What is the role of batteries and fuel cells in achieving net-zero?

Professor Michael Short, director of the Centre for Sustainable Engineering at Teesside University, explores the role that batteries and fuel cells will need to play in the energy transition.

Following the lead of the UK, many governments worldwide have made commitments to achieve net-zero carbon emissions by 2050. This drive towards a zero-carbon economy requires many technological and social innovations, and energy storage devices including batteries and fuel cells have a key role to play.

Batteries and fuel cells help to convert and store energy from a specific time and location (typically when there is abundant supply) to another time and/or location where it can be more effectively used (typically when there is abundant demand).

When integrated with appropriate conversion and control interfaces, batteries and fuel cells allow for higher system performance and increased resilience across a wide range of timescales, conditions, and applications.

Batteries have a wide range of applications, ranging from grid storage (e.g. capacity reserve), renewables integration, powering electric vehicles (EVs) – typically used for lighter applications such as private passenger cars – and consumer products such as mobile phones.

The UK has one of the most advanced ancillary services marketplaces operating in support of its electricity grid. Batteries and fuel cells can support a wide range of services including short-timescale frequency response services, through to long-duration balancing services.

The transition to electric vehicles

The largest impact on emissions involving batteries will involve the transition to EVs. On average, EVs tend to have substantially lower greenhouse gas emissions than conventional vehicles.

Increasing penetration of renewables to further decarbonise the grid and support EV charging will lead to further improvements, and by 2050 emissions from UK EVs should reach near-zero greenhouse gas emissions.

However, the battery manufacturing sector in the UK will need to grow its current capacity of approximately 2GWh to roughly 60GWh by 2030 (approximately three gigafactories) and 100GWh (approximately five gigafactories) of annual capacity by 2035.

Encouragingly, Nissan has just announced details of a new £1bn battery gigafactory that will enable its Sunderland car plant to massively increase production of electric vehicles, to follow others planned in the North East, North West, and Midlands.

Increasing penetration of EVs places heavy loads on electrical grids and infrastructure upgrades are required. EV batteries and chargers also present as potential key storage assets to ensure grid balance and peak shaving in Vehicle-to-Grid (V2G) and Demand Response applications.

A potential drawback is that repeated cycling of charge/discharge operations in V2G can unnecessarily degrade battery capacity and lifetime, and new business models around EV batteries are likely required to reflect these competing stakeholder needs.

Securing affordable and plentiful supplies of critical materials for battery manufacturing, notably cobalt, is also a pressing concern, as is safe and effective battery disposal and recycling.

The crucial role of fuel cells

Batteries will not be suitable for all applications. Energy and power density limitations mean that for extreme applications, other energy sources will be better suited; this is where fuel cells have a crucial role to play.

Currently, principal applications for fuel cell technologies are in transportation (primarily hydrogen vehicles, typically used for heavier applications such as buses and lorries), for stationary uses such as off-grid combined heat and power provision, or for providing portable power e.g. to replace mobile diesel generators.

When combined with electrolyser technology, ‘reversible’ fuel cells may also be used for dynamic storage of electrical energy, and although end-to-end efficiency is still quite low at the current time, this is an active area of research and may open other application areas currently dominated by batteries.

The aerospace, railway, and maritime sectors are clearly candidates with potential for adoption of alternative fuel cells for aircraft, trains, shipping, and cargo handling. At present, material handling vehicles such as forklift trucks and loaders continue to be the most commercially mature fuel cell transport application, notably in North America but increasingly so in Europe.

Continued R&D into retrofitting existing technologies to make them compatible with fuel cell technologies is vital to global decarbonisation efforts. This would also present opportunities in the UK to capture a sizeable share of the growing global market in retrofitted appliances.

Currently, there are a limited number of small but highly-skilled fuel cell manufacturers in the UK with the capability and ambition to position themselves as leaders in this field, but further investment and scale-up is needed to support widespread rollout of commercially viable technologies.

The UK is in a strong position to become a significant force in battery and fuel cell markets. However, the global landscape is competitive, with other nations competing aggressively.

Continued investments in battery and fuel cell research and innovation, infrastructure upgrades and workforce training/upskilling are vital to unlocking our technical potential, creating the right business environment, and bringing forward the next generation of engineers and scientists.