Monthly Archives: December 2016

No, there is no scenario “100% renewable energies”

Translation of french site :

“Politicians and journalists affirm it: it would be possible, in France, to increase to 100% of renewable energies. Where do they get that information? No French energy transition scenario asserts that it is possible to dispense with fossil and nuclear energies, even with a drastic reduction in energy consumption.

Electricity or Energy ?

The assertion that it would be possible to switch to 100% of renewable energies generally comes from a study by the French Agency for the Environment and Energy Management (ADEME) published in 2015 on a France fueled  by 100% in renewable electricity. But electricity accounts for less than 23% of France’s final energy consumption. With 100% renewable electricity, we would come out of nuclear power but we would solve less than a quarter of the energy problem.

Why would it be desirable to use only renewable energies ? Because they will never fail, but also because they emit few air pollutants hazardous to health and CO2 that warms the climate. Fossil fuels, ie oil, gas and coal, are responsible for hundreds of thousands of deaths worldwide every year because of the pollution they generate, they represent the number of deaths of hundreds of Chernobyl Every year, not to mention the consequences of global warming. The important thing is to do without fossil fuels, ie oil, gas, and coal.

However, in France, these energies serve very little to produce electricity, they are mainly used for transport and heating. It would therefore seem desirable to replace petrol cars with electric cars, petrol trucks with electric goods trains, gas or oil heaters with electric heat pumps, industrial heating systems with coal, oil or gas By electrical systems … But this should logically increase the consumption of electricity. We must therefore look at the energy problem as a whole and not just under the prism of electricity.

The energy transition scenarios:

– the Negawatt scenario predicts that virtually all will be spent on nuclear power, but not on fossil fuels, which would still represent 10%. This scenario predicts a drastic reduction of primary energy consumption by 66%.

– the Greenpeace scenario resulted in a similar decrease in energy demand of 63% without completely removing fossils.

To reduce consumption, among the proposals of Negawatt, Greenpeace and the Virage energy association: 70% reduction in clothing consumption, 50% in household products, 50% in cosmetics and toiletries, 50 % of meat consumption, 50% of dryers, dishwashers, freezers, audio-visual equipment, 50% of the size of refrigerators, use of collective washing machines, decrease in the comfort temperature of the dwellings , The size of dwellings which should be collective, the increase in the number of inhabitants per household, the disappearance of the vehicle as we know it today, the reduction in long-distance tourism and air travel, …. These changes may be considered necessary, but they are absolutely incompatible with the economic growth sought by the vast majority of policies.

– ADEME published in 2013 scenarios of energy transition “ADEME’s contribution to the development of energy visions 2030-2050”. They do not at all lead to the conclusion that nuclear and fossil fuels can easily be dispensed with. In the “median” scenario, they recommend a 47% reduction in final energy consumption. Renewable energies would then supply 55% of the needs, the rest being assured by oil, gas and nuclear which would have a significant role. According to the scenarios nuclear production would go from 251 to 670 TWh per year (it was in 2015 of 417TWh).

– The National Agency for the Coordination of Research for Energy published in 2013 three scenarios allowing to divide by 4 the CO2 emissions: while developing largely the renewable energies and without leaving the nuclear energy, Energy savings would go from 27% to 41% through sustained energy efficiency efforts.

– the Negatep scenario of the association “Save climate” foresees a division by 4 of CO2 emissions, despite a reduction of only about 18% of the final energy consumption. Fossil fuels would be largely replaced by renewable energies (+150%) but also by nuclear power (+46%) capable of producing carbon-free electricity, the production of which would increase by 61%.

No French scenario therefore claims that it is possible to replace fossil and nuclear energies by renewables, even drastically reducing consumption.

