1. Introduction
In recent decades, renewable energy has developed enormously throughout the world. The transition to renewable energy sources is considered both in academic and business societies as an essential step towards the formation of a circular economy and achieving sustainable development goals [
1,
2].
The average annual growth rate of installed capacity of renewable energy sources (RES) in the period from 2009-2018 amounted to 8.4% [
3], and, starting from 2015, net capacity additions for renewable power are higher than for fossil fuels and nuclear all together [
4]. The average annual growth rate of energy generation based on renewable energy sources in the period from 2009–2017 amounted to almost 6% (
Figure 1). At the end of 2017, investments in renewable energy-based electricity generation for the first time in history exceeded investments in traditional types of electricity generation (including nuclear energy), most of which came from countries with developing economies [
5]. In 2018 global investment in RES (including large hydropower plants) reached USD 288.9 billion. Despite an 11% decrease compared to 2017, that was the fifth year in a row that investment exceeded USD 230 billion [
4].
Today, almost all countries of the world have goals at the state level for the development of renewable energy [
5,
6,
7,
8]. However, despite significant progress in electricity generation, the introduction of renewable energy technologies in the heat supply and heat generation sector, including for industrial needs, is still slow, despite the fact that these types of final energy consumption have the most significant shares in the global energy balance. Thus, according to REN21 statistics of 2016, 51% of all energy consumed in the world is spent on heat supply, and this sector contributes nearly 40% of global energy-related CO
2 emissions [
4]. The share of modern renewables in final heat consumption globally is only 9.8% and distributed between the following modern technologies [
5]:
1. Biogeneration: boilers using solid biomass; the use of biogas in central heating systems; the addition of biogas to the gas supply grid; the direct use of biogas for cooking.
2.
Solar collectors: used for heating water and, to a lesser extent, heating buildings. In recent years, the scale of use in central heating systems and industry has increased significantly [
5].
3. Geothermal energy: used in central heating systems, for swimming pools, greenhouses, as well as in industry. All three technologies together contribute 8% in final heat consumption.
4. Heating with renewable electricity: the use of electricity generated by solar panels, wind farms, etc., for the operation of heat pumps in the residential, commercial, and industrial sectors. In 2016, this sector contributed 1.8% of the final heat consumption.
The use of solar energy in the heat supply of buildings in the residential and commercial sectors has a rather long history and is well studied in the literature [
9,
10,
11], while the use of solar energy in industrial production is currently only developing. The primary constraint so far is the impossibility of providing round-the-clock heat supply to the production process using solar energy. To overcome this technical barrier, it is necessary to install additional equipment like heat storage systems, which significantly increase the cost of the entire solar installation [
11,
12,
13]. The high initial cost of acquiring and installing equipment (solar collectors and heat storage systems) is the second most crucial constraint, which is especially essential for small and medium enterprises that do not have a sufficiently large volume of current assets [
12]. At the same time, government support measures for the development of this type of renewable energy sources are not yet widespread. So, in 2018, according to REN21 [
4], already 135 countries of the world carried out various government policy measures aimed at supporting renewable energy in the electricity generation sector, while incentive measures for renewable energy technologies in the heating sector were introduced in only 20 countries.
Currently, the use of solar energy is most developed in the food industry [
14], primarily because most of the production processes associated with food processing are low-temperature (
Table 1). So, for example, processes such as various types of drying, cleaning, washing, heating water, pasteurization, and sterilization do not require temperatures above 250 °C, which can easily be achieved using various types of solar collectors. The second most common user of solar collectors is the textile industry, in which many production processes (such as cleaning, drying, washing, pressing) do not require high temperatures [
15,
16,
17].
Depending on the required temperature level of the production process, various types of solar thermal collectors are used, from the most straightforward and cheapest air flat-plate collectors, suitable for temperatures up to 100 °C to the more complex Fresnel collector or parabolic trough collectors for temperatures up to 400 °C [
14,
15,
16,
17].
This study aims to review the current state of the world market of industrial solar collectors and assess the possibilities of their application in individual industrial sectors of the Russian Federation. The rest of the paper is organized as follows: in
Section 2 we describe materials for the study and basic methodology;
Section 3 gives a brief overview of the research background and particular main trends and status-quo of industrial solar collectors in the world and in Russia; in
Section 4 we present the results of calculations for estimation of the expected economic efficiency of industrial solar collectors in the southern regions of Russia and estimation of the potential for their use in the Krasnodar Region;
Section 5 discusses the results of the study and gives some policy recommendations; the final section concludes the study and discusses its added value for academic literature.
