Solar photovoltaic energy or PV solar energy directly converts sunlight into electricity, using a technology based on the photovoltaic effect. When radiation from the sun hits one of the faces of a photoelectric cell (many of which make up a solar panel), it produces an electric voltage differential between both faces that makes the electrons flow between one to the other, generating an electric current.
There are three types of solar panels: photovoltaic, generators of electricity to be supplied to homes; thermal, installed on houses to receive the sun directly; and thermodynamic, which operate in varying weather conditions, i.e. at night, when it’s raining or cloudy.
When photovoltaic technology first began, it was used to provide electricity to satellites. According to APPA (the Spanish Association of Renewable Energy Producers), development of photovoltaic panels sped up in the 1950s and has now become an alternative to the use of fossil fuels.
Electricity generated by solar photovoltaic panels is inexhaustible and does not pollute, and thus contributes to sustainable development as well as favoring local employment. Likewise, it can be exploited in two different ways: sold to the electricity grid, or consumed in isolated locations where there is no conventional electricity network.
As such, it is an especially effective system for remote and rural areas, which cannot be reached by electric power lines, or they are difficult or costly to install, and in countries receiving many hours of sunlight per year.
The cost of installing and maintaining solar panels, whose average useful life is over 300 years, has come down noticeably in recent years, as photovoltaic technology has developed. It requires an initial investment and small operational budget, but, once the photovoltaic system is installed, the “fuel” is free and available for life.
Over the next decade, solar energy will become the cheapest source of electricity in many parts of the world, as the cost of photovoltaic panels falls continuously, assures the International Business Times, reporting on research carried out by the German think tank Agora Energiewende.
Since the 1980s, panels for generating electricity from the sun have been falling in price at around 10% per year. At this rate, the technology will be able to provide 20% of global energy needs by 2027.
The reputed business magazine Fortune cited a study that concludes solar energy will be offering more new jobs than the oil sector by the end of this year. In the US, according to the Solar Foundation, jobs grew in 2015 in the solar energy sector for the third year running.
The global market for photovoltaic energy is expected to grow by around 20% in the next two years, adding at least 60 GW in 2016 and over 70 GW in 2017, according to a study by PV Market Alliance (PVMA). The same organization believes demand will continue to increase mainly due to strong growth in India, China, the US and several emerging markets.
Indeed, says PMVA, from data gathered on its renewable energies website, the integration of 51 GW worldwide in 2015 meant the sector set a new record for installed photovoltaic capacity, with Asia the top continent in this respect (thanks to the activity in China and Japan).
In photovoltaic solar panels, peak capacity refers to the amount of kW installed, whereas nominal capacity refers to the capacity of the inverter (the electrical equipment that converts the electricity generated by the panels so it can be used by consumers).
In principle, nominal capacity defines the limit of the plant (one cannot produce more than the inverter can convert). Nevertheless, photovoltaic facilities always install a peak capacity greater than the nominal – more panels – to assure 100% of inverter capacity is used.
A solar photovoltaic plant will be well designed if the peak capacity – panels installed – ensures the inverter can function at 100% capacity whenever it is required.
ACCIONA is a leader in the solar photovoltaic energy field, for its pioneering character in the expansion of this technology in Spain, its international expansion, and its experience in the building of big photovoltaic facilities, having installed or constructed almost 500 MWp in ownership and for customers. These include the 94.3 MWp plant at Sishen in South Africa, the biggest such producer in Africa. ACCIONA has also built, as a contractor for FRV, the biggest photovoltaic in Australia at Royalla (24 MWp), near Canberra. We are also constructing El Romero Solar in the Atacama Desert (Chile), one of the top 10 photovoltaic plants in the world with 246 MWp.
Why was ACCIONA such a pioneer in the development of photovoltaic in Spain? Well, at the start of the 21st Century, it led the construction of the first big plants in Spain. In 2001, we installed the biggest PV plant at the time (1.2 MWp) at Tudela, which is still working perfectly, and over the following 10 years connected another 17 new plants across the country under the “solar farm” system where infrastructure is shared by small individual proprietors.
This track record has made ACCIONA one of the most experienced companies in building big photovoltaic installations, able to carry out highly competitive projects on a large scale and to the most demanding standards, anywhere in the world.