Solid municipal waste disposal and wastewater treatment are important issues in the modern urban economy. Landfill gas can be considered as both a harmful air pollutant and a valuable fuel. However incineration was the most widespread way to prevent methane and hydrogen sulfide release into the athmosphere. The feasibility of various energy-related technologies including internal combustion engines and fuel cells for landfill gas utilization to produce electricity and heat was evaluated in terms of capital and operation expenses, lifetime, air pollution, and cogeneration possibility. The specific cost of energy was used as a criterion for technologies comparison. The calculation technique involved a mass and energy balance, including the pretreatment of landfill gas. Expenses related to the replacement of key components after the end-of-life and the payments for air pollutant emissions were also taken into account. The calculations were verified for the Timokhovo landfill (Moscow region, Russia), where five 2 MW gas-piston engines operating on biogas are currently installed. The gross and technical energy potentials of landfill gas in the Russian Federation were estimated and presented in the form of maps using QGIS software.

Reducing greenhouse gas emissions remains a topical issue in fundamental and applied scientific research, including in terms of analyzing developed and applied CO2 capture technologies. The main focus is on methods of carbon dioxide burial in stable geological formations, absorption, filtration, etc. The absorption of carbon dioxide during photosynthesis is usually associated with terrestrial biota, although aquatic organisms have a higher productivity of photosynthesis. The use of microalgae as photosynthetic agents is determined mainly by their value for obtaining high-quality food and feed additives, pharmaceutical products, and biofuels, but it is important to consider their effectiveness in the associated absorption of CO2. When producing products with a long carbon sequestration period, this method can be included in the list of effective carbon capture technologies. To estimate the specific energy costs for CO2 absorption, proven cultivation methods were considered: open-plane cultivators (microalgae Arthrospira platensis, growth rate from 20 to 40 g/m2 per day on dry matter) and cylindrical closed photobioreactors (microalgae Chlorella vulgaris, growth rate 0.7 g/dm3 per day in dry matter). Based on experimental results of microalgae cultivation under conditions of elevated CO2 concentrations, it is shown that specific energy consumption is in the range from 27 to 768 GJ/t when cultivating A. platensis microalgae and from 59 to 373 GJ/t in microalgae cultivation of C. vulgaris. The greatest energy costs are required for heating and lighting microalgae plantations as well as for separating biomass from the culture liquid for microalgae with small cell sizes. Specific energy consumption can be reduced by maximizing the use of natural light and waste heat from industrial facilities and optimizing biomass collection systems.

Nowadays, it is important to create the optimal technology for the absorption of flue gases with high CO2 content. In this regard, the aim of the investigation is to study the five different microalgae strains (Chlorella vulgaris, Chlorella ellipsoidea, Elliptochoris subsphaerica, Gloeotila pulchra, and Arthrospira platensis) under the influence of flue gases. The cultivation of microalgae was carried out in the atmosphere of flue gases with a gas flow rate of approximately 1 L·min−1 at high CO2 concentrations (3, 6, or 8%—from lower to higher concentrations), under continuous (24 h·d−1) illumination intensity of 200 µmol quanta·m−2·s−1 and a constant temperature of 27 ± 1 °C. The duration of the experiments was 12 days. Chlorella vulgaris and Chlorella ellipsoidea demonstrated the highest biomass growth rate at CO2 = 6% (0.79 and 0.74 g·L−1·d−1, respectively). The lowest growth rate (0.21 g·L−1·d−1) was achieved for Arthrospira platensis at CO2 = 3 and 6%. There was no significant drop in pH in the entire series of experiments. The results of microscopy showed a lack or a minimal number of dead cells in the strains under selected conditions. The obtained results can be used for further development of CO2 capture and storage technologies.

