Energy is the ability of matter to do work. It is a conserved quantity: it can be transferred from one object to another but cannot be created or destroyed.
Saving energy lowers utility bills and reduces air pollution that causes or exacerbates many health problems. It also helps the environment by reducing mining, oil drilling and nuclear power plant accidents.
Sources of Energy
Humans have long harnessed energy from nature: the sun’s rays to warm homes, wind to sail ships and power mills, and gravity to move water in rivers. Energy from these sources has also helped plants grow, animals migrate and fly, and volcanoes erupt.
Scientists divide energy into two kinds: kinetic energy, which comes from moving matter, and potential energy, which is stored in the microscopic particles of matter. Humans need to transform kinetic energy into potential energy to do work.
The main nonrenewable sources of energy are coal, oil and natural gas. These resources must be extracted from the Earth using energy-consuming equipment, resulting in air pollution and other environmental problems. Some fossil fuels, such as coal, also contribute to global warming. Nuclear energy is another source of electricity, produced through fusion or fission reactions. However, these sources can be dangerous if accidents happen. All of these types of energy cause deaths – some from air pollution, others because of accidents while extracting or transporting the raw materials, and still others from the construction, operation and maintenance of plants.
Energy Conversion
The energy we use comes from many different sources. Some are renewable, others are not. Renewable sources are those that can be used over and over again. Examples include sunlight, wind, and water. Non-renewable resources, such as coal and oil, must be replaced after being used up. They take thousands of years to form again.
Scientists have developed methods of converting one type of energy into another. But people have been doing it for a long time, long before scientists came up with the term “energy conversion.”
For example, when we burn wood, chemical energy in the wood turns into heat and light energy. Then electricity from the lights is transmitted through wires to our homes.
Energy Conservation
Many government policies encourage or require energy conservation practices. For example, car companies often set fuel economy standards for cars and buildings set energy efficiency ratings for new construction.
The energy efficiency rating system used in residential housing is known as the Home Energy Rating System (HERS). This national benchmark is a key factor in mortgage financing.
Energy efficient lighting and appliances, insulating existing buildings, and installing new insulation are examples of energy conservation measures (ECMs). Larger building projects are sometimes combined into guaranteed energy savings Performance Contracts by ESCOs experienced in these types of projects.
Lowering energy consumption through ECMs is good for the environment and saves money. It also reduces the need for power plants that might otherwise extract fossil fuels from fragile ecosystems and/or increase greenhouse gas emissions into the atmosphere. This is important because these finite resources are limited, and reducing reliance on them moves countries towards energy independence. It also reduces the pressure on the power grid.
Energy Efficiency
Energy efficiency enables services to be delivered using less energy. For example, an air conditioner that uses half as much energy as a standard unit provides the same cooling output and service.
Energy-efficient practices are the easiest and most cost-effective way to combat climate change, reduce energy costs for consumers, improve the competitiveness of U.S. businesses, and contribute to energy equity, particularly for low-income households. EERE’s four technology offices support these goals by developing and deploying a range of technologies for buildings, industry, transportation, and electricity grids.
Although energy savings from EE programs often fall short of expected outcomes, research indicates that this gap is caused by a variety of factors, including hidden costs and market failures such as credit constraints. Continued research into the drivers of these gaps will help us better understand how to overcome them. (See Newell and Siikamaki 2014, Ayres et al 2013, Alberini and Bigano 2015). EERE works to advance these efforts through a broad range of partnerships and initiatives. Star Plus Energy
