Brunel: Hydrogen combustion engines key to achieving net zero

New research from the Brunel Centre for Advanced Powertrain and Fuels reveals that hydrogen combustion engines are crucial for the UK to meet its net zero targets.

The study

Researchers at Brunel University conducted a comparative analysis of hydrogen and petrol, using a combustion engine originally designed for petrol.

They compared power output, efficiency, combustion characteristics and emissions.

The study concluded that hydrogen was more efficient than petroleum, as well as producing negligible NO_X and no CO, CO₂ or HC emissions under a wide range of operating conditions.

Hydrogen fuel allows the engine to operate under lean conditions i.e. the engine uses less fuel for the same power output. 

These lean conditions produce higher engine thermal efficiency and low cyclic variability.

Overall, the study concludes that hydrogen is a reliable fuel, which simultaneously reduces environmental impact.

What does this mean for the automotive industry?

Various alternative fuels are currently being explored to help reduce the emissions of the automotive industry.

Alcohol-based fuels have shown promise but are seen as a short to medium term solution. A different fuel is needed to satisfy long-term net zero regulations. 

There are limitations to battery electric vehicles (BEVs), such as their range, refuelling time and cost. Some experts also note environmental concerns with battery production and disposal.

In this study, hydrogen was used in an engine designed for petrol. This suggests that hydrogen could replace petrol with only minor modifications to existing combustion engine vehicles.

Hydrogen combustion engines can be manufactured using existing supply chains and existing combustion engines can be adapted to burn hydrogen.

This makes hydrogen more sustainable and affordable, as well as less wasteful as current fossil fuel engine parts can be re-used or repurposed.

This also suggests that further performance gains can be made with an engine specifically designed for hydrogen.

Notably, the hydrogen engine was more efficient than the petrol engine across the complete load range. 

This means hydrogen has the potential to revolutionise the automotive industry, including heavy goods vehicles (HGVs), which have so far struggled with alternative fuels such as electric batteries.

This makes hydrogen a promising zero-carbon alternative fuel, which can be used alongside current infrastructure whilst significantly reducing environmental impact. 

What does this mean for policy in the UK?

The UK’s Net Zero Strategy includes a target to achieve net zero by 2050. The new Labour government are also reinstating the 2030 ban on the sale of new petrol and diesel cars.

So far, BEVs have received over £2 billion worth of government investment, despite their limitations. 

BEVs have struggled in particular with HGVs, marine vessels and non-road mobile machinery. This means BEVs are unlikely to be able to replace all fossil fuel engines across the automotive industry.

Despite the promise of hydrogen, there is currently a lack of public investment in, and policy on, the development of the hydrogen economy, including hydrogen combustion engines. 

Studies like this continue to put pressure on the government to recognise hydrogen’s potential. 

Professor Xinyan Wang and Professor Hua Zhao have used the study’s publication as an opportunity to put forward policy recommendations.

They recommend that the government should recognise the potential of hydrogen to help meet the UK’s net zero targets.

They have called on the government to invest in dedicated R&D programmes for hydrogen combustion engines. Private sector investment could also be encouraged by clearer regulations on the use of hydrogen combustion engines.

They also suggest the UK could become a global leader in hydrogen technology, which would strengthen the economy and create jobs.