Isothermal compressed wind energy storage using abandoned oil/gas wells or coal mines

Wind energy has rapidly increased and is expected to continue to do so over the next few decades. This will exacerbate the issue whereby its intermittent energy production does not generally coincide with energy demand. This can be addressed by integrating cost-effective energy storage with wind farms. The present study develops a concept that leverages the capacity of underground reservoirs of abandoned oil or gas wells to avoid the costs of expensive storage vessels and employs isothermal processes for the compressed air energy storage to improve round-trip efficiency. By levelizing the production using compressed air energy storage, the electrical generator size (and associated) cost may be reduced while maintaining the same average power production. These generator cost savings are projected to offset the cost of the storage system, so increased dispachtability is obtained with little to no added cost. This allows the predicted Cost of Valued Energy to be lowered by more than 10% for a typical wind farm, used as a case study. In addition, the simulated dispatchability ratio can reach 86.7%, which is far better than the 55.7% of a wind farm without storage. Importantly, the siting of wind farms near abandoned wells and mines also has the potential for significant new infrastructure investment and jobs in areas that might be economically-depressed. However, experimental verification with a pilot facility combined with ramifications of operational costs and geological factors are needed to demonstrate and quantify the benefits of this concept.