Chancellor Joel I. Klein and the Director of the Mayor's Office of Long Term Planning and Sustainability, Rohit T. Aggarwala, today announced that the Department of Education (DOE) has taken a major step towards reducing energy consumption by City schools by analyzing the energy efficiency of the district's 1,260 school buildings through a process called benchmarking. Benchmarking gives a detailed understanding of the efficiency of each building, and helps the Department of Education target efficiency efforts where they will have the greatest impact. The effort is part of the City's overall efforts to achieve its PlaNYC target of reducing municipal government energy consumption and carbon emissions by 30 percent by 2017. Chancellor Klein and Sustainability Director Aggarwala also announced that the Department of Education is the first public school district in the nation to join the Green Schools Alliance, a nonprofit initiative committed to promoting energy efficiency, resource conservation and environmental awareness and responsibility in schools. Through the Green Schools Alliance, schools share experiences and expertise to lower their energy consumption and carbon footprint. Benchmarking is regarded as necessary because a building's energy bills alone do not provide an understanding of the building's efficiency. Benchmarking uses the total energy consumed in a building and adjusts for other factors—hours the building is occupied, total square footage, building type, and other factors—so that an owner or manager can understand whether high energy bills are really due to inefficiency. The Department of Education used the "Energy Star Portfolio Manager" online benchmarking tool, a widely-recognized standard created by the U.S. Environmental Protection Agency; the use of this tool is the first step in most professional energy audits and is a pre-requisite for the US Green Building Council's LEED rating for existing buildings. Forty-five private schools launched the Green Schools Alliance in October 2007 in response to Mayor Bloomberg's PlaNYC challenge of reducing greenhouse gas emissions. Since then, the GSA's membership has grown to more than 200 schools nationwide, which participate in myriad GSA programs that motivate and support school communities to make energy and climate a priority. GSA also offers on-line tools and resources to support schools at its Web site. The Department of Education is the first public school system in the nation to join the GSA, and will encourage its schools to participate in the GSA's Green Schools NYC, an on-going school resource-sharing event and the Green Cup Challenge, an annual national, student-driven event that supports school-based efforts to measure and reduce electricity use.