This is how hydrogen generator sets can decarbonize power

Generator sets (gensets) are a mainstay of emergency and mobile power generation. From disaster recovery to off-grid deployment in emerging markets, remote islands and critical infrastructure, their reliability and flexibility make them indispensable across a wide range of backup and standalone applications.

Traditionally powered by diesel or natural gas, gensets are now being adapted to run on hydrogen as part of the energy transition.

Mitsubishi Heavy Industries (MHI) Group has just tested a six-cylinder 500 kW-class hydrogen engine generator set at its Sagamihara plant in Japan. The genset proved to operate stably with 100% hydrogen fuel in all phases, from startup and rated output to shutdown.

Where will we see these gensets in action?

What are gensets and how do they work?

A genset combines an engine and an electric generator or alternator to produce electricity.

Gensets burn fuel — typically diesel or gas — to produce mechanical energy that drives the alternator, converting the energy into electricity. They are normally used in locations where grid electricity is unavailable or unreliable, either as a temporary failover system or a constant off-grid energy source.

They are also frequently used for on-site power generation in factories or commercial facilities even when grid electricity is available, to improve energy efficiency by capturing and reusing the waste heat generated.

While gensets are already playing a vital role in the global energy mix, their importance has been growing. The industry is predicted to expand from $42 billion in 2023 to more than $68 billion by 2032.

While traditionally fossil fuel-powered, companies including MHI have been working on decarbonizing this key source of power generation by converting it to hydrogen. One of the key pathways for the energy transition, hydrogen burns without emitting CO₂ and can be produced using low-CO₂ or emission-free ‘green’ technologies.

What will hydrogen gensets be used for? 

While many applications will evolve from the current uses of gensets, new ones are also emerging.

Distributed power generation to meet fast-growing energy demand 

Grids are straining to meet rapidly rising energy demand and accommodate a growing share of renewable energy sources, particularly in local hotspots with large concentrations of energy-intensive industrial sites or power-hungry data centers.

To ensure energy is available as needed, hydrogen gensets can be brought online as a decentralized power source that supplements the grid or can even operate off-grid.

While low-carbon hydrogen production is increasing, it remains scarce. Most hydrogen is still produced using fossil fuels. In 2023, less than 1% of total hydrogen production was from low-emission sources, according to the International Energy Agency (IEA).

However, around a sixth of global hydrogen supply is currently generated as a by-product in sectors such as steel, chemicals and semiconductors. These industries are likely to become the earliest adopters of hydrogen gensets, converting a waste product into a free energy source. 

Hydrogen filling stations run under their own steam 

With hydrogen a key pathway for decarbonizing heavy transport, trucks and buses are seeing the most significant growth globally. China is the largest single market using hydrogen in transportation, followed by Korea, the US, Europe and Japan.

As hydrogen's ‘fueling’ infrastructure expands with filling stations along major roads and motorways, it could enable another application for hydrogen gensets. The most efficient way to transport and store hydrogen is in liquid form. However, some liquid hydrogen evaporates, leading to energy loss.

Feeding this boil-off hydrogen into a genset can produce electricity for the filling station and its locality, transforming a waste product into usable power.

Powering hydrogen ports

Ports present another promising opportunity for hydrogen gensets, driven by two main trends.

First, many hydrogen production projects are being developed near ports due to their proximity to renewable energy sources like offshore wind. Access to low-cost, local electricity makes these sites well-suited for producing clean hydrogen via electrolysis — the process of extracting hydrogen from water using electricity. A notable example is the Port of Newcastle Clean Energy Precinct in Australia, where MHI is a partner.

Second, in countries with limited renewable resources — such as Japan, South Korea and Germany — ports will be essential hubs for hydrogen imports.

Together, these trends support the case for using hydrogen to power port infrastructure. Hydrogen gensets are already being trialed to power heavy-duty cranes and gantries used for unloading and moving containers from ships. And as hydrogen production and transport continue to scale in coastal areas — and ports decarbonize operations — their role is likely to expand.  

Driving decarbonization a step at a time

Gensets have long played a critical role in meeting peak energy demand across a range of settings. Now, as technology providers begin transitioning them to hydrogen — with commercial models expected in the coming years — their potential applications are set to grow significantly. Thanks to their scalability and cross-sector versatility, hydrogen-powered gensets could emerge as key enablers of the energy transition.