Deployment of solar power to energy grids depends largely upon local conditions and requirements. Many industrialized nations are installing significant solar power capacity in their grids as a reliable economic supplement or alternative to other power sources. Long distance transmission allows remote renewable energy resources to be used to displace fossil fuel consumption. Solar, hydro and wind sources can't be moved closer to high population cities, and solar costs are lowest in remote areas where local power needs are the least. Connection costs alone can determine whether any particular renewable alternative is economically sensible. Costs can be prohibitive for transmission lines.

Most electrical grids are relatively local, as transporting electricity more than about 350 miles (560 km) was not efficient. However, newer, higher voltage lines now make possible transmission over 4,000 miles (6,400 km), allowing the development of a global energy grid.

A global energy network makes enormous sense if we are to meet global energy needs with a minimal impact on the world's environment. Such advances (in long distance transmission) may even make possible the visionary suggestion ... that the Eastern and Western hemispheres be linked by underwater cable to assist each other in managing peak energy demand, since the high daytime use in one hemisphere occurs at precisely the low night time consumption by the other.

—Nobel Laureate, and former U.S. Vice President Al Gore[1]

A global energy grid will allow bringing solar power from the sunny Middle East and Mexico to Europe and North America.

Solar power plants use one of two technologies

Africa

June 7, 2007 Rwanda formally opened Africa's largest solar energy plant, Kigali Solaire, on Mount Jali, 250 kW, near the city of Kigali.[2]

Asia

India

Main article: Solar power in India

Government support and subsidies have been major influences in its progress.[3] India's very long-term solar potential may be unparalleled in the world because it is one of the few places with an ideal combination of both high solar power reception and a large consumer base in the same place. India's theoretical solar potential is about 5000 trillion KW·h per year (i.e. 600 TW), far more than its current total consumption. The Rajashtan government has set aside a 35,000 km² area of the Thar desert for solar power.[4]

The grid-connected solar power as of June, 2007 was 2.12 MW.[5]

Israel

In 2005, the Israeli government announced an international contract for building a 100 MW solar trough plant to supply the electricity needs of more than 200,000 Israelis living in southern Israel. The plan may eventually allow the creation of a gigantic 500 MW power plant, making Israel a leader in solar power production.[6]

Japan

As of 2004, Japan had 1200 MWe installed. Japan currently consumes about half of worldwide production of solar modules, mostly for grid connected residential applications.

South Asia

Solar power in South Asia

South Korea

South Korea installed about 21 MW of photovoltaics in 2006, mostly because of feed in tariffs.[7]

Australia

Main article: Solar power in Australia

The largest solar power station in Australia is a 400 kW (peak) photovoltaic array at Singleton, New South Wales.

Other significant solar arrays include the 220 kWp array on the Anangu Pitjantjatjara Lands in South Australia, the 200kWp array at Queen Victoria Market in Melbourne and the 160kWp array at Kogarah Town Square in Sydney.

A 30 MWe solar thermal `coal saver' system is currently under construction at Liddell power station by Macquarie Generation and Solar Heat and Power. The system used `compact linear Fresnel reflector' technology developed in Australia. It will provide solar-powered steam to the 600 MW black coal power station's boiler feedwater heater. The project is funded by Macquarie Generation in order to meet its requirements under the Australian Mandatory Renewable Energy Target (MRET) scheme.

A 154 MW (peak) solar power station in Victoria will soon begin construction.[8] [9]

A building-integrated photovoltaic (BIPV) installation of 60 kW in Brisbane (at the Hall-Chadwick building) has an uninterruptible power supply (UPS) which gives around 10-15 minutes worth of emergency power in the event of the loss of electricity supply. Any power not used by the UPS is connected to the grid and goes towards reducing the building's overall power bills.

Numerous smaller arrays have been established, mainly in remote areas where solar power is cost-competitive with diesel power.[10]

Europe

Main article: Solar power in the European Union

Crete

A large solar PV plant is planned for the island of Crete. Research continues into ways to make the actual solar collecting cells less expensive and more efficient.

Germany

Main article: Solar power in Germany

Germany was the fastest growing major PV market in the world in 2005, particularly because of implementing a Feed in Tariff. In 2005, 837 MWp of PV were installed. The German PV industry generates over 10,000 jobs in production, distribution and installation. Over 90% of solar PV installations are in grid-tied applications in Germany. The balance is off-grid (or stand alone) systems.[11]

Completed in 2006, the 12 MW Solarpark Gut Erlasee photovoltaic system, near Arnstein in Bavaria, Germany, is currently Germany's largest PV system [12]. The 10 MW Solarpark Bavaria in Germany was also the largest PV installation when completed in 2005, covering 25 hectares (62 acres) with 57,600 photovoltaic panels [13].

