Solar Power

Located 150 million km from the sun, Earth receives just one-billionth of the sun’s colossal power output. But even that tiny fraction, some 120,000 trillion watts, showers Earth with more energy in one hour than all the energy consumed by humans in an entire year. link
Solar power is probably, along with wind power, the most  readily available solution to clean energy alternatives. Technology is advancing rapidly to make solar energy both efficient and low-costThis page provides illustrations of technological developments around the world and examples where solar is being used, looking at both Photovoltaic (PV) and Concentrated Solar Power (CSP) alternatives. 

(March 2018) China is the largest solar producing energy country with 78GW, followed by Japan (42.75GW) and Germany (41.22GW). USA (40.3GW) and Italy (19.28GW.) See top 10 here.



  • News from around the world
  • Explaining difference between PV and CSP and Suncatcher
  • Costs of solar energy
  • Desertec and desalination
  • Other technical news
  • Floating solar
  • Feed-in tariffs and municipal lending
Every day the sun provides approximately 170,000 terawatt hours of energy – 
about 2,850 times the energy required by people around the world.

  • In 40 minutes of daylight the sun releases upon the earth the amount of energy that is consumed by the entire population of the planet in one year.
  • All the energy stored in Earth’s reserves of coal, oil, and natural gas is matched by the energy from just 20 days of sunshine.
  • Currently we harness about 1% of this energy. 

How much land would it take to power the world’s major cities by solar? This interactive site takes a look to see how little land is needed to power world cities by solar. link

News from around the world

April 2018: Solar power eclipsed fossil fuels in new 2017 generating capacity. Globally, a record 98 GW of solar power capacity was installed in 2017 with China contributing 53 GW, according to U.N., with the cost of generating electricity from large-scale solar photovoltaic technology falling by 15%. (Net new capacity from fossil fuels in 2017 was 70 GW.) link 

March 2018: In 2017, newly installed solar PV capacity worldwide reached 102GW, 37% higher than 2016. Cumulative installed PV capacity surged 33.7% to 405 GW. In China, newly installed and cumulative installed PV capacity reached 53 GW and 130 GW respectively, accounting for 51.8% and 32.2% of the total. For the first indicator, the country has ranked first worldwide for five consecutive years while, for the second, it has held the leading position for the last three. link 

July 2018: India’s solar generation capacity hit 24.5GW early 2018 (beats 20GW target by 4 years)- link

February 2018: International Solar Alliance (ISA) to launch 121 projects at New Delhi summit. ISA, a brainchild of India and France launched at the Paris summit in 2015 has the aim to efficiently exploit solar energy in the countries that lie between the tropics. The agreement is to be signed March 11 between the ISA and India, the latter being the nation that is home to its headquarters and is leading the intergovernmental coalition to kick-start solar projects globally. The ISA is the first treaty-based intergovernmental organization to be based in India that aims to help sunshine-rich developing countries tap solar energy at more affordable prices through aggregating both demand and risks in order to bring down costs and secure investments of solar developers. link   (Link to ISA)  

April 2017: Global installed PV capacity reaches 303 gigawatts. The IEA reported that 75GW of solar were installed globally in 2016 bringing the installed global photovoltaic capacity to at least 303 gigawatts. This was an increase of 51GW in 2015 and 40GW in 2014. The 2015 total of 227GW of PV cumulatively installed around the world meant solar power made up more than 1.2% of global electricity demand. link

See editorial:  How solar energy will transform in 20 years – link

May 2017: Ten countries that lead the world in solar energy (note: this order can change quickly; India replaces Britain) – link

Page on USA solar

December 2016: Solar power now cheaper than wind. Now, unsubsidized solar is beginning to outcompete coal and natural gas on a larger scale, and notably, new solar projects in emerging markets are costing less to build than wind projects, according to fresh data from Bloomberg New Energy Finance. The overall shift to clean energy can be more expensive in wealthier nations, where electricity demand is flat or falling and new solar must compete with existing billion-dollar coal and gas plants. But in countries that are adding new electricity capacity as quickly as possible, renewable energy can beat any other technology in most of the world without subsidies. link

