About solar energy technologies

Background - 1 July, 2016
Power from the sun is already mainstream in many parts of the world, and the future looks brighter still. Solar energy not only produces electricity, it also heats, cools, lights and does countless other jobs. Solar's potential is limited only by our imagination and willingness to seize this opportunity. Energy from the sun could easily provide several times the world's current energy use with technology we have today.

Solar's amazing success story

Around the world clean, abundant solar energy is transforming communities and improving lives. Since the late 1990s, solar and wind installations grew faster than any other power plant technology across the world.  Solar's expansion comes with a huge drop in costs. Solar photovoltaics (PV), along with wind power, are now cost-competitive with new coal power in many regions.

Solar is also creating jobs. By 2030 the solar PV industry alone will employ 9.7 million people equal to the number working in the coal industry today.

How solar technology works

Today we use the sun's energy to produce electricity in two main ways:

  • solar photovoltaic technologies

  • concentrating solar power technologies (also called solar thermal energy)

Photovoltaics: power from light

Photovoltaic technology uses light to generate electricity.  

Photovoltaic systems contain cells that convert sunlight into electricity. Inside each cell are layers of semi-conducting materials.  When light falls on the cell, it creates an electric field across the layers, causing electricity to flow. The more intense the light, the more electrical power generated.  

Importantly, a PV system does not require bright sunlight to generate power.  It can harness diffuse sunlight and generate electricity even on rainy days.

Today photovoltaics are a mainstream technology, and almost every passing year sets a new record for new installed capacity. Surging growth over the last few decades has also seen photovoltaics' costs plummet by about two hundred times from US$77 per watt in 1977 to less than 40 cents per watt today.

Photovoltaic systems will be a major power source in our 100 percent renewable energy future, providing about one fifth of our power.   

Concentrating solar power: from sunlight to heat to power

Also known as solar thermal energy, concentrating solar power uses large mirrors to concentrate the sun's rays. This concentrated solar energy then heats a liquid, solid or gas, which in turn is used to generate electricity, usually from steam.

Concentrating solar power systems need very sunny locations, with direct sunlight (beam radiation or direct normal irradiation) not dispersed by clouds, fumes or dust. Good locations include Australia, South Africa, North Africa, the Mediterranean, parts of China and the US desert southwest.  Plants set up in remote deserts can transmit their clean power to population centres where it's needed.

A major advantage, concentrating solar power can be paired with systems that store the sun's heat for later use.  These thermal storage systems allow us to generate power sourced from the sun's energy even when the sun isn’t shining!

Concentrating solar power is reliable and increasingly cost competitive. Compared to photovoltaics, we expect it to play a smaller but still important role in our 100 percent renewable energy future. It could provide as much as 12 percent of the world's power within the coming decades.

Our solar revolution — the sky's the limit

Solar energy is amazingly flexible. It can be used almost anywhere to do almost anything. Each passing year brings exciting new solar technology advances.

You may already know that solar PV can both heat and cool homes when paired with air source heat pumps (pumps that absorb heat at one place and release it in another). Another popular solar heating solution is simple, affordable solar hot water systems.

But solar does so much more! It is used to light streets to increase public safety, and to turn Dutch bike paths into energy generators. Solar-powered vehicles include cars, buses, and even small aircraft.

Other exciting breakthroughs promise to further expand our use of solar. These include plug-and-play photovoltaic solar systems, clear glass solar collectors that turn windows into power generators, and printed solar cells that could allow us to produce solar energy on almost any surface.

People powered solar movement gains energy

A growing grassroots movement is tapping clean solar energy to improve lives and help the climate. In many countries the rooftop solar movement is helping people take control of their own energy supplies and make important progress toward 100 percent renewable energy.

A thriving people-powered solar movement is also underway in India, where micro-solar water pumps help farmers grow crops. And in Nigeria, where solar powered cook stoves and lamps replace kerosene and wood, so people can breathe easier while saving money and time.

People power is also behind exciting new ways to finance and build solar projects. Around the world, people are joining local energy groups to fund community solar farms. Others are investing in ventures that directly fund solar projects, and earn them interest while the projects' users save money on power bills.

What is Greenpeace doing?

Greenpeace is campaigning to accelerate the planet-wide shift to a bright new future of solar and other renewable sources. Our Energy [R]evolution analysis shows this 100 percent renewable energy future is possible all that's needed is political action.  Greenpeace's solar campaigns around the globe work to ensure clean, low-cost solar power is available to everyone. We find new ways to use solar to build healthy, more resilient communities.

What can you do?

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