- Posted by: Администратор
The transition to low-carbon energy, as one of the main options for solving the problem of global warming due to carbon dioxide emissions into the atmosphere in all spheres of human activity, is becoming increasingly relevant. How is this problem solved? What alternatives does the domestic energy industry have? To these and other questions to the readers of the journal “Academy of Energy. Maxim Anatolyevich Savitenko, Director, and Boris Adamovich Rybakov, Ph.D., Chief Technologist of the ANO Center for Research and Scientific Developments in the Field of Energy “Hydrogen Technological Solutions” are responsible.
“EA”: Does carbon dioxide alone lead to global warming?
Of course not. The number one greenhouse gas is water vapor. It is followed by methane, nitrous oxide and other gases.
Unfortunately, the efforts of developed countries to reduce the rate of increase in the average temperature of the atmosphere are reduced to reducing carbon dioxide emissions into the atmosphere.
If we consider the problem of global warming more deeply, then in addition to greenhouse gases, many types of human activity lead to emissions of thermal energy into the atmosphere.
A simple example. If you heat a stove or fireplace with firewood, then water vapor, carbon dioxide and thermal energy fly out through the pipe into the atmosphere. All these components lead to an increase in the ambient temperature. Part of the thermal energy that maintains a comfortable air temperature in your home eventually also enters the atmosphere and will contribute to global warming.
If we take into account only carbon dioxide emissions into the atmosphere, then the electricity produced at nuclear power plants can be classified as climate neutral. But for steam condensation in steam turbine condensers at nuclear power plants, so-called “wet” cooling towers are used, steam from which enters the atmosphere.
“EA”: And do water vapor significantly affect the climate?
– Water has the strongest effect on the thermal balance of the planet Earth. But developing an adequate mathematical model that could accurately show the role of water in climate change is not an easy task.
We all know that water can be in three aggregate states: liquid, solid (ice) and gaseous (steam). But it is enough to pay attention to clouds that are at different distances from the earth or water surface. They block the sunlight from us, which leads to a decrease in the air temperature under the clouds.
Speaking of water vapor, you need to understand that it is transparent and not visible to the human eye. But we should know that in clear weather, water vapor dissolved in the air retains infrared radiation (thermal energy) of the Earth. As the temperature rises, the ability of the air to dissolve water vapor increases. Consequently, the greenhouse effect caused by water vapor increases.
“EA”: We are increasingly hearing about hydrogen technology solutions. If we take hydrogen and, say, methane. As a result, what is more environmentally friendly to get the same amount of energy?
– When burning 1 kg of hydrogen, 9 kg of water is formed in the form of water vapor.
Opponents of hydrogen combustion say: “We will not burn hydrogen, but will receive electricity in fuel cells.” They “forget” to report that water vapor is formed at the outlet of the fuel cell, in addition to electricity.
Burning 1 kg of methane generates 2.75 kg of carbon dioxide and 2.25 kg of water vapor.
It should be taken into account that when burning 1 kg of hydrogen, 120 MJ of thermal energy is released if the water vapor is not condensed, and 141.8 MJ if the resulting water vapor is condensed.
When burning 1 kg of methane, 50 MJ of thermal energy is released, if the heat released during condensation of water vapor is not taken into account. Therefore, to obtain 120 MJ of thermal energy generated by burning 1 kg of hydrogen, it is necessary to burn 2.4 kg of methane. Accordingly, when burning 2.4 kg of methane, 6.6 kg of carbon dioxide and 5.4 kg of water vapor will “fly away” into the atmosphere.
That is, when burning an equivalent amount of methane, more carbon dioxide and less water vapor will be released into the atmosphere.
EA: What is the effect of individual greenhouse gas emissions from the combustion of natural gas and carbon?
– When comparing greenhouse gas emissions into the atmosphere, a different effect will be obtained if only carbon dioxide is taken into account and if total emissions of carbon dioxide and water vapor are taken into account.
We just talked about comparing the emissions of hydrogen and methane into the atmosphere, which is the main component of natural gas. And the composition of the latter varies from field to field. If we talk about natural pipeline gas, which is produced in Russia, then its composition is quite stable. At the same time, its mass heat of combustion is slightly lower than the mass heat of combustion of methane and is on average equal to 48.5 MJ/kg.
To obtain an amount of energy equivalent to burning 1 kg of hydrogen, it is required to burn 2.47 kg of natural gas. At the same time, 6.8 kg of carbon dioxide and 5.6 kg of water vapor will enter the atmosphere.
In addition to methane, natural gas contains ethane, propane, butane, pentane, hexane and other hydrocarbons, as well as oxygen, carbon dioxide, nitrogen and other gases.
