Is it time to replace diesel gensets with hydrogen fuel cells?

Hydrogen fuel cells offer reliable, flexible and zero-emission off-grid power generation that supports energy security


Multiple industries are facing up to the reality that there is now a range of power needs that cannot be based on the energy grid. From construction, to building, to manufacturing, to data centers, to events, the truth is that many sectors of the global economy need an alternative to the grid. These industries also require independent energy storage to provide resilience, for example if the grid is unstable or goes down. Some companies have power requirements that must be faster than a grid connection. Others need control over their power contracts to sustain company growth. There are countless diverse use cases for off-grid energy generation and storage depending on location and industry, but all end-users share three common requirements: reliability, flexibility, and practicality.


These industries are currently still being supplied by diesel generators, which have been honed over the decades and meet a lot of the end-users’ needs. However, these industries are also being urged and legislated to decarbonise, and the inconvenient truth is that diesel generators themselves produce high greenhouse gas emissions, including harmful local emissions such as SOx, NOx and particulate matter.


It’s clear that diesel gensets must be phased out, but in a very complex energy environment, potential customers also need expert guidance when choosing the most appropriate alternative solutions. Below, we outline the advantages and disadvantages of hydrogen fuel cells.


Is cost still a barrier? 

The common misconception that many people still have about hydrogen fuel cells is that the up-front expense of the fuel cell solutions and the current price of the fuel itself would appear to make them “too expensive.” However, this assumption fails to take account of the capital and operating expenditure balance, and of hydrogen fuel cell technology’s huge potential benefits in terms of flexibility, resilience and — something which is increasingly important considering recent world events — energy security. Essentially, fuel cells using green hydrogen can offer independence from other nation’s fossil fuels.

The cost outlay of procuring hydrogen fuel cell solutions cannot be shied away from. However, once acquired the technology is remarkably low maintenance. Unlike a diesel generator, a hydrogen fuel cell has no complex working parts, and simply consists of an anode, a cathode and an electrolyte. This is significantly less costly; the technology works on demand and with minimal maintenance hours required.

We must also consider the myriad potential applications of hydrogen fuel cells, and how they distinguish themselves from more traditional solutions. In fixed-site applications, the capital sunk into diesel generators spends most of its time sat idle. Diesel generators are typically only called upon to provide power in the short term; they operate as back-up when things go wrong (and consume considerable quantities of carbon-emitting fuel while doing so). An example is the provision of emergency power during grid outages for critical assets such as hospitals and data centres.

By contrast, hydrogen fuel cells can be operated right across the working day. In addition to providing a carbon-free and local emissions-free solution to energy needs when grids fail, hydrogen technology can cater for peak shaving needs (that is, providing extra energy capacity for short periods of time when demand exceeds supply from grid-based sources) and be used habitually to complement conventional energy sources when hydrogen is in ready supply, such as when it is a by-product of refining processes. This provides further benefits in terms of OPEX costs and their use continually at a very low power rate can be ramped up very quickly as and when necessary.

Hydrogen versus battery-electric

In stationary applications, the debate should not be about whether battery-electric or hydrogen fuel cells should be chosen over each other. These technologies can be complementary, and their individual strengths and benefits should be recognised. Firstly, in these circumstances there will always be a grid connection, even if supply is occasionally (or repeatedly) interrupted. Secondly, we need to consider where the energy resides.

With batteries, energy — of a very high density — has already been generated. It is stored within the cells, and typically there is enough capacity for 1-2 days’ use; like diesel generators, battery-electric systems are often used as an emergency back-up source and is a much cleaner one.

With hydrogen fuel cells, the energy potential is held in the as-yet unused fuel. The capacity is not therefore in the cell itself and is readily augmentable, assuming a fuel supply can be guaranteed. This means that hydrogen fuel cells can provide support, in the form of peak shaving, or act as a longer-term solution should grid supply continue to be problematic for longer than anticipated.

Shaping the grid of the future

Where hydrogen fuel cell technology truly excels is in how it can help to shape grid dependency, or even remove it altogether. It can also help to significantly extend the use of micro-grids.

Some of the potential applications are rather more short-term. For instance, clean power supply at construction sites is a possibility. Another is support for off-site events; PowerCell Group technology is currently being used by a major electric vehicle manufacturer. Use of diesel generators runs counter to the company’s mission and promises, and risks compromise. Hydrogen fuel cells are therefore used to satisfy the power needs of its display and habitation systems. The company’s technology has also been used, with very short lead times, to provide power for a COVID hospital.

Looking into the future, we can see that there will be a move away from dependency on more centralised power generation at larger facilities, and wasteful transmission over great distances. The trend is towards smarter grids, with grid-sharing becoming a feature, and many more distributed power generators.

These power generators, which can even be individual households, can be contributors to national or regional grids, or operate as discrete systems. There is the opportunity for remote communities to be entirely self-sufficient in terms of their energy needs, using renewable means of generation. Ultimately, a new generation of hydrogen fuel cells already exists and are ready to replace diesel gensets. They have a critical role to play in the energy transition and into the long-term future, by providing adaptability and resilience.