Decarbonizing the grid means storing energy from renewable sources. Aquifers can do that.
About 12% of the world’s total energy demand comes from heating and cooling homes and businesses. New research suggests that using groundwater to maintain comfortable temperatures could reduce natural gas and electricity consumption in this sector of the United States by 40 percent. This approach, called aquifer thermal energy storage (ATES), could also help prevent blackouts caused by increased electricity demand during extreme weather.
“We need storage to absorb fluctuating energy from solar and wind, and most people are interested in batteries or other types of electrical storage. I was wondering if there was an opportunity to use geothermal energy storage because of the occupancy I currently have at the Andlinger Center for Energy and the Environment at Princeton University.
“With ATES, we’ve found that we can store huge amounts of energy and it can be stored for long periods of time,” said Perera. “As a result, energy demands for heating and cooling in extreme hot and cold weather can be met without placing additional strain on the grid, making the city’s energy infrastructure more resilient.”
The study, published this week in Applied Energy, shows that ATES can help decarbonize the U.S. energy system by storing intermittent renewable energy for use when the sun isn’t shining and the turbines aren’t spinning. It is the first exploration of how it fits into the larger goal of After building a comprehensive technical and economic simulation of the energy system, the authors concluded that ATES, alongside other technologies such as storage batteries, could help end our dependence on fossil-fuel-derived backup power sources for heating. and found to be an attractive option for cooling energy storage. Enables a fully playable grid.
Aquifer Thermal Energy Storage (ATES) uses natural groundwater to store energy that can be used to heat and cool buildings. Combined with wind and solar energy, ATES becomes a zero-carbon option for climate control. These diagrams show how water is moved upwards for heating during hot weather, then pumped and stored until winter. The same process occurs in winter, storing cold water for summer use. (Credit: Jenny Nuss/Berkeley Lab)
put thermodynamics to work
TES is a fun and simple concept that takes advantage of the heat absorption properties of water and the earth’s natural geological features. Water is pumped from existing underground reservoirs and heated at the surface with ambient heat, surplus energy from the sun in the summer, or wind-heated at any time of the year. Then pump it back.
“Earth is a very good insulator, so it actually stays pretty hot,” says Berkeley Lab’s associate director of the Energy Earth Sciences Division and the Resilient Energy, Water and Infrastructure domain. Responsible co-author Peter Nico explains. “So if you pull it up in the winter months later, that water will be much hotter than the air around it and can be used to heat a building. It can also be put back together and stored until cooling is needed in hot weather.
Although ATES is not yet widely used in the United States, it is gaining recognition internationally, especially in the Netherlands. One of the main benefits is that these systems get “free” heat energy from seasonal temperature changes. This can be enhanced by adding artificial heating and cooling generated by electricity. As such, it works very well in areas with high seasonal variations, but may work anywhere as long as there is wind or solar power to connect. Designed to avoid impacts, the water used is often from aquifers deeper than the drinking water supply and does not introduce chemicals into the water.
how does that work?
To get concrete numbers to estimate how much energy ATES could save on the U.S. grid and how much it would cost to deploy, the team used a computational model of the Chicago neighborhood. I designed a case study. This virtual neighborhood consists of 58 two-story single-family homes with typical residential heating and cooling, connected to a simulation of an energy grid with multiple possible energy sources and storage options, including ATES. consisted of housing. We used future climate projections to understand how much of a neighborhood’s total energy budget is currently accounted for by heating and cooling demands, and how this may change in the future. Finally, a microgrid simulation for the neighborhood, including renewable energy technologies and ATES, was designed and evaluated for techno-economic feasibility and climate resilience. Bringing all these factors together in one model would not have been possible without the diverse expertise of the team across energy geosciences, climate sciences, and building sciences.
The results show that adding ATES to the grid can reduce consumption of petroleum products by up to 40%, but is 15-20% more costly than existing energy storage technologies.
“On the other hand, however, energy storage technology offers significant cost savings and could easily become profitable just a few years after the development of ATES. It’s very important to start building a prototype system,” said Perera.
“ATES requires less space compared to above-ground tank-based water or ice storage systems. It is efficient and can be scaled up to heat and cool large communities.” Urban Systems Division.
Another major benefit of ATES is that it will become more efficient as climate change makes the weather more extreme in the coming years. While there are many downsides to the hotter summers and harsher winters that the world’s major climate models predict, one upside is the ability to supercharge the amount of free thermal energy that can be stored in ATES. “You’re making lemonade, right? When these extreme heat events occur, you can also save some of that heat for when extreme cold events occur.
ATES also makes future grids more resilient to outages caused by high power demand during heatwaves, which are very frequent these days in many populous US regions, including Chicago. ATES-powered cooling uses far less power than air conditioners, so you only need enough power to pump the water.
“It’s a very real thing, and this work was about showing us how to offset that value against cost,” says Nico. “This technology is ready so to speak. We just need to do it.”
Original: Groundwater could be an eco-friendly heating and cooling solution
Than: Lawrence Berkeley National Laboratory | Swanson School of Engineering
