For many years, humanity has been preoccupied with obtaining cheap energy from alternative renewable resources. The transformation of air masses, the tides of ocean waves, geothermal waters - all this is considered as an additional inexhaustible potential as opposed to fossil fuels.
The most promising renewable source is solar energy. After all, it has an enormous resource, carries light and heat, which set in motion all the vital systems on our planet. That is precisely why man envisioned huge prospects for this in himself. Despite a number of shortcomings in this area, solar energy in Russia is gaining momentum.
How electricity comes from light
The conversion of sunlight into electrical energy is called the photoelectric effect. It occurs when a powerful luminous flux falls on the surface of a semiconductor, and in this case silicon. Under its action, detachment of electrons takes place, which is a stream of charged particles called electricity.
The sun constantly generates a huge amount of radiant energy. Each square meter of its surface gives 63 MW to the space. Of course, not all of this energy has a visible spectrum needed to produce electricity.
Having passed the distance between the Sun and the Earth, the light flux loses its intensity, and a square meter of the surface of our planet takes only 0.9 kW. But this is not all the losses. The best of photovoltaic cells can convert 18% of the light output.
Therefore, under the best circumstances, solar cells will produce 160 watts per square meter.
Who leads the market for solar energy
Today, China is the undisputed leader in the processing of solar energy. Its share is 60% of the total electricity received by the world community in this way. The second place is taken by the United States. They produce 10.4%. In an honorable third place is India. Its share is 7.8%. Further descending are Japan, Germany and Brazil. The development of solar energy in Russia does not yet enable it to become one of the leaders. But does this mean that a temperate climate does not allow the proper use of the resource of the most powerful source?
Is there enough sun in Russia
According to the Institute of Energy Strategy, Russia has a huge potential for solar energy, which is expressed in the equivalent of 2,300 billion tons of standard fuel. The economic resource is much smaller - 12.5 million tons of standard fuel. But this is more than enough, given the fact that the amount of energy received from the Sun in 3 days will be greater than all the electricity produced over the year by traditional methods.
The amount of solar radiation varies greatly due to the geographical location of Russia. In hot regions, it is 1400 kWh / m2, and in cold regions - 810 kWh / m2. Also, this indicator depends on the time of year. In the summer months it is higher, and in winter - vice versa.
The prospects for solar energy are very high for some regions.
These include:
- Far Eastern District;
- Western and Southern Siberia;
- areas surrounding the Black and Caspian Seas.
According to the operator of the Unified Energy System, the share of electricity production in solar energy in Russia is 0.03% of the total.
To date, over 10 solar power plants operate in Russia, which produce a total capacity of 72.5 MW.
The development of solar energy in Russia
An active consideration is underway of projects for the construction of power plants on the territory of the Crimean Peninsula. To make it non-volatile, it is necessary to generate an additional 2.5 billion kW. It is planned to partially cover this need with the help of solar and wind energy, which will additionally produce 196 million kW. into the general power grid.
In other parts of Russia, in particular, in the city of Narimanov, it is planned to build a solar power plant with a capacity of 25 million kWh / year. The Far East is not far behind. To meet the energy demand, the construction of a 40 MW solar power plant is planned in the Republic of Sakha.
Another 5 projects will be implemented after 2018. Thus, the construction of large solar power plants in Russia is not a distant future.
Autonomous power supply for a private house
In Western countries, for example, in Germany, the transfer of a private house to the supply of electricity from solar panels is encouraged. Moreover, if surplus resources are formed, then they are bought from the population. Thus, in the daytime they are sold to a company supplying electricity, and at night when there is no sun, electricity is bought back. In Russia, such a system does not work. However, if solar panels produce more energy than necessary, it can be stored in batteries.
How the number of solar panels is calculated
In order to calculate the number of solar panels to supply the house, you need to find out how much kW was spent during the month. Then divide the resulting number by 30. This will be the average value of the required amount of electricity per day. In order to have a power reserve for charging batteries, you need to take an additional factor of 1.6. After that, you can start choosing solar panels.