2. Methods
The information base of the study was the analytical materials of the project of the World Energy Agency "Integration of Solar Heat into Industrial Processes" (IEA SHC Task49 / IV SHIP), materials of the REN21 expert network and the analytical agency Solar and Wind Energy. The current state and the trends in the development of solar heat in Russia was studied based on the data of Austrian Institute for Sustainable Technologies (IFA Solar Heating and Cooling Program), and the data of Russian Litvinchuk HVAC Marketing Agency (
http://www.litvinchuk.ru/), which specializes in research for heating, air conditioning, and cooling systems markets. The data for assessing the potential of using solar collectors in the industry of the Krasnodar Region were obtained from the statistical collection “Krasnodar Territory in Figures, 2016” [
18] and open data from the Federal State Statistics Service, presented on the official website in the section Technological Development of Economic Sectors / Energy Efficiency (
https://www.gks.ru/folder/11189).
The traditional approach is widely used to calculate the economic efficiency of industrial solar collectors in Russian scientific literature (see, for example, [
11,
19]). This approach is based on calculating the payback period of equipment
T (years) through the cost of replaced energy, the cost of energy produced by the solar collector, and the coefficient of efficiency of conversion of solar energy into thermal energy (the conversion factor) by the formula:
where
—cost of heat generated by the solar collector (rubles/m2);
—cost of replaced energy (rubles/kWh);
—-the total intensity of solar radiation in the plane of the solar collector (kWh/m2);
—the conversion factor of solar energy into heat.
This approach gives the most accurate results in the case of calculating the economic efficiency of a particular solar collector installed in a certain way in a specific geographic location but is poorly suited for predicting and assessing the economic potential of using solar collectors on a scale of the industrial sector of the region. Firstly, it does not take into account changes in the value of money over time (discount coefficient), and secondly, it requires data on the exact locations of all industrial facilities on which the installation of solar collectors is planned. When calculating the regional potential for such a region as the Krasnodar Territory, with an area of 76,000 square km and a length from north to south of more than 320 km, and from west to east of more than 350 km, this approach creates significant computational difficulties [
20] and at the same time does not give any advantages over less accurate methods, since it still leads to the need for data averaging.
Therefore, in this study, we used an approach based on the construction of a linear regression model based on statistics on the performance of flat solar water collectors in different regions of the world presented in the source [
15]. The explanatory variable (proxy) in the model is the level of solar insolation. Further, the calculated value of the productivity of the solar collector was substituted into the formula
LCOE (levelized cost of energy) [
21,
22]:
where
—the unit cost of equipment, taking into account the installation (euro /m2);
—equipment maintenance cost in year t (according to [
23] is assumed to be equal 0.25%–0.5% depending on the type of collector);
—the amount of energy produced in year t;
—the life cycle of equipment (years);
—discount rate, reflecting the change in the value of money over time (for calculations in euros, as a rule, it is assumed to be equal to 3%).
Values and were taken as average for equipment of a similar class, as the average value of labor costs in countries with a comparable standard of living and wages, and as the average inflation rate in Russia over the past five years.
One can quickly notice that the advantage of our approach is, on the one hand, simplicity, and, on the other hand, taking into account essential factors affecting the economic efficiency of the solar collector, such as the costs of its installation and maintenance, the life cycle of the solar collector, and the change in the cost of money over time. Schematically, the logic of our study is reflected in
Figure 2.
Thus, to achieve the main goal of the study, we needed to solve the following two problems: 1) to analyze the structure of industrial production in the region and assess the volume of low-temperature industrial processes, and, possible demand for industrial solar collectors; 2) to determine under what conditions a transition of low-temperature industrial processes to solar energy can be economically feasible.
5. Discussion and Policy Applications
As our analysis demonstrated, the market for industrial solar collectors is a rapidly growing segment of the global market for renewable energy technologies, which is currently developing with minimal government support measures, mainly due to market mechanisms. This indicates the commercial attractiveness of the technology, especially in countries with a high level of solar insolation and well-developed industries characterized by seasonality and a significant proportion of low-temperature processes.
For the southern regions of Russia, the use of industrial solar collectors can be considered a commercially viable alternative to the construction of new boiler houses and heating grids in the case of the creation of new enterprises for processing agricultural products in areas where there are no central heating systems and poorly developed heating grids. Also, the installation of solar collectors can be considered an investment-attractive option for the modernization of worn-out and outdated equipment of traditional boiler houses of industrial enterprises, which allows partially replacing hydrocarbon sources. In both cases, the development of industrial solar collectors will help to reduce the energy and carbon intensity of the Russian economy [
42,
43] and increase the share of renewable energy in the country’s energy balance. This will help the country to fulfill its obligations under the Paris Climate Agreement [
35,
44].
