Tucson Electric Power (TEP), a subsidiary of Fortis Inc., is building the plant on the site of an existing generating station that currently consists of both natural gas-fired and renewable energy assets. TEP selected a Wärtsilä smart power generation solution offering fast-start flexibility, which is well equipped to address intermittency and other challenges associated with an expanding renewable energy portfolio. TEP, which is working to deliver at least 30 percent of its power from renewable sources by 2030, booked the order with Wärtsilä in October 2017.
"As we add more solar and wind, we'll need a resource that will respond quickly and reliably to the variable production of renewable resources," said Conrad Spencer, director of the modernization project for TEP. "The latest generation of Wärtsilä natural gas-fueled engines take just a few minutes to start and reach full output, and they are more efficient than gas turbines."
The Wärtsilä engines will replace two of the existing plant's older steam generators, thereby improving the plant's overall efficiency. This will also reduce the plant's emissions of nitrogen oxides (NOx) by approximately 60 percent, equaling about 350 tons per year. Furthermore, the Wärtsilä engines require minimal amounts of water for cooling, which is an important consideration in Arizona's hot, dry climate.
"This plant will facilitate the integration of renewables into TEP's existing generation portfolio. Power from renewables is unavoidably intermittent, and by offering a resource that can respond rapidly to sudden losses, TEP will be able to reduce fuel costs, use less water, and reduce emissions," commented Jussi Heikkinen, Market Development Director at Wärtsilä North America Inc.
The scope of supply is for ten Wärtsilä 50SG gas-fueled engines, as well as engineering and commissioning services. Delivery of the equipment will commence in autumn 2018 and the plant will be built in two phases, with half the units coming online in mid-2019 and the remainder by early 2020.
Wärtsilä has a strong footprint and a proven track-record in the USA where its installed base, including projects under construction, exceeds 3000 MW.