To operate an autonomous power supply system, in addition to solar panels, you must at least have an inverter, without which the voltage in the home network will be only 12 or 24 volts.
Solar panels
The phenomenon of energy conversion of sunlight was discovered back in the 19th century. Selenium was used as a semiconductor producing electricity. It had an efficiency of about 1%. During this time, technology has stepped forward and modern solar panels for private homes have an efficiency of up to 35%. By their design, they are divided into 3 varieties:
- Monocrystalline. The photocells of these panels are made of a single crystal. They have the highest prices and efficiency. These devices can be recognized by their rich blue color.
- Polycrystalline. These batteries are made of several silicon wafers, which affects the conversion of light to electricity worse. However, lower cost affected their wide distribution. Most often, solar panels for private homes install this type.
- Thin film. These batteries are a powder semiconductor deposited on a flexible base. Therefore, they can be mounted on any surface. The disadvantage is low efficiency.
From what principle was applied in the manufacture, how much the solar battery costs will depend.
Inverter
The solar battery consists of many photovoltaic modules that produce a voltage of 0.6 volts. The minimum indicator that the battery should give out is 14 volts, so the elements for converting energy are connected in series. This voltage should be enough to charge the batteries, which are allocated excess electricity. But how to make it possible to use household appliances, because the voltage in the home network is 220 volts?
For these purposes, an inverter is used. Its task is to convert 12 volts to 220. In addition, alternating current is used in the network, and solar panels generate direct current. It is the inverter that converts electrical energy in such a way as to give characteristics that correspond to the home network.
Controller
The controller is the main distribution device in an autonomous energy supply system. The inverter, batteries, electric cable of the city network are connected to it. Why is this done?
In the daytime, when the solar panels generate excess electricity, the controller directs the surplus to charge the batteries. Then, in the evening and night hours, when there is no solar energy, this device sends electricity from the batteries to the inverter connected to the network of the house. But there are cases when the current in the so-called "reservoirs" becomes insufficient to carry out any tasks. Then the controller decides to take the necessary electricity from the city network. Thus, he carries out effective management.
Batteries
The main problem of solar energy is the need to use batteries. These elements of the power plant significantly increase the cost of the system. Cheap car options will not work here because of their quick failure. Even in gentle mode, they have not been working for more than three years. Intensive work shortens their service life to a year. If there is a need for energy storage, then you need to consider other options:
- Lithium iron phosphate batteries (lifepo 4). This is the best option, because it has an efficiency of up to 98%. This means that he gives almost as much energy as he receives. Manufacturers promise a service life of about 15 years, 3000 charge cycles with a discharge of 80% and 5000 cycles with a discharge of 50%. The cost of such a battery with a capacity of 240 A / h is more than 50 thousand rubles.
- Lead-acid traction batteries. Such batteries are installed on electric cars, electric forklifts. They are able to tolerate deep discharge. Service life is 10-12 years. Prices for such batteries start at 30 thousand rubles.
- Nickel-cadmium batteries. This is one of the most expensive varieties. The cost of a battery with a capacity of 250 A / h starts at 70 thousand rubles. These batteries are good in that, following the manufacturer's recommendations, they last a long time. In addition, when the capacity decreases over time, it can be returned to the training cycles of discharge-charge.
Rechargeable batteries are consumables for solar energy. In Russia, prices for suitable batteries are unreasonably high, and greatly reduce the profitability of using natural resources. You need to purchase such a device only from trusted manufacturers.
Experience in use in private homes
How much does a solar battery cost? Is there any economic benefit from using them?
According to various sources, the cost of equipment offered by manufacturers to receive electricity from the sun is in the range of 40-300 thousand rubles. for a medium-sized house. In this range is the price of both ready-made kits and individual elements.
The equipment is designed for a service life of 20 years and above. The exception is batteries.
If you take the cost of payments for electricity, add the price of heating to it, then the amount will be at least 50 thousand rubles a year. This is for central Russia. Thus, a set worth 300 thousand rubles, which is capable of delivering from 3 to 5 kW in its peak value, pays for itself in a few years.
If we analyze the rate of decline in prices for such products, then the use of solar panels becomes justified.