Middle River Power plant upgrade
September 30, 2023
5 min read

High Desert Power Plant: Empowering California

Resilient power generation includes lowering emissions, increasing output, and improving efficiency. Turbine upgrades at the High Desert power plant in California show how, step by step, energy companies like Middle River Power can decarbonize their operations and begin the process of energy transition.

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.

Evolution of power plants during the energy transition

Upgrades have brought more power plant efficiency to a combined cycle power plant that was already much lower in emissions than coal-fired generation. And its future is bright too, with new fuel and integration possibilities.

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.

MRP steps up its game: More power, lower heat rate

MRP currently manages approximately 3,000 MW of power generation assets, operational or under development, in California, Texas, Virginia, Illinois and West Virginia. In California, MRP is a market leader in building utility-scale solar power projects as well as battery energy storage systems, and as such plays a significant role in attaining the state’s decarbonization benchmarks. In order to ensure reliable and affordable electricity supply amidst this ongoing transformation, and given the cost, time, and processes involved in building new power plants, the company approached Siemens Energy about ways to obtain the maximum performance from its conventional assets.

Gas turbine upgrade

With the latest turbine upgrades, the High Desert combined cycle power plant can support California’s decarbonization drive by providing more dispatchable power with lower emissions and a lower heat rate.

High Desert Power Plant in San Bernardino County, CA

Benefits of the upgrade for High Desert Power Project

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.

Proactive preparations for the High Desert power plant: Digitally secure and hydrogen-ready

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 NOx 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.

Sustainable, reliable, affordable power

The High Desert Power Project is a showcase for how existing assets can be optimized to deliver sustainable, but also reliable and affordable electricity.

Advances in resilience

All told, the combination of these measures added significant rapidly dispatchable energy and made the grid stronger and more stable, but the High Desert power plant turbine upgrade involved considerably less time, effort, and costs than the commissioning of a new plant would have involved. Having more capacity and stability is a boon for California’s consumers, but also for MRP’s commercial position. Safe in the knowledge that its turbines will not become stranded assets in the coming hydrogen economy, the company is already considering multiple other options to further decarbonize its operations, step by step. 

MRP is just one of many power suppliers around the globe that have chosen Siemens Energy to develop sustainable solutions for the future, now. The High Desert Power Project is a showcase for how we can help our customers secure additional benefits from assets in their portfolio and deliver sustainable, but also reliable and affordable power. The framework conditions may differ from country to country and across regions, which is why we take a flexible and adaptable approach in developing tailored solutions. It is likely that the demand for energy will continue to grow in most parts of the world, and the energy systems will need to grow accordingly in all of their facets. In some places, bigger steps are feasible, while in others smaller steps may be more realistic.

Energy trilemma resolved at High Desert Power Plant

As an energy technology company with 94,000 transition pacemakers working across the whole energy system, we are advancing side by side with our customers and providing them with the solutions that make the energy transition possible: Products and services, both innovative and conventional, that allow them to decarbonize their energy and increase industrial efficiency. 

The result: A strengthened system that delivers energy to where it’s needed.