Introduction

Fuel Cells.

By Mark Cain
5 October 2026

Fuel Cells in New Zealand: How They Work, What Is Available and Where They Perform Best

A fuel cell is an electricity generator. It does not store electricity in the way a battery does and it does not burn hydrogen like an engine. Instead, it continuously converts the chemical energy of a supplied fuel into electricity through an electrochemical reaction.

That distinction gives fuel cells an unusual combination of qualities: electric-motor performance without combustion, quiet operation, useful efficiency at modest scale and a running time determined largely by the amount of fuel available. It also creates their main limitation. A fuel cell is only one part of a complete energy system; hydrogen must first be produced, compressed or otherwise stored, transported and supplied at the required purity.

How a Hydrogen Fuel Cell Works

The fuel cell technology most often encountered in New Zealand is the proton exchange membrane fuel cell, usually shortened to PEMFC or PEFC.

Each cell contains an anode, a cathode and a thin polymer electrolyte membrane between them. Hydrogen enters the anode side, where a catalyst separates each hydrogen molecule into positively charged hydrogen ions and electrons.

The membrane allows the hydrogen ions to cross but blocks the electrons. The electrons must therefore travel through an external circuit, creating useful direct-current electricity. At the cathode, oxygen from the air combines with the returning electrons and hydrogen ions to form water. Heat is also released.

The overall reaction is:

Hydrogen + oxygen → electricity + water + heat

A single cell produces less than one volt under load, so many cells are connected in series to form a stack. A usable generator or vehicle then surrounds that stack with its “balance of plant”: air filtration and compression, hydrogen pressure regulation and recirculation, cooling, water management, sensors, valves and electronic controls.

The stack produces DC electricity. A stationary system normally uses power electronics to condition that output and an inverter to supply standard AC electricity. A fuel cell vehicle sends the electricity to an electric traction motor. Most modern systems also include a battery.

The battery starts the system, captures regenerative braking, handles sudden power peaks and allows the fuel cell stack to operate more steadily and efficiently.

Hydrogen fuel cells produce no carbon dioxide, soot or nitrogen oxides at the point of operation when supplied with pure hydrogen. Their lifecycle emissions, however, depend on how the hydrogen was made and delivered. Renewable hydrogen can provide a low-emissions pathway.

The Main Fuel Cell Families

Fuel cells are classified mainly by their electrolyte and operating temperature.

Proton Exchange Membrane Fuel Cells

PEM fuel cells operate at comparatively low temperature, generally below 100–120°C. They start quickly, respond rapidly to load changes and have high power density. These attributes make them the leading choice for cars, trucks, boats, forklifts, portable generators and backup power.

Their disadvantages include the use of platinum-group catalysts, a requirement for high-purity hydrogen, sensitivity to contaminants such as carbon monoxide, and the cost of humidification, cooling and air-compression equipment. Stack life is strongly influenced by starts, stops, contaminants and operation at extreme loads.

Alkaline Fuel Cells

Alkaline fuel cells conduct hydroxide ions through a liquid alkaline electrolyte or an alkaline membrane. They can use less costly catalysts and can achieve high electrical efficiency. They were among the first practical fuel cells and became well known through space applications.

Their major weakness is sensitivity to carbon dioxide—even the small concentration in ordinary air can affect some designs. Electrolyte management and system complexity have limited mainstream terrestrial deployment. They are not a significant established New Zealand product category today.

Phosphoric Acid Fuel Cells

PAFCs operate at roughly 150–200°C and have historically been used for stationary combined heat and power. They tolerate some fuel impurities better than low-temperature PEM systems, and their heat is more useful for buildings and processes.

They are relatively large, slow to start, expensive in catalyst content and commonly deliver only about 37–42% electrical efficiency. Although commercially mature internationally, they are not prominent in New Zealand’s present distributed-power market.

Molten Carbonate Fuel Cells

MCFCs operate at approximately 600–700°C. They can internally reform natural gas or biogas into a hydrogen-rich gas, use non-precious catalysts and serve hundreds-of-kilowatts to multi-megawatt stationary applications. Electrical efficiencies are commonly around 50%, with much higher total fuel utilisation possible when heat is recovered.

High temperature and a corrosive molten electrolyte cause durability, corrosion and slow-start challenges. They are best suited to continuously operated industrial generation, not mobile or frequently cycled applications. Currently no broad, established New Zealand supply offering is evident.

Solid Oxide Fuel Cells

SOFCs use a solid ceramic electrolyte at approximately 500–1,000°C. They can achieve around 50–60% electrical efficiency and can use hydrogen, natural gas, biogas or other reformed fuels. Their hot exhaust makes them attractive for combined heat and power, and even higher system efficiencies are possible in large hybrid cycles.

