The hydrogen economy’s role in a carbon neutral future
Co-edited by Alicat & Crowcon
The COP21 Paris agreement has pledged to take action to keep global warming below 2°C, meaning global annual greenhouse gas emissions will need to go down 85% by 2050. This spells out a lot of work for the top two sectors contributing to global greenhouse gas emissions – energy and transport.
Here we will explore the hydrogen economy’s role in developing a more sustainable, carbon neutral future, linking directly to the UN sustainability goals 7 and 13 (affordable & clean energy and climate action) and indirectly to several others.
First and foremost, where are we getting our hydrogen from?
Hydrogen production methods have significant impacts on the efficiency and environmental impact of the hydrogen economy. While we would like for all hydrogen to be entirely carbon neutral, this is not the case. Following is a color system, where hydrogen is categorized based on production method:
- Brown hydrogen is made from the gasification of coal, which emits CO2 into the air as it combusts.
- Grey hydrogen is produced using fossil fuels, such as natural gas.
- Blue hydrogen is made in the same way as grey, but carbon capture and storage (CCS) technologies prevent the release of CO2, enabling the captured carbon to be safely stored deep underground or used in industrial processes.
- Green hydrogen is, as its name suggests, the cleanest variety and produces zero carbon emissions. It is primarily produced using electrolysis powered by renewable energy, like wind or solar power, to produce a clean and sustainable fuel. Electrolysis splits water (H2O) into hydrogen (H2) and oxygen (O2), so there is no waste and all parts are used with zero environmental impact. If the energy used for electrolysis is taken from renewable sources this can be counted as ‘green fuel’ because there are no negative impacts on the environment.
We are of course interested in the green hydrogen – but that only makes up a small percentage of hydrogen used in the hydrogen economy. Fortunately, electrolysis is undergoing technological advances due to companies such as Siemens Energy and ITM Power, and the industrial scale production of carbon neutral green hydrogen is becoming more of a reality.
So what role does hydrogen, especially green hydrogen, play in decreasing the emissions within the high carbon producing sectors of energy and transport?
Hydrogen energy for fuel cell powered transport
Since road transport accounts for ~12% of all greenhouse gas emissions (fig 3), decarbonizing this sector is critical to accomplishing COP21 goals. Both hydrogen fuel cell electric vehicles (FCEVs) and battery electric vehicles (BEVs) are able to lower this number by providing greener alternatives to combustion engines. The hydrogen FCEV is particularly promising, emitting only water as an exhaust product and having a greater driving range and much shorter fueling times than BEVs. These features make FCEVs a great choice for trucks, trains, and buses – and even large automotive and aerospace manufacturers are shifting their focus toward hydrogen fuel cell research divisions in order to reach carbon neutrality.
Static hydrogen fuel cells can power buildings and regulate temperature
Another 17.5% of greenhouse gas emissions come from the energy used to power buildings and regulate temperature (fig 3). This can be remedied with large scale hydrogen fuel cell systems that provide renewable energy to commercial and residential buildings. Hydrogen generated energy can even be used in remote locations, pairing well with solar panel technology.
Static fuel cells also offer advantages over batteries – they don’t lose reduction capacity over time and lower temperatures won’t lead to power loss.
Hydrogen in fossil fuel intensive industries
Other energy intensive industries such as iron and steel are also working on reducing reliance on fossil fuels by incorporating hydrogen into energy production sources – with the added bonus of minimizing the risk of dangerous carbon products such as carbon monoxide. One promising tactic is blending hydrogen with natural gas in natural gas grids, utilizing already existing infrastructure and shifting toward carbon neutrality and the elimination of fossil fuel usage.
Like all new emerging technologies, there are both technical and socio-economic challenges faced in the wide scale adoption of hydrogen technologies. But given the potential benefits presented by the hydrogen economy and the momentum it has gained recently, these systems will no doubt become more prevalent in the coming years in order to achieve carbon neutrality.