Choosing solar panels for your home

Not so long ago, free electricity seemed like something out of science fiction. But engineering is moving forward and now the share of alternative energy is becoming larger. Gradually, more and more people are using autonomous solar systems based on solar panels. They become an effective source of free energy with reasonable financial investments. Solar energy is converted into electrical energy through photocells, and you receive it absolutely free. At the same time, the sun is a renewable and free source of energy. Solar systems are becoming increasingly popular amid rising tariffs for electricity and heat. The production of solar panels on an industrial scale has been launched in the USA, Europe, China, and some CIS countries. In Russia, there are factories in Moscow, Zelenograd, Krasnodar, and Ryazan.

Solar batteries as part of solar systems are used mainly to generate electricity for private homes, country houses, as well as various mobile structures that are located far from power lines. In the southern regions, such installations can be found in rest homes, sanatoriums and other institutions. In fact, solar panels can be installed in any home where there is a need for additional electricity. Of course, there must be free space to install the system. A solar cell consists of a set of photovoltaic converters connected in a series circuit. The batteries themselves can be combined in parallel or in series to increase the power of the system.

Types of solar panels

Solar panels for the home are usually classified by the type of solar cells from which they are assembled. These photocells differ in their manufacturing technology and surface. There are three main types:

• Photocells made of amorphous silicon. Batteries made from these elements are often called film coatings or. The thickness of the semiconductor layer in them is 80–100 microns. They have not yet been widely used due to their low efficiency. Perhaps a little later, with further improvement, they will become more in demand. So far, the main problem with them is to create the same directionality in silicon crystals;
• Photocells made of silicon monocrystals. The most expensive and efficient elements that allow you to assemble batteries that operate in cloudy weather. The production technology of such solar cells uses slow cooling of molten silicon. The result is a homogeneous single crystal of silicon in the form of an ingot. After cooling, it is cut into plates and heat treated to form the necessary structure on the surface. Typically these solar cells are dark blue in color;
• Photocells made of polycrystalline silicon. In this case, the technology of forming crystallization centers is used in the production of photocells. One ingot produces several crystals. Their subsequent heat treatment is the same as for single-crystal plates. In terms of electrical characteristics, they are inferior to single crystals and are cheaper. Externally, they differ in areas on the surface of different colors.

Important parameters of the solar system

When choosing solar panels for your home, you should take into account the climatic conditions of your region. The effectiveness of their work will depend on this. The region should also be taken into account when choosing the type of photocells discussed above. In the southern regions of Russia, in order to save money, you can install polycrystalline ones. There are many sunny days and it is not very cold in winter. For use in the north, it is better to use single crystals that can operate in diffuse sunlight.

Key Features to Pay Attention to:

• Efficiency Usually at the level of 12-15%;
• High resistance;
• Tightness and case material. Usually made of aluminum profile;
• Glass. It's better if it's hardened.

Typically, electric or gas energy is used to heat a house, while the solar system simply supplies the necessary current to the network, working in conjunction with the main source of electricity. There are systems that include, which are connected to a boiler or heating system. In this case, during installation you still need to allocate space for the collector.

As already mentioned, solar panels work as part of solar systems. In addition to them, it includes:

• Battery (one or more);
• Inverter;
• Wires, fasteners.

It is worth noting that during the operation of a solar system for a home, the batteries will have to be changed quite often. The solar panels themselves last 25-30 years. During operation, the current from the solar panels charges the battery, and from it, through the inverter, electricity is supplied to electrical appliances in the house.

As a result, the battery is constantly being charged and discharged. Knowing the price and service life of a conventional one, you can estimate the cost of replacing it when operating a solar system.

One more point is worth noting. Advertising convinces us that solar panels do not require maintenance, but this is not true. The surface of the panels must be regularly cleaned from dust and dirt, and in winter from snow. Otherwise, the efficiency of their work is significantly reduced. And if the panels are installed on the roof or on the facade, the cleaning procedure will be fraught with difficulties. Only with clean panels will your small solar power plant for your home be able to operate at full capacity.

There is also a negative effect from heating batteries in the hot season. Because of this, their efficiency decreases and electricity production decreases.

Today, the advantages and disadvantages of solar panels allow us to talk about these energy sources as the most promising for the near future. Why is it so good and what allows us to talk about the advantages of batteries not only for the home, but also for large enterprises and factories. This article is intended not only to highlight all the advantages, but also to reveal disadvantages that are either kept silent by manufacturers or not disclosed upon sale.

