Can we build wind turbines with wind turbines? Does a 100% wind turbine scenario make sense?
(Image by https://unsplash.com/@karsten_wuerth )
The method chosen to make this estimate:
To try to answer this question, this article chooses an approach based on stocks, rather than on principles and models to avoid making implicit assumptions which may not be verified in practice, in particular in the future, depending on the evolution of the climate, the availability of resources or politics.
Abbreviations
EnR: Renewable Energies.
PV: Photovoltaic panels.
EROI: Energy Returned on Energy invested / Energy return of a wind turbine.
EV: Electric vehicles.1. What is the EROEI of a wind turbine today
It is considered that a wind turbine provides after one year one to two times the quantity of energy equivalent to the energy which was necessary for its production.
In other words, a wind turbine that has a lifespan of 25 years, produces between 25 and 60 wind turbines during its life (if it is only used for that).
EROEI
Ref https://en.wikipedia.org/wiki/Energy_return_on_investment#Wind_turbinesHowever, this value can be very misleading, in fact, the different stages of the production of a wind turbine today use fossil fuels . The extraction of the metals necessary for the production of a wind turbine, their transport and their transformation (blast furnaces) is done by industrial machines that consume fossil fuels (oil and coal, respectively).
We will therefore take into account the fact that in the absence of fossil fuels the EROI of a wind turbine becomes a fraction of what it is when using fossil fuels, i.e.:
Ep = 1 year.Ee = Ep/NWith:
Ee = EROI of a wind turbine produced with renewable energies (e: Electric)
Ep = EROI of a wind turbine produced with renewable energies (e: Electric)2. What is the lifespan of a wind turbine?
In round numbers, it is agreed that the lifespan of a wind turbine is approximately 25 to 30 years :
Tv = 25 to 30 years oldRef https://en.wikipedia.org/wiki/Wind_turbine#Technology3. Quantity of wind turbines that can be produced with a wind turbine today over its lifetime:
Qp = T * Ep = 1 * 30 = 30 wind turbinesOr: With a wind turbine produced with machines using fossil fuels, we can today produce enough energy to extract (or buy) oil, to in turn extract metals and transform them, to in turn produce 30 wind turbines.
4. Does this mean that each wind turbine will systematically produce 30 wind turbines?
No , because this purely theoretical value must be corrected by practical considerations (material limits).
5. Limit 1: Energy production
Wind turbines are not intended for the sole purpose to produce other wind turbines but essentially to generate energy for replacing fossil fuels. Most of the energy produced by a wind turbine (or: the largest fraction of the park considered) is itended for use by households and by the industry (heating, transport, housing, food fertilizers (food), drinking water, etc.)
Let’s call F the fraction that remains to make new wind turbines:
Let’s fix this value F at 10% to fix an order of magnitude
F=10%=0.1In this case, the maximum number of wind turbines that can be produced by a wind turbine during its lifetime becomes:
Qp' = Q * F = T * Ep = 30 * 0.1 = 3 wind turbines (over 30 years).6. Limit 2: Produce wind turbines without fossil fuels.
As explained under point 1, producing wind turbines without fossil fuels requires first producing said energy by renewables, then storing it in one way or another (unresolved issue to date, see Appendix 1: Storage )
As it is difficult to anticipate the exact value of this efficiency loss factor in the transition from wind turbines produced by fossil fuels to wind turbines produced by renewable energies, let us name it simply: P , for “Loss of efficiency”.
In this case, the number of wind turbines produced by a wind turbine in one cycle (during the 30 years of its operating life) becomes:
Qe = Qp' * PTo fix ideas, let’s assume that this factor P is between 1/2 (P = 0.5) and 1/100 (P = 0.1).
In these two respective cases, we get:
Qe = Qp' * P = 3 * 0.5 = 1.5 wind turbines over 30 years.Qe = Qp' * P = 3 * 0.1 = 0.3 wind turbines over 30 years.7. Limit 3: Energy effect of rarefaction of metals.
Renewables (solar panels (photovoltaic), and wind turbines) require large quantities of metals for their construction (in particular tons of copper and tons of iron).
This results in an increase in the extraction of these metals in proportion to the planned deployment of wind farms.
This increase in extraction results in a depletion of metal deposits: Concretely, from year to year it is necessary to extract more and more tons of copper/iron to have one gram of copper or iron.
This, in turn translates to the fact that it takes more and more energy to extract a ton of metal from the ground as wind farms and or PV are deployed.
This translates into a corrective factor, let’s call it A (for “mining wealth depletion”).
Taking this factor into account, the number of wind turbines produced by a wind turbine during its lifetime, with energy mainly Renewable and taking into account the rarefaction of metals becomes:
Assuming that after a few years of intensive exploitation of the iron and copper mines we arrive at an impoverishment of -25%, the factor A in this case becomes A = 0.75 (100% — 25%) and the number of wind turbines produced in the life of a wind turbine becomes:
Qe = Qp' * P * A = 3 * 0.5 * 0.75 = 1.1 wind turbines over 30 years.In this case, the useful energy produced by a wind turbine during its entire lifetime is barely enough to produce a new wind turbine.
Qe = Qp' * P = 3 * 0.1 = 0.2 wind turbines over 30 years.In this case, the useful energy produced by a wind turbine throughout its lifetime is not enough to ensure its replacement.
Ref
> https://en.wikipedia.org/wiki/Peak_copper
> https://en.wikipedia.org/wiki/Peak_minerals
> https://youtu.be/LsWc-9CrRkkClimatic factors.
The change will also influence the production of renewables, since the extraction of metals (wind turbines) and the production of semiconductors requires large quantities of water. This factor is already causing problems for copper mines in South America.
Ref
> https://www.circleofblue.org/2016/south-america/conga-mine-peru-halted-water-concerns-civic-opposition/
> https://www.circleofblue.org/2016/south-america /conga-mine-peru-halted-water-concerns-civic-opposition/Political factors.
The gradual end of globalization, the trade in raw metal from China (in particular), etc. also work against the Q value calculated above.
- Either the metals are extracted locally and a correction factor must be taken into account which takes into account the low concentration of metals in the country concerned.
- Either we continue to bring metals from the other side of the planet, in which case the energy deployed for transport must be subtracted from that produced by the wind turbines, in which case a given wind farm is still less able to produce wind turbines since an additional part of its energy must be sacrificed for said transport.
Is a 100% wind turbine scenario realistic?
Energy consumption in France:
Ref https://fr.wikipedia.org/wiki/Energy_in_FranceRenewable energies represent approximately 10% of energy consumption in France:
French energy mix:
Ref https://enerdigit.fr/mix-energetique/An estimate published in an article by Jean-Marc Jancovici in 2000 (updated in 2014) estimates that:
"To supply 500 TW.h (i.e. 500,000 GW.h) with wind turbines supplying 20 GW.h per km², it would be necessary to "plant" a favorable surface of:
490,000 ÷ 20 ≈ 25,000 km²
i.e. approximately 5% of the metropolitan territory, this which roughly represents the area currently occupied by cities, roads and car parks, even if in fact the areas are not fully mobilized and remain largely available for another use (cultivation in particular).It is obvious that if the number of "full power equivalent" hours is only equal to 2000 on 1% of the territory, then the calculations below underestimate the number of machines to be installed and the surface mobilized, because some of the wind turbines would then be installed in places where the annual energy produced would be much lower than it is today, for a wind turbine of the same nominal power of course.With wind turbines of 2 MW nominal power (which are around 100 m high), thus providing around 4 GWh per year in favorable areas, it would take around 125,000 wind turbines to produce the 500 TWh mentioned above.
> Ref https://jancovici.com/transition-energetique/renouvelables/pourrait-on-alimentation-la-france-en-electricite-uniquement-avec-de-leolien/The total energy consumption in France is approximately: 2571 TWh in 2020.
Assuming that the order of magnitude of the estimate made by JM Jancovici is correct, then to supply the 2571 TWh needed to satisfy the total energy demand of France, then it would take about 5 times as many wind turbines as for cover France’s purely electrical energy needs (500 Twh).
N = 2571 / 500, or about 5 times the values for electricity.In this “100% wind turbine” scenario, it would therefore be necessary to:
> Ref https://jancovici.com/transition-energetique/renouvelables/pourrait-on-alimentation-la-france-en-electricite-uniquement-avec-de-leolien/> Ref https://www.statistiques.developpement-durable.gouv.fr/edition-numerique/chiffres-cles-energie-2021/6-bilan-energetique-de-la-franceThe wind power deployment in Germany spanned more than 20 years:
Ref https://en.wikipedia.org/wiki/Wind_power_in_Germany#StatisticsIt therefore seems a huge challenge to want to install 25 times more wind turbines in France between 2022 and 2050 than there are today in Germany, knowing that the German wind program took about 20 years.
At the rate followed by the deployment of the German wind farm, it would therefore be take about :
25 * 20 = 500 yearsto deploy a 100% wind solution.
