High Desert Power Plant: Empowering California

It's the equivalent of your car getting more miles to the gallon: The upgrade of the High Desert 830 MW combined cycle gas-powered plant, owned by Avenue Capital and operated by Middle River Power (MRP) in San Bernardino County, California, not only increased the power output by over 60 MW on hot days but also made the plant one of the most efficient thermal generators in the state. The High Desert Power Project showcases some of the many options for managing issues like grid stability, the need for dispatchable power sources, and fluctuating output from renewable sources by leveraging the full potential of existing assets to provide readily available power during periods of low wind and sunlight.

Over the years, the Siemens Energy team completed multiple upgrades at High Desert power plant. In 2018 the plant underwent modifications from an FD2 to an FD3, adding an additional 12MW per unit to the plant. The most recent was an FX performance upgrade of the three Siemens Energy SGT6-5000F gas turbines as well as a ULN, or Advanced Ultra Low NOx combustor upgrade. The generators also received attention in addition to new Siemens Energy transformers to allow for the higher electrical output. Overall, the modifications increased the output by up to 60 MW—the equivalent of adding another power plant to the grid. NOx were reduced by up to 64% pre emissions controls resulting in significantly less ammonia use. Carbon monoxide was reduced by up to 50%. The heat rate also showed improvement, which helps efficiency and longevity. Additionally, the ULN combustor modifications allow for the utilization of hydrogen as a fuel source in the future.

In several steps between 2018 and 2023, we helped our partners at MRP to stake out a “made-to-measure” approach towards boosting the efficiency with a whole-system upgrade of the High Desert facility and its three Siemens Energy SGT6-5000F gas turbines.

Our journey began with a feasibility study to define how the existing combined cycle power plant and its components could be improved to play a stronger role in California’s decarbonization drive by providing more dispatchable power with lower emissions and a lower heat rate. Following discussions about new advances in research and development and how they can be used for megawatt gain and heat rate reduction, the performance upgrade was first modeled and then successfully implemented resulting in today's High Desert Power Project. Notably, significant parts of this work took place during the peak of the 2020–2021 COVID-19 pandemic.

The High Desert upgrade project has taken the first steps in its role in the energy transition at multiple levels. As a result of the service package, the super-efficient turbines now operate with lower CO and NO_x emissions, ready to deliver stable and affordable electricity to a more sustainable energy system via a grid that will be increasingly based on decentralized generation from renewable in-feed. And the facility has been made future-ready in other ways as well: The SGT6-5000F gas turbines are now 30 percent hydrogen-ready, powered by expertise and technology that will ensure all turbines in our Siemens Energy portfolio are ready to operate on 100 percent hydrogen by 2030.

Our experts further enhanced High Desert’s resilience by installing cybersecurity measures to protect the state-of-the-art digital control systems against intrusions and attacks. Managed Detection and Response (MDR), powered by EOS.ii™, deploys machine learning, artificial intelligence, and our deep operational technologies expertise to give MRP’s security team visibility into the operations of this power plant, which constitutes an important element of California’s critical infrastructure.