The trade-offs are slow warm-up, thermal-cycling limitations, specialist high-temperature materials and potential degradation of ceramics and seals. SOFCs can be an excellent stationary option where they run continuously, but they are not a direct substitute for a fast-starting emergency generator unless kept hot or paired with another device.

Direct Methanol Fuel Cells

A direct methanol fuel cell, or DMFC, is related to PEM technology but feeds liquid methanol mixed with water directly to the anode. Methanol is easy to transport and has much higher volumetric energy density than compressed hydrogen, making DMFCs useful for low-power equipment in remote locations.

They are generally less electrically efficient and slower to respond than hydrogen PEM systems. Because methanol contains carbon, a DMFC emits carbon dioxide during operation. Its advantages are autonomy, quiet operation and convenient liquid-fuel logistics rather than zero-carbon exhaust.

What Fuel Cells Are Available in New Zealand?

New Zealand does not yet have a deep, commodity fuel cell market.

Availability often means a supported demonstration, limited fleet, specialist import or project-based supply rather than a product held widely in stock. The clearest current offerings and operating examples are concentrated in PEM and direct-methanol technology.

Current hydrogen products and projects in New Zealand use fuel cells made by Hyundai, Toyota, Ballard and SFC Energy. Locally visible systems include complete vehicles and generators as well as project-based equipment supplied or integrated through specialist companies such as Powerbox Pacific, Renewable Innovations and New Zealand Hydrogen.

How Efficient Is a Fuel Cell?

There is no single fuel cell efficiency figure. Results depend on chemistry, fuel, load, temperature and whether the number describes a bare stack, a net DC system, delivered AC power or combined electricity and useful heat.

Figures also use either the lower heating value or higher heating value of hydrogen; quoting one without the basis can produce an apparently better result.

As broad lower-heating-value ranges:

Indicative Electrical Efficiency by Fuel Cell Type
Indicative Electrical Efficiency by Fuel Cell Type
Fuel cell type	Indicative electrical efficiency	Important qualification
Hydrogen PEM	About 45–60%	Direct hydrogen; net system efficiency is below gross stack efficiency
Alkaline	Up to about 60%	Clean hydrogen and CO₂ management required
Phosphoric acid	About 37–42%	Total CHP efficiency can exceed 80% if heat is genuinely used
Molten carbonate	About 45–55%	Large, steady stationary plant; potentially higher in hybrid cycles
Solid oxide	About 50–60%	Best under steady high-temperature operation
Direct methanol	Commonly about 20–35%	Lower electrical efficiency offset by simple liquid-fuel storage

The US Department of Energy’s fuel cell comparison gives representative stack values of about 60% for direct-hydrogen PEM and alkaline cells, 40% for PAFC, 50% for MCFC and 60% for SOFC. A commercial system includes air compressors, pumps, fans, cooling, controls and an inverter, so power delivered to the load is lower.

Fuel cells can also provide useful heat. If hot water or process heat would otherwise have been produced separately, combined heat-and-power utilisation may reach approximately 70–90%. This is not 90% electricity: it is electricity plus captured heat. Low-temperature PEM heat is suitable for some hot-water or low-temperature duties, while PAFC, MCFC and SOFC offer progressively higher-quality heat.

The efficiency of a fuel cell must not be confused with the round-trip efficiency of hydrogen energy storage. If renewable electricity is converted to hydrogen, compressed, stored and later converted back to electricity, losses occur at every step. A representative chain might be 60–70% efficient in electrolysis, lose further energy in compression and storage, and return 45–55% through the fuel cell generator. Overall electricity-to-electricity efficiency is therefore commonly only around 25–40%, well below a lithium-ion battery system.

Hydrogen may nevertheless be useful when storage must last days, weeks or seasons, or when transported fuel is more practical than a very large battery. Efficiency is only one measure of system value.

Performance Benefits Compared with Other Electrical-Power Technologies

Fuel cells are not a universal replacement for batteries, generators or grid electricity. Their value is strongest where quiet, low-emission power, long runtime or rapid refuelling solves a practical constraint.

Compared with Diesel Generators

A hydrogen PEM generator offers very low noise and vibration, no combustion exhaust at the point of use and high efficiency at relatively small scale. It produces no carbon dioxide, soot, sulphur oxides or combustion nitrogen oxides during operation. This can be valuable at events, hospitals, telecommunications sites, urban construction, tunnels and environmentally sensitive locations.

Fuel cells have fewer major moving parts than piston engines and can retain reasonable efficiency at part load. Modular units also allow capacity and redundancy to be added incrementally. They do not need oil changes, diesel particulate filters or exhaust after-treatment.