Experimental studies and assessment of the state of cyanobacteria/microalgae Arthrospira platensis in a sustainable consortium with heterotrophic bacteria were carried out grown by bubbling culture medium with microalgae by a mixture of flue gases and air. The investigations were carried out in an experimental sample of a gas chamber with photobioreactors, which was supplemented by a designed flue gas generation system. The CO2 content in the gas mixture was 3, 6, and 8%. The resulting growth rate of microalgae biomass density was 0.21 g/l per day at CO2 concentrations of 3 and 6%, 0.27 g/l per day at 8%. The present growth rate was 1.75 – 2.25 times higher than the growth rate in experiments conducted when growing this microalga in mixtures of air and CO2. An increase in the amount of carbohydrates in biomass to 29.4% and the lipid content at the level of 21 – 23% was recorded, which makes biomass attractive for biofuel production.

At present the use of organic waste for energy production has become a significant part of the world energy industry. Thereby both the problem of energy supply and waste disposal are solved. In connection with the large volumes of annually formed resource, the ability to provide inexpensive logistics and the demand for ener gy at the level of local consumption the task of recycling agricultural waste is of particular interest. The paper presents a methodology for assessing the crop waste energy potential, taking into account the type of crops, the energy content and specific features of their processing to produce thermal energy. The regions of the Russian Federation leading in the production of cereals, sunflower and corn, i. e. Stavropol Territory, Krasnodar Territory and Rostov Region, were chosen as study areas, both due to the significant energy potential and the available experience of producing energy from wastes in the South of Russia. The quantities of thermal energy that can be obtained from the waste of these crops are determined (the totals for all crops are 14 600 000, 30 500 000 and 29 100 000 million Gcal/year for the regions, respectively), as well as the share of heat supply coverage in the residential sector of the regions (124, 120 and 160%, respectively). The cluster analysis methods allowed identifying groups of districts that are self-sufficient in terms of the local energy resource, as well as potential “donors” of fuel from waste. The results are displayed on charts and a series of maps.

The problem of municipal solid wastes' (MSW) utilization is one of the most actual all over the world nowadays. In Russia, landfills are still the main way for MSW utilization. However, waste decomposition, leading to landfill gas generation, causes, on the one hand, a lot of complaints from local people mainly due to hydrogen sulphide emissions. On the other hand, landfill gas, containing 40–60 vol

This work is centered on the comparative appraisal of various waste gas mixtures which can be utilized for electric power and heat generation using solid oxide fuel cells (SOFCs), on the main sources of these gases, and on technological aspects related to their use. Particular emphasis is given to the waste gases produced by municipal solid waste landfills and industry, including coke oven, blast furnace and converter gases from metallurgy, gas from underground coal mines, agricultural and food industry produced biogas, and hydrogen-containing wastes from chemical industrial processes. The advantages and limitations of SOFCs are analyzed with respect to the mature technologies based on reciprocating internal combustion engines and gas turbines, where successful pilot projects of the waste gas utilization were well documented in the literature, and other types of fuel cells. The high-calorific waste generation dynamics, gas purification methods and state-of-the-art SOFC developments are briefly addressed.

A brief review of geoinformation systems (GIS) intended for collection, storage, integration, analysis, and graphical interpretation of spatial and temporal data on various technologies for the application of renewable energy sources (RES) to make substantiated decisions on the development of RES based energy (here in after referred to as renewable energy) is presented. The development of the geoinformation system “Renewable Energy Sources of Russia” (GIS “RES of Russia”) commenced in 2010 and was performed by specialists from the Faculty of Geography of Lomonosov Moscow State University and JIHT RAS. It is focused on the spatial mapping of solar and wind energy resources for the territory of Russia. The initial data for the assessment of these resources are formed mainly on the basis of satellite measurements, mathematical modeling and verification of the results against ground-based meteorological observations. The geographic information system also contains data on operating and designed renewable energy facilities and scientific, educational, and commercial organizations engaged in this area. As the geoinformation system has been developing, it has been supplemented with information on the distribution of geothermal energy resources and the energy of small rivers over the territory of Russia as well as with estimates of the specific capacity of solar and wind energy installations, the gross and technical potential of crop, livestock, horticulture, and viticulture waste. The paper briefly describes the methods and approaches employed for the development of GIS, including those for improvement of resource data spatial resolution and calculation of renewable energy sources technical potential considering hi-tech advancements. Lines for further development and improvement of the domestic geoinformation system are formulated.

