July 29, 2010 at 22:57EROEI
Recently on Habré the topic " Solar energy has fallen to the nuclear level " was published , which resulted in fierce debate about the appropriateness of using price as an indicator of efficiency. After reviewing the comments, I was surprised to find that they did not mention such an indicator as EROEI. And I thought that the Khabrovsk people would be interested to know about him.
EROEI (ratio of Energy Return On Energy Invested) is expressed in a very simple formula:
EROEI = energy received / energy consumed
In order to produce oil, it is necessary to expend energy on its extraction. To get the decay energy of the uranium core, you need to spend energy on the extraction and enrichment of uranium. To receive energy from a solar battery, it is necessary to expend energy on its production.
EROEI is a universal indicator of the effectiveness of the energy production method. From the point of view of EROEI there are no renewable and non-renewable sources of energy - there are sources whose EROEI decreases with time and sources whose EROEI increases.
EROEI is often criticized, primarily for problems with its calculation. However, unlike the price per kWh, efficiency, occupied area and many other indicators, EROEI is in excellent correlation with reality and perfectly explains the processes occurring in the energy sector.
Let's start with EROEI oil. In the 1930s, EROEI oil reached numbers of 100 or more. Not a single source of energy has come close to this figure. Ultra-high EROEI oil makes it an ideal energy carrier; therefore, the use of oil is extremely effective. Although this is a non-renewable resource, the non-use of such a rich source of energy seems simply silly.
EROEI oil has since been steadily declining; in 1970 it was about 30, and in 2000 - from about 10 to 20 (it is easy to guess that, for example, the EROEI of Russian oil is much lower than that of Saudi). Nevertheless, oil remains a very promising source of energy, although a decrease in EROEI forces it to gradually be replaced.
And here we are faced with the first seemingly incomprehensible paradox, which is perfectly explained with the help of EROEI. As you know, proven reserves of tar (oil) sands are several times higher than oil reserves. Quite often there are allegations that their development will become economically viable at a price of n (30, 50, 100 - I have met different options) dollars per barrel of oil. But the development of these fields is practically not carried out, although only in Canada explored deposits of 1.7 trillion barrels.
The fact is that, in addition to environmental problems, there is also a purely physical problem: EROEI of tar sands is about 2/3. Even according to the most optimistic estimates, the EROEI of oil sands does not exceed 5 - this, of course, is more than one, but still small. If pessimistic estimates are true, then at no price for oil will tar sands become an effective source of energy. The same, in general, is true for oil shales.
EROEI of other non-renewable energy sources - coal and gas - is slightly lower than the oil index, and very much depends on specific technological conditions (for example, gas liquefaction is a very energy-intensive procedure). EROEI gas can range from 16 to just 2, EROEI coal - from 14 to 1.5.
An interesting question is EROEI atomic energy. By themselves, the energy costs of organizing the operation of a nuclear reactor are small, but the extraction and, especially, the enrichment of uranium ore is a very energy-intensive process. EROEI NPP lies in the range from 5 to 10. It should be noted that, if it were not for the low efficiency of converting the energy of fission of uranium into electrical energy, this figure would be much higher (up to 20). For French nuclear power plants (and France receives most of the electricity through nuclear power plants), EROEI averages 6.5 . This is not so much, on the one hand, but not so little, on the other. The EROEI NPP as a whole has already come close to oil performance, and for Russia, probably, exceeded it.
EROEI hydropower is very good - up to 50 on large rivers, and in exceptionally good conditions - up to 200 or more. However, the vast majority of suitable rivers are already covered by hydroelectric power plants, therefore EROEI hydropower is quite arbitrary. Some sources give a scatter of numbers for currently real projects in 5-15, which, however, is pretty good. EROEI for tidal and geothermal power plants lies in the range of about 1.5-10.
The same goes for EROEI wind turbines. In good conditions, this indicator can reach 50 or more, but in more or less real conditions the spread of EROEI is from 5 to 30 ( here is a fairly large study on this subject, including with figures for other energy sources).
A very difficult situation with solar energy is mainly due to the fact that it is difficult to accurately assess the life of the system components. However, even the most optimistic estimates rarely predict an EROEI above 10. Under adverse conditions, the EROEI of a solar installation may be even less than unity. Apparently, solar power plants remain the most inefficient of all alternative energy sources. Therefore, despite significant support, there are quite few solar power plants, despite the attractiveness of this method of generating energy.
And finally, a special song - the so-called biofuel. By and large, a significant part of this business is simply a scam: EROEI of most fuels of vegetable origin (in particular, from corn) less or slightly more than one. The costs of fuels and lubricants and various fertilizers for growing biomass exceed the income in the form of biofuels. Relatively competitive only sugar cane biofuel (EROEI about 8).
And finally, a very interesting picture: the EROEI dynamics of the main energy sources (and the forecast until 2020):
Materials for further reading:
art-of-arts.livejournal.com/tag/%D0%BA%D0%BE%D0%BC % D0% BF% D0% B8% D0% BB% D1% 8F% D1% 86% D0% B8% D1% 8F
netenergy.theoildrum.com
www.eoearth.org/article/Energy_return_on_investment_%28EROI%29_for_wind_energy
www.energybulletin. net / 53475
PS And yes, as Saudi Arabian Oil Minister Sheikh Ahmed Zaki Yamani said, the Stone Age did not end because the stones had run out and the Oil Age would not end because the oil would end.
