Organisations can use computer models to estimate how much they can reduce the financial costs and CO2 emissions associated with their computing infrastructure. These estimates can be used to evaluate actual data, so measure how successfully policy objectives have been implemented. For instance, an organisation might estimate that it can reduce its overall night time electricity consumption by 50%, by asking people to turn their desktop computers off at the end of each working day. These estimates can then be compared to actual meter readings. If the reduction in consumption is not as expected the discrepancy can be investigated. This approach can be summarised as: 1. Estimate current consumption in terms of financial costs and CO2 emissions 1. Drawing up a list of interventions and quantify the expected outcomes 1. Deliver objectives 1. Monitor performance and investigate any discrepancies Here we describe tools that can be used to estimate current consumption and quantify the benefits of a range of interventions.<> = Desktop computing = == Basic calculation == == Full life-cycle modelling == This model builds on the basic calculation but makes it easier to factor in calculations relating to: * the effect of different power management policies * CO2 emissions that result from electricity consumption * CO2 emissions that result from purchasing equipment * recycling costs This model aims to provide a more complete representation of the parameters that need considering to build low-carbon ICT systems. The models were designed and written by Howard Noble during the [[http://projects.oucs.ox.ac.uk/lowcarbonict/|Low Carbon ICT project]], which was funded by the [[http://www.jisc.ac.uk/whatwedo/programmes/exemplars.aspx|JISC Institutional Exemplar Programme]]. The software was written in the [[http://ccl.northwestern.edu/netlogo/|NetLogo]] programming language == Tutorials for constructing low-carbon ICT models == Taking the modelling approach even further it is now possible to construct models from code fragments entirely using an internet browser. This tool can be used to build new models relating to low carbon ict, and explore the problem in a more in-depth manner. = SustainIT audit = = BCS data centre tool =