April 2016: International solar alliance to mobilize $1 trillion. During the historic signing of the Paris Climate Agreement at the UN, the first meeting of the International Solar Alliance also took place. When launched at the Paris summit, 120 countries signed onto the alliance declaring: “United by our objective to significantly augment solar power generation in our countries, we intend making joint efforts through innovative policies, projects, programmes, capacity building measures and financial instruments to mobilize more than $1,000 billion of investments that are needed by 2030 for the massive deployment of affordable solar energy.” link

June 2015: Around 40GW of solar power was installed in 2014. A record amount of solar power was added to the world’s grids in 2014, pushing total cumulative capacity to 100 times the level it was in 2000. link

January 2014: Middle-East looks at $50 billion to spend on solar power by 2020. The Middle East, spearheaded by the oil-rich Persian Gulf monarchies, could spend up to $50 billion on developing solar power over the next seven years, says the Middle East Solar Industry Association. The MESIA group estimates the region will install 12,000-15,000MW of solar power by 2020, with another 22,000-25,000GW from other renewable energy sources such as wind and hydro-power. link

June 2012: Japan poised to become second biggest market. Japan is poised to overtake Italy and become the world’s second-biggest market for solar power as incentives starting July propel sales. It could eventually top Germany, which holds the No. 1 spot. link
March 2010: Solar power could make up as much as 25% of the world’s total electricity production by 2050 – link

                 How solar is expanding around the world – nine examples  

China: By the end of 2016, total PV capacity in China had increased to over 77.4 GW. More on China’s solar ambitions on China page. 

India: May 2017: India has quadrupled its solar capacity in the last three years to 12GW. This will almost double again this year, with India adding 10GW in 2017; another 20GW is in the pipeline. link

Morocco: (February 2016) Morocco begins phase one of world’s largest solar plant. The power station on the edge of the Saharan desert will be the size of the country’s capital city by the time it is finished in 2018, and provide electricity for 1.1 million people. Noor 1, the first section at the town of Ouarzazate, provides 160MW of the ultimate 580MW capacity. link 

Italy:  At the end of 2017, total installed capacity in Italy was 19.7GW following only modest additions since 2011. link

Spain: Spain had reached a cumulative grid-connected installed PV power of 4.674MW as of the end of 2016, corresponding to approximately 6.6% of Spain’s total power generation capacity. link

South Africa: The 96MW Jasper solar farm, the continent’s biggest, located near Kimberley in South Africa, is now fully operational. link  At the end of 2016, South Africa had 1529MW of solar capacity, 200MW of which were CSP. link 

Saudi Arabia: January 2013: Saudi Arabia is targeting 54GW of renewable energy by 2032 with solar intended to make up around 42GW of the total. link  

Philippines: (March 2016) The 63.3MW Calatagan solar farm in the Philippines, the biggest solar farm in Luzon, claims to be able to power the noontime energy needs of western Batangas. The Calatagan Solar Farm is one of the first of dozens of solar projects completed this year. Experts have said that the Philippines, because of its abundant sunlight, can become one of the world’s first 100% renewable energy-powered economies. link 

UAE:  (March 2013) UAE opens world’s largest CSP solar power plant. The 100MW Shams 1 is the world’s largest concentrated solar power plant in operation said Sultan al-Jaber, head of Abu Dhabi’s Masdar, which oversees the emirate’s plan to generate 7% of its energy needs from renewable sources by 2020. Masdar now produces 10% of the world’s CSP energy. link  (BBC video)

PV – CSP and SunCatcher

Photovoltaics are those solar panels placed on roofs etc. that so far dominate the solar market. They can be added on buildings anywhere to convert sunshine to electricity direct to the structure. Generally energy output is described in kilowatts produced, and their efficiency of converting the sun’s energy to grid-ready electricity is between 8 and 15%. CSP however has an efficiency level of between 15 and 19% and becomes cost-effective when producing in large plants on megawatt scale. The SunCatcher is the most efficient at about 31%

There are three major types of CSP (Concentrating solar thermal power) systems

Power Tower Systems use a large field of Sun-tracking mirrors known as heliostats to focus sunlight onto a central receiver at the top of a tower. The receiver contains a heat-transfer fluid which is heated by the concentrated sunlight. The heat-transfer fluid is used to create steam which drives a conventional turbine generator to produce electricity. CSP has one major advantage over PV, dispatchability. Current CSP plants can store thermal energy for up to 16 hours.

