Technical writer and power expert Steve Nendick examines how fleet managers can be empowered while meeting the sustainable off-highway machinery power challenge.
Fleet managers continue to juggle pressures to minimise costs while maximising productivity and returns for their businesses. They are also facing increased pressure from shareholders to be more sustainable and look towards a zero-carbon future.
Emissions regulations have been around for over 25 years, pushing the industry to invest in technology to reduce particulate and oxides of nitrogen emissions. The progression from EU Stage I to Stage V has brought these exhaust constituents to near-zero levels.
However, CO2 emissions have never been included in these regulations. It is expected that CO2 limits could be included in the potential Stage VI regulations, but these are not anticipated until the end of the decade.
So with no official push to move to lower carbon solutions, what should fleet managers do?
There are several options available that would result in minimal changes to current operating processes.
Machinery with the latest Stage V engines
Today’s products that meet EU Stage V emissions are light years ahead of their predecessors in technology and capability. Significant improvements can be made by replacing older machines with Stage V engine machines, which are cleaner, more efficient and more reliable.
The latest units are clean for urban sites with no visible smoke, helped by the latest exhaust aftertreatment technology. Engine noise is substantially reduced, while power density has increased, meaning smaller machines can potentially do the job of larger machines, positively impacting operating costs.
Improved fuel efficiency helps to not only reduce running costs, but also CO2 emissions too.
And longer service intervals reduce oil and filter usage, lowering maintenance costs and the environmental impact.
Renewable fuels across the fleet
Renewable fuels such as HVO100 – hydrotreated vegetable oil – can lower emissions by up to 90 per cent compared to diesel ‘from well-to-wheel’. For every 1000 litres of fuel, operators could save on average of over 2200kg of net CO2 from switching to HVO, which is fossil-free, sulphur-free and oxygen-free, and requires no engine modifications to use. As a cleaner-burning fuel, fewer filter changes are needed, lowering maintenance costs.
HVO100 can be supplied through the same infrastructure as conventional diesel. However, it does cost more to produce, given it is made from renewable sources such as vegetable oils or animal fats, which require more complex processing.
In Europe, this price difference is 10–15 per cent higher depending on the region. It is more prevalent in countries with a stronger renewable focus (eg Scandinavia, Netherlands).
While more expensive, the lower maintenance costs could offset the upfront cost, making it attractive for organisations looking to reduce their carbon footprint and emissions without investing in new vehicles or machinery.
Other renewable fuels, such as natural gas, could become a solution. To date, the additional installation costs and long payback period have prevented any major industrial adoption of compressed natural gas (CNG) or liquified natural gas (LNG).
Manage fleets more proactively with available technology
Many of the latest electronic engines have features like stop–start or idle shut-off. Machines are often left idling for lengthy periods between jobs, and adopting these features saves fuel, protects the engine’s durability, and reduces site emissions and noise.
Many of the latest machines have integrated telematic systems, and retrofit options are available for those that don’t.
The latest fully electronic engines, equipped with an array of sensors that monitor and protect, are compatible with these solutions. They enable fleet managers to connect remotely and look after their valuable assets.
Using telematic systems does come at a cost to the business, from the initial installation, monthly subscription and software integration to the resource for monitoring the output.
However, return on investment can be justified in a number of ways:
Data analysis helps to optimise operations, ensuring fleets match production needs and haul trucks are loaded with the correct payloads
Reducing idle time cuts fuel consumption, cost and emissions
Detecting potential service problems in advance reduces repair costs and unnecessary downtime
Enabling predictive maintenance schedules allows for extended service intervals without affecting durability
Technicians being able to arrive on-site with the correct parts and tools on the first trip improving service efficiency
Overall equipment utilisation is enhanced by extending life and avoiding acquiring unnecessary machinery
Train the operators
Having trained people who can operate machinery at their optimal levels will maximise fuel efficiency and reduce potential damage to the unit. Inexperienced people are more likely to use machinery in such a way that increases fuel consumption, cost and emissions. Using telematics to gather data could help improve operator training.
There will come a time when low- and zero-carbon solutions will become more prevalent in the market, but this will take some time. Until that time, fleet managers have several options available to them to improve the sustainability of their operations without affecting productivity.
Currently, no solution can match clean diesel’s flexibility and range capability so it will likely remain the power of choice for the foreseeable. It will take time, patience and investment, but, low- and zero-carbon power will eventually grow its share in industrial fleets.
So what does the future look like? What will be the most appropriate power source for quarries and construction site machines?
The main zero-carbon fuel choices are battery electric or hydrogen, provided the hydrogen is produced using clean energy. Which is the most suitable, and why?
Battery-electric
Electric industrial equipment will deliver zero emissions with substantially reduced noise pollution for quarries and construction sites. If you include electricity-generated emissions to power electric vehicles (EVs), they will still have a significantly smaller lifetime carbon footprint than today’s machines. For companies that value sustainability, the environmental benefits could justify the higher initial investment, provided the charging infrastructure aligns with the operational needs.
Diesel-powered machinery is traditionally less expensive to purchase upfront compared with battery-electric power. Due to the battery technology installed, the cost of electric equipment can be 20–40 per cent higher than diesel, depending on the type and size of the machine.
