Solar energy
“Use of solar energy is near a solution”. This was the headline in the New York Times on 4 April 1931. It turned out to be a premonition, since, 80 years later and electricity is being supplied to millions of human beings in the world from renewable energies such as solar. Humanity has now declared its readiness to accelerate the transition to a low-carbon economy, conscious of the finite nature of fossil fuels and their prejudicial effects on the environment as the main cause of global warming.
As the Chilean poet Pablo Neruda chimed in El Sol: “I am a man of light, of so much rose, such predestined clarity, I will die from shining”. Solar energy, on the other hand, will never die of shining, since the Sun still has 6.5 billion years of life according to NASA. Indeed, in rather less time, solar technology in some countries has evolved to compete with conventional sources of electricity generation. In just a few decades’ time, it will become the major part of a sustainable energy system for the world.
Additionally, the conditions for the development of solar energy could not be more perfect: the Sun bathes the Earth hourly with enough light and heat to fulfill global needs for a whole year; in other words, solar radiation can satisfy our energy needs 4,000 times over.
As the publication Renewable Energies Info estimates, the Earth’s surface receives 120,000 Terawatts of solar irradiation, “which represents 20,000 times more power than the whole planet needs”. Backing this argument further, the Union of Concerned Scientists says that as little as 18 days of solar irradiation on Earth contains as much energy as all the world’s coal, oil and natural gas reserves put together.
The NYT article put forward the suggestion that Humanity “will no longer have to fear the exhaustion of coal reserves foreseen within the next few hundred years, if Dr Lange’s theory is right”. Well, the words of German solar energy scientist, Dr Bruno Lange, back in 1931, have been proven right.
What is solar energy?
Solar energy is that produced by the Sun’s light – photovoltaic energy – and its warmth – solar thermal – for the generation of electricity or the production of heat. Inexhaustible and renewable, since it comes from the Sun, solar energy is harnessed using panels and mirrors.
Photovoltaic solar cells convert sunlight directly into electricity by the so-called photovoltaic effect, by which certain materials are able to absorb photons (light particles) and liberate electrons, generating an electric current. On the other hand, solar thermal collectors use panels or mirrors to absorb and concentrate the Sun’s heat, transferring it to a fluid and conducting it through pipes to use it in buildings and installations, and also for electricity production (solar thermoelectric).
What are the benefits of solar energy?
Solar energy offers many benefits that make it one of the most promising energy forms. Renewable, non-polluting and available planet-wide, it contributes to sustainable development and job creation where it is installed.
Likewise, the simplicity of this technology makes it ideal for using in rural or difficultly accessed areas isolated from the network. An example is the rural region of Cajamarca in Peru, where ACCIONA has developed several projects to facilitate electrical self-sufficiency for inhabitants. Solar energy is also useful for generating electricity on a large scale and injecting it into the network, especially in regions where the meteorology provides for lots of hours of sun per year.
Solar capture modules are relatively easy to maintain, which, along with the continuing, sharp reduction in cost of photovoltaic cells, explains the present favorable outlook for solar technology. Solar plants also do not emit polluting gases and are silent.
Another advantage of energy borne from the Sun is its ability to generate local wealth, by lessening energy dependence on abroad. While it is certain that solar energy – like wind – is intermittent and directly depends on the weather and day-night cycles, rapid advances in electricity storage technologies are reducing this dependency and will lead to the increasing share of solar in the energy system.
Summary of the benefits of solar energy
- Renewable
- Inexhaustible
- Non-polluting
- Avoids global warming
- Reduces use of fossil fuels
- Reduces energy imports
- Generates local wealth and jobs
- Contributes to sustainable development
- It is modular and very versatile, adaptable to different situations
- Can be applied alike for large-scale electricity generation and on a small scale in areas isolated from the network
How is solar energy obtained?
The sun provides energy in two different ways:
- It provides heat tapped by mirrors that focus sunlight on a receiver that contains a fluid which reaches temperatures up to 1,000 ° C. The heat transforms the fluid in steam which moves a turbine and finally produces electricity.
- It provides light that is converted into electricity through photovoltaic solar panels. Photovoltaic panels are formed by groups of cells or solar cells that convert light (photons) into electrical energy (electrons).
Sources: Energía solar fuente inagotable | Sostenibilidad para todos, Renewable energies: Solar | Sustainability for all, Energíasrenovablesinfo.com, neruda.uchile.cl, seia.org, nationalgeographic.com, cleantechnica.com, nytimes.com, ucsusa.org
WHAT IS ACCIONA DOING IN THE AREA OF SOLAR ENERGY?
ACCIONA Energy is a global leader in renewable energies and, especially, in the development, construction, operation and maintenance of solar photovoltaic and thermoelectric plants, with over 20 years’ experience in the sector. It carries out solar photovoltaic and thermoelectric projects both as an owner and for third party customers.
In solar photovoltaic (PV), ACCIONA Energy pioneered the installation of large capacity plants (over 1 MW). In 2001, the company built its own plant at Tudela (Navarre), at the time the biggest solar PV facility in Spain with 1.2 MWp. Since then, it has become one of the most specialized companies in this field with 241 MWp of installed capacity, distributed across 26 large facilities, both in ownership and for third parties. Our latest big project is constructing the Sishen plant in South Africa (94 MWp), which has the biggest output on the African continent. Now we are building El Romero Solar in the Atacama Desert, Chile, which is one of the Top 10 plants in the world at 246.5 MWp.
In the solar thermoelectric or concentrating solar power (CSP), energy sector, ACCIONA also has a lot of experience. The company currently operates five own plants in Spain and one in the US, totaling 314 MW of capacity, managed by its Infrastructure division. It has also recently undertaken large projects for customers, such as the plants at Bokpoort in South Africa and Noor 1 in Morocco.
