Given the importance of public sector spending on goods and services - in Europe this amounts to 14% of GDP - integrating sustainability criteria into public procurement processes has the potential to create markets favorable to adoption of such technologies, processes or services and create economies of scale that will drive down prices.

To integrate Green Public Procurement (GPP) criteria, it is valuable to have clear environmental targets - what is the city's environmental footprint, by how much can it be reduced, and by when. Purchasing can then be linked to these objectives, with those responsible, mandated and empowered to include the sustainability dimension in published tenders. Whilst such clarity is not required to get started - and requires some effort - over time it will give direction and purpose.

Designing these criteria is a careful balancing act between function, cost, and environmental impact. The most mature technology will almost certainly be the cheapest, but it is important to recognize that sustainable technologies that are effective and cost comparable to mainstream alternatives are available.

To this end, it is critical that the whole-life cost of a given procurement is included, as this will be where many of the hidden benefits will be found: increased efficiency, reduced resource use, recyclability, facilitated waste disposal to name but a few. Furthermore, it is critical to conduct market engagement with suppliers to inform them of your needs and ambitions, and to understand what alternative solutions exist.

This is a shortened version of an article ICLEI wrote for the Solutions Guide for Cities, a publication of the Solar Impulse Foundation. The full article can be found here.