This summer, high above the skyline of Hong Kong, a construction crane was busy assembling the city’s future—and showcasing a global shift in the way buildings are made.
At the Gammon Construction work site, currently erecting the Hong Kong Science Park, this battery-powered crane represents an early example of the coming shift (PDF, p. 14) toward all-electric construction sites. Such heavy-duty equipment typically runs on electricity, requiring so much power that most operators run dirty diesel generators on-site to avoid shorting the grid. But in this case, large, camper-size lithium-ion batteries called Enertainers power the crane and other on-site machines, proving that there is an alternative to the usual on-site construction emissions.
Gammon’s work site is one of the first of the company’s planned all-electric projects. Plummeting battery costs are one factor making it easier to increase sustainability and reduce emissions. According to Stefan Schneider, managing director at Zurich-based SUNCAR HK AG (a firm focused on construction-equipment electrification), three major barriers have prevented contractors from going electric: It’s more expensive to buy electric construction equipment, relatively few options are available for those with the budget, and limited battery performance has meant that operations required excessive stops and starts for recharging.
Better technology, as well as evolving local regulations and mandates, are speeding the adoption of renewable construction gear. In Norway, the first zero-emission construction site launched last year in Oslo, and the city mandated (PDF, p. 6) all construction sites achieve this sustainability goal by 2025. The country’s industry leaders say electric or hydrogen options will be available and widely used by 2030. Meeting both goals means significant emissions savings; an analysis by the Oslo climate agency found that construction accounts for between 5% and 10% (PDF, p. 6) of the annual emissions of peer cities.
Construction-equipment manufacturers have signaled that more electric vehicles will soon be rolling off assembly lines. Doosan Bobcat announced that a new line of excavators with hybrid hydraulic/electric systems will go on sale before the end of 2020, and Volvo will begin booking orders for electric excavators and wheel loaders this year, as well. By 2023, 19 all-electric or fuel-cell versions of heavy trucks will be available in North America, up from five on the market today, according to a Rocky Mountain Institute analysis.
Anyone who has had the misfortune of living next to an active-duty construction site—the constant noise; funky generator fumes; loud, beeping trucks encircling the block from morning to night—can intuit the advantages of an all-electric, battery-powered build.
“There have been few regulations for health, emissions, and noise on construction sites,” Schneider says. “That’s led to a lack of attention in the public about the possibility of working with zero-emission construction.” By using electric construction equipment, most of the fumes and commotion are eliminated; workers and the public also avoid exposure to toxic smoke and nitrous oxide.
Construction companies can reap additional benefits from ditching diesel. Electric engines are more dependable and require less maintenance: Studies show that the larger upfront cost is offset by more years of dependable service. Recharging replaces refueling, typically a dirty job on big machines. And less noise and pollution can yield longer construction hours: Because it wasn’t burning fuel, the Gammon site in Hong Kong could work beyond the legally allowed window of operation, speeding up the entire job. If auto-emissions regulations are any guide, cities can implement such rules to help push the industry toward greener gear.
Construction machinery has already gotten cleaner in the United States due to Environmental Protection Agency emissions standards, which also demanded better performance. (Current Tier 4 regulations allow only scant amounts of nitrogen oxide and particulate matter.) But as battery power becomes cheaper, stronger, and more dependable, there aren’t as many excuses against using electric cranes and heavy machinery, Schneider says. SUNCAR HK AG even engineered battery-powered excavators ranging from 1.6 to 16 tons, along with an all-electric drilling rig (in cooperation with Liebherr) called LB16 unplugged; Norwegian company Nasta manufactures an electric 38-ton excavator.
“Some machines that have very high fuel consumption are hard to equip with batteries to work a full operation day,” he says. “But it’s possible to run most of the time from the grid with a cable.”
Test sites for heavy electric vehicles have shown promising results. Volvo and global construction firm Skansa ran a 10-week trial at the Vikan Kross quarry in Gothenburg, Sweden. They found the more sustainable solution led to a 98% reduction in on-site emissions, 70% reduction in energy costs, and an overall 40% drop in operator costs.
Those numbers show why industry leaders want to move toward electric. While most vehicles still run on a hybrid electric/hydraulic setup, it is possible to convert to all-electric operations by replacing hydraulics with electric actuators (small, electromechanical moving parts) operated by complex computer coding that mimics traditional hydraulic movement. Many companies currently have all-electric prototypes in the field for testing, suggesting more of these options will soon be for sale and on the job.
Green heavy machines can also accelerate the shift toward cleaner transportation in general. All-electric construction runs parallel with initiatives in California and elsewhere to electrify trucking and transportation, another big source of carbon emissions. The biggest single source of transportation emissions in the United States (27%) is from freight movement, mostly done by large trucks. The California State Air Resource Board recently rolled out aggressive new rules mandating all-electric trucking by 2045. California, Oregon, and Washington are pushing for the creation of the West Coast Clean Transit Corridor Initiative, which would create a network of electric vehicle charging stations for freight haulers along Interstate 5, a major north-south throughway that runs from the Canada border to the Mexico border.
Construction sites are messy, but the entire ecosystem—from shipping goods to powering the grid—needs to be electrified for the industry to achieve true emissions reduction. Luckily, there are increasing options for electric machinery that can do the hard but necessary work of building a cleaner future.