They are not maintenance free. Air compressors, pumps, fans, filters, valves, cooling loops, batteries and power electronics still require service, and the stack degrades over time. Hydrogen storage occupies more space than diesel for the same delivered energy, fuel availability remains limited, and today’s delivered renewable hydrogen is generally much more expensive than diesel on an energy basis. A diesel genset is easier to refuel almost anywhere in New Zealand and has an extensive service network.

Compared with Batteries

Batteries are generally more efficient, simpler and cheaper for short-duration storage and everyday light-duty electrification. They respond almost instantaneously, have no fuel supply, and can recover electricity with round-trip efficiencies often above 80%. Where a site needs minutes or a few hours of backup, a battery will commonly be the better first option.

A fuel cell becomes more interesting as required duration or mobility increases. Adding fuel cell runtime mostly means adding hydrogen storage; adding battery runtime means adding more electrochemical cells, weight and cost. Hydrogen can be delivered to a depleted site, and a vehicle can be refuelled in minutes rather than waiting for a large battery to recharge. This can benefit heavily utilised trucks, remote critical loads and resilience systems designed for multi-day outages.

The strongest architecture is often hybrid. A battery manages startup, sharp peaks and regenerative energy, while the fuel cell supplies sustained power and recharges the battery. This allows a smaller fuel cell stack to operate in a stable region and improves response and durability.

Compared with Engines and Turbines Using Hydrogen

A fuel cell generally converts hydrogen to electricity more efficiently than a small combustion engine, especially at part load, and avoids combustion NOx. It is quiet and mechanically simple at the conversion stage. Hydrogen engines, however, tolerate less-pure fuel, use familiar manufacturing and service skills, respond robustly to harsh duty and may cost less initially. Large combined-cycle turbines can be highly efficient and may suit grid-scale operation better than fuel cells, although hydrogen-capable equipment and emissions control require careful design.

Compared with Solar, Wind and the Electricity Grid

Solar panels and wind turbines harvest primary renewable energy; a fuel cell consumes a manufactured fuel. They are therefore complementary rather than direct equivalents. Solar or wind can make hydrogen when renewable electricity is available, and a fuel cell can return power when generation is low. The price paid is lower round-trip efficiency.

Compared with a reliable grid connection, onsite fuel cell electricity will usually be more expensive. Its value lies in resilience, location, clean operation and autonomy. A properly designed system can operate when the grid is down, but only if it has sufficient hydrogen inventory, black-start capability, functioning auxiliaries and an electrical arrangement that can safely island from the network.

Where Fuel Cells Offer the Greatest Value in New Zealand

Fuel cells are most compelling where several advantages occur together:

A quiet, emissions-sensitive site needs dependable power;
Backup must last much longer than an economical battery duration;
Hydrogen can be stored onsite or delivered reliably during an emergency;
Equipment has high daily utilisation and fast refuelling creates operational value;
Vehicle weight, payload or range makes a very large battery difficult;
Renewable hydrogen is already produced locally or nearby;
Both electricity and useful heat can be consumed; or
Diesel logistics are costly, vulnerable or environmentally undesirable.

They are less compelling for ordinary short-duration household backup or grid-connected loads that can be electrified directly. In those cases, batteries, demand flexibility and direct renewable electricity normally use substantially less primary energy.

The practical New Zealand market today is therefore not “fuel cells everywhere.” It is targeted use of predominantly PEM systems in transport, marine, critical backup, remote hybrid power and clean temporary generation, alongside direct-methanol systems where the ease of storing liquid fuel outweighs their lower efficiency and carbon emissions.

The Bottom Line

A fuel cell combines hydrogen and oxygen electrochemically to make DC electricity, water and heat.

In New Zealand, commercially visible hydrogen systems are overwhelmingly PEM-based, from Renewable Innovations UPS backup modules, New Zealand Hydrogen trailer power systems and Toyota generators to Hyundai trucks, Toyota cars and specialist marine powertrains. Direct-methanol fuel cells are also established in low-power remote applications. Other chemistries are technically important but do not yet have the same local presence.

A complete hydrogen PEM system will commonly deliver around half of the hydrogen’s lower-heating-value energy as electricity. That is better than many small combustion generators, particularly at part load, but well below the efficiency of storing and returning electricity through a battery once hydrogen production is included.

Fuel cells should consequently be selected for the jobs in which their distinctive strengths—long runtime, rapid refuelling, low local emissions, quiet operation, modularity and reduced storage weight—are worth the additional cost and fuel infrastructure. Used that way, they can complement New Zealand’s batteries, renewable generation and electricity network rather than compete with them indiscriminately.