The energy sector is responsible for the majority of greenhouse gas emissions that cause global warming. The development of renewable energy is a central aim of the European Commission's energy policy. Italy has the principal high temperature geothermal deposits in the EU and alone represents 97.9% of the total European capacity in 2004. Tuscany has already reached the European goal of 25% of RES (Renewable Energy Source) established for 2010, thanks to the geothermal energy presence in its territory. Geothermal energy production in the South Tuscany area, which falls into the Siena and Grosseto Provinces, has been developed since 1969 and in 2004 had 2,360 GWh of net energy production. The aim of this paper is to point out the importance of geothermal energy in reducing greenhouse gases emissions at a local scale, carrying out emissions inventories of the concerned Provinces with the IPCC methodology. The electrical energy production in 2000 was enough to cover all the electrical energy consumptions in both Provinces. Applying a strictly geographical approach to the electrical energy consumption, the greenhouse gas net balances for both the Provinces decrease more than 50% that if we use a responsibility one. © 2007 WIT Press.