Solar systems in order to increase the energy efficiency of residential and commercial buildings

In recent years, the issue of energy stability and security has become one of the most important world and national issues, so it is of great importance for the Republic of Serbia. Many countries, for the sake of faster economic and economic development, have neglected the importance of preserving their environment, but it is encouraging that more and more specific measures are being taken against the ruthless exploitation of our planet, as well as the fight against “leaving a mark” on nature. One of the ways to prevent major damage and start moving towards sustainable development is the introduction of the concept of energy efficiency and obtaining energy from renewable sources. The state itself contributes decisively to the greater use of solar energy in most developed countries in the world in terms of support, better information and other forms of affirming the use of solar energy. The technically usable energy potential of all types of renewable energy sources in the Republic of Serbia is very significant and is estimated at over 4.3 million tons of oil equivalent per year. Of that, about 15% of the reserves lie in the use of solar radiation.

The average solar radiation in Serbia is about 40% higher than the European average, but even so, the use of solar energy for the production of heat and electricity lags far behind when compared with the countries of the European Union. Even more, Serbia is an example of a country that has invested very little in the use of renewable energy sources, although, as stated, it has significant resources at its disposal. With the increase in awareness of the importance of this form of sustainable energy, conditions are created for the development and functionality of a sustainable market for solar thermal and photovoltaic systems, which is of great importance for the economy and the preservation of the natural environment in Serbia.

Solar energy is no longer an “alternative” energy, as it was wrongly considered until recently. Considering the variable price of classic energy sources (fuel oil, gas, and electricity), of which oil and gas are not renewable and whose prices tend to rise permanently, the use of this most efficient renewable energy source becomes an absolute imperative.

Economic and ecological reasons lead to investment and drive investments in projects of application of photovoltaic and thermal systems in new construction of residential buildings and business facilities. In order to significantly increase their application in construction (for residential buildings and commercial buildings), an incentive is needed from the state and financial institutions (banks, investment funds, etc.). The state encourages the environment for such investments, but also by granting the status of a privileged producer with incentive feed-in tariffs, tax and other benefits, etc. Commercial banks in Serbia, according to already established practice from developed countries of the world, approve more favorable loans for investments in the field of renewable energy sources than is the case for conventional technologies.

Sector of the farm

The building sector is one of the most important consumers of energy, and it is believed that around 50% of the total energy produced is spent in buildings, primarily for heating and cooling the space. Adhering to the concept of sustainability, buildings have recently been realized in the world in which the method of construction is based on ecological principles. This principle is used in the planning and design of new residential buildings and business facilities, as well as in reconstruction. Many residential buildings or business buildings have already been built in the world that produce the energy they need by themselves. They do not need any other source of energy during the year. To create sustainable buildings, the long-term goal must be to build buildings that do not need more energy than they can produce themselves.
The use of renewable energy should not be considered as a replacement for conventional energy sources, but as a modern supplement aimed at saving energy and reducing the emission of carbon dioxide into the atmosphere. However, there is still a widely held opinion that renewable energy can only be used efficiently and economically in new buildings. This attitude also extends to solar architecture, as solar thermal and photovoltaic installations can be particularly well integrated if they are planned together with the building as a whole early in the design process. Of course, numerous possibilities remain available for achieving aesthetically pleasing and interesting solutions even on previously built buildings. A special incentive for the wider application of solar energy, both in new and in constructed buildings, is the fact that solar heating is among the cheapest forms of heating when looking at renewable energy sources.

By reducing the consumption of classic primary energy sources and replacing these types of energy with solar energy, the following positive effects are achieved:

  • reduction of greenhouse gas emissions, primarily CO2, which contributes to environmental protection, reduction of global warming and sustainable development,
  • reducing dependence on energy imports,
  • creation of new jobs,
  • increasing security of energy supply,
  • increasing competitiveness on a macro and micro level,
  • reducing energy costs,
  • emergence of new production programs and services.
Based on the above considerations, it can be concluded that solar energy systems provide:
  • good energy efficiency,
  • significant energy savings,
  • longevity,
  • a relatively quick return on investment through the obtained energy,
  • free energy in the period after the return of the investment,
  • favorable price-performance ratio of the system,
  • simple installation, simple use and safety at work,
  • environmentally reliable installation,
  • minimal maintenance cost.
In short, the following advantages of solar energy as a source of energy for heating and preparation of sanitary hot water and for obtaining electricity could be listed:
  • is free and available,
  • it is ecologically clean (there is no combustion, so no harmful gases are emitted),
  • belongs to renewable energy sources, so resource depletion cannot occur unlike coal, oil and gas,
  • contributes to sustainable development, whereby sustainable development means the development of society that is stable over a long series of generations, i.e. energy resources are used to the extent provided by the renewal of nature, in combination with classic energy sources, it increases the energy efficiency of the plant.

Of course, there are limitations and disadvantages that prevent even more intensive use of solar energy. They are primarily reflected in the fact that solar radiation is extremely variable in both direction and intensity. Heat gains are variable during the day and they depend on the height of the sun during the day, cloudiness, precipitation, etc., as well as during the year. In winter, when it is most needed, solar radiation is the least.

The process of our country’s accession to the European Union requires the harmonization of Serbia’s energy policy and the determination of special numerically expressed goals for the share of renewable sources in total energy production. Following global trends and keeping in mind the importance of preserving the environment and mitigating the effects of climate change, the Government of the Republic of Serbia made a decision to encourage the production of electricity from renewable sources by introducing a preferential (feed-in) tariff that allows investors in such systems to return the investment in a short period and make a significant profit. Incentive measures for the purchase of solar electricity depend on the capacity of the power plant and the location, i.e. whether it was built on land or on a building.

Feed-in tariff

Otherwise, the trend in the world is for the price of the feed-in tariff to be lower than the price of electricity paid by the end user, i.e. to bring the price of produced green energy, and thus solar energy, to the level of the price of electricity obtained from fossil fuels. In other words, there is a trend to lose subsidies, to finance green energy projects from real sources without any benefits. In this sense, in the new Law on Energy, the final customer of electricity will bear the burden of renewable sources of electricity. Additional pressure on the energy market is exerted by the future liberalization of electricity trade, as well as obligations towards the Energy Community, of which Serbia is a member.

It should be added that there are systems in the world that have not found a place in subsidizing here. We are talking about BIPV systems (Building Integrated Photovoltaics), i.e. solar systems that are located on the facades of buildings.