator that does not reference any other component of your business or process. Examples include:
- litres of water used per year
- tonnes of waste produced per year
- staff salary costs
Relative environmental indicators
In most businesses, the use of relative indicators will form the vast majority of their KEPIs. These are sometimes referred to as 'specific measures'. Examples include:
- kilograms of waste disposed of per item manufactured
- amount of energy used per piece of machinery run
- litres of water used per member of staff
These indicators can also be expressed as a percentage. If you intend to do this, the production throughput then becomes relevant. Examples include:
- percentage of raw material (input in tonnes) that becomes product (output in tonnes) - ie a measure of raw material yield
- percentage of waste produced that is recyclable
- percentage of effluent reused
Weighted environmental indicators
If you produce a wide range of products via a correspondingly wide range of processes, you may need to use a more sophisticated method of KEPI. In these circumstances, you should apply factors to give a weighted indicator.
For example, in a surface coating line there are variations in water consumption between batches of different products. Batch A requires treatment in three tanks, with rinsing after each stage, and uses 30 litres per item. Batch B requires treatment in five tanks, with rinsing after each stage, and uses 75 litres per item. To compare performance on days when different products are being made, you would need to apply a weighting factor based on the number of batch A and B products - number of A + number of B x 30/75 litres.