19% of our electricity was generated  by nuclear fuel in 2013. 

19% of our electricity was generated  by nuclear fuel in 2013. 

19% of our electricity was generated  by nuclear fuel in 2013. 

On average, even after passing through hundreds of kilometers of air on a clear day, solar radiation reaches Earth with enough energy in a single square meter to run a mid-size desktop computer-if all the sunlight could be captured and converted to electricity.

On average, even after passing through hundreds of kilometers of air on a clear day, solar radiation reaches Earth with enough energy in a single square meter to run a mid-size desktop computer-if all the sunlight could be captured and converted to electricity.

Most direct uses of primary energy are limited to generating heat and motion. Electricity, by contrast, is extremely versatile, with a wide range of complex applications. 

Most direct uses of primary energy are limited to generating heat and motion. Electricity, by contrast, is extremely versatile, with a wide range of complex applications. 

Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

On average, a typical coal-burning power plant in 2013 was about 33% efficient in converting heat energy into electrical power. A gas-fired plant was about 42% efficient. And in natural gas combined-cycle power plants—in which waste heat from a natural gas turbine is used to power a steam turbine—generation may be as much as 60% efficient.

On average, a typical coal-burning power plant in 2013 was about 33% efficient in converting heat energy into electrical power. A gas-fired plant was about 42% efficient. And in natural gas combined-cycle power plants—in which waste heat from a natural gas turbine is used to power a steam turbine—generation may be as much as 60% efficient.

All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

A typical incandescent lamp (traditional light bulb) that consumes 60 watts of power produces around 800 lumens. A compact fluorescent lamp emits the same amount of light while using only 13 watts. And an LED lamp consumes only 10 watts to give off the same 800 lumens.

A typical incandescent lamp (traditional light bulb) that consumes 60 watts of power produces around 800 lumens. A compact fluorescent lamp emits the same amount of light while using only 13 watts. And an LED lamp consumes only 10 watts to give off the same 800 lumens.

A typical incandescent lamp (traditional light bulb) that consumes 60 watts of power produces around 800 lumens. A compact fluorescent lamp emits the same amount of light while using only 13 watts. And an LED lamp consumes only 10 watts to give off the same 800 lumens.

In 2014, 10% of our total energy use came from renewable energy sources, such as biomass, wind, solar, and hydropower.

In 2014, 10% of our total energy use came from renewable energy sources, such as biomass, wind, solar, and hydropower.

In 2014, 10% of our total energy use came from renewable energy sources, such as biomass, wind, solar, and hydropower.

New technologies for drilling have led to increases in supply of oil in the U.S. in the decade up to 2014.

New technologies for drilling have led to increases in supply of oil in the U.S. in the decade up to 2014.

New technologies for drilling have led to increases in supply of oil in the U.S. in the decade up to 2014.

New technologies for drilling have led to increases in supply of oil in the U.S. in the decade up to 2014.

Fossil fuels represent the largest source of stored solar energy, resulting from the transformation of biomass over millions of years into oil, natural gas and coal. 

Fossil fuels represent the largest source of stored solar energy, resulting from the transformation of biomass over millions of years into oil, natural gas and coal.