California’s Public Utilities Commission has issued an order that requires the state’s major utilities to take financial account of greenhouse gas emissions in power purchases from fossil-fuelled facilities. The PUC has adopted an $8/ton to $25/ton range value for a so-called greenhouse gas ‘adder’. This measure is designed to allow cleaner sources of energy to prove that they are cost-effective when greenhouse gas emissions are considered. The measures, which affect utility giants Pacific Gas & Electric, Southern California Gas and San Diego Gas & Electric, are expected to boost renewable generation over gas-fired plants.