EROEI (ratio of Energy Return On Energy Invested) is expressed in a very simple formula:
EROEI = energy received / energy consumed
In order to produce oil, it is necessary to expend energy on its extraction. To get the decay energy of the uranium core, you need to spend energy on the extraction and enrichment of uranium. To receive energy from a solar battery, it is necessary to expend energy on its production.
EROEI is a universal indicator of the effectiveness of the energy production method. From the point of view of EROEI there are no renewable and non-renewable sources of energy - there are sources whose EROEI decreases with time and sources whose EROEI increases.
EROEI is often criticized, primarily for problems with its calculation. However, unlike the price per kWh, efficiency, occupied area and many other indicators, EROEI is in excellent correlation with reality and perfectly explains the processes occurring in the energy sector.
Let's start with EROEI oil. In the 1930s, EROEI oil reached numbers of 100 or more. Not a single source of energy has come close to this figure. Ultra-high EROEI oil makes it an ideal energy carrier; therefore, the use of oil is extremely effective. Although this is a non-renewable resource, the non-use of such a rich source of energy seems simply silly.
EROEI oil has since been steadily declining; in 1970 it was about 30, and in 2000 - from about 10 to 20 (it is easy to guess that, for example, the EROEI of Russian oil is much lower than that of Saudi). Nevertheless, oil remains a very promising source of energy, although a decrease in EROEI forces it to gradually be replaced.
And here we are faced with the first seemingly incomprehensible paradox, which is perfectly explained with the help of EROEI. As you know, proven reserves of tar (oil) sands are several times higher than oil reserves. Quite often there are allegations that their development will become economically viable at a price of n (30, 50, 100 - I have met different options) dollars per barrel of oil. But the development of these fields is practically not carried out, although only in Canada explored deposits of 1.7 trillion barrels.
The fact is that, in addition to environmental problems, there is also a purely physical problem: EROEI of tar sands is about 2/3. Even according to the most optimistic estimates, the EROEI of oil sands does not exceed 5 - this, of course, is more than one, but still small. If pessimistic estimates are true, then at no price for oil will tar sands become an effective source of energy. The same, in general, is true for oil shales.
EROEI of other non-renewable energy sources - coal and gas - is slightly lower than the oil index, and very much depends on specific technological conditions (for example, gas liquefaction is a very energy-intensive procedure). EROEI gas can range from 16 to just 2, EROEI coal - from 14 to 1.5.
An interesting question is EROEI atomic energy. By themselves, the energy costs of organizing the operation of a nuclear reactor are small, but the extraction and, especially, the enrichment of uranium ore is a very energy-intensive process. EROEI NPP lies in the range from 5 to 10. It should be noted that, if it were not for the low efficiency of converting the energy of fission of uranium into electrical energy, this figure would be much higher (up to 20). For French nuclear power plants (and France receives most of the electricity through nuclear power plants), EROEI averages 6.5 . This is not so much, on the one hand, but not so little, on the other. The EROEI NPP as a whole has already come close to oil performance, and for Russia, probably, exceeded it.
EROEI hydropower is very good - up to 50 on large rivers, and in exceptionally good conditions - up to 200 or more. However, the vast majority of suitable rivers are already covered by hydroelectric power plants, therefore EROEI hydropower is quite arbitrary. Some sources give a scatter of numbers for currently real projects in 5-15, which, however, is pretty good. EROEI for tidal and geothermal power plants lies in the range of about 1.5-10.
The same goes for EROEI wind turbines. In good conditions, this indicator can reach 50 or more, but in more or less real conditions the spread of EROEI is from 5 to 30 ( here is a fairly large study on this subject, including with figures for other energy sources).
A very difficult situation with solar energy is mainly due to the fact that it is difficult to accurately assess the life of the system components. However, even the most optimistic estimates rarely predict an EROEI above 10. Under adverse conditions, the EROEI of a solar installation may be even less than unity. Apparently, solar power plants remain the most inefficient of all alternative energy sources. Therefore, despite significant support, there are quite few solar power plants, despite the attractiveness of this method of generating energy.
And finally, a special song - the so-called biofuel. By and large, a significant part of this business is simply a scam: EROEI of most fuels of vegetable origin (in particular, from corn) less or slightly more than one. The costs of fuels and lubricants and various fertilizers for growing biomass exceed the income in the form of biofuels. Relatively competitive only sugar cane biofuel (EROEI about 8).
And finally, a very interesting picture: the EROEI dynamics of the main energy sources (and the forecast until 2020):
Materials for further reading:
art-of-arts.livejournal.com/tag/%D0%BA%D0%BE%D0%BC % D0% BF% D0% B8% D0% BB% D1% 8F% D1% 86% D0% B8% D1% 8F
netenergy.theoildrum.com
www.eoearth.org/article/Energy_return_on_investment_%28EROI%29_for_wind_energy
www.energybulletin. net / 53475
PS And yes, as Saudi Arabian Oil Minister Sheikh Ahmed Zaki Yamani said, the Stone Age did not end because the stones had run out and the Oil Age would not end because the oil would end.