This document discusses three approaches to considering environmental aspects in electricity generation: 1) Applying environmental costs only to the evaluation of new electricity sources, 2) Requiring utilities to dispatch both new and existing generators based on environmental costs, and 3) Requiring consumers to pay an electricity price that reflects full environmental costs. The study contrasts the implications of these three approaches, finding that applying environmental costs only to new investments may lead to lower investment in clean technologies, increased use of polluting existing generators, and higher emissions. Applying costs to dispatch generally results in more investment in clean technologies, lower emissions, and only moderate price increases. Environmental electricity pricing also has a small impact on consumer demand for natural gas.