http://www.windows.ucar.edu/modules/energy/

Energy Choices and Climate Change is a new online module designed for the public that takes a look at issues related to energy and climate change. In the scenarios within the module, you will be able to make choices about the types and amount of energy used and see what effect your decisions have on the amount of greenhouse gases emitted to the atmosphere. Your goal is to reduce the amount of greenhouse gases added to the atmosphere from fossil fuel emissions while keeping costs within reason.

- from Windows to the Universe newsletter, Nov. 2009
http://www.windows.ucar.edu/windows.html