Solar energy is a huge, inexhaustible and clean resource.

Solar power generation is a clean alternative to electricity from produced fuel, without air and water pollution, the absence of global environmental pollution and no threats to our public health. Only 18 sunny days on Earth contain the same amount of energy as is stored in all the reserves of the planet coal, oil and natural gas. Outside the atmosphere, solar energy contains about 1300 watts per square meter. After it reaches the atmosphere, about one third of this light is reflected back into space, while the rest continues to follow to the surface of the Earth.

Averaged over the entire surface of the planet, a square meter collects 4.2 kilowatt-hours of energy each day, or an approximate energy equivalent of almost a barrel of oil per year. Deserts with very dry air and some cloudiness can get more than 6 kilowatt-hours per day per square meter on average throughout the year.

Conversion of solar energy into electricity

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Photovoltaic (PV) panels and the concentration of solar energy (CSP) objects capture sunlight can turn it into useful electricity. Roof PV panels make solar energy viable in virtually every part of the United States. In sunny locations such as Los Angeles or Phoenix, a 5 kilowatt system produces an average of 7,000 to 8,000 kilowatt-hours per year, which is roughly equivalent to using a typical US household electricity.

In 2015, nearly 800,000 photovoltaic systems were installed on rooftops across the United States. Large-scale PV projects use photovoltaic panels to convert sunlight into electricity. These projects often have outputs in the range of hundreds of megawatts, and these are millions of solar panels installed on a large area of ​​land.

How do solar panels work

Solar photovoltaic (PV) panels are based on high, but surprisingly simple technology that converts sunlight directly into electricity.



In 1839, the French scientist Edmond Becquerel discovered that some materials would emit sparks of electricity when struck with sunlight. The researchers found that in the near future this property, called the photoelectric effect, could be used; The first photovoltaic (PV) cell was made from selenium in the late 1800s. In 1950, scientists at Bell Labs redefined technology and, using silicon produced in photovoltaic cells, were able to convert the energy of sunlight directly into electricity.

PV cell components

The most important components of a PV cell are two layers of semiconductor material, usually consisting of silicon crystals. The crystallizing silicon itself is not a very good conductor of electricity, so impurities are intentionally added to it — a process called the doping stage.



The bottom layer of photovoltaic cells usually consists of doped boron, which, in conjunction with silicon, creates a positive charge (p), while the top layer doped with phosphorus, interacting with silicon, is a negative charge (n).



The extra electrons from the n-layer can leave their atoms, while the p-layer captures these electrons. Rays of light "knock out" electrons from the atoms of the n-layer, after which they fly into the p-layer to occupy empty spaces. In this way, the electrons run in a circle, leaving the p-layer, passing through the load and returning to the n-layer.


solar-powered unmanned aircraft

Each cell generates very little power (a few watts), so they are grouped in the form of modules or panels. Panels are then either used as separate units or grouped into larger arrays.

The transition to an electrical system with a large amount of solar energy provides many advantages.



The cost of solar batteries is rapidly decreasing (in 1970, -1kWh of electricity generated from them cost $ 60, in 1980 - $ 1, now -20-30 cents). Due to this, the demand for solar panels is growing by 25% per year, and the annual volume of sold batteries exceeds (in terms of power) 40mW. The efficiency of solar cells, which reached 18% in the laboratory in the mid-1970s, is currently 28.5% for crystalline silicon cells and 35% for gallium arsenide and gallium antimod two-layer plates. Promising elements of thin-film (1-2 µm thick) semiconductor materials have been developed: although their efficiency is low (no higher than 16%), the cost is very low (no more than 10% of the cost of modern solar cells). Soon, scientists believe that the cost of 1 kW-h will be equal to 10 cents, which will put solar energy in first place in the energy independence of many countries.

Perovskite "cheaper" solar energy

Back in 2013, the news spread across the expanses of the network: the mineral perovskite will revolutionize the solar energy industry. Application instead of silicon perovskite will reduce the cost of electricity production using solar panels. Perovskite (calcium titanate) was discovered at the beginning of the 19th century in the Ural Mountains, named after L.A. Perovsky (famous lover of minerals). As a component of the photocell began to be used in 2009.

The batteries are covered by an innovative low-cost photocell, the main advantage of which is that it can convert much more parts of the sunlight into energy. Perovskites are a crystalline structure that allows you to absorb sunlight with maximum efficiency. According to preliminary estimates, the use of perovskite-based batteries can reduce the cost of a kilowatt of energy by seven times.

“The main advantage of new photocells lies not so much in efficiency, but in the fact that the material is damn cheap. Perovskite-based batteries that do not use silicon can make solar energy really massive. ”

Solar energy for data center

10% of all electricity produced in the world is consumed by server farms. Since energy-efficient networks and renewable energy sources are now being introduced in all industries, the data center has not stood aside. The negative impact of server farms on the environment has long been on the lips of environmentalists. Therefore, the owners of data centers seek to reduce the negative impact of their data centers, resorting to advanced energy-saving and "green" technologies of power generation, this can include free cooling, a system of local generating capacity based on renewable energy sources.



As a way out - a solar power station next to the server farm, in those countries where climatic conditions allow. It is ideal for server farms that are deployed in the tropics or subtropics. After all, the use of solar panels on the roof of the data center, in addition to providing "green energy", also helps to reduce the thermal load on the building, since the shadow they create minimizes the amount of heat absorbed by the roof. The solar power plant will reduce the overall negative effect of the data center on the environment, and increase the reliability of data centers located in regions where interruptions in the operation of the central power grid are observed.


large power plant based on renewable energy sources near the Apple data center in Maiden, North Carolina (USA)

Switch, together with the energy company Nevada Power, began the construction of a 100 MW solar station near Las Vegas. In the American media, Switch is called the "troublemaker" in the market for commercial data centers; it is one of the largest players in this industry. The company is engaged in the construction and support of datacenter facilities - buildings and engineering infrastructure without actually computing equipment, its main model of interaction with customers is colocation.


the largest in the world solar power plant Iwanpa with a capacity of 400 MW

In 2015, the United States and Japan began to develop a new mechanism for powering the data center with solar energy. The project involves the study of new opportunities "... the use of a bunch of generating capacity based on solar energy and HVDC class systems (high DC voltage) used to distribute electricity generated by solar panels at the data center level." Such a combination of HVDC and solar panels will provide an opportunity to deploy a single backup power system based on batteries, thus it will be possible to save on capital and operating costs.

Interesting

German architect Andre Broesel from the company Rawlemon has created a solar battery in the form of a moving glass ball. He calls it the generator of the new generation, which will catch the maximum number of rays, as it is equipped with a system for tracking the movement of the sun and sensors for changing the weather, which is 35% more efficient compared to standard solar panels.



In 2015, the Japanese energy company Shimizu Corporation announced its intention to build a large solar power plant on our planet’s natural satellite, the Moon. A power station in the form of rings with solar panels will encircle the moon following the example of the planet Saturn and transmit energy to Earth. From such a solar station Shimizu Corporation expects 13 thousand terawatts of energy / year. The cost and the date of commencement of such a space construction are not yet known.



The institute of progressive architecture in Catalonia has developed a solar panel that can function on plants, moss and soil. The advantage of this technology is the rejection of hazardous toxic materials and heavy metals in the production of solar panels. Here special bacteria are used in tiny fuel cells located in the ground under the plant roots. Bacteria are needed to produce cheap energy in mini-batteries. Plants will ensure the life cycle of bacteria, and water will serve as feed for the entire system. Such an innovative system can work in areas where there is not much sunlight if the plants are replaced with moss, as it can grow in the shade.