A new energy storage system is using a crane and concrete blocks to address one of the biggest issues of renewable energy while cutting expenses by half compared to existing technologies.
A Czech-Canadian scientist, Vaclav Smil is a Professor Emeritus at the Faculty of Environment and Geography at the University of Manitoba (Canada), who wrote dozens of books and hundreds of papers, many of them on energy, using an uncompromising and realistic approach.
Smil is known for his continuous debunking of claims and unreal expectations from new energy technologies, including and especially renewables.
Regarding past experiences (with coal, for example) on which Smil bases most of his arguments, he doesn’t put a big faith in energy transition that’s taking up much of the debate around climate change.
”Give me mass-scale storage and I don’t worry at all. With my wind and photovoltaics, I can take care of everything. But we are nowhere close to it,” he told Science.
Concrete-Based Cheap Energy Storage
Currently, there’s no cost-effective, efficient, and scalable way to store the excess power generated during off-peak hours to be used later.
Electricity must be consumed as and when produced.
Battery technology can store energy for hours at best, which could help meet the needs of the day, for example during the night when solar plants stop.
A Swiss startup called Energy Vault (EV) is proposing the use of concrete to build utility-scale energy storage systems.
The concept of Energy Vault’s system is simple: a crane uses excess electricity from the grid to lift huge cylindrical blocks of concrete and stack them around. Then, the system lets the concrete blocks fall in a controlled way to retrieve the same energy that lifted them up through a generator.
To prove the viability of its energy storage system, EV has built a demo version in Milan (Italy), which cost it $2 million and nine months of preparation.
A full-scale system, ten times bigger than the scale model, would use a 400-foot tall crane with six arms to lift 35-metric-ton concrete blocks, to yield 20 MWh, around the same daily power needs of 2,000 Swiss homes.
By recovering about 85% of the energy used to lift the concrete blocks, the efficiency of EV’s system is on a par with lithium-ion batteries (90%).
For even more sustainability, EV has thought of using waste material like demolition debris to make concrete blocks and cut the use of cement by a factor of six.
EV’s solution would make it possible to overcome the intermittency issue of renewable energies, and, at $150 per kWh compared to Li-ion batteries’ $280-350 per kWh for example, provides a low-cost alternative to existing storage technologies.