Energy efficiency
Energy efficiency refers to the ratio of useful work produced by an energy system to the energy input required for its operation. This efficiency can theoretically range from 0 to 100 percent, though it is typically less than 100 due to thermodynamic limitations. Enhancing energy efficiency is crucial for addressing climate change and reducing reliance on fossil fuels. For instance, substantial energy savings could be realized in the United States, with estimates suggesting that up to 75 percent of electricity could be conserved through cost-effective efficiency measures.
Implementing energy-efficient practices, such as improved insulation and energy-efficient heating and cooling systems, can significantly lower energy use in homes and businesses. Programs like Energy Star, initiated by the U.S. Environmental Protection Agency, aim to promote energy-efficient products and practices, yielding substantial savings in energy costs and reductions in greenhouse gas emissions. For example, Energy Star's initiatives are projected to save billions of kilowatt-hours of electricity and reduce air pollution significantly. Such strategies not only contribute to environmental sustainability but also enhance energy security by decreasing the demand for imported energy sources, emphasizing the global need for effective energy management.
Subject Terms
Energy efficiency
Definition
The efficiency of an energy-producing system is defined as the benefit derived from operating the system divided by the cost necessary to operate it. It can theoretically vary between 0 and 100 percent. The benefit is the net amount of work produced by the system during its operating time, while the cost is determined by how much energy must be provided in order to generate this work. According to the laws of thermodynamics, only part of the input energy will be converted into work, so the energy efficiency will always be less than 100 percent.
Significance for Climate Change
Market strategies, economic policies, and political interests have generally assigned a lower priority to the implementation of energy-efficiency measures to reduce global warming than increases in energy production. If energy efficiency were properly addressed, promoted, and increased, world demands for energy production could be decreased and climate change stabilized. By increasing the energy efficiency of homes, vehicles, and industries, fossil fuel usage and global warming could be reduced, and the energy security of a nation could be increased by decreasing the demand for imported petroleum. About 75 percent of the electricity consumed in the United States could be saved by implementing energy-efficiency measures that cost less than the electricity itself.
As an example, energy-efficient strategies that have continually been implemented in California since the mid-1970s were projected to reduce greenhouse gas (GHG) emissions to at least 1990 levels by 2020 while keeping per capita energy consumption approximately the same. The top priority in California’s energy policy is to reduce fossil fuel usage by promoting and providing more energy-efficient homes, vehicles, and businesses, which will reduce climate change–causing GHG emissions. High-performance windows, properly installed insulation, and energy-efficient cooling, heating, and lighting systems can reduce energy use in a standard home by at least 15 percent. Similar policies could be adopted worldwide.
In 1992, the Energy Star program was created in the United States by the Environmental Protection Agency to reduce energy consumption and GHG emissions. Initially established to identify and promote energy-efficient products, the program was expanded to include energy-efficiency labels for residential heating and cooling systems, new homes, and commercial and industrial buildings. Energy Star has also promoted the use of more efficient power supplies, home appliances, electronic systems, light-emitting-diode (LED) traffic lights, efficient fluorescent lights, and energy management equipment for office systems to reduce energy consumption, global warming effects, and air pollution. By 2024, the program had helped US families and businesses save 5 trillion kilowatt-hours of electricity, avoid more than $500 billion in energy costs, and achieve 4 billion metric tons of greenhouse gas reductions.
Bibliography
“Efficiency Potential.” American Council for an Energy-Efficient Economy. ACEEE, 2024, www.aceee.org/topic/efficiency-potential. Accessed 24 Oct. 2024.
"Energy Efficiency." United States Department of Energy, www.energy.gov/eere/energy-efficiency. Accessed 24 Oct. 2024.
Large-Scale Distributed Systems and Energy Efficiency. Ed. Jean-Marc Pierson. Wiley, 2015.
Massey, Nathanael. "Is Energy Efficiency Finally Reducing the Use of Electricity?" Scientific American, 26 Feb. 2014, www.scientificamerican.com/article/is-energy-efficiency-finally-reducing-the-use-of-electricity/. Accessed 27 Jan. 2023.
Saunders, Harry D., et al. "Energy Efficiency: What Has Research Delivered in the Last 40 Years?" Annual Review of Environment and Resources, vol. 46, 2021, pp. 135-65, doi.org/10.1146/annurev-environ-012320084937. Accessed 24 Oct. 2024.