Portugal

Main article: Solar power in Portugal

On April 27, 2006, GE Energy Financial Services, PowerLight Corporation and Catavento Lda announced that they will build one of the world’s largest solar photovoltaic power projects. The 11-megawatt solar power plant, comprising 52,000 photovoltaic modules, will be built at a single site in Serpa, Portugal, 200 kilometers (124 miles) southeast of Lisbon in one of Europe’s sunniest areas. [14]

Spain

Main article: Solar power in Spain

In March 2007, Europe's first commercial concentrating solar power tower plant was opened near the sunny southern Spanish city of Seville. The 11 megawatt plant known as PS10, produces electricity with 624 large heliostats. PS10 is the first of a set of solar electric power generation plants to be constructed in the same area that will total more than 300MW by 2013. This power generation will be accomplished using a variety of technologies. [1]

Two 50 MWe solar thermal trough power plants, AndaSol-1 and AndaSol-2, are being built in the region of Andalucia, each with a 510,120 m² solar collector field and six hours’ thermal storage. The AndaSol-1 project obtained financial closure in May 2006 and has received a €5 million grant from the European Commission’s (EC) Fifth Framework Programme, along with financial support from the German Federal Ministry for Environment. Construction started in July 2006 and will be completed in 2008. [2]

A 15 MWe solar-only power tower plant, the Solar Tres project, is in the hands of the Spanish company SENER, employing United States molten salt technologies for receiver and energy storage.

The Plataforma Solar de Almería (PSA) in Spain, part of the Center for Energy, Environment and Technological Research (CIEMAT), is the largest center for research, development, and testing of concentrating solar technologies in Europe.[15]

United Kingdom

Main article: Solar power in the United Kingdom

In the United Kingdom, the second tallest building in Manchester, the CIS Tower, was clad in photovoltaic panels at a cost of £5.5 million and started feeding electricity to the national grid on November 2005.[16]

North America

United States

Main article: Solar power in the United States
A laundromat in California supplements water heating with solar panels on the roof.

The world's largest solar power plant, the solar trough-based Solar Energy Generating Systems (SEGS), is located in the Mojave Desert. Solel[17], an Israeli company, operates the plant, which consists of 1000 acres (4 km²) of solar reflectors and produces 354 MW (compared to the largest PV plant of 12 MWp). At the beginning of 2005, this plant was estimated to produce 90% of the world's commercially produced grid-connected solar power,[6] however the rapid growth of photovoltaics has increased the percentage generated with photovoltaics. By the end of 2006 624 megawatts of photovoltaics had been installed in the US,[18] and 830 megawatts by the end of 2007.[19] In the near future, very large scale photovoltaic projects are proposed which "could generate many times the current primary global energy supply".[3] To compensate for night time energy needs large pumped storage capacity would also be needed.

In some areas of the United States, PV electric systems are already competitive with utility systems. As of 2005, there is a list of technical conditions that factor into the economic feasibility of going solar: the amount of sunlight that the area receives; the purchase cost of the system; the ability of the system owner to sell power back to the electric grid; and most important, the competing power prices from the local utility. For example, a photovoltaic system installed in Boston, Massachusetts, produces 25% less electricity than it would in Albuquerque, New Mexico, but yields a greater savings on utility bills since electricity costs 60% more in Boston.

In addition to these considerations, many states and regions offer substantial incentives to improve the economics for potential consumers. Up until December 31, 2008 homeowners can claim one federal credit of up to $2,000 to cover 30% of a photovoltaic system's cost and another 30% credit of up to $2,000 for a solar thermal system. After that there is no limit on the 30% credit through the end of 2016. Fifteen states also offer tax breaks for solar, and two dozen states offer direct consumer rebates.[20]

Solar One was a pilot solar thermal project in the Mojave Desert near Barstow, California. It used heliostats, and molten salts storage technology, to achieve longer periods of power generation. It was rebuilt as Solar Two, which elaborated on the success of Solar One. It was an R&D project, partly financed by the US federal Department of Energy. Solar Two used liquid salts as a storage medium in order to continue to provide energy for much of the time when sunlight is not available. Its success has led to the larger Solar Tres project in Spain.

Nevada Solar One is the third largest solar power plant in the world, generating 64MW. It is being built in Boulder City, Nevada. [21] Nevada Solar One will use parabolic troughs as thermal solar concentrators, heating tubes of liquid (solar receivers), instead of the power tower concentrator (as Solar One used).

On August 11, 2005, Southern California Edison announced an agreement to purchase solar-powered Stirling engines from Stirling Energy Systems over a twenty year period and in quantities (20,000 units) sufficient to generate 500 megawatts of electricity.[22] These systems — to be installed on a 4,500 acre (18 km²) solar farm — will use mirrors to direct and concentrate sunlight onto the engines which will drive generators. Less than a month later, Stirling Energy Systems announced another agreement with San Diego Gas & Electric to provide between 300 and 900 megawatts of electricity.[23]

On January 12, 2006, the California Public Utilities Commission approved the California Solar Incentive Program[24], a comprehensive $2.8 billion program that provides incentives toward solar development over 11 years.

A survey conducted in May 2007 showed that 87% of Americans think that solar electricity should be an option for all new home construction, up from 77% a year ago.[25]

In April 2007 MMA Renewable Ventures, a MuniMAE company, announced they will be leasing 140 acres (0.57 km2) at the western edge of Norris Air Base in Nevada to build a 15 MW PV system by the end of the year, slated to be the countries biggest, and is expected to generate over 25 million KWh/year.[26] The power plant, Nellis Solar Power Plant, was completed in December, 2007.

On July 25, 2007, PG&E signed an agreement with Solel, the same firm that runs the SEGS plants (see above), for 553 megawatts of solar power in the Mojave Desert.[27]. If completed on schedule (2011), it will displace SEGS as the largest solar power plant in the world.

Mexico

Mexico is already the greatest solar energy producer in Latin America and it is planning a solar trough based plant with 30MW which will use a combined cycle gas turbine about 400MW to provide electricity to the city of Agua Prieta, Sonora. The World Bank has financed this project with US$50 million.