By Najing Li, Product Manager for Sustainable Power, Volvo Construction Equipment
The construction industry is at a crossroads as decarbonization shifts from a corporate buzzword to an operational obligation. While the benefits of electric heavy equipment — like simplified maintenance and the reduction of jobsite emissions — are increasingly well-documented, a significant hurdle remains: charging in remote or off-grid locations.
Unlike diesel, which can be delivered via a fuel truck, electricity requires a more nuanced infrastructure strategy when a jobsite is miles from the nearest utility grid. To bridge this gap, contractors are turning to a new generation of mobile power solutions and charging strategies.
Remote refuelling
For decades, the standard procedure for remote power involved loud, diesel-powered generators. But with more fleets incorporating electric equipment, the goal is to create a charging ecosystem that is as kind to the environment as the machines are.
Electric equipment offers built-in climate friendliness because it doesn’t idle, while a traditional diesel machine may spend 30 to 50 per cent of its shift idling — burning fuel, making noise and racking up operating hours while sitting still.
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The decibel- and fume-reducing benefits of electric machines carry over to their refuelling solutions, which source energy from the grid, the sun or even wind.
The variety of options continues to expand and makes fleet electrification more viable than it might seem at first glance.
BESS
Mobile power banks, often referred to as battery energy storage systems (BESS), serve as high-capacity reservoirs of electricity.
They consist of multiple large-scale battery packs assembled into a single, transportable system.
The benefits of using a BESS include:
- High output and scalability: BESS units can be sized to meet specific jobsite needs, with some heavy-duty models offering capacities of 1,000 kWh.
- Cost and power stability: The systems can store energy when it’s most abundant or least expensive and use it during peak demand periods to avoid higher utility rates.
- Portability: Many units are designed for mobility with a regular truck or trailer, allowing them to follow the crew across a large jobsite. For instance, Volvo’s PU130 is a Level 2 charger that easily fits on a small trailer.
- Battery energy storage systems also come with drawback, such as:
- Primary source requirement: A BESS is a storage solution, not a generator. It eventually needs to be recharged via a grid connection.
- Physical size: Large high-capacity units can be heavy and require specialized transport logistics.
Solar power
Solar-powered charging systems use photovoltaic panels to capture renewable energy directly on site. These are increasingly popular due to falling costs and their degree of scalability.
The pros of solar panels include:
Logistical simplicity: Solar arrays eliminate the need for regular fuel deliveries and the handling of hazardous materials.
Flexible deployment: Solar-powered solutions come in many shapes and sizes, including trailers with fold-out panels, panels mounted on shipping containers or fixed ground arrays for long-term projects. Some BESS units even come with solar panels to provide a trickle charge throughout the day.
Operational agility: Mobile trailers allow contractors to reposition their power source to optimize sunlight exposure or move with the project’s progress.
There are cons to using solar power, including:
- Intermittency: Solar energy production depends on weather conditions and daylight hours. While integrated battery storage helps mitigate this, extended periods of low sunlight can reduce the available charge. In some situations, small wind turbines are used to supplement solar output.
- A bigger footprint: Compared to a fuel tank, solar-powered chargers usually require more space to generate a comparable amount of energy, which may be a constraint on cramped urban sites.
- Limited scale: While integrating solar arrays is feasible and efficient for compact machinery due to their lower energy demands and smaller battery capacities, scaling this solution up for larger machines presents infrastructure challenges to achieve the necessary output.
Opportunity charging
Transitioning to electric equipment requires a shift in operator behaviour, moving away from the refill-when-empty diesel mindset toward opportunity charging. This involves plugging in the machine during any available downtime, such as lunch breaks or shift changes.
Opportunity charging presents several benefits, including:
Advantages:
- Increased uptime: Topping off when the opportunity arises allows many electric machines to work a full shift. For example, using a DC fast charger can boost the 48-volt batteries on most compact machines from empty to full in 40 to 90 minutes.
- Battery longevity: Modern lithium-ion batteries thrive when kept between a 20 per cent and 80 per cent state of charge. Avoiding deep discharges helps extend the lifespan of the battery.
- Infrastructure flexibility: Many compact electric machines can charge using standard 120-volt or 240-volt outlets, making it easy to plug in wherever a basic power source is available.
One important practice is to use an AC slow charger at least once a week. This allows the battery management system to balance the battery packs, ensuring they charge and discharge evenly for optimal health.
The path forward
While BESS units, solar arrays and fast chargers require up-front capital, prices are stabilizing and these costs are typically offset by long-term savings. Plus, many regions and projects offer incentives and tax credits for both electric machines and the infrastructure needed to support them.
Determining the right setup for your fleet and site takes a bit of planning. Your OEM is a great place to start because they want you to succeed, as do charging solution manufacturers. They can consult with you to ensure a smooth transition.
Fleet electrification is a journey that will take time, but non-construction industries like landscaping and waste and recycling are proving that it’s a viable and worthwhile shift.
Off-grid charging is no longer just a concept — it’s a tangible way to work toward a quieter, cleaner and more efficient construction future.
