Electric Site research project showing “groundbreaking” results
By Andrew Snook
The results are in from the 10-week field test of the Electric Site research project in Sweden, and the results are even better than anticipated.
Volvo CE stated that the results are “groundbreaking,” with the field tests showing a 98 per cent reduction in carbon emissions, a 70 per cent reduction in energy cost and a 40 per cent reduction in operator costs. The company added that the combined results support the potential for a 25 per cent reduction in total cost of operations; however, this is currently just a prediction since Volvo CE’s prototype machines are part of a research project and are not commercially available, making it impossible to give a guaranteed figure.
Previous to the field tests, Volvo CE predicted that this project could show the potential of reducing carbon emissions in these work steps by upwards of 95 per cent, and could show the potential of a 25 per cent reduction in total cost of operation.
The SEK 203-million (approximately $30 million) project – created by Volvo CE and Skanska Sweden in partnership with the Swedish Energy Agency and two Swedish universities – was designed to electrify certain transport stages in quarry operations from excavation to primary crushing and transport to secondary crushing though the use of autonomous and electric vehicle prototypes; new work methods; and site management systems to create a complete site solution.
The project began in October 2015 with the first field test commencing this past September at Skanska’s Vikan Kross quarry, near Gothenburg, Sweden. During the 10-week field test, the quarry operated at full production of 750 tph.
“Over the last 10 weeks, we’ve made incredible progress, learnt a lot and seen huge potential in the Electric Site solution’s environmental, efficiency, safety and cost benefits,” says Uwe Müller, chief project manager for the Electric Site at Volvo CE. “In fact, we have decided that we want to learn more, so we will extend our test period with Skanska until the end of the year. The results we have seen so far confirm that this research project is a step towards transforming the quarry and aggregates industry and creating emission-free quarries.”
“With climate change reshaping our industry, we need to find new, sustainable solutions and build partnerships with organizations that have different competencies,” added Anders Danielsson, president and CEO of Skanska. “Our ambition is that this collaboration with Volvo CE will help us and our customers to reduce our carbon footprint. The power of partnership will make it happen.”
The inefficiencies identified in quarry operations previous to the field test included, but were not limited to, machine fuel consumption, inefficient machine usage (idling times, poor bucket filling, etc.), and in the total cost of site operation and processes.
One process identified as inefficient was the use of wheel loaders to handle materials coming out of the primary crusher. The materials were falling to the ground, only to be picked up moments later by wheel loader operators, creating an additional, unnecessary step for loading the material on the transporting vehicles to move them to the secondary crushing operations.
“With the fully autonomous haulers that are designed to line up behind each other with an overlap on the bucket, it enable to have a direct loading from the crusher deleting the loading step for the wheel loader,” Müller explained during an press conference earlier in the year.
The test site uses a fleet of eight Volvo CE HX2 autonomous, battery-electric load carriers, which transport the material from the primary mobile crusher up to the secondary static crusher. The electric load carriers use lithium ion batteries to power two electric motors that drive the machine; with the hydraulics driven by an additional electric motor. The HX2 is fitted with a vision