The sun is not only the star of our solar system but it is also THE star of the new alternatives…
Renewable Energy post one: The Sun
When science creates history
Solar energy has been used for hundred of years, and one of the first people to use it was the Ancient Egyptians to warm their home with specifically designed houses. It is not until 1839 that E. Becquerel, a French physicists discovered that the exposition to light of a material can create a voltage and in 1953 at the Bell Laboratory that the silicon solar cells were discovered. That was the birth of photovoltaic energy, the transformation of light (photons) into electricity (voltage).
Electrons are freed in the solar cells by the influence of an external source of energy. In the photovoltaic system, this energy is brought by the photons, the components of light, which hits electrons and induces a current flow, and therefore electricity.
What makes solar energy so valuable
– The solar cells are mostly made of silicon, which is the 2nd element most abundant on Earth’s crust. Great, we wont run out!!!
– The use of panels made of solar cells is widely spread nowadays and constitute a clean source of energy. Clean considering there is no polluting factors involved and the panels are recyclable.
– Solar energy constitutes a free source available and its inexhaustible. The sun doesn’t send the bill, after you paid for the panels its free!!!
– The proprieties of the system make it durable and solar cells can be used for decades. No fear of replacing the panels every years.
– Additionally, solar power has gain economic competitiveness in recent years, solar photovoltaic are now more attractive than coal in various countries. The solar watt went from 66 dollars in 1970 to 55 cents in 2015 for the US. In some countries you can use but also sell this energy.
Solar power does not only refer to photovoltaic solar technology but also to the solar thermal technology. The later captures the sun’s heat which is either used directly like with the low-temperature solar thermal power or is converted into electricity. Low temperature solar thermal are increasingly used in bioclimatic architecture. You know the design of really funky houses connected with nature which accounts for environmental conditions to maximize thermal comfort inside. The sun is used to heat up a water supplies, which can cover up to 80% of hot water uses and provide a floor heating system. The radiation heats up a fluid connected to a heat exchanger connected to the water supply.
High temperature solar thermal uses parabolic mirrors to collect the sun’s light which heats water or another substance, creates steam, runs turbine and produces energy.
Why the world doesn’t rely on solar energy then ?
There are some issues with this form of energy itself: it can be inconsistent in some countries where solar energy is less available on cloudy days, and it is not equally distributed on the planet. Techniques to distribute the energy to the cloudy areas would need to be put in place which remains fairly expensive to this date. But the main issue holding back solar energy remains the lack of efficient storage system.
Simultaneously, the main slow down is the supremacy of fossil fuel energy. Our entire civilization relays on fossil fuel: power, transportation, light, fertilizer and pesticides, construction materials, most pharmaceutic products, synthetic fibres. The richest corporations of the world built their empire based on the way our system works. So we have a fundamental problem on how our societies function and the way WE see the world. The vision of the planet as a gigantic reservoir that we can be exploited until the last resource is depleted has to be reviewed.
But we are on the right path and in some parts of the world solar energy has become a priority…
A feel – good story: La Reunion
Located in the Indian Ocean, La Reunion enjoys around 1350 hours of sunlight every year and decided to exploit this advantages to its maximum. In 2015, the island has managed to produced 36 % of its electricity with renewable energy (solar, biomass and hydropower combined) and aims to reach 100% by 2025. There are 3 major cases in this story:
1. A project in St Pierre built a large-scale photovoltaic system of 8000 modules spread on top of 3 industrial buildings covering 12000 m2 which produce 1.45 MW of energy. They reduced their CO2 emissions by 1400 tonnes each year. Not only this system produces energy but it also provides insulation of the buildings, reduce the need for air conditioning and the energy consumption of the buildings themselves. The solar panel are hurricane-resistant up to 210km/h of winds.
2. In St Joseph, a project launched by Akuo Energy uses solar panels installed on the rooftops of greenhouses. This solar farm covers 1.3ha, supplies more than 1000 peoples with clean energy, produce more than 2000MWh of electricity. It also produces organic vegetables sold at the local market and served in local canteens.
3. Last but not least, Akuo Energy developed a solar farm at the « Le Port » city detention centre. 27000 photovoltaic panels were put in place providing electricity for 12 000 homes and 6000 m2 of solar greenhouses. This project was build with the Ministry of Justice and assists in the reinsertion of the prison population with training programmes in building solar panels. Inmates learn also how to use the land and grow vegetables.
Also, the company EDF is developing new technologies for better storage capacity to compensate the irregularities happening with less production between peak generating times or when energy is consumed. A battery bank has been installed in St André being one of the largest examples of energy storage in Europe.
This story is a great example where the space can be shared between renewable energy and agriculture. Greenhouses produce energy on their roofs with solar panels, produce vegetables from the soil, crops are protected from hurricanes, rain water is collected which provides a total autonomy with water. Such projects create employment and can help communities with social rehabilitation. What are we waiting for ?
If you enjoyed the read and are interested in other alternatives, follow my next post with my next feel-good story in Iceland on the quest of Geothermal Energy…
Illustration and top photo from the author of this blog.
Ksudiram, S. (2008). The Earth’s Atmosphere. Springer Berlin Heidelberg. doi: 10.1007/978-3-540-78427-2
Scheer, H. (2004). Solar economy (1st ed.). London, England: Earthscan.