27-01-2022 | By Robin Mitchell
A proposed project for generating green hydrogen in Dorset has amassed £6.5m in funding from multiple sources. What is green hydrogen, what is the projects proposal, and what challenges does hydrogen face as a fuel source?
As the concern for the climate and environment increases, so does the desire to move towards a zero-carbon lifestyle. Achieving this may never be possible as there will always be some aspect of human activity that produces CO2 (plastic production, waste, and energy reserves). Still, many technologies can drastically help to reduce CO2 emissions.
One technology being explored is hydrogen, as it produces water vapour when reacted with oxygen via ignition or electrolysis instead of CO2 (however, it can be argued that water vapour is far more damaging as a greenhouse gas than CO2). But while the use of hydrogen may not produce CO2, how it is produced is critical to its environmental impact.
Simply put, hydrogen gas can be produced in several ways, including electrolysis of water and the use of steam and natural gas. Hydrogen that is formed by breaking down natural gas with steam results in the production of CO2, which is no different from burning natural gas outright. This type of hydrogen gas is referred to as blue hydrogen.
Hydrogen that is formed via electrolysis, whose electrical power is sourced from renewable sources, produces no CO2. Thus, this type of hydrogen is ideal for reducing CO2 emissions and is referred to as ‘green’ hydrogen.
A recent venture to produce hydrogen fuel from renewable sources, called Dorset Green H2, has raised over £6.5m in funding from multiple sources, including the Dorset Local Enterprise Partnership Growing Places Fund, a grant from the Low Carbon Dorset scheme, and a bank loan from Canford Renewable Energy.
The idea behind the project is to create a green hydrogen plant that will take energy from nearby renewable sources and then electrolyse water to produce hydrogen gas which will then be compressed and stored. It is estimated that the 0.87MW electrolyser will produce up to 120,000kg of green hydrogen each year. This will then be used to fuel heavy goods vehicles, which have been shown to benefit the most from hydrogen fuel.
However, what makes this site of particular interest is that it will increase hydrogen production in the electrolyser by extracting gas emitted from local landfills in a similar process to blue hydrogen. Despite this process producing CO2, it is better than allowing the gas to naturally escape as methane is a bigger greenhouse gas than CO2.
Hydrogen as a source of renewable energy is not without its faults, and other solutions such as batteries can sometimes prove to be more efficient. The energy required to electrolyse water and store hydrogen is so great that it is frequently an order of magnitude less efficient than using a battery when considering the energy lost during transportation and conversion back into electricity.
This inefficiency will prevent hydrogen cars from becoming as popular as electric cars. However, hydrogen-powered heavy goods vehicles will undoubtedly become the norm due to a unique problem inherent in battery-based vehicles; increased storage = increased weight.
Simply put, fuels such as gasoline and hydrogen have excellent weight to energy ratios whereby doubling the size of a tank effectively doubles the range with a minuscule amount of weight increase. Batteries, however, are one of the biggest components of the weight of a vehicle and doubling the size of the battery does not double the range.
Furthermore, adding too many batteries to a heavy goods vehicle to increase its range can reduce profitability. The vehicle’s total weight is limited by road law, and an increase in battery weight takes away from the total carry capacity. Considering that an electric HGV battery can weigh in tons, this is a significant dealbreaker in their practical use (this is why Tesla HGVs won’t ever exist).
Thus, we conclude that hydrogen as a green fuel will find itself to be highly suitable in HGV, where weight must be minimised. Of course, where this hydrogen comes from is also an important factor, as using non-green hydrogen defeats the purpose of switching over to hydrogen in the first place.