Advantages of solar panels

• The very first plus is inexhaustibility and universal availability of energy sources. The sun is present almost anywhere on the planet and in the near future, it is not going to disappear anywhere. If this source of energy disappears, then we will definitely not worry about where to get electricity from.

• The second advantage of solar panels is their environmental friendliness. Every consumer fighting for the health of his native planet considers it his duty to purchase environmentally friendly energy sources such as a windmill or, in our case, solar panels. But it’s the same here with electric cars. The batteries themselves are environmentally friendly, but during their production, as well as during the production of batteries, power plants and various conductors, toxic substances are used that pollute the environment.

• By the way, speaking of comparison with wind turbines, solar panels are much quieter. They don't make any sounds at all compared to noisy windmills.

• Batteries wear out very slowly, because there are no moving parts, unless you use drives in your system that turn the solar cells towards the energy source. However, even with such a system, solar panels last up to 25 years or even more. Only after this period, if the batteries are of high quality, their efficiency begins to decrease and they gradually need to be replaced with new ones. Who knows what technologies will exist in a quarter of a century? The following batteries may last you for the rest of your life.

• By installing such an energy source for your home, You won't think about the fact that your energy supplier will suddenly cut off your home for technical reasons. from energy supply. You are always your own boss. More precisely, its electricity supply system. There are no problems with sudden price increases or with energy transportation.

• Once your solar power plant has paid for itself, You will essentially receive free energy into your home. Of course, first, over a certain period, you need to recoup the investment.

• Another advantage of solar power plants is expandability. The question depends only on the area available to you. It is the modularity of the batteries that allows you to easily increase the system power if necessary. You just need to add new solar panels and power them into the system. Although these advantages of solar power plants are offset by a significant problem, namely the need to equip large areas. We are talking about square kilometers of solar cells.

• The solar panel does not consume any fuel, which means You are not dependent on fuel prices, just as you do not depend on fuel supplies. The advantages of solar panels are also a continuous supply of electricity.

Pros and cons of solar panels

Despite all the above advantages, batteries also have a lot of disadvantages that need to be assessed when choosing source of energy. It is important to understand all the disadvantages before purchasing, so that later you can be prepared for what you will have to face. For a number of reasons, solar panels are used more often as an auxiliary source, rather than as the main one.

• The very first drawback is the need for large initial investments, which are not required for a normal connection to the central power grid. Also, the payback period for investments in an electrical network with solar panels is very vague, because everything depends on factors that do not depend on the consumer.

• Low level of efficiency. One square meter of an average performance solar panel produces only about 120 watts of power. This power is not enough even to work normally on a laptop. Solar panels have a significantly lower efficiency compared to traditional energy sources - about 14-15%. However, this drawback can be considered quite conditional, because new technologies are constantly increasing this indicator and development does not stand still, squeezing more and more energy efficiency out of the same areas.

• The CIS countries are sunny batteries are quite expensive, because the state does not support the purchase of such energy sources and does not in any way subsidize the desire of its citizens for “green” energy. Of course, the situation abroad is much better. After all, the United States is interested in the country's transition to environmentally friendly energy sources.

• Another drawback - operating efficiency dependent on weather conditions and climate. For example, solar panels lose their efficiency during cloudy weather or fog. Also, at low temperatures, in winter, the efficiency of solar panels decreases. And if the panel is not of good enough quality, then even at high temperatures. Therefore, it is still necessary to support solar panels with some basic energy sources, or use hybrid solar panels. It is also important that solar panels can work differently in different latitudes of the planet. In each individual area, a different amount of solar energy comes out per year. Therefore, the efficiency of a solar system also depends on the location of your home. However, it also depends on the time of day, because at night there is no sun, which means there is no energy production.

• Batteries cannot be used as a source of energy for equipment that consumes a lot of power.

• Solar power system requires a large amount of auxiliary equipment. Batteries for energy storage, inverters, as well as a special room for installing the system. For example, nickel-cadmium batteries lose significant power when the temperature drops below zero Celsius.

• In order to produce more power from solar energy, large areas are needed. If we talk about an industrial-scale solar power plant, then these are square kilometers. Of course, when using panels for everyday use, you will not need such areas, but still take this point into account if you want to expand.

These are the pros and cons of solar panels. We hope our article helped you decide what you need.

