Ernst & Young published an interesting report yesterday on how corporations are diversifying their conventional energy strategy.  The choice of an energy mix optimization strategy depends primarily on the corporation’s risk/reward profile and investment horizon.  Corporations, such as IKEA and Google, are implementing three main approaches: (1) Purchasing power directly from an off-site project; (2) Investing equity in an off-site project – with or without a power purchase agreement; (3) Purchasing energy from an on-site project.