Mill Creek 5 Generating Unit

A new state-of-the-art natural gas combined-cycle generating unit will be LG&E and KU’s most efficient and advanced baseload generating unit.

rendering of Mill Creek 5 generating unit

Mill Creek 5, a 640-megawatt natural gas combined-cycle generating unit, is now under construction and expected to begin powering customers’ homes and businesses in 2027.

Mill Creek 5, which will be LG&E and KU’s most efficient and advanced generating unit, was approved in 2023 by the Kentucky Public Service Commission as the least cost approach to the utilities’ generation investment plan, which also includes adding a significant amount of new solar, a 125-megawatt battery energy storage system and the company’s largest number of energy efficiency programs in its history.

How Mill Creek Unit 5 works

diagram of how a gas turbine works

Mill Creek 5 (MC5) is a very complex generating unit that will produce electricity through both a gas turbine and a steam turbine. Here is how it will work.

  1. An electric motor starts the rotation of the gas turbine/generator shaft (1) that extends the length of the unit.
  2. The shaft facilitates the suction of air into the compressor (2) via its rotating blades.
  3. Natural gas combusted between the compressor and the gas turbine (3) heats that air, which then expands as it exits the turbine. This causes the shaft to rotate with greater force. (The electric motor then stops running.)
  4. This force is transferred to the generator (4) and converted to electricity for our customers.
  5. The hot air exiting the gas turbine in Step C enters the Heat Recovery Steam Generator (HRSG) (5) that heats the steam, which flows (6) to and rotates the steam turbine (7).
  6. The rotating steam turbine shaft (8) then couples to the gas turbine/generator shaft (1) at a clutch mechanism providing more energy to the generator. Capturing the energy from otherwise unused exhaust heat increases the efficiency of this unit from 43% to 64%.
  7. Mill Creek Unit 5 will be the first unit in LG&E and KU’s fleet to use duct firing at times of peak energy demand. Duct firing adds heat in the duct work (9) between the gas turbine and the HRSG. That provides more steam to the steam turbine, enabling it to generate more energy.

Mill Creek 5 Key Facts

  • Nameplate capacity: 640 megawatts
  • Estimated completion: 2027
  • Fuel source: Natural gas
  • Cost: $902 million
  • Environmental benefits: Mill Creek 5 will use among the most efficient generating technology currently available and produce 65% less carbon per megawatt hour than a coal-fired unit.

Project updates

An official groundbreaking for Mill Creek 5 was held on Nov. 13 and work on the new unit is underway. Customers and neighbors will notice related activity in and around the area, and care is being taken to minimize traffic and other impacts during all aspects of construction. We’ll continue to update this page with project milestones over the course of the construction.

Throughout the course of the project, we will keep you up to date on events related to the work. Here are some points about the current activity.

  • Nearly 200 contractors are currently onsite. This number will gradually increase to 500 in 2026.
  • Traffic has increased, entering through Mill Creek Gate 3 off Dixie Highway. To address potential concerns, we’ve made modifications to the entrance that help mitigate traffic issues for our workers and you. These changes include additional traffic lanes and security gates as well as lighting. Construction signage on Dixie Highway alerts vehicles about the increased activity at this gate.
  • We recently received approval for an acceleration/deceleration lane along Dixie Highway to support merging vehicles and reduce the risk of collisions. Construction is underway and in May, the southbound side of Dixie Highway will be reduced to one lane.
  • A water truck continuously sprays water on the roads and construction areas to control dust.
  • The change on the skyline is a 327-foot-tall tower crane erected to support the new unit’s construction.
  • Normal work hours are currently 7 a.m. to 5:30 p.m., Monday through Saturday.

Project partners

Major project partners involved in the engineering, manufacturing and commissioning of Mill Creek 5 include GE Vernova; Vogt Power International Inc., a Babcock Power Inc. subsidiary; and TIC–The Industrial Company, which also will provide on-site construction oversight.

At the height of construction, LG&E and KU expect to have an additional 500 contract personnel working on site.

Gallery

groundbreaking ceremony at Mill Creek 5 construction site
Mill Creek 5 construction site
Mill Creek 5 construction site