Pilot programs in New Hampshire and Massachusetts provide several examples. A significant question in the certification debate is whether green power certification should encompass green marketing as well as green power. Generally speaking, this resource is renewable energy. Such donations may or may not lead to environmental improvement, and no renewable energy is added. Energy efficiency is one of the most cost-effective ways to reduce the environmental pollution caused by electricity generation, but it does not provide green power.
Green marketing is a legitimate approach to selling products, including electricity supply.
To answer this question, policymakers and energy advocates must consider carefully whether their goal is environmental improvement or the development and commercialization of renewable energy technologies. They may have different agendas but, perhaps more important, consumers who might respond to a green offer have various reasons for their interest. Renewable energy, rather than environmental improvement, seems to account for more of these motivations. One may have a preference for how green power is positioned but these concepts are still being discussed. Perhaps a hierarchical system of certification would allow for market innovation.