The paper presents the potential of the wind resources for energy supply in the Kamchatka Territory. This region is isolated from the United Energy System of Russia and has a large number of remote settlements. The possibility of using wind energy resources in the region to replace diesel power plants and to reduce CO2 emissions are assessed. Estimates of the average power output values of the wind turbine Enercon E-53 810 kW, on the basis of hourly data on wind resources over a 10-year period (2011-2020) and the share of consumer load coverage for 11 settlements in the region are calculated. Territorial distribution of the specific power generation potential for this wind turbine model is presented with the use of GIS technologies. Daily and seasonal variations in productivity and share of load coverage, as well as the territorial distribution of these characteristics of the energy supply potential by the use of wind resources, are determined.

Тhe article contains the estimation of global investment costs required for the global energy transition to zero-carbon economy by 2050. The evaluations are based on the data on global energy supply and its forecast to 2050, assumption that all the global energy needs are to be satisfied only through non-carbon facilities, and data on investment costs per unit for the facilities that use different types of non-carbon energy carriers. The authors conclude that the total costs of the energy transition worldwide are some $120 trillion, and that achieving the goal of totally non-carbon economy by the middle of the century would require a sharp, two-threefold, increase in investments in energy supply comparatively with the modern level, including acceleration in development of hydro and nuclear energy.

The influence of elevated CO2 concentrations on the growth and viability of various microalgae strains was studied. Arthrospira platensis, Chlorella ellipsoidea, Chlorella vulgaris, Gloeotila pulchra, and Elliptochloris subsphaerica were tested. The cultivation of microalgae was carried out at constant CO2 concentrations (0.04, 3, 6, or 9%—sequentially from lower to higher concentrations), under constant (24 h·day−1) illumination with an intensity of 74.3 µmol quanta·m−2·s−1, and a constant temperature of 23.5 ± 0.5 °C. The optical density of the microalgae biomass, pH, and the chemical composition of the culture medium were measured. Microscopy (including the cytochemical microscopic method) was conducted to monitor the state of the microalgae. The highest biomass growth rate (0.37 g·L−1·day−1), among all experiments, was achieved for Chlorella vulgaris at CO2 = 3% and for Chlorella ellipsoidea at CO2 = 6 and 9%. The lowest growth rate (0.12 g·L−1·day−1) was achieved for Arthrospira platensis at CO2 = 3 and 9%. The microscopy results showed the absence or a minimum number of dead cells of the strains under selected conditions. The ability to maintain the viability of cultures up to significant concentrations of CO2 = 9% was due to adaptation (gradual increase in CO2 concentrations in the experiments).

Measures to support electricity generation at low-power plants using the renewable energy sources as well, which were introduced in the Russian Federation, actualized the task of assessing the effectiveness of such legislative initiatives. The paper presents and tests a methodology for assessing the performance and economic efficiency of network photovoltaic stations, depending on physical-geographical and socio-economic factors. The results of assessing the potential performance of stations in various regions of Russia, obtained on the basis of archives of data on incoming solar radiation for the period from 2010 to 2020, are presented with one hour resolution. It is shown that economic efficiency of Solar Microgeneration Stations (SMS) in the study areas varies widely depending on the combination of such factors as the amount of solar radiation, retail and wholesale electricity tariffs, and the regime of electricity consumption by SMS owners. Despite significant solar energy resources, the payback period of photovoltaic stations in the regions of Southern Siberia (Irkutsk, Ulan-Ude) turned out to be the longest among all areas under study because of the established tariffs for electricity sale and purchase. Optimal conditions for the operation of such stations are characteristic only for the regions of Russia that belong to non-price zones and territorially isolated energy systems of the wholesale market (Magadan and Kaliningrad regions, Kamchatka, Primorsky Krai), where high wholesale electricity prices make the payback expectable within the guaranteed life of the station equipment (20 years).

