Solar Power

Enough sunlight hits Earth in just 90 minutes to power the planet for an entire year

Despite this, in 2023, only 5.1% of electricity in the US came from solar energy. Solar panel technology has nonetheless made significant advancements since the 19th century, largely due to NASA's efforts in the space race.

Solar power is converting the sun's energy into thermal or electrical energy

Solar energy is the most abundant renewable energy resource. It can be captured in photovoltaic cells to generate electricity, solar heating and cooling technologies for temperature control, and concentrated solar power to drive steam turbines.

View breakdowns of the world's and each nation's electricity comes from

These charts show how the shares of generated electricity sources—solar, wind, hydro, nuclear, bioenergy, oil, gas, and coal—have changed since 1985. Since 2010, an increase in renewable sources has offset the share lost by nuclear and fossil fuels.

The Ancient Chinese harnessed solar power for heating and cooling 6,000 years ago

Neolithic Chinese homes faced south for winter sun warmth, while overhangs shielded them from high summer sun. These efforts also influenced urban planning, with cities aligning streets east-west for optimal solar exposure.

The first rooftop solar panels were installed in 1883

In 1883, New York inventor Charles Fritts created the first solar cell by coating selenium with a thin layer of gold. The cell achieved energy conversion rates of 1 to 2% compared to the 15 to 20% of modern photovoltaics.

View an interactive chart of energy conversion efficiencies for various photovoltaics

This National Renewable Energy Laboratory visualization provides maximum confirmed efficiencies for nearly 30 research PV cell technologies from August 1975 to today. Concentrator multi-junction cells have led the field since 1993. (Desktop recommended site.)

Solar energy alone can fully power the world if transmission hurdles can be resolved

When light strikes a photovoltaic cell, electrons are loosened, which travel through a circuit where the energy can be used. Distributing energy from high solar intensity regions and storing energy for non-daylight hours is logistically challenging and costly.

Home energy performance can be boosted through home orientation and shading

When designing a home, placing living areas to the north maximizes sun exposure during winter, while eaves and awnings can limit excessive summer heat. Breezeways and entry air locks can also reduce the dependence on heating and cooling costs.

Solar panel manufacturing begins with silicon extracted from sand

The silicon is purified and shaped into wafers less than 0.2 millimeters thick, coated and connected through a criss-cross pattern of narrow and wider metal, followed by multiple rounds of lamination before bonding to a weatherproof panel.

A 1,000 square kilometer patch of solar panels in Africa can power most of Europe

The $500 billion Desertec initiative would have constructed massive solar farms in the Sahara and expansive electrical transmission networks across continents. However, the plan was built on concentrated solar power technology, which is more expensive and less practical than photovoltaics.