Dish/Engine Systems use a parabolic dish to focus sunlight onto a receiver located at the focal point of the dish. The dish tracks the Sun in order to take full advantage of the available solar energy. The receiver contains a fluid or gas which is heated by he concentrated sunlight. The heated fluid is used to drive a Stirling engine to produce electricity.  
Parabolic Trough Systems use parabola-shaped reflectors to focus sunlight onto a tube that runs along the focal-line of the reflectors. A heat-transfer fluid inside the tube is heated and used to generate steam to drive a conventional turbine generator which then produces electricity. link

June 2015: CSP bright future.
Solar photovoltaic (PV) systems have seen explosive growth because of their stunning 99% price drop in the past quarter century. As a result, the other form of solar power, concentrating solar thermal power (CSP), is a small fraction of the solar market. But the International Energy Agency (IEA) says CSP has a very bright future too because it enables cheap, efficient storage, which allows CSP plants to provide electricity long after the sun has set. The IEA suggests 11% of global electricity will be generated by concentrating solar thermal power in 2050. The key attribute of CSP is that it generates primary energy in the form of heat, which can be stored 20 to 100 times more cheaply than electricity, and with far greater efficiency. Commercial projects have already demonstrated that CSP systems can store energy by heating oil or molten salt, which can retain the heat for hours. link

January 2017: CSP prices falling fast – link   

In 1962, 3,600 solar batteries power Telstar, the world’s first communications satellite. History of solar cells – read

July 2016: China huge backer of solar CSP providing 24 hour energy. China as a whole has plans to build some 10,000MW of CSP in the next five years. CSP has one huge potential advantage compared to PV – the heat it generates can be stored over 20 times more cheaply than electricity and with far greater efficiency. link

 Costs of solar energy

September 2017: Cost of U.S. solar drops 75% in 6 years, ahead of federal goal. The goal was set by the Obama administration in 2011 and known as the SunShot Initiative. Now cost-competitive with fossil fuels, the DOE  set a new goal to reduce the cost of solar even further: 3 cents per kilowatt-hour by 2030. link

December 2013: CPV outlook – demand doubling – costs falling – link

January 2015: Solar energy competitive and on the rise. As the cost of solar energy production continues to fall, the market is experiencing something of a boom. In many parts of the world, it has become cheaper to produce solar power than diesel oil, gas, coal or nuclear energy. Preliminary statistics suggest that solar energy generation rose by 45GW in 2014, and achieved an output akin to that of 11 large coal or nuclear power stations. But experts say the big boom is yet to come, and are predicting an increase of 50GW for 2015, and a continued upward trajectory in the ensuing years. By 2020, 4% of the world’s energy demand could be met with solar power. link

March 2013: Unsubsidized solar reaches grid parity. Deutsche Bank released new analyses concluding that global solar market will become sustainable on its own terms by the end of 2014, no longer needing subsidies to continue performing.  link

July 2010: Crossover point reached – solar now more cost effective than nuclear – NC Warn report (pdf)

July 2011: Roof panels additional energy benefits. Researchers find solar PV panels have the extra benefit of cooling buildings as well as providing a source of alternative energy. The research team also found that the solar panels had insulating benefits – enabling the building to retain heat during the nighttime. The team found that the cooling effect of the solar panels impacted the building’s total energy costs and amounted to a 38% reduction in annual cooling load – the rate at which heat is removed from a conditioned space and the amount required to maintain a constant temperature. link

September 2009: Solar in desert regions face conflicts where water is a major factor. Lack of water availability means less efficiency and higher costs. In California alone, plans are under way for 35 large-scale solar projects that, in bright sunshine, would generate 12,000MW of electricity, equal to the output of about 10 nuclear power plants. link

 Desertec and desalination

Desertec – the Sahara project that could supply all of Europe’s energy.   August 2017: Desertec Sahara dream didn’t die. A few years ago, the company Desertec made a splash with its ambitious plans to harvest gigawattsful of solar energy from the Sahara Desert and ship it off to solar-thirsty Europe. Well, Desertec crashed and burned but the dream didn’t die. London based Nur Energie has just filed a plan with the Tunisian government to export 4.5 gigawatts of solar power from the northeastern edge of the Sahara to Europe. According to Nur, 4.5 gigawatts is enough to supply more than 5 million typical European. link

