Imagine a fossil fuel-free jobsite, where we are not consuming petrochemical-based fossil fuels. It’s possible – for those willing to make the investment and test new processes on their next construction site
Disregarding vehicular energy requirements, which may still require fossil fuels for generations depending upon the location, let’s focus on emissions at the site.
Electric battery vs hydrogen-powered construction equipment
A fossil fuel-free jobsite means we must create a zero-emission construction fleet. There are already options for those willing to make the leap – electric battery or hydrogen-powered equipment.
Battery-powered machinery, while promising with comparable range to gasoline or diesel, faces significant drawbacks.
High-voltage recharging takes two to eight hours, causing inefficiencies and project downtime.
In contrast, hydrogen-powered machinery offers the same range as batteries but eliminates refuelling downtime, presenting a more efficient alternative.
The long-term savings achievable with these technologies can easily offset the upfront costs of switching from gasoline or diesel machinery, while contributing to the fossil fuel-free worksite.
Converting existing machinery to hydrogen
It is also possible to convert existing gasoline or diesel equipment models to hydrogen with minimal machine redesign.
This can be achieved by converting to a hydrogen combustion engine, which operates similarly to traditional internal combustion engines (ICE), with cylinders pumping compressed hydrogen gas rather than gas or diesel. Just like an ICE, a spark ignites the hydrogen gas, creating power to drive the machinery.
This can often be a more affordable and simpler option to reduce fossil fuel consumption on the jobsite.
Balancing sustainability and cost
Burning hydrogen in internal combustion engines poses a challenge due to potential pollutant emissions like NOx and particulate matter, known to harm human health.
Stringent legislation against such emissions is increasing, prompting the need for cleaner alternatives. While increasing air in the combustion chamber can reduce NOx, it compromises efficiency. Another approach involves taking out the combustion reaction’s “flame”, effectively reducing harmful pollutants.
Hydrogen fuel cells generate electricity efficiently. However, their implementation is complex and costly.
Alternatively, flameless combustion reactions offer a fuel-agnostic solution, utilising high-temperature exhaust heat recovery to produce pollutant-free power from any fuel.
This allows flexibility in leveraging the most cost-effective and abundant renewable fuels, like hydrogen, providing a practical and environmentally friendly option.
Protecting profit margins necessitates balancing sustainability and cost daily during the energy transition.
This means sites can deploy fuel-agnostic generators at scale today and see immediate carbon and pollution reduction benefits – much to the benefit of site teams, the environment and the local community, offering an alternative and lower-risk entry point for transitioning to a fossil fuel-free jobsite.
The environmental impact of hydrogen: Safety concerns and storage challenges
Another downside of using hydrogen as an energy source is safety. Hydrogen has a small molecular size. If it leaks through solids and mixes with air, it can be explosive, like gasoline or diesel. Not naturally occurring, hydrogen must be extracted from fossil fuels, compressed and used to create a chemical reaction for electricity in construction machinery.
Storage tank infrastructure is critical to safety with hydrogen and hydrogen fuel cell technology. OEMs have to create space for hydrogen storage tanks since they are bulkier than tanks holding liquid gasoline or diesel fuel. The much larger footprint required of hydrogen storage poses a challenge in terms of energy security.
While a 1,000-litre diesel bowser provides three to four weeks of power, the same footprint of hydrogen gives enough power for only two to three days.
Additionally, the hydrogen supply chain is much less mature than that of diesel and comes with more uncertainty, so switching to hydrogen means businesses face a significantly increased risk of project delays. The penalty for this is fines, which impact already-narrow profit margins.
Maintaining the integrity of hydrogen storage tanks is crucial due to hydrogen’s volatility.
A leak could significantly harm the environment. In the short term, a hydrogen leak has 33 times the global warming potential of CO2.
Although CO2 lingers longer in the atmosphere than hydrogen, long-term effects can be more severe. Hence, the focus should be on deploying meticulously crafted systems for hydrogen production, distribution and utilisation.
Weighing emission savings against carbon footprint
Do emissions saved from using hydrogen outweigh the fossil fuels required to produce it, which requires the use of fossil fuels, most commonly natural gas?
This can result in a carbon footprint that can be greater than natural gas-fired power due to the construction of fuel cells and the logistics involved in compressing, transporting, and then either combusting or converting hydrogen to electricity in a fuel cell.
The aim is to get to hydrogen produced using surplus green electricity from wind and solar, with only about 44% of the UK’s total energy demand today delivered by renewable, there is still a long way to go to scale this infrastructure sufficiently to produce the amount of green hydrogen we need to displace the amount of diesel used in the construction industry alone.
We have to take the whole lifecycle of producing hydrogen into account to ensure there isn’t a greater carbon footprint produced in the transition to hydrogen power.
Fossil fuel-free jobsites: A call to action for the construction industry
Certainly, there are companies dedicated to developing the infrastructure and machinery required for deploying a zero-emission construction fleet.
Reducing our carbon emissions on the jobsite is not only beneficial for our planet but also provides a cleaner and safer environment for people working on jobsites – crucial for attracting a skilled labour force.
Our next generation of talent highly values companies that are innovative and proactively taking measures to improve sustainability.
A fossil fuel-free jobsite is possible through a construction fleet that is either electric or hydrogen powered, and there are many OEM companies paving the way for the construction industry to decrease its carbon footprint in a very tangible way.
Matt Wheelis
Senior Vice-President of Strategy
Build & Construct Division
Nemetschek Group
*Please note: This is a commercial profile.