It is also crucial that the use of solar collectors instead of hydrocarbon alternatives for the heat supply of industrial processes has a positive impact on the environment not only at the stage of direct operation of the solar collector but throughout the entire life cycle, including the stages of extraction and processing of raw materials for production of solar collectors, the stage of their production, the stages of transportation and installation, as well as disposal after use [
45]. Thus, the use of solar collectors not only helps to approach the achievement of the goals of decarbonization of the economy, but also is fully integrated into the concept of transition to a circular economy.
Nevertheless, despite the relatively high level of commercial attractiveness and environmental efficiency, the development of solar collectors in Russia, in our opinion, needs certain measures of state support. Given the fact that the general concept of government incentives for development of renewable energy in Russia is aimed primarily at developing national production of equipment for renewable energy sources [
46], it is advisable to direct measures of state support for the development of solar collectors not only to create effective demand (for example, through the system of purchase and installation subsidies for the solar collector), but, first of all, aiming to support existing Russian manufacturers of solar collectors with their technologies and competencies in this field. The creation and expansion of effective demand for solar collectors through customer subsidies can lead to the occupation of the domestic market with products of world leaders that can compete in price due to large-scale production [
47]. Based on international practices, several types of government incentives can be proposed: (i) the government co-financing of demonstration projects of Russian manufacturers; (ii) the introduction of property tax benefits for enterprises using solar collectors in industrial processes; and (iii) the introduction of accelerated depreciation on solar collectors for industrial enterprises [
48,
49]. Also, the Russian practice of stimulating innovative production is rich in positive examples of the development of new enterprises through obtaining the status of a resident of the Skolkovo innovation cluster.
An analysis of the official websites of leading Russian manufacturers of solar collectors (JSC VPK NPO Mashinostroeniya (Moscow), LLC Novy Pole (Moscow), LLC Altenergiya (Krasnodar Region), ANDI Group (Moscow), GreenSun Technologies (Vladivostok)) shows that all of them ( except the Novy Pole company, which has created its own brand and a whole line of products) need serious adjustments to their marketing strategy, development of after-sales services, and diversification of product sales channels. Given this situation, the co-financing of demonstration projects can be proposed as the most likely effective form of state support.
6. Conclusions
In our study, we investigated the prospects for the development of solar collectors in the industry of the southern regions of Russia. As a basis for calculating the demand for industrial solar collectors, we considered the structure of heat supplies and the industrial production of a specific territory. It was shown using the example of the Krasnodar Region that the potential for energy savings in the region’s industry due to the introduction of solar collectors is at least 16–17% of the total volume of thermal energy produced. Converting such a volume of thermal generation to solar energy will require the installation of 5,300,000 m2 of solar collectors, which will create more than 60,000 new jobs in the region.
The economic efficiency of solar collectors is still insufficient to compete with conventional boiler houses operating on cheap hydrocarbon fuels (expected average LCOE 3.8–6.6 rubles/kWh comparing current tariffs 1.5–2 rubles/kWh in a district heating area). However, the installation of solar collectors may well be considered as an investment-attractive option for the modernization of worn-out and outdated equipment of traditional boiler houses of industrial enterprises, which allows partially replacing hydrocarbon sources and lowering the carbon intensity of the Russian economy. As a measure of state incentives for the development of industrial solar collectors in Russia, we offer state co-financing of demonstration projects of Russian manufacturers. This will increase the level of awareness of the population and businesses about the capabilities of this technology, as well as increase the technical competencies and innovation potential of companies involved in the production and installation of solar collectors.
The results of our study can be useful in developing and improving federal and regional programs for the development of renewable energy in Russia and improving the energy efficiency of the Russian economy, as well as the industrial policy of the Russian Federation. They allow policymakers to more clearly classify the industrial enterprises that are most suitable for the introduction of solar collectors and to introduce more effective incentives for the development of this type of renewable energy. Also, these results can be used to calculate the required size of subsidies (or carbon taxes) which allow balancing the economic efficiency of solar collectors with the current hydrocarbon thermal generation technologies in the region.
The results of our study may be applicable outside of Russia. The proposed "demand-side" approach and algorithm for developing a regional strategy for increasing energy efficiency and the reduction of carbon intensity in the industrial sector can be used in other countries and regions.