The Northern United States Renewable Energy Association, in its 2008 publication Solar Energy, writes:

“Of all the available renewable energy sources, solar energy and solar panels cause the least damage to the environment. Electricity produced using solar panels does not have a harmful effect on the air masses. And it does not pollute either surface or underground waters, does not deplete natural resources and does not pose a danger to either the animal world or human health.

The only really dangerous effect of this type of energy is associated with the production of some toxic substances and chemicals, such as cadmium and arsenic, which are used in the production of solar panels. But, by and large, these negative effects are minimal in scope if there is a well-thought-out policy in terms of their reuse and proper disposal.

Future

In turn, Ken Zweible, Director of the Institute for Solar Energy Analysis at the University of Georgia, in Washington, as well as James Mason, Director of a solar cell company, and Vassilis Fenakis, Chief Research Engineer at Brookhaven National Laboratory, in their joint article from In 2007, the journal Scientific America wrote about plans for the future.

“We believe that by about 2050, solar cell technology will be able to produce almost 3,000 GIGAWATTs of electrical energy, in other words BILLIONS of watts. About 30,000 square miles of rows of solar panels would be mounted facing the sun on fixed stands. Yes, these squares can seem simply incredible. But the battery lines already installed show that the available land needed to produce each gigawatt-hour of solar power in the Southeast still requires less than the same amount of energy produced by traditional coal-fired power plants.

Research conducted by the Energy Laboratory in Kolo shows that there are more than enough land resources in the South-East of the country. There is no need to touch areas sensitive to the penetration of machines and people. There is also no need to somehow interfere with the lands of populated areas in this regard or even go deeper into difficult territories. The beneficial nature of solar energy itself, its environmental friendliness, including reasonable water consumption, reduces concerns about the environmental effects of batteries to a minimum."

In 2008, the Energy Efficiency of Renewable Solar Energy (EERE) posted the following material on its website in the “Why Solar Energy Is So Important” section:

“Small electrical substations cause little damage to the environment, just like solar panels. Surprisingly, while so easily producing the electrical energy a person needs, solar panels do not pollute the environment and do not produce emissions and waste that are risky for fauna and flora. This energy production requires neither liquid nor gaseous fuel, it does not need to be transported or burned."

In turn, Vassilis Fenakis, a senior researcher at the Center for Engineering Sciences at Brookhaven National Laboratory, in a 2004 article “Cadmium telluride circulation and its harm during the production of solar cells” in the section on renewable and renewable energy writes:

“If we take a broad view of the problem, the environmental risks from solar panels are minimal. The estimated air emissions from production are 0.02 grams of cadmium telluride per GIGAWATT hour of electrical energy produced over the life of the solar module, which is very low.

Large-scale use of solar panels does not pose any risk to human health and living beings. And recycling modules that have already served their service life almost completely eliminates the concerns of “green” people about the harmfulness of this type of electrical energy production.

During their operation, solar modules do not produce environmental pollution, and moreover, by gradually replacing traditional types of fuel (gas, oil, coal), they bring significant benefits to the environment. Cadmium telluride in solar batteries actually turns out to be much more nature-friendly than all other types of cadmium batteries currently in use, including the famous nickel-cadmium ones.

Minuses

However, not everything is so simple in the matter of environmental safety from the huge MASS of solar panels.

In the chapter entitled “Solar and Wind Energy Are Unproductive and Harmful to the Environment,” the author, Paul Driessen, Ph.D. and fellow of the Building Tomorrow Committee, writes:

“Producing 50 MEGAWATTs of electrical energy using gas combustion plants will require approximately 2 to 5 acres of land. To get the same amount of energy from solar modules you will have to cover - attention! - about a THOUSAND acres of land with solar panels (and this is even taking into account the optimistic figures for energy production of 10 watts per square meter or 5% efficiency at peak production).

An equally important problem is to provide free access to trucks with water in order to wash all this “forest” of solar modules. Meeting California's energy needs with solar modules, for example, would require sacrificing tens of thousands of acres of land. But these prairies are called almost the most unique and beautiful examples of real Wildlife. Wild Wild West. This is one of the most majestic and beautiful landscapes in all of America, and it will have to be sacrificed on the altar of solar energy, along with the animal and plant life of this territory.

The California Energy Commission's Public Interest Energy Public Interest Research (PIER) program, Electric Energy Research Institute (EPRI) in a November 2003 report entitled "Potential Health and Environmental Harm Associated with the Production and Use of Solar Cells", available on the EPRI website , wrote the following.

