BaroMar's Innovative CAES Technology
Israeli company BaroMar is set to pilot a novel energy storage system that promises to be the most economical solution for long-term grid stabilization of renewable energy, according to a New Atlas report published on May 6. The technology, known as Compressed Air Energy Storage (CAES), captures excess renewable electricity for later use during high-demand winter months.
CAES traditionally uses surplus electricity to drive a compressor, which forces air into large tanks. The compressed air is then stored at high pressure and later released through a turbine to generate electricity. The process is inherently cost-effective, but BaroMar claims its new system significantly outperforms conventional CAES for long-duration storage.
Underwater Storage Tanks: A Cost-Effective Solution
BaroMar's power plants will be located near coastlines with access to deep waters. Instead of expensive high-pressure tanks, the company takes advantage of the water column's pressure to store the compressed air in considerably cheaper containers.
The tanks are made of concrete and steel, topped with a rock-filled cage that secures them at depths ranging from 656 to 2,297 feet. They feature numerous water inlets and are initially filled with seawater. The compressor and power generator system is located nearby on dry land.
When there is excess electricity available, the compressor pumps ambient air into the tanks through a pipeline at pressures between 290 and 1,015 psi, depending on the depth. The compressed air displaces the water from the tank. However, since the hydrostatic pressure of the water outside counterbalances the air pressure inside, the tank does not need to be as robust or costly as its land-based counterpart, which contains air at much higher pressure than the surrounding atmosphere.
Energy Discharge Process
To release the stored energy, the system allows the air to flow back through the pipeline, into a heat recovery system, and then through an expansion turbine that drives the generator. At the opposite end, the tank is refilled with water, ready to be displaced again when the compressor operates.
Pilot Project and Efficiency Performance
A pilot project in Cyprus is underway, aiming for a round-trip efficiency of around 70%. This is comparable to the efficiency of the world's largest CAES facility – a 100-MW, 400-MWh plant in Zhangjiakou, northern China. The efficiency is notably high for conventional compressed air systems. Of course, the pilot plant is significantly smaller, with a storage capacity of only 4 MWh.
Cost Advantages and LCoS
BaroMar claims its system has lower costs than other Long-Duration Energy Storage (LDES) solutions, thanks to the low-cost tanks, extended lifespan, and minimal to zero underwater maintenance expenses. By operating a 100-MW plant capable of storing 1 GWh of electricity for 350 days per year over a 20-year lifespan, the company estimates a Levelized Cost of Storage (LCoS) of $100 per MWh, compared to around $131 per MWh for other LDES technologies.
Summary
BaroMar's underwater air storage system combines the efficiency of CAES with the cost-effectiveness of deep-sea storage. The innovative tank design and optimized compressor system promise significant cost benefits, potentially making this technology a game-changer for long-term grid stability and integration of renewable energy.