The National Academies: What You Need To Know About Energy

The National Academies

What You Need To Know About Energy

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Electricity

Electricity can’t be mined from the ground like coal or captured from moving air like wind. So it is called a secondary source of energy, meaning that it is derived from coal and wind, as well as other primary sources, including natural gas, nuclear reactions, and hydropower. Electricity plays such an essential role in contemporary America that its supply and demand are often examined separately from the primary sources used to produce it.

Electricity generating plants now consume two-fifths of U.S. energy from all sources, including about 90% of America’s coal and nearly 30% of its natural gas.

Experts predict a 26% increase in demand for electricity in the United States by 2030. In practical terms, that means an equivalent increase in demand for coal and gas, at least for the next decade: Electricity generating plants now consume two-fifths of U.S. energy from all sources, including about 90% of America’s coal and nearly 30% of its natural gas.

Altering that situation poses considerable challenges. According to EIA projections, during the next two decades, renewable sources such as solar, wind, and geothermal are unlikely to substantially change the mix of our energy supply. And integrating the energy from many of these renewable energy sources would likely require expansion of the electric transmission system, such as the addition of more power lines. While nuclear generation is a zero-atmospheric-emissions alternative that already produces one-fifth of America’s electricity, efforts to increase that capacity face two large, though not insurmountable, hurdles: high capital investment costs associated with the construction of new nuclear power plants and resistance from citizens groups that oppose the use and storage of radioactive material.

Getting electric power to consumers may be as much of a challenge as creating it. Generating stations are usually built away from load centers because sites are easier to find and fewer people are disturbed by the accompanying noise, emissions, and activity. This power must be delivered by a high-voltage transmission system that has become increasingly stressed in recent years as growing demand has outstripped capacity. Widespread blackouts are possible, as evidenced by the August 2003 disruption to 50 million customers from Ohio to New York and Canada. New transmission lines are difficult to build because of uncertain cost recovery and public opposition. Building small plants near customers, known as distributed generation, may become more important in order to meet demand and maintain reliability.

Upgrading the U.S. electric power transmission and distribution system to the level of a “Smart Grid” represents a significant investment but would yield numerous benefits. New technologies and equipment would improve reliability, resulting in fewer system failures and quicker restoration of power when blackouts occur. Unlike the current grid, a large fraction of generation could come from renewable and intermittent resources, benefitting the environment, and a modern grid would allow for the creation of wholesale energy markets, better price signals to customers, and a more distributed system of power generation.

Despite EIA’s conservative estimates for the relative contribution of renewable and nuclear energy sources in U.S. electricity generation over the coming decades, AEF committee findings suggest that, with a sustained effort and accelerated deployment, renewable sources could power more than 25% of U.S. electricity needs by 2035 and nuclear energy could also supply considerably more energy than EIA projects over the same time period. Much will depend on the public will, U.S. government policy, and the market price of existing and alternative energy sources.

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Energy Hands-on

What do you know about energy?

Renewable energy (solar, wind, geothermal, hydroelectric, biofuels, waste, and wood) accounted for what percentage of the total energy supply in the United States in 2008?

  • Sorry, that’s incorrect.

    Renewable energy accounted for 7% of the total U.S. energy supply in 2008, less than any other type of energy source.

  • Correct!

    Renewable energy accounted for 7% of the total U.S. energy supply in 2008, less than any other type of energy source.

  • Sorry, that’s incorrect.

    Renewable energy accounted for 7% of the total U.S. energy supply in 2008, less than any other type of energy source.

Energy Defined

Energy Intensity

A measure of a nation’s energy efficiency, typically represented through the amount of energy used per unit of gross domestic product (GDP).

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