High Efficiency, Low Cost & Robust Hybrid SOFC/IC Engine Power Generator

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Project Term:
09/07/2018 - 03/26/2024

Critical Need:

In our carbon-neutral future, energy-dense fuels will continue to be economically critical energy storage media in many stationary and transportation applications. To preserve our climate, however, we must rapidly transition to fuels synthesized from carbon-neutral resources rather than extracted from fossil reserves. These fuels are likely to be more expensive than their fossil counterparts. It is also unclear which of many current carbon-neutral options (e.g., hydrogen, ammonia, synthetic aviation fuel) will be adopted at scale. Given this uncertainty and cost risk, fuel flexibility and ultra-high conversion efficiency will be especially critical energy conversion system performance metrics. Solid oxide fuel cell and engine integrated systems offer the potential for ultra-high efficiency (>70%) and fuel flexibility at an attractive cost (<$1/W). Additional development is required to address a number of outstanding challenges including achieving the low-loss integration of fuel cells with engine-based waste recovery cycles and operation of fuel cell stacks at elevated pressure with acceptable life.

Project Innovation + Advantages:

The Colorado School of Mines (Mines) will develop a hybrid power generation system that leverages a pressurized, intermediate-temperature solid oxide fuel cell (SOFC) stack and an advanced low-energy-content fuel internal combustion engine. In Phase II, the team will develop and test three SOFC sub-module building blocks (CERES Power and Mines) and then integrate them into a 100 kW-capable pressure vessel package, and develop efficiency-enhanced 2nd generation Kohler engine and balance-of-plant hardware, including novel, positive displacement rotating machinery from Air Squared; build a full-scale, high-efficiency inverter (Kohler Power Systems). Further, the team will build out the hybrid system test facility at Colorado State University and develop the necessary control system (Mines), and integrate the components and perform up to 1 year of integrated testing, demonstrating start-up, load-change, and steady-state operation at 70% efficiency. Finally, they will perform extended techno-economic analysis and develop technology-to-market plans with Kohler Power Systems, the commercialization partner.

Potential Impact:

The INTEGRATE program is developing a new class of distributed and ultra-efficient (>70%) fuel to electric power conversion systems for commercial and industrial customers.


Distributed electrical generation systems can produce highly reliable and resilient electric power supplies.


High electric efficiency and decreased reliance on combustion would result in lower greenhouse gas and air pollutant emissions. These systems also provide the opportunity for faster and more economically viable transition to a carbon neutral power generation sector.


These systems’ high efficiency and avoidance of electric grid transmission and distribution costs offer the potential for lower cost electric power.


ARPA-E Program Director:
Dr. David Tew
Project Contact:
Prof. Robert Braun
Press and General Inquiries Email:
Project Contact Email:


Kohler Co.
Colorado State University
Air Squared Inc.

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