While electric equipment has a higher initial cost, the total cost of ownership over several years can be lower than diesel, thanks to reduced fuel and maintenance costs. The break-even period depends on the machine’s usage but typically ranges from three–five years for high-utilisation equipment.
Using electric power is generally less expensive than diesel fuel, providing potential savings of up to 50–75 per cent in fuel costs over the machinery’s life. So an electric excavator’s fuel cost per hour can be significantly lower than a diesel equivalent.
Electric machines have fewer moving parts, so they should in turn require less maintenance. For example, items such as oil changes and fuel filters should not be required, potentially reducing service costs by 25–50 per cnt compared to traditional machines.
The range of battery-electric machines with a single charge is lower than that of a tank of diesel fuel. The packaging of the battery system in traditional machine designs is also a challenge for manufacturers when considering weight, mobility and sightlines. This technology seems more suited to smaller, more compact machinery particularly operating in urban areas.
Operationally, the balance between charging infrastructure, machine range, and charging speed needs to be calculated carefully. Site location, access to the grid and required charging capacity are critical to success.
Renewable power generated from solar or wind could enable machines to charge independently from the grid, perhaps to reduce the draw from the grid during peak periods. Portable battery-changing systems coupled with charging during scheduled downtime would further extend the operating range of electric machines.
Hydrogen fuel
Combustion engines and fuel cells are two ways to use hydrogen as a fuel for construction and quarrying equipment.
Combustion engines
Hydrogen combustion engines are updated versions of today’s internal combustion engines, which burn hydrogen instead of diesel. They function similarly to a conventional diesel but are spark-ignited rather than compression-ignited. Their combustion process has no carbon emissions, only water vapour and minimal oxides of nitrogen emissions due to high combustion temperatures. Aftertreatment systems can be used to manage these oxides of nitrogen emissions. The real advantage of using hydrogen combustion engines is that they can deliver similar levels of power and torque to diesel but have zero carbon emissions using green hydrogen. This makes them suitable for heavy-duty applications like construction and quarrying, where high-power output is essential.
In addition, the fact their design is so similar close to traditional engines means they fit in the same machine installations and be maintained by the same service networks and technicians.
Hydrogen combustion engines are also less expensive to produce and install than fuel cells, as they can be adapted from existing engine technology, making them a simpler and more affordable option for companies transitioning from diesel.
Fuel cells
Fuel cells convert hydrogen into electricity through an electrochemical reaction.
This electricity goes into a battery that powers electric motors, which move the machine. They operate as a hybrid system, using the batteries for instant torque and peak power demands.
With only water and heat as byproducts, fuel cells are cleaner and more efficient than combustion engines, with 40–60 per cent efficiency rates.
Fuel cells make better use of each hydrogen unit, lowering fuel consumption and total operating costs.
Fuel cells have fewer moving parts, although they do need componentry for controls, air handling, and cooling systems as a package.
From a maintenance perspective, fuel cells have membranes that will degrade over time and need to be replaced. The harder the cells work, the more rapid the degradation of the membranes. They are also susceptible to damage from dust and vibration.
Fuel cells are currently more expensive than hydrogen combustion due to their complex technology and limited production numbers. However, costs are expected to decrease over time as production scales up and the technology becomes more mainstream.
Fuel cells and hydrogen combustion engines benefit from fast refuelling times compared to diesel. This is a significant advantage over battery-electric machines.
Hydrogen management
Like battery-electric, infrastructure investment is required to keep the fleet fuelled. Hydrogen delivery, storage and handling on-site need to be managed safely and efficiently. This means being located close to a hydrogen hub would be advantageous. Centralised hubs close to production sites are being set up to minimise transportation needs, reduce costs and minimise safety risks.
Hydrogen is not an easy fuel to manage. It needs to be stored in tanks as a compressed gas under high pressure, and the pressure and temperature need to be closely monitored. Staff members overseeing the hydrogen need specific training on its unique properties and emergency protocols to manage leaks and fires.
The small size of hydrogen molecules also means they can easily leak, forming potentially explosive mixtures in the air. Since hydrogen has no smell or colour, specialised sensor equipment is needed to detect leaks. Adequate ventilation is required in facilities to help disperse any leaks and prevent dangerous gas buildup.
Hydrogen will also impact certain metals, making them brittle, so pipes and containers need to be specified with this in mind.
Any business’s chosen carbon-reduction solution is likely to be defined by connecting to the most appropriate, cost-effective and accessible infrastructure. Electric and hydrogen supply create challenges that must be safely and efficiently managed to maximise productivity and environmental benefits.
In the case of machines, battery-electric power is better suited to smaller, more compact machinery with lower duty cycles, especially for construction in urban sites.
Hydrogen combustion engines are better suited to heavy-duty quarrying machinery, where strong power and torque are needed. The remote nature of quarry operations means they are beneficial where operators and their maintenance staff are already familiar with traditional engine servicing and maintenance.
Hydrogen fuel cells are more suitable for applications where zero emissions and lower noise are prioritised, and noise and vibration can be minimised, such as enclosed areas and environmentally sensitive locations with tighter emissions and noise restrictions.
Due to the focus of major cities on delivering air quality improvements through zero-emissions vehicles, we will likely see these solutions implemented in on-road applications before volume off-road use. AB
