The EU has issued some helpful (if lengthy) guidance called Buying Green - a handbook explaining how to introduce environmental factors into the procurement process.
The new handbook deals with the issue which has been the subject of some debate among procurement professionals - is it appropriate to consider green credentials at PQQ stage? The procurement regulations are quite clear on what can be taken into account at PQQ stage (see Regulations 23 24 and 25). There is a brief reference to environmental management measures at Regulation 25(2)(h) but consideration of this is limited to where it is necessary for the performance of the contract.
There is no clear basis in the Regulations on which you could ask for example do you have an environmental impact policy in place? and score that as part of the PQQ. However the Buying Green paper points out at pages 34 and 35 a number of areas where green credentials could be legitimately built in to standard PQQ questions for example by asking about past experience of contracts with similar environmental requirements.