See Boehmer-ChristiansenS.A., Climate Change and the World Bank: Opportunities for Global Governance, Energy & Environment, vol. 10, no. 1., p.
6.
One example is the Canadian utility Ontario Hydro which bought certificates worth 10.000 t of CO2 for the price of 3 US $ per ton from US based Southern California Edison. Ontario Hydro intends to partly offset its additional emmissions due to the shutdown of several nuclear power plants. The certificates were generated with efficiency improvements at Southern California's hard-coal fired power plant of Mohave and registered at the US Department of Energy.
7.
The emissions reductions refer to a basket of 6 gases: CO2, CH4, N20, PFC, HFC and SEF6, weighted by their global warming potentials.