January 2015: Desertec’s plan for Saharan sun to power Europe burns out. As a concept, Desertec was ambitious. Produce abundant clean electricity for Europe from vast concentrating solar power (CSP) plants in the deserts of North Africa and the Middle East. But after five years attempting to turn theory into practice, the consortium formed in 2009 is effectively dead in the water after being abandoned by the majority of its shareholders. It was planned the infrastructure would meet as much as 15% of Europe’s electricity needs by 2050. However, in October 2014 companies chose not to renew their contracts as part of the consortium. link   July 2013: Desertec in trouble –link

Desalination traditional (energy inefficient) or solar alternative. Desalination removes unwanted minerals from saltwater so it can be used for drinking or agriculture
May 2016: Countries are turning to solar power to turn saltwater into drinkable water. Saudi Arabia uses around 300,000 barrels of oil every day to desalinate seawater, providing some 60% of its fresh water supply. That’s not sustainable. Finding a way to produce fresh water without burning fossil fuels is critical not just for the desert countries of the Middle East but for a growing number of places around the world. The new Al Khafji plant in Dubai will produce nearly 16 million gallons of fresh water a day, enough to supply the local population. The Spanish solar company Abengoa, which is helping build the plant calls it “the world’s first large-scale desalination plant to be powered by solar energy.” Unfortunately, solar-powered desalination is expensive: as much as three times the cost of water from grid-powered plants, according to the World Bank. Desalination plants need to run 24 hours a day, requiring expensive battery packs to supplement solar power when the sun’s not shining. Thanks to increased efficiency and the falling price of solar power, costs are expected to fall rapidly: from more than $50 per 1,000 gallons today, in the Middle East, to half of that by midcentury. But that’s still likely too much to make solar-powered desalination economically viable without government subsidies, even in places such as the Middle East that are optimal for solar power. linkJuly 2015: Californian company explores solar desalination. WaterFX’s technology has several advantages over traditional desalination plants, including “not contributing to climate change,” cleaning up local salty, toxic irrigation drainage, and being more cost-effective., probably one-fourth the cost of conventional desalination. link
Other technical news

June 2018: Europe’s first solar panel recycling plant opens in France. The new plant in southern France has a contract to recycle 1,300 tonnes of solar panels in 2018 – virtually all solar panels that will reach their end of life in France this year – and is set to ramp up to 4,000 tonnes by 2022. The first ageing photovoltaic (PV) panels – which have lifespans of around 25 years – are just now beginning to come off rooftops and solar plants in volumes sufficiently steady and significant to warrant building a dedicated plant. link

June 2016: Is 13% solar energy by 2030 possible? The global share of electricity generated by solar power could leap from 2% in 2016 to 13% by 2030 as falling costs drive investments around the world, according to a study by IRENA. Solar capacity increased from 177GW in 2014 to 227GW in 2015, driven largely by rapid expansion across the US, China and Japan. In contrast, renewables growth in the EU has markedly slowed. link

August 2015: New ‘green’ antenna could double solar panel efficiency. Scientists from the University of Connecticut have developed a new type of antenna that could facilitate twice the amount of efficiency in existing solar panels which usually only capture 11 to 15% of the available energy. The antenna collects much more of the blue photons of the light spectrum than existing devices do. The key to the new technology is organic dye and while that process might sound complicated, it’s actually not too difficult or expensive to do. What’s more, the materials involved are compostable and kind to the environment if they need to be abandoned. link

August 2015: The Solar Sunflower – harnessing the power of 5,000 suns. The Solar Sunflower is a Swiss invention assisted by IBM. Combining both photovoltaic solar power and concentrated solar thermal in one neat package, efficiency around 80% is possible. The problem is, focusing the power of 5,000 suns on a single point brings heat to 105C., which needs a clever cooling system which is solved by a hot-water cooling technology. Cost is the next hurdle. link