Therefore, an accurate assessment of greenhouse gas emissions from the combustion of natural gas can only be made by having its component composition.
“EA”: How deep studies have been conducted to determine the role of water vapor and carbon dioxide in global climate warming?
– Let’s remember how the theory of global warming itself appeared. In 1824, the French physicist Joseph Fourier suggested that the earth’s atmosphere could increase the surface temperature. He also first used the phrase “greenhouse effect” in 1827.
At the beginning of the XIX century, scientists became convinced that the temperature of the earth’s surface does not depend only on direct solar radiation. This confirmed Fourier’s theory that the atmosphere returns some of the already reflected radiation to the planet’s surface.
The father of the theory of global warming is considered to be the Swedish chemist Svante Arrhenius. Back in 1896, he calculated that doubling the composition of CO2 in the atmosphere could cause warming of the average temperature of the Earth’s surface from 5 to 6 degrees Celsius. It is important to note that coal was burned in Europe in those years. For his research, this scientist received the Nobel Prize.
However, repeated calculations revealed serious errors and controversial assumptions in his calculations and he was forgotten for a long time, as well as about possible global warming.
After the 2nd World War, the topic of the greenhouse effect was raised by the American military. It is clear that their research had nothing to do with the climate: they were looking for ways to use infrared radiation and checked its passage through the Earth’s atmosphere. Water and CO2 vapors did not pass infrared rays.
In 1961, Irishman John Tindall identified water vapor and carbon dioxide as the main atmospheric factors of the greenhouse effect and suggested that changes in the composition of the atmosphere could affect climate change.
Until the end of the 20th century, these were just controversial theories that periodically arise in scientific debates and do not appear in public policy.
In the article “Rising Levels of Human-Caused Water Vapor in the Troposphere will Intensify Climate Change Projections”, written by Rick Pantaleo in 2014, it is reported that scientists are considering water vapor, which is the most important ingredient for maintaining life on Earth and a key driver of global warming.
Further research by scientists from the University of Miami Rosenstiel School of Marine and Atmospheric Science and from Florida confirmed that the increase in water vapor levels in the troposphere will play an increasing role in climate change in the coming years. It was assumed that the increasing amount of water vapor in the atmosphere was caused by human activity, which was subsequently confirmed.
The article “The Importance and Nature of the Water Vapor Budget in Nature and Models”, Lindzen, Climate Sensitivity to Radioactive Perturbations: Physical Mechanisms and Their Validation (1996) reports quantitative data on the effect of water vapor and carbon dioxide concentrations on the greenhouse effect. The author reports that with a clear sky, the contribution of water vapor to the reflection of long-wave radiation is 75 W/m2, while the contribution of carbon dioxide is only 32 W/m2. That is, the contribution of water vapor to the greenhouse effect exceeds the contribution of carbon dioxide to the greenhouse effect by 2.34 times.
Russian researchers also claim in their publications that water vapor is an important greenhouse gas.
In the article “Spectroscopy of the greenhouse effect” (Sorovsky Educational Journal, volume 7, No. 10, 2001) Tonkov M. V. Writes: “The main absorbing gases in the Earth’s atmosphere are water vapor and carbon dioxide.”
Ptashnik I. V. in his dissertation on the topic “Continuous absorption of water vapor in the centers of the near-infrared bands” (2007) reports that “water vapor, despite its relatively small partial content in the Earth’s atmosphere, is the most important component that determines its radiation balance. The absorption bands of water vapor and the areas between them (the “wings” of the bands), called “transparency windows” of the atmosphere, absorb up to 70-80% of the solar radiation incident on the atmosphere. Water vapor is also one of the most important greenhouse gases in the atmosphere.”
In his dissertation for the degree of Doctor of Physico-mathematical Sciences on the topic “Experimental study of induced and continuous absorption of IR radiation by the main atmospheric gases” (Obninsk 2014), Yu. V. Baranov concludes that “binary absorption coefficients for a mixture of carbon dioxide with water vapor are approximately an order of magnitude higher than the values for pure CO2”.
“Scientific Russia” (2018) in the article “Nizhny Novgorod physicists have understood the reason for excessive absorption of energy by water vapor” reports that “Water vapor strongly absorbs electromagnetic waves in the range from radio to ultraviolet. This makes it the main greenhouse gas of the atmosphere, and, therefore, a factor that has a significant impact on the Earth’s climate.”
Despite a large number of scientific publications confirming the role of water vapor in the greenhouse effect, no official document recognizes this fact.
EA: What is the advantage of hydrogen energy?
– It should be noted that our research is devoted to the application of hydrogen technologies in the energy sector, primarily in thermal energy. After all, it is in it that hydrocarbon fuels such as coal, fuel oil and natural gas are burned.
