The growth of renewables is creating jobs, making electric grids more resilient and expanding energy access in developing countries. It also is far safer than coal, oil and gas.
In physics, work is defined as force times distance. The law of conservation of energy states that while energy can be changed from one form to another, it cannot be created or destroyed.
Definition
Energy is the capacity of an object or system to do work. It takes many forms, including kinetic and potential energy. The SI unit of energy is the joule, named after physicist James Prescott Joule. Other units of energy include ergs, calories, British thermal units, and kilowatt-hours.
Potential energy is power that an object has because of its position or its atoms’ and molecules’ electron arrangements. Once an object begins moving, its potential energy turns into kinetic energy.
Other types of energy include electromagnetic energy carried by photons, the elastic energy stored in solid objects, chemical energy associated with chemical reactions, and the thermal energy of microscopic particles inside a system. Due to the law of conservation of energy, mass-energy equivalence, an object that has no motion or is at rest has the same amount of energy as an object with any other kind of movement. It can, however, change forms of energy. For example, a battery containing chemical energy can be transformed into electrical energy when its cells are connected to an electric circuit.
Sources
A wide variety of energy sources fuel our modern world. Oil, natural gas, coal, nuclear power, renewables, and waste each provide us with an immense source of energy that can be harnessed.
Renewable energy sources replenish naturally and are safe for the environment. They include solar, wind, biomass, and hydropower.
While the majority of our energy still comes from fossil fuels, newer sources are catching up fast. A recent study by NREL found that if the nation met just one goal—an 80 percent renewable electricity standard by 2050—it could cut power plant emissions by 277 million metric tons annually.
Some countries get a high share of their energy from low-carbon sources – Iceland, for example, gets 79% of its energy from clean sources, mainly through hydropower and geothermal. Use the interactive charts below to see how other countries break down their energy sources. Ticking the ‘Relative’ box allows you to switch between a higher-level breakdown (fossil fuels, nuclear and renewables) and a more detailed breakdown by source, including the percentage from each source.
Uses
Energy allows us to do work — it fuels our bodies as we move through the day, regulates internal processes and repairs cells. People use it to run cars and boats on roads, cook food in our homes and offices, make ice in freezers and send astronauts into space.
Residential uses of energy include watching television, taking a shower, heating and cooling our homes and powering appliances. These are the most common energy end uses, and account for almost forty percent of U.S. energy consumption.
Most of the other end-uses of energy in the United States are for water heating, lighting and refrigeration. These are nearly universal and year-round home energy needs, and account for about 27% of household energy consumption on average. In the commercial space, energy is used for a variety of purposes including heating, cooling and lighting buildings and spaces as well as powering computers, fax machines and printers. Energy saving initiatives in the commercial sector are often focused on corporate-level energy use to curb the culture of waste that can exist in our workplaces.
Conservation
In the 1960s, conservationism emerged as a global trend armed with scientific data and supported by legislation to protect the environment on local and global levels. This included concerns about the Greenhouse Effect, depletion of the ozone layer, toxic spillages, and nuclear testing.
Energy conservation is a key component of this movement as it helps people protect the planet’s natural resources. It also offers consumers financial benefits like lower electricity bills and tax credits.
By conserving energy, consumers can help reduce the use of fossil fuels such as coal, which emits carbon dioxide into the air. This helps to slow the effects of climate change and saves plants and animals from being destroyed. It also cuts down on pollution, which can cause or aggravate asthma and other serious health issues. In addition, polluted air exacerbates the spread of infectious diseases. Lastly, it makes a significant impact on the local and global economy by reducing the need to build more power plants, which are unsightly, noisy, and cause pollution. Star Plus Energy