March 2014: Massive mirrored dishes could make solar cheaper for allSo much sunlight hits the Earth each day that the world’s entire electricity needs could be met by harvesting only 2% of the solar energy in the Sahara Desert. Of course, using solar power as the world’s only energy source hasn’t been possible yet, in part because solar equipment is expensive to make (and getting the power out of the desert would be no easy feat, either). But researchers at IBM think they’re one step closer to making solar universally accessible with a low-cost system that can concentrate the sunlight by 2,000 times. The system uses a dish covered in mirrors to aim sunlight in a small area; as the sun moves throughout the day, the dish follows it to catch the most light. Other concentrated solar power systems do the same thing, but quirks of this design make it much more efficient: A typical system only converts around 20% of the incoming light to usable energy, while this one can convert 80%. link

November 2009: Solar power could be produced cheaply in specially designed optical fibres, say researchers. Optical fibres could conduct sunlight into a building’s walls where the nanostructures would convert it to electricity. link

September 2010: Spray-on solar cells make windows generate electricity. The technology, which is called the Solar Window, aims to provide solar energy to building facades by spraying an electricity-generating coating on to glass. During the demonstration, the researchers compared the cost of the SolarWindow technology to traditional rooftop solar systems saying that the SolarWindow technology provides up to three times more savings in electricity costs. link
 Floating solar

June 2016: Floating solar a win-win solution for drought-stricken areas. Installing floating solar photovoltaic arrays, sometimes called “floatovolics” can produce renewable energy while shielding significant expanses of water from the hot desert sun. Floatovoltaic projects are now being built in places as diverse as Australia, Brazil, China, England, India, Japan, South Korea, and California. And nowhere could they prove as effective as on lakes Mead and Powell, the two largest man-made reservoirs in the US. For example, if 6% of California’s Lake Mead’s surface were devoted to solar power, the yield would be at least 3,400MW of electric-generating capacity, substantially more than the Hoover Dam’s generating capacity of 2,074 megawatts. link

 Feed in tariffs and municipal lending schemes

May 2013: Feed-in-Tariff (FIT). Historically, FITs have been associated with a German model in which the government mandates that utilities enter into long-term contracts with generators at specified rates, typically well above the retail price of electricity. In the United States, where FITs are comparatively new, FITs or similarly structured programs are mandated to varying degrees in a limited number of states. However, a different model has also emerged in which utilities independently establish a utility-level FIT, either voluntarily or in response to state or local government mandates. A FIT is a performance-based incentive rather than an investment-based incentive, and in that respect is more similar to production tax credits and the renewable energy credits of an RPS market than to investment tax credits or other investment subsidies. In the United States, FITs are typically used in combination with one or more of these other incentives. link

April 2011: In Oakland, a creative strategy for financing the city’s solar roofs – link

December 2015: Community solar option. More than three-quarters of households in the U.S. are unable to install a rooftop solar system on their own home. But for residents in at least 24 states, according to a June report, community solar gardens are emerging as an option. Power generated by community solar in the U.S. is predicted to more than double between 2015 and 2016, as more states, utilities and companies get on board. link

August 2013: California organization makes solar energy affordable to those unable to finance. California-based GRID Alternatives installs solar systems on low-income households in California, Colorado and soon, in New York and New Jersey. The organization has installed 3,500 solar systems in California so far, projects that according to the organization have saved the homeowners $80 million in energy costs and will result in the reduction of 250,000 tons of greenhouse gasses over their lifetimes. Once the solar system is installed, the homeowner pays GRID two cents for every kilowatt-hour that the solar panels produce, which typically results in energy bill savings of 80%. link

June 2011: Google invests $280 million for home solar roofs. Search giant Google is investing $280 million in SolarCity, a company that leases out solar panels to home owners. The new fund will give SolarCity the capital it needs to create more reasonable financing options for home owners interested in planting solar panels on their roofs and don’t necessarily have the cash to buy panels outright. The leases for the residential solar panels can last upwards of 15 years. SolarCity is currently the number two provider of residential solar panels behind SunRun. link  [In 2005 27megawatts of residential photovoltaic were installed in the U.S. and 58MW by 2007. By 2010 264MW were installed according to the Solar Energy Industries Association.]                 


August 2011: Large solar arrays concern for desert animals. Builders of large solar array farms in Israel’s Negev region and in places like California’s Mojave Desert have had ongoing problems with nature lovers, environmentalists, and Native American Tribes. A recent study conducted by Israel’s Nature and Parks Authority indicates that building giant solar array farms could be fatal to thousands of wild animals that live in the fragile ecosystem of these desert regions. link

European Photovoltaic Industry Association.