In modern energy, various technologies for absorbing carbon dioxide from the atmosphere are being considered, including photosynthetic microalgae. An important task is to obtain maximum productivity at high concentrations of CO2 in gas–air mixtures. In this regard, the aim of the investigation is to study the effect of light intensity on the biomass growth and biochemical composition of five different microalgae strains: Arthrospira platensis, Chlorella ellipsoidea, Chlorella vulgaris, Gloeotila pulchra, and Elliptochloris subsphaerica. To assess the viability of microalgae cells, the method of cytochemical staining with methylene blue, which enables identifying dead cells during microscopy, was used. The microalgae were cultivated at 6% CO2 and five different intensities: 80, 120, 160, 200, and 245 μmol quanta·m−2·s−1. The maximum growth rate among all strains was obtained for C. vulgaris (0.78 g·L−1·d−1) at an illumination intensity of 245 µmol quanta·m−2·s−1. For E. subsphaerica and A. platensis, similar results (approximately 0.59 and 0.25 g·L−1·d−1 for each strain) were obtained at an illumination intensity of 160 and 245 µmol quanta·m−2·s−1. A decrease in protein content with an increase in illumination was noted for C. vulgaris (from 61.0 to 46.6%) and A. platensis (from 43.8 to 33.6%), and a slight increase in lipid content was shown by A. platensis (from 17.8 to 21.4%). The possibility of increasing microalgae biomass productivity by increasing illumination has been demonstrated. This result can also be considered as showing potential for enhanced lipid microalgae production for biodiesel applications.

Decarbonization of the power industry requires the search of methods for cutting down the greenhouse gas emissions into the environment, including utilization of carbon dioxide generated during combustion of hydrocarbon fuels at power facilities. One of the promising methods is the capture of carbon dioxide by biota, not only by terrestrial plants but also by aquatic organisms, including specially cultivated microalgae. In this work, the efficiency of the capture of carbon dioxide with a concentration of approximately 6 HCO_3^ - , CO_3^2 - ) by microalgae during the bubbling of cultural liquids with a gas–air mixture with different carbon dioxide content was performed. In general, good viability of A. platensis microalgae (high quality of biomass and high rate of its growth) was demonstrated when it was cultivated in an atmosphere with a high concentration (6

In this work, experimentally evaluated the viability of a consortium microalgae Arthrospira platensis rsemsu P Bios with heterotrophic bacteria when cultivated in a gas-air mixture with high concentrations of CO2 (from 0.04 to 9%). A laboratory setup was created to test the viability of microalgae strains at high concentrations of CO2. The experiments were carried out using 12 photobioreactors with a culture medium volume of 4 L each, placed in a gas chamber, which makes it possible to create elevated CO2 concentrations in the gas-air medium. The maximum growth rate of biomass of microalgae A. platensis is 170 mg/(l per day), the maximum absolute increase in biomass for 12 days is 1540 mg/l. The relatively low growth rate and absolute increase in the biomass of A. platensis at all concentrations of CO2 in the gas-air mixture may indicate that this culture requires a longer laboratory adaptation to high concentrations of CO2. The high cell viability found in all experiments by cytochemical staining of cells with methylene blue indicates the acquired tolerance of the culture to elevated CO2 concentrations (3–9%). However, after 12 days of the experiment with 9% CO2, morphometric signs of cell suppression are detected, which is expressed in deviations of the cell shape from normal, elongation (lack of division) and an increase in the number of dead cells. Quantitative characteristics of the microalgae consortium viability have been obtained.

Hydrogen energy technologies are considered as the cutting-edge clean energy technologies all over the world. Novel concept of hydrogen energy development in Russia, proposed by Government has hydrogen technologies equipment development, production and introduction into domestic market as one of the tasks. Foreign experience shows that governmental support is very important for successful branch development. Waste hydrogen from chlorine industry utilization can be energy-efficient and attractive niche for fuel cells and hydrogen-fuelled heat engines application. Lifetime and capital costs are important parameters for technology choice decision. Energy cost and hydrogen consumption comparison were carried out for gas microturbines (MGT), fuel cells (FC) and internal combustion engines (ICE) in this paper. Analysis showed polymer electrolyte membrane fuel cells and gas microturbines to be the most promising technology in this niche while for internal combustion engines lifetime is an issue. Solid oxide fuel cells need significant capital costs decrease for successful market introduction. Solid oxide fuel cells, MGT and ICE have also additional advantage for Russian conditions due to high-potential heat production possibility.