Modern gravity power projects use a similar logic to hydroelectric dams.  Dan Myers, Unsplash

The force of gravity holds great promise for decarbonizing electricity

The general business of gravity is nothing new: what goes up must go down.

Over the past decade, scientists have sought a new approach to this force of nature, exploring how it can generate zero-carbon electricity through what has been dubbed the “gravitational force.”

Let’s take the legendary story of the fall of Isaac Newton’s apple as an example, but let’s take it. Instead of having an apple hanging over him, Newton takes an apple and raises it above his head, giving that apple his energy. This energy is then stored in the apple until it falls, when the force of gravity releases the energy in the form of motion as it falls to the ground.

Gravity-powered batteries are reshaping this concept on a much larger scale. Steve Tapper, Chairman and CEO of Gravity Power, describes it as a game-changing technology. “[It’s] Capable of removing carbon from the grid by 80 to 90 percent without increasing costs to consumers and without harming the environment,” he says of his California company.

So, could this cornerstone of modern physics help accelerate the transition to a sustainable future and support countries’ goals to achieve carbon neutrality by 2050?

How it works

Gravity has been used to power mechanical movement since the Dutchman Christian Huygens invented the pendulum clock in the 17th century.

Modern gravity force involves lifting a heavy object with a pump, winch, or motor to generate gravitational potential energy. When the mass itself is lowered to its original height, it activates a generator that converts kinetic energy into electricity. Using this principle, gravitational force can now be generated from skyscraper lifts, decommissioned mine shafts, and the downhill momentum of electric trucks and trains, to name a few. Whole structures that support such processes are considered to be gravity batteries.

Modern gravity power projects use a similar logic to hydroelectric dams. Dan Myers, Unsplash

The concept is similar to hydroelectric power stations – the first of which was built in Switzerland in 1907 – which pump water up the heights and release it down the slopes to generators when electricity is needed.

However, storing pumped hydropower requires large tracts of land, must be near a water source, is not scalable once built, and often uses carbon-intensive materials that are harmful to the environment, according to Robert Baconi, Energy Chairman and CEO. Vault, a Swiss-American company founded in 2017, has become one of the leaders in its sector.

“Energy Vault’s gravity-based solutions are built on well-understood foundations in the physics and mechanical engineering of pumped hydroelectric storage, but replace water with custom-made composite blocks that can be made from low-cost, locally sourced materials,” he says. .

anytime anywhere

As solar and wind energy gain momentum to replace fossil fuels such as coal, gas, and oil, the full potential of both renewable energies has been hampered by a simple fact of nature: the sun doesn’t always shine, and the wind doesn’t always blow. This is where the force of gravity can fill a crucial niche. The beauty of this technology is that it can be used at any time, is relatively cheap and can be applied almost anywhere.

Energy Vault CEO and co-founder Robert Baconi.  Alex J Berliner, ABImages
Energy Vault CEO and co-founder Robert Baconi. Alex J Berliner, ABImages

In fact, it is intended to supplement rather than replace other renewable energies – so much so that it must be near the grid connection that supports renewable energy. When surplus renewable energy is stored, it is used to raise the heavy mass to its potential height. Then, when solar and wind energy sources are unable to deliver during peak periods of electricity use, the mass is lowered to its original power generation location.

Energy storage is fast becoming a big business for investors — the global market is expected to attract about $620 billion in investments by 2040, according to BloombergNEF forecasts. Currently, chemical batteries dominate this segment, with lithium-ion making up 93 percent of the energy storage technology mix in 2020, based on figures published by the International Energy Agency.

“[Gravity] Adriaan Korthuis, co-founder and managing partner at Climate Focus in Amsterdam, says the technology responds to a major bottleneck in power grids that are dominated by renewables. “Electricity storage is a major challenge in our global transition to renewable energy.”

Cheaper and cleaner

It is also much cheaper and cleaner to generate energy through gravity than renewable energies that rely on chemical batteries for storage. At 6.5 cents per kilowatt-hour, it costs less than half that of lithium-ion, which degrades over time and has a potentially serious environmental impact through mining and disposal, according to Gravity Power.

Based on the ‘standard cost of energy’ – a benchmark that measures the total cost of operating a facility divided by the electricity it is expected to produce over its lifetime – gravitational force is more cost-effective than pumped hydrogen, hydrogen. , energy flow and lithium-ion technologies, according to the company.

Grid-connected energy storage is needed in three categories: short duration (less than 1 hour) for frequency regulation; Long duration (8 to 16 hours) of switching from higher emission energy sources to low emission energy sources in one day, known as “Day Generation Conversion”; and very long durations (days, weeks, or seasons) for occasional periods when renewable energy is in low production, according to Taber.

“The wind and solar industries grew rapidly because energy buyers made available long-term, fixed-price purchase agreements,” Taber says. “similar [purchasing] The tool will accelerate the addition of long-term energy storage to the grid.”

Korthuis of Climate Focus assesses the technology on a more cautious tone.

“The obvious challenges for this technology, as with any technology in the early stages of development, are the possibilities for scaling, and in the energy loss when converting electricity to storage and from stored energy to electricity,” he says.

sustainable bricks

The Energy Vault takes a different approach to the force of gravity by building towers the size of a 20-story building. It provides electricity through a 100-megawatt-hour crane system powered by artificial intelligence to generate kinetic energy when the grid requires additional supplies. Composite bricks of local soil, mine tailings, coal ash and decommissioned wind turbine blades are used as weights, thus reusing materials intended for landfills and avoiding the use of emission-inducing concrete.

Expanding gravity-powered batteries can reduce the need for lithium.  Otton Barros, DSR/OBT/INPE
Expanding gravity-powered batteries can reduce the need for lithium. Otton Barros, DSR/OBT/INPE

Switzerland-based Lugano has attracted investors such as Softbank ($110 million), Saudi Aramco and BHP, the world’s largest mining company. Mining companies are able to take advantage of the technology by redeploying the abandoned infrastructure of decommissioned mines and diversifying their strategy as countries rapidly switch to renewable energies.

China Tianying, a public recycling company in China, also committed $50 million for the Energy Vault’s initial public offering and another $50 million for a license to use the technology.

“Following successful research and development, and demonstrating our technology on a trial scale, we are now commercializing and deploying our technology globally, starting in China where we have laid the foundation stone for the EVx gravity energy storage system, with additional near-term deployments planned in the United States and Australia,” Piconi says.

The 100 megawatt-hour project began with Energy Vault in China in March 2022. The company sees great potential for uptake of the technology in emerging markets, such as China and India, which are among the largest emitters of greenhouse gases.

The transition to renewable energy is gaining momentum with the emergence of this fledgling industry, whose leaders see few barriers to its widespread adoption beyond access to enough land for their tall towers and subterranean corridors. Gravity may prove to be the missing link in the energy chain that enhances the potential of the sun and wind to decarbonize the world’s electricity grids.

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