“The production of solar cells itself involves the use of certain toxic gases, explosive volatiles, corrosive liquids and suspected carcinogenic – cancer-causing – reagents. The magnitude of possible negative effects on human health and Nature in the case of the production of solar panels varies depending on the toxic materials used, their saturation, intensity of use, and the duration of their exposure to humans under production conditions.”

Spent modules

Disposal of significant volumes of used solar modules in a specific area leads to an increased risk to human health in that area. It is also detrimental to local flora and fauna. Leakage of chemicals from disposed modules has the potential to contaminate local soil and surface water.


Flora and fauna in these areas may be severely impacted in the immediate vicinity of possible leaks or accidental releases into the atmosphere. Leaks can lead to explosive concentrations of hazardous substances around the production facilities where modules are produced. And this is a direct and obvious threat to the health of people working here.

The surrounding water, air, and soil will absorb harmful chemical emissions. Contaminated water will poison the soil, and the inhaled air will also be partially poisoned by emissions.

Hit the living

“Emissions of chemical toxic compounds during the production of solar modules lead to a weakening of the resistance of living beings to diseases and a deterioration in their fertility, that is, the ability to produce healthy, full-fledged offspring. There is also increased mortality and poor growth in children and young animals. The intensity and severity of negative impacts will vary depending on the amount and type of harmful substances released during the production of solar capture modules..."

Based on materials from the Electric Energy Research Institute (EPRI), 2003. California Energy Commission.

In turn, Howard Hayden, Ph.D., Professor Emeritus at the University of Connecticut, in the 2005 book “Solar Trap: Why Solar Energy Hasn’t Conquered the World” writes:

“The Barstow, California, solar array, codenamed Solar #2, covers 52.6 hectares (nearly 130 acres) of land and produces approximately 10 megawatts of electricity at peak output. Productivity reaches only 16%. For such installations like “Solar-2”, in order to produce the same amount of energy as a typical 1000 megawatt power plant using conventional fuel, 33,000 (!) hectares of land will need to be covered with solar modules in a year. Or in other words, 127 square miles of area! And this is already serious damage to the environment.

The number of solar panels on our planet is constantly growing, but there is no talk of any qualitative breakthrough in this area yet. Perhaps, when engineers figure out how to reduce the area of ​​​​solar modules and how to organize their self-cleaning, when they remove some volatile dangerous compounds and gases from the production chain, then things will go better. But from an environmental point of view, solar power plants are still not completely harmless to the environment.

Depletion of natural resources and worsening environmental problems are the main reasons for the development of renewable energy sources:

Billions of kilowatts of radiant energy are sent to Earth by the Sun, the source of life on our planet. Using this energy and converting it into much-needed electricity is achieved by using solar panels as converters. Solar batteries are one of the most promising sources of electricity for both industrial enterprises and household use.

A solar battery (module, panel) is a direct current photovoltaic generator, the operating principle of which is based on the physical property of semiconductors: photons of light knock electrons out of the outer orbit of semiconductor atoms, creating a sufficient number of free electrons to generate an electric current. When the circuit is closed, an electric current occurs. To obtain the required amount of power, usually one or two elements are not enough. Therefore, they are combined into panels, where they are connected in parallel or in series to obtain the required current and voltage parameters. The area of ​​such panels varies from a few square centimeters to several square meters. As the number of panels increases, the power produced also increases. Conversion efficiencysolar energy in electricity depends not only on the area of ​​the battery, but also on the intensity of sunlight and the angle of incidence of the rays, which means the efficiency of the battery is determined by its location (geographical latitude), weather, time of year and day.

The main advantage of a solar battery, as well as solar energy in general, is the general availability and inexhaustibility of the energy source (the Sun).

The theoretically recognized environmental safety of solar panels increases the number of potential consumers of solar energy, especially among fans of “green” technologies. It should be noted here that toxic substances are often used in the production of solar cells and in the materials used for their production, as well as in additional equipment for solar power plants (batteries).

Solar panels have virtually no wear and tear since they contain no moving parts and rarely fail.

Long service life without deterioration in performance characteristics - 25 years or more, which is confirmed by many years of practice.

The functioning of solar panels does not depend on technical problems of energy suppliers.

Solar batteries do not require fuel, which makes it possible not to depend on fuel prices or transportation problems.

In addition, solar panels are silent, which compares favorably with wind systems.

The energy generated by solar panels is actually free (one “but” - all this is only after the initial capital has already been invested in the solar energy system and it has paid off).

