Alternative fuel cell technologies can be broken down into high and low temperature operation, writes Maia Benstead, technology analyst at IDTechEx
High operating temperature FCs are generally utilized for continuous power generation, whereas low temperature operation results in quick start-up times for back-up power use.
The high temperature operation of MCFCs (above 650°C) makes them a particular competitor to SOFCs. With a similar ability to operate on hydrogen carrier fuels via internal reforming, MCFCs can also be used for continuous, high-power generation. Isolation of the thermal exhaust, through operation in a combined heat and power mode (CHP) for general heating purposes, increases their efficiency to over 80% from typically around 60%.
MCFCs require carbon dioxide (CO2) as well as oxygen and hydrogen fuel to operate, meaning they have been considered for carbon capture applications alongside power generation, particularly for the industrial sector, where an added value stream incentivizes market uptake.
Their uptake is generally found to be for industries where a CO2 exhaust gas stream is available for fuel cell operation, with market growth primarily in application areas such as wastewater plants and chemical refineries.
Low temperature alternatives, such as AFCs and PAFCs have proven technological legacies dating back to the NASA space missions. PAFCs, despite being one of the earliest commercially available FCs, have seen more limited growth uptake, with key manufacturers choosing to transition into the development of PEMFC or SOFC technologies.
PAFCs operate at medium temperature ranges, typically 150-200°C. This allows for reasonably fast ramp-up times (<hour) to deliver maximum power outputs, and for the cogeneration of heat and electricity, again increasing efficiencies to over 80%. However, their acidic and liquid operating environment presents significant safety risks requiring regular maintenance and monitoring, so far limiting commercial opportunities and market uptake.
AFCs were one of the original FC technologies tested for the NASA space missions. By operating at temperatures typically around 20-200°C, the technology can rapidly respond to power demand changes. The large-scale development of AFCs continued primarily until the emergence of proton exchange membrane fuel cells (PEMFCs), with many manufacturers and research teams choosing to develop this technology instead.
Their ability to operate using non-noble metal catalysts, such as nickel metal, has led to increased interest in their uptake, as a lower-cost alternative to PEMFCs. AFCs are now considered a back-up power competitor to PEMFCs, with the technology considered a durable and high efficiency alternative.
As a specification variation of PEMFCs, DMFCs are a low temperature alternative, able to operate using methanol fuel. DMFCs utilise a proton-exchange membrane and operate at temperatures typically 50°C to 120°C. This again allows for rapid response times to power demand changes, with DMFCs typically used for back-up power applications, particularly for remote monitoring and telecoms. Their ability to operate using low cost and widely available methanol fuel has helped to drive use cases; however, limitations to their power densities again hinder widespread uptake. IDTechEx finds that the DMFC market will be restricted to more specific and niche use cases.
The spread of fuel cell technologies available within the market provides customers with access to a variety of systems designed for their specific power requirements. However, comprehensive analysis of the market and players finds that many manufacturers of alternative FC technologies have begun to transition to the production of PEMFCs or SOFCs, the exception however is AFCs. Despite this period of transition, many market players continue to manufacture alternative FC technologies, with IDTechEx finding the combined MCFC, PAFC, AFC and DMFC market demand is anticipated to rise to 750 MW annually by 2035.
For more details on the varying types of fuel cells available on the market and how adoption is anticipated to change over the coming decade, see IDTechEx’s market report “Stationary Fuel Cell Markets 2025-2035: Technologies, Players & Forecasts”.
However, alternative fuel cell technologies like alkaline fuel cells (AFCs), molten carbonate fuel cells (MCFCs), phosphoric acid fuel cells (PAFCs) and direct methanol fuel cells (DMFCs) still compete for market share.
In its latest report, IDTechEx explores not only the PEMFC and SOFC markets but analyses the viability of alternative FC types as stationary power generation technologies, finding the technologies will account for over 10% of annual demand by 2035, with a cumulative market share of over $676-million.