Do distributed energy resources result in more pollution, or less? Our final installment of the series from Oak Ridge National Laboratory answers the question.
The most economical energy savings might be found in grid efficiency.
The U.S. government has focused on energy and electricity to be part of the solution for some of the toughest challenges facing the United States including climate change, energy security, infrastructure investments and the need to invigorate the American job market. The American Recovery and Reinvestment Act is helping to fund these efforts and includes more than $16 billion for the DOE Office of Energy Efficiency and Renewable Energy’s (EERE) programs and initiatives. The Obama administration also has called for reducing CO 2 emissions to 1990 levels by 2020, with a further 80-percent reduction in these emissions by 2050.
Other federal and state legislative initiatives call for an increased focus on energy efficiency and peak demand management. The American Clean Energy and Security Act (ACES), introduced in the house in June 2009, attempted to establish a standard that requires utilities to achieve an increasing percentage of their power supply through a combination of energy-efficiency savings and renewable energy initiatives ( e.g., 6 percent in 2012, 9.5 percent in 2014, 13 percent in 2016, 16.5 percent in 2018, and 20 percent in 2021 through 2039).
Efficiency measures can be applied throughout the electricity value chain from generation through power delivery, as well as during the time electricity is being used. The industry has a good understanding of efficiency options, costs and impacts in power plants through heat-rate improvements and at customer sites resulting from the efficiency programs they conduct. However there is no clear understanding of the cost, service, power-quality or reliability impact when applying efficiency measures to transmission and distribution (T&D).
A kilowatt-hour saved in generation, power delivery or through end-use efficiency measures is a kilowatt-hour less generated, and helps reduce fuel costs and carbon emissions, and, if measured and verified, it might help to meet expected efficiency mandates. The electric industry is the largest single user of electric power, consuming approximately 12 to 15 percent of the electricity produced when operating auxiliary loads in generation plants and substations, or through losses occurring in T&D.
The cost of saving a kilowatt-hour of energy through transmission or distribution efficiency measures might be lower than saving the same kilowatt-hour through end-use efficiency measures. There is a need for measuring, managing, comparing and understanding all efficiency opportunities across the end-to-end electricity value chain, including T&D efficiency.
Assessing the Challenge
The percentages across both transmission and distribution equate to approximately 300 million MWh based on a U.S. annual generation total of 4,157 million MWh. That is roughly equivalent to the electricity needed to power approximately 29 to 35 million homes ( Electric Power Industry 2007: Year in Review , EIA report released Jan. 21, 2009). Reducing the losses by 20 percent would result in a reduction equivalent to the electricity needed to power 6 million to 7 million homes.
Ultimately, electric energy is lost in the form of heat. The current-carrying components get hot as they deliver energy to the