One of the advantages of photovoltaic systems is modularity. As energy consumption and/or finances increase, a homeowner using solar panels as an electrical source can increase the system's output by adding additional photovoltaic modules.

However, despite the significant number of advantages, solar panels are more often used as an auxiliary source of power supply.

There are several reasons for this, and the most significant of them are the high cost of the solar battery and insufficient efficiency. On average 1 sq. A meter of solar battery area produces no more than 120 W of useful power. This energy is not enough even to run a computer. On average, the efficiency of solar panels used to power buildings is 14%, which is less than the efficiency of traditional energy sources.

The high cost of batteries also determines the long payback period, and, consequently, the high price of the energy produced during this period. With the improvement of existing technologies and the emergence of new developments, this disadvantage is gradually being overcome. In general, solar panels in modern Russian conditions are still an expensive pleasure. The situation is better in the West, thanks to government programs to support green technologies and large investments in solar production.

Solar panels are ineffective in winter, as well as in cloudy and foggy weather. Dependence on weather conditions forces the use of solar panels in conjunction with other alternative energy sources as part of hybrid systems, as well as the use of storage systems to store energy in case of bad weather.

The flow of solar energy to the surface of the earth depends on the latitude and climate of the area. In different places around the globe, the amount of solar energy falling on the earth can vary greatly.

For devices that consume high power, solar panels are not suitable.

The use of power systems based on solar panels requires the installation of additional equipment (batteries, inverters, etc.) and the availability of auxiliary premises to accommodate it.

Solar power plants do not generate electricity at night and do not operate efficiently in diffuse solar radiation in the mornings and evenings. The orientation of solar panels relative to the Sun allows them to increase the current they generate, but the daily orientation of the batteries is quite difficult. Existing solar tracking systems (trackers) to some extent save the situation and increase the efficiency of the system, but they are expensive and require maintenance. Therefore, their use is usually limited to large power systems. Considering that the peak of electricity consumption occurs in the evening hours and power fluctuations are possible when the weather changes, it is necessary either to use efficient electric batteries (and this is also a problem for now), or to build powerful pumped storage stations, which also occupy considerable areas, or to use the concept of hydrogen energy, also for now far from perfect. It should be noted that nickel-cadmium batteries do not perform well at high and low temperatures. Lowering the battery temperature below 0° C leads to a significant decrease in their power.

To accommodate powerful power plants for industrial purposes, vast free territories are required. For example, a 1 GW power plant requires several tens of square kilometers of area. This problem is now being successfully solved by placing solar panels on large solar power plants at a height of 1.8 - 2.5 meters, which makes it possible to use the land under the power plant for various agricultural needs, for example, grazing. In addition, there are still quite large areas in the world that have not been developed by humans (for example, deserts). The use of solar balloon power plants can also be a solution to the problem of finding large areas of land for solar power plants.

The surface of solar panels must be periodically cleaned of dust and other contaminants, which causes certain difficulties in the case of large power plants covering several square kilometers.

The efficiency of photocells decreases when they are heated and, since they operate under solar radiation that heats them, there is an urgent need to install cooling systems, usually water.

After 30 years of operation, the performance of photovoltaic cells begins to decline.

A significant disadvantage of solar batteries is the presence of toxic substances in the composition of the solar cells themselves (lead, cadmium, gallium, arsenic, etc.) and the use of toxic substances in their production, despite the environmental friendliness of the electricity produced. After 30-50 years of using batteries, the problem of their disposal inevitably arises, which has not yet been resolved from an environmental point of view.

Types of solar silicon batteries.

There are several types of solar silicon batteries, depending on the manufacturing method. The most efficient type of solar panels are made from monocrystalline silicon. Apart from a slight darkening of the technological polymer, which is a sealant for the plates, solar cells practically do not change their technological parameters over a long service life.

Solar batteries made of polycrystalline silicon have a maximum efficiency of up to 15% and a service life close to the service life of monocrystalline silicon. The cost of polycrystalline silicon is slightly lower than monocrystalline silicon.

With a sufficient number of solar cells, it is possible to create a solar battery with almost any voltage and current and capable of charging any type of battery. It's all about the cost of such a solar battery. Of course, we should not forget that a powerful solar battery will occupy a large area for its installation. It should also be noted that if full solar illumination of the battery occurs for a limited time of day, then it is advisable to use a solar battery that provides an accelerated charging current, the value of which is within 0.15-0.3 of the battery capacity.