US researchers have been investigating how aquifer thermal energy storage (ATES) could be used to store wind and solar energy while covering heating and cooling energy needs during extremely hot or cold periods. They modeled a distributed energy system in a Chicago neighborhood and found that ATES could reduce consumption of petroleum products by up to 40% at a slightly higher cost than other forms of storage.
“We found that ATES can store a huge amount of energy and store it for a long time,” said researcher ATD Perera. “As a result, the need for heating and cooling energy during extremely hot or cold periods can be met without increasing the additional burden on the grid, making urban energy infrastructure even more sustainable.”
The researchers performed a simulation using a stochastic optimization model and designed distributed multi-energy systems (DMES) that use ATES as long-term thermal storage. In the proposed system configurations, renewable electricity from wind and solar energy is used to pump water from existing underground reservoirs and heat this water on the surface in summer or during times when wind power is high. Then the same water can be pumped back down to start the cycle again.
“It actually stays pretty hot because the Earth is a pretty good insulator,” said researcher Peter Nico. “So when you pull it up in the winter, months later, the water is much warmer than the surrounding air and you can use it to heat buildings. Or vice versa, you can draw water and let it cool, then put it back down and store it until you need cooling during the hot summer months. It’s a way to store energy as temperature underground.”
Academics looked at costs, network integration levels and fuel consumption. They then designed a case study of a Chicago neighborhood of 58 two-story single-family homes with typical residential heating and cooling systems.
“The results showed that adding ATES to the grid could reduce the consumption of petroleum products by up to 40%, although it would cost 15-20% more than current energy storage technologies,” the researchers explained. “But on the other hand, energy storage technologies have received drastic cost savings, and after only a few years of ATES development, we can easily reset.”
The team presented their findings “Enhancing Climate Change Resilience Using Seasonal Energy Storage (Aquifer Thermal Energy Storage) in Distributed Energy Systems”, published recently Applied energy.
“ATES will also make the future grid more resilient to outages due to high power demand during heat waves – which are quite common today in many densely populated areas of the United States, including Chicago,” they concluded. “Because ATES-controlled cooling uses much less electricity than air conditioners, it only needs enough power to pump the water.”