At PowerGen 2023: Repowering Coal with Hydrogen

Coal plant reutilization overview

Dr. Una Nowling, Global Technology Leader, Fuels and Combustion at Black & Veatch presented a project for converting a coal power plant to hydrogen at PowerGen 2023. Rankine-cycle coal-to-natural-gas conversions have been implemented in some locations throughout the world, but a conversion from coal to 100% hydrogen has never been done at a utility-scale power plant. Significant questions still need to be addressed regarding the hydrogen repowering of coal plants. Tallgrass MLP Operations is working toward converting a nominal 250 MW coal-fired power plant to 90-100% hydrogen. This presentation discusses data from a recently completed feasibility study, along with lessons learned from other coal-to-hydrogen conversion and co-firing studies.

There are many different considerations for the conversion process. Hydrogen is suitable for transport, in aerospace, heat production, and power generation through Rankine and Brayton cycle. There is potential for a hydrogen economy down the line. The most significant issue currently facing these pilot projects is, regardless of success, the fact that obtaining hydrogen in production-scale levels is almost impossible. Pipeline and infrastructure to transport the unique properties of hydrogen is also severely lacking. What ends up happening? Lots of impressive tests, with very little to move forward with in a sensible fashion.

Dr. Nowling proposed the idea that smaller plants are more suitable for hydrogen use, defining “small” as under 300 MW in power generation. The sunk-cost fallacy plays a role in determining the feasibility of implementing hydrogen, and so each plant requires a unique understanding of the specific equipment involved. For example, older equipment may be preferred due to being less of a financial risk to convert, since it’s paid off, but newer equipment tends to be more reliable and future proof. An alternative to hydrogen in the decarbonization track is ammonia, due to its greater adaptability capabilities into existing infrastructure.