– The “Wind Water Sun” scenario from Stanford University in California claims to be able to supply all the world’s energy needs with renewables without loss of comfort. A project so ambitious that criticism of its realism is not lacking. At the French level, too little detail is given so that we can understand by what miracle it would be possible to do what the French studies do not claim to be able to do. The production potentials used are superior to those of all other French scenarios, the problems of intermittence and storage of solar and wind electricity seem to be clearly underestimated. Yet at the current rate of installation of wind turbines in France (about 1 GW per year), it would take more than 150 years to reach the necessary power of this scenario, while the lifetime of a wind turbine does not exceed 25 years .

A 100% renewable electricity ?

If the goal is not to fight against the deadly air pollution and the dangerous global warming but to do without the nuclear, then the question of whether in France we can produce the amount of electricity that we currently consume only with renewables is relevant.

The ADEME study “A 100% renewable electric mix” published in 2015 is not a transition scenario since it does not explain how to move from the current system to this new system. This is a “prospective and exploratory” job. It seems to me that the enthusiasm aroused by this study can be moderate because it considers in its “reference” scenario:

– Electricity consumption down to 422 TWh per year, compared with approximately 440 TWh (net consumption) in 2015; Despite 10 million electric vehicles (out of 38 million vehicles currently in France), despite population growth and probably economic growth.

– The use of wood or biogas to produce electricity, these sources of energy would then be less available for heating.

– Times where it would be necessary to import electricity from abroad, not necessarily produced by renewables.

– Battery storage with poor environmental performance would require several million tons of batteries with a limited lifetime.

– An increase in the number of Energy Transfer Stations by pumping (artificial lakes or dams allowing indirect storage of electricity), without specifying where to build new immense reservoirs of water. Let us recall the strong opposition to the construction of the Sivens dam.

– A large storage by “Power to gas”, a technique used to transform electricity into gas (hydrogen or methane) and eventually into electricity. This technique is promising but still stammering and without real feedback. It currently exists only in experimental form, relying heavily on it is therefore quite ambitious.

– An enormous development of wind power, the production of which would be 303 TWh per year whereas it was at most 160 TWh in the report published by Ademe in 2013. Wind power production in France was 21 TWh in 2015 , It would take at least 10 times more wind turbines than today.

– An optimistic load factor for terrestrial wind power of 31% whereas it is currently only 23% (the load factor is the ratio between the real average power and the installed capacity, it gives an account of the fact that The wind does not always blow enough).

– An installed wind power of 96GW against 10GW in 2015. Knowing that less than 1GW has been installed in France in recent years, it would take 86 years at the same rate to arrive at this power, but the lifetime of a Wind turbine is less than 25 years.

– Significant delays in consumption (60 TWh) of factories, heating of houses, heating of water or use of electrical appliances. Sometimes, depending on the wind, it may be necessary to shift them off when production is insufficient. It is therefore a trend towards less comfort since it would sometimes have to shift the working hours of employees, avoid heating his dwelling when it is cold, cooking when hungry …

– A supply-demand adjustment modeled too finely, the authors themselves stressing that the management of the stability of the electricity grid is not treated in the study.

Independently of the problems of intermittence and storage, this study of Ademe specifies that the maximum theoretical productible of renewables is, in France, 1268 TWh. But Ademe stresses that “there is no guarantee that production and demand will always fit”. This figure does not mean that all this energy is available: it should be removed from the inevitable loss of transport and storage, and especially what one would not be able to store because not necessarily produced at the moment we need it. This figure of 1268 TWh, although seemingly optimistic, is still considerably lower than the French energy consumption (1900 TWh in final energy paid by the consumer, almost 2900 TWh in primary energy before any transformation) and only confirms the conclusion we should considerably reduce our energy consumption to get out of fossils and nuclear power.

Historically, there has never been an economic growth associated with a decrease in energy consumption and this decoupling seems very unlikely. Therefore, policies that advocate the replacement of fossil and nuclear energy by renewables should begin by explaining how they will manage unemployment, public deficits, health, pensions, education, security, social welfare, etc. Economic decline.”


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