Conclusion
- The current Scenarios proposing a 100% RE system are wrong, because they are based on EROEI values of the wind turbines, themselves based on ideal past estimates, presupposing abundant and cheap oil available to extract metal ores , water available in large quantities (therefore no global warming), abundant transport of raw materials by cargo vessels, international policies (globalisation) easily allowing these exchanges, abundant coal to reduce copper and iron ore into metal, then to transform iron into steel, etc.
- As Jean-Marc Jancovici has often pointed out, the additional contribution of nuclear energy would make it possible to restore the balance to a certain extent and perhaps make the deployment of renewable energies viable under certain assumptions (climate stability, political stability , social stability, etc.).
Ref https://jancovici.comAppendix 1: Storage
- Hydrogen: Decreases the final energy available by a factor ranging from 50% to 10% (thus requires two more wind turbines).
- Batteries: high CO2 cost (metals).
- STEP, dams, etc: Limited to regions where the relief allows it.
- Gravity (with concrete blocks): No sense (varies linearly with the mass of concrete), therefore requires prohibitive surface and volume.
- Gravity (Underwater bladders): No sense (insufficient height difference).
Ref
> https://www.spglobal.com/marketintelligence/en/news-insights/latest-news-headlines/hydrogen-technology-faces-efficiency-disadvantage-in-power-storage-race-65162028
> https:// www.wattisduurzaam.nl/38139/energie-opslaan/reservoirs/what-to-think-of-that-award-winning-dutch-ocean-battery/Appendix 2: Reduction of iron ore with hydrogen
- requires about 3,000 to 7,000 wind turbines per blast furnace.
> "The implementation of an industrial-scale electrolysis facility currently represents a considerable investment, exceeding one billion euros for a 200MW facility. The rise of renewable energies, and the search for storage solutions for the surplus of electricity produced by these sources, is driving the development of electrolysis solutions for the production of hydrogen."> Ref https://www.alcimed.com/fr/les-articles-d-alcim/lhydrogene-pour-la-production-dacier-mythe-ou-reality/Appendix 3: Recycling
Allow:
- To reduce the energy cost of maintaining an existing wind farm (therefore, to reduce the fraction of the total power that must be dedicated to maintenance, since the “ore extraction” part is absent in the use of recycled metals).
Does not allow:
- To extend the existing wind farm (by definition, if only wind turbines are recycled).
Would allow to exercise arbitrations:
- If, for example, one decides that the individual electric car is not the solution (after a few decades of EV deployment), if we then recover the metals from the EVs and use them to produce electric public transport, on the one hand, and wind turbines on the other hand, then it could be possible -temporarily- to increase an existing wind farm to the extent of the stocks of metals released by said recycling.
Appendix 4: Maximum achievable power.
Example from Germany:
By the end of 2021, a total of 28,230 onshore turbines with a combined capacity of approximately 56 gigawatts (GW) were in operation across the country.
Ref
> https://www.cleanenergywire.org/factsheets/Additional Ref
> https://en.wikipedia.org/wiki/Wind_power_in_Germany
> https://www.wind-energie.de/english/statistics/statistics-germany/
> https://www.cleanenergywire.org/factsheets/ german-onshore-wind-power-output-business-and-perspectivesExample from France:
Ref https://www.edf.fr/groupe-edf/espaces-dedies/l-energie-de-aaz/tout-sur-l-energie/produire-de-l-electricite/l-eolien-en-chiffres"The connected onshore wind power was 17.932 GW at the end of the first quarter of 2021, according to official figures published by the government, ranking us in 4th position in Europe for the countries producing the most wind energy. This is equivalent to 2030 installations spread over the territory, i.e. 20 new installations and 1% additional compared to the last quarter of 2020. This weak growth is also to be qualified, when we know that the power connected in Q1 2021 is 19% lower than in the same period in 2020 , this due to less favorable climatic conditions (in particular)."The capacity of the French wind farm being calculated on the power in GW and not on the number of wind turbines strictly speaking, the exact figures on the number of wind turbines in France in 2021 are not yet known. However, the last figure 2018 official report indicates that the French wind farm was made up of 6,500 onshore wind turbines. By following the progress of wind energy on the territory in recent years, the number of onshore wind turbines in France in 2021 is estimated at 8,000, spread over 1380 farms, in metropolitan France and overseas Here is a map to visualize the distribution of wind farms in France by region: here.Ref https://energy-transition.eco/wind-energy-2021/
Appendix 5: Required area / Arbitration with the needs of agriculture, housing.
A 100% wind turbine scenario would require, as seen in the previous sections, to sacrifice a quarter of the surface of France to install wind turbines there, in fact this would come into conflict with the needs of agriculture (food needs of the population ), those of housing and industry.
