TRIBUNE – The ruin of some makes the fortune of others. Since February 14, 2022, ten days before Russia’s invasion of Ukraine, the American company Energy Vault has been listed on the New York Stock Exchange and its stock has increased by 50% when it produces absolutely nothing.
This op-ed was written in response to the article: Renewable Energy Storage: Energy Vault Explores Gravity-Based Solution
The raw materials crisis caused by tensions between Russia (2e world hydrocarbon producer) and NATO countries (1is world consumer of hydrocarbons) no doubt has something to do with it; Energy Vault promises to revolutionize the storage of renewable energies, nothing less! One of the main pitfalls of natural energies, such as solar or wind, lies in their evanescence. It is very difficult to store them; they must therefore be consumed immediately. Moreover, when there is little or no sun, when the wind is scarce, photovoltaic parks and other wind farms become cumbersome, polluting, expensive, even though they no longer produce anything. The ideal would be to be able to store the excess energy produced to restore it during lean periods. This ideal is precisely what the Energy Vault company has been trying to sell to the whole planet since its creation in 2017.
The technology offered by Energy Vault is based on a very basic principle: exploiting the potential energy of gravitation to store renewable energies. In practice, it involves consuming the electricity produced to raise huge blocks of concrete into the air. The latter restore their energy by letting them fall slowly towards the ground. Using magnificent computer-generated videos, Energy Vault stages the dance of concrete blocks, moved by huge cranes 200 meters high controlled by artificial intelligence. The computer graphics have hardly been released when version 2.0 is already ready to be launched: a titanic hangar gathering hundreds of concrete blocks providing the population with green, free and inexhaustible energy.
Let’s stop dreaming for a moment and calculate the yield and cost of such a process. In its most recent version, Energy Vault proposes to store energy in blocks of 35 tons raised to 80 meters in height, in a hangar of approximately 300 meters on each side. A block could thus, at most, store 7.6 kWh on a square meter. The hangar would accumulate a maximum energy of 684 MWh in total. Knowing that a person in France consumes an average of 6 kWh per day, Energy Vault’s solution would be enough to power a city of 16,000 inhabitants for… a week. Given the loss of energy by friction and the Joule effect, it would in fact be necessary to count on four or five days of reserve at the most. There really is nothing to spend the winter!
At first glance, the Energy Vault solution appears like a scam to any citizen with a basic physics background. Now let’s see how much a single storage shed would cost. A cubic meter of concrete weighs 2.5 tonnes; 14 m3 of concrete per block would therefore be needed, i.e. 1,260,000 m3 of concrete. This represents half of the great pyramid of Cheops! And again, the great pyramid is not perched 80 meters at the end of cables stretched by AI-controlled cranes, which would be an incredible technological feat. Architects had fun evaluating the cost necessary to rebuild the pyramid of Cheops with modern means: one billion euros and five years of labor for a few thousand workers. We must not neglect either the maintenance costs of such a shed; concrete is a material sensitive to erosion and the incessant friction of the moving parts would put the whole structure to the test. Ten to twenty percent of storage units should be decommissioned to allow for daily servicing, replacement of faulty items, and heavy structural maintenance. The management of water sanitation already heavily indebted small communities, while it is not the sea to drink. Advance more than a billion euros, even over five or ten years, is totally inaccessible for a small town of 16,000 inhabitants.
If the whole of France wanted to store even four days of electricity for its entire population, which would be starving, it would have to provision at least 4,250 billion euros every ten years, almost twice the country’s GDP. , more than fifty times the turnover of EDF, and this only to store four days of reserve. It would still be necessary to produce it, this energy…
Imagine the quantity of material to be mobilized for the construction of the equivalent of a few thousand Cheops pyramids throughout the territory. The country’s annual production would not be enough, not to mention the appalling pollution that this would cause, because concrete or any other composite material of the same ilk, whatever its quality, pollutes horribly. Concrete is responsible for 8% of global CO2 emissions. If the goal of green energy is to reduce the carbon footprint of human activities, with Energy Vault, you’ve failed!
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Energy Vault is therefore a beautiful scam that has already monopolized hundreds of millions of dollars in bogus investments. However, the storage of energy by gravitational potential is really nothing new. The pumped storage technique is a good example. We dig a large hole in height, or even choose one already available, then fill it with water, which creates a reserve that can be immediately mobilized via pipes and reconstituted by electric pumps. The natural elevations allow differentials not of 80 meters, but of several hundred meters. Unlike the blocks of the pharaonic Energy Vault scam, the reserve water is free, indestructible, reusable indefinitely and can even be supplemented by rainwater, bringing its own energy, which is already considerable; it is from it that comes that of the hydraulic power stations. This technique already provides 10% of energy storage in Japan, a country which alone has 25% of the world’s hydroelectric reserves. Closer to home, the most curious can take a look at the Grand’Maison dam in Isère: 132 million useful m3 at a height of 160 meters, the equivalent of 120 Energy Vault hangars for a modest cost equivalent to only a fraction of the price of a single shed. The process is economical, it works very well and it has proven itself, unlike the improbable assembly of Energy Vault.
Elon Musk had already proposed to us the scam of the Hyperloop, this high-speed train traveling under vacuum, a science fiction idea beaten down by an army of honest and competent engineers, rightly contesting the feasibility of the thing. Nearly ten years later and a few hundred million dollars swallowed up, the mountain has not even given birth to a mouse hair. Elon Musk’s fortune, on the other hand, has increased fivefold. Ecology is just a new market, a renewable source of plucking pigeons. The predators do not know the crisis, on the contrary, they feed on it.