A 22.7 MW flexible gas power plant delivered to Benndale, Mississippi, USA by the technology group Wärtsilä commenced commercial operations on 8 April, 2020, allowing electricity to be sold to the grid. The plant is owned by Cooperative Energy, a member owned electric cooperative, and was supplied by Wärtsilä on a full Engineering, Procurement & Construction (EPC) contract. The new plant will provide flexible power generation for Cooperative Energy to extend their use of renewable energy in the future. It is also critical for reliability of the system due to the threat of hurricanes in the region.

The plant has two highly efficient Wärtsilä 31SG gas engines as prime movers. The diesel version of the Wärtsilä 31 has been recognised by Guinness World Records as being the world’s most efficient 4-stroke diesel engine. The gas-driven Wärtsilä 31SG can provide simple-cycle efficiency levels in excess of 50 percent, compared to approximately 40 percent with modern gas turbines. It also has the fast-starting flexibility to respond rapidly to continuously changing load patterns, which is necessary in systems with inherently intermittent solar and wind sourced energy.The partnership between Wärtsilä and Cooperative Energy will continue via a 10-year service agreement, covering maintenance of the engines and related auxiliary equipment. The Wärtsilä lifecycle solution also includes spare parts, asset diagnostics, and response time guarantees should an unplanned event arise. This allows Cooperative Energy to focus on its core business, secure in the knowledge that the plant is available to operate when needed, and that all covered equipment is maintained to ensure the required performance.

“As a not-for-profit electric cooperative, our mission is to provide our members with electricity that is both reliable and economical. The Wärtsilä engines provide efficiency that is far greater than any of our simple cycle units, while also adding flexibility to our generation fleet. We greatly appreciated the competence and support that Wärtsilä has provided throughout this project,” said Trey Cannon, Cooperative Energy’s Director of Generation Projects.

Toni Haarala, Project Manager at Wärtsilä, commented: “It is always exciting to see progress in action, and this next generation flexible power plant represents real energy sector progress in terms of efficiency and flexibility. We have enjoyed an excellent relationship with Cooperative Energy, and it’s rewarding to see this plant now in full commercial operation.”

The modular design of the Wärtsilä flexible engine power plant enables future expansion of the plant, should that be needed. Additional engines and auxiliaries could easily be added by extending the engine hall.

At the same time, as the world moves towards a 100 percent renewable energy future, flexible and fast-starting response is essential in order to balance the power system when wind and solar generation fluctuate. Wärtsilä engines can reach full output in a matter of minutes from the start signal making this technology complimentary to any system with high share of renewables.

Wärtsilä currently has an installed base of over 3,700 MW in the USA.