Reusing old oil and gas wells may offer green energy storage solution

Transferring from fossil fuels to renewable vitality sources like wind and photo voltaic would require higher methods to retailer vitality to be used when the solar just isn’t shining or the wind just isn’t blowing. A brand new examine by researchers at Penn State has discovered that profiting from pure geothermal warmth in depleted oil and gasoline wells can enhance the effectivity of 1 proposed vitality storage resolution: compressed-air vitality storage (CAES).

The researchers lately published their findings within the Journal of Power Storage.

CAES crops compress air and retailer it underground when energy demand is low after which extract the air to create electrical energy when demand is excessive. However startup prices presently restrict industrial growth of those initiatives, the scientists mentioned.

The researchers proposed a brand new geothermal-assisted compressed-air energy storage system that makes use of depleted oil and gasoline wells—the Environmental Safety Company estimates there are round 3.9 million in the US—and located it may possibly enhance effectivity by 9.5% over the present know-how. This implies a bigger proportion of the vitality saved within the system might be recovered and changed into electrical energy, probably boosting earnings for operators.

“This improvement in efficiency can be a game changer to justify the economics of compressed-air energy storage projects,” mentioned Arash Dahi Taleghani, professor of petroleum and pure gasoline engineering at Penn State and corresponding writer on the examine. “And on top of that, we could significantly avoid the upfront cost by using existing oil and gas wells that are no longer in production. This could be a win–win situation.”

Reusing depleted oil and gasoline wells would permit operators to entry geothermal warmth in sizzling rock formations underground, eliminating upfront costs of drilling new wells and probably making the know-how extra interesting to business, the scientists mentioned.

Gases like compressed air improve in strain as temperatures improve, which means the heated wells may probably retailer extra vitality, in accordance with Taleghani. When electrical energy is required, the heated, compressed air is launched, driving a turbine to supply energy.

“Without taking advantage of the geothermal setup, you could not get enough encouraging numbers,” Taleghani mentioned, explaining that the workforce used numerical modeling simulations to search out that putting CAES programs in deserted oil and gasoline wells considerably elevated the air temperature within the programs. “And on top of that, drilling new wells may not justify the economics of this type of storage. But by combining these two factors, and by going back and forth through modeling and simulation, we found this could be a very good solution.”

Power storage choices like CAES are notably essential within the transition to clean energyin accordance with the researchers, as a result of they assist deal with the intermittent nature of renewable sources. By storing extra renewable vitality and releasing it when wanted, vitality storage contributes to grid stability and reliability.

“The problem is that sometimes when we need energy, there is no sunshine or there is no wind,” Taleghani mentioned. “That’s a big barrier against further expansion of most of the renewable energy that is available to us. That’s why it’s very important to have some storage capacity to support the grid.”

Repurposing depleted oil and gas wells may additionally assist mitigate potential environmental impacts of deserted wells and probably present new job alternatives in areas with wealthy vitality business traditions, the researchers mentioned.

In Pennsylvania alone, regulators estimate there are tons of of 1000’s of orphaned and deserted wells. If these wells are improperly plugged, or broken, they will leak methane into the environment and groundwater.

“If we use existing wells, we are basically hitting two birds with one stone,” Taleghani mentioned. “First, we are sealing these wells. That stops any potential leaks. And then if we are repurposing these wells for energy storage, we are still using the infrastructure that is in place in these communities. It can potentially maintain employment in the area and allow communities to be part of the energy future.”

Additionally contributing to the examine from Penn State had been Derek Elsworth, G. Albert Shoemaker Chair in Mineral Engineering and professor of vitality and geo-environmental engineering; and Qitao Zhang, a postdoctoral scholar, each within the John and Willie Leone Household Division of Power and Mineral Engineering.