In parallel, we are studying ways to produce “green” hydrogen using renewable energy sources from the sun and wind.
We have noticed that in addition to electricity, water is required to produce hydrogen by electrolysis.
In accordance with the decree of the Government of the Russian Federation, it is planned to export from 15 to 50 million tons of hydrogen by 2035. To produce 1 kg of hydrogen by electrolysis, approximately 50 kWh of electricity and 9 liters of desalinated water are required. It is easy to calculate that the production of 50 million tons of H2 will require 2500 million kWh of electricity and 450 million tons of demineralized water!
It is difficult to talk about the advantages of using hydrogen in the energy sector without discussing the specific technology of its conversion into energy.
We concentrate our research on the combustion of a mixture of hydrogen and natural gas in boilers and gas turbine installations, as well as the development of systems for condensing water vapor of flue gases. After cleaning the condensate, it can be used to produce hydrogen by electrolysis. Thus, it is possible to make a significant contribution to reducing the consumption of water necessary for the production of hydrogen, as well as to a significant reduction in water vapor emissions into the atmosphere. When the water vapor of flue gases condenses, the specific emissions of carbon dioxide into the atmosphere are significantly reduced.
In our opinion, it makes sense to produce hydrogen at the place of its consumption, and to deliver electricity from renewable energy sources to the places of hydrogen production via DC power lines.
So far, there are no incentives in Russia to reduce carbon dioxide emissions into the atmosphere, but, nevertheless, we must be ready to offer technical solutions that will reduce greenhouse gas emissions into the atmosphere, both with and without the use of hydrogen.
It is known that the cost of “green” hydrogen is significantly higher than the cost of an equivalent amount of natural gas. But recent events in Europe have shown that natural gas prices have risen to values exceeding the cost of hydrogen production by water electrolysis using electricity obtained from renewable energy sources.
EA: What do you think are the prospects for hydrogen technologies in Russia and in Europe?
– Recently, the Ministry of Industry and Trade published an Atlas of Russian projects for the production of low-carbon and carbon-free hydrogen and ammonia, which includes 33 projects. Without taking into account the project of constructing a tidal power plant in the Penzhinskaya Bay of the Kamchatka Territory, where it is planned to produce 5 million tons of hydrogen by 2031.
The total hydrogen production of the remaining projects on the territory of the Russian Federation for the production of hydrogen intended for export should amount to 1.6 million tons by 2030.
The available information is not enough to discuss in detail the technical solutions that are planned to be used in the implementation of these projects.
The first question is: which electrolyzers will be installed at hydrogen production plants: domestic or foreign? How is it planned to transport hydrogen? The stages of project development are unclear, their cost and the projected price of hydrogen are unknown. It is unclear who will be the consumer of hydrogen in the territory of the Russian Federation?
Judging by the atlas of Russian hydrogen projects, “green” hydrogen and “green” ammonia are planned to be produced using the energy of existing hydroelectric power plants and the energy of “new” tidal power plants.
As a rule, large hydroelectric power plants are located in Siberia, that is, far from possible hydrogen consumers, and to produce hydrogen using the energy of future thermal power plants, huge investments will be required in the design and construction of tidal power plants themselves, as well as in seawater purification systems and hydrogen production plants, which will require powerful electrolysis plants. As well as for hydrogen, which is planned to be produced next to the hydroelectric power station, the issue of hydrogen delivery to consumers remains open.
As for Europe, they are 10 years ahead of us, if not more. In the EU countries and in the UK, the production of electrolyzers and fuel cells, equipment for SES and wind farms has been established. It is planned to put into operation 6 GW of electrolyzers in 2024 and 40 GW in 2030.
If we take the utilization factor of the installed capacity of electrolyzers equal to 0.45, that is, the electrolyzers will work 4000 hours a year, then 500 thousand tons of “green” hydrogen will be produced in the EU countries in 2024, and about 3 million tons in 20230.
The EU has already conducted tests of mixing hydrogen with natural gas and transporting this mixture through a gas pipeline, as well as burning a methane-hydrogen mixture in household gas-using devices.
In a number of European countries, the state encourages the installation of solar panels on the roofs of individual houses, on the roofs and facades of multi-storey buildings. As for the wind farm, hundreds of GW offshore power plants are already being built and planned to be commissioned in Europe.
Calculations have shown that wind farms and SES built in Europe will be able to cover the needs of all European countries in “green” electricity. Hydrogen will play the role of a “secondary” energy carrier, which will allow accumulating excess energy and using “green” hydrogen to generate energy in the absence of the sun or wind.
As for the use of natural gas in European countries after 2050, this is the topic of a separate study.