Neuwing Energy Ventures, a New York-based marketer of energy-efficiency certificates, would perform an initial assessment of IBM customers' sprawling data centers -- the massive, air-conditioned facilities that store information and route anything from eBay purchases to e-mail. IBM would identify potential energy savings areas for its clients, and Neuwing would grant the IT firms certificates for the total megawatt-hours no longer needed to cool or operate the data center equipment. Each certificate would equal 1 megawatt-hour (MWh) per annum, said Rich Lechner, IBM's vice president for IT optimization. Clients could sell the certificates to utilities subject to state renewable portfolio standards, as well as sell to other companies that aim to reduce their carbon footprint through energy savings. The value of the energy efficiency certificates, historically in the $2-$10 range, is determined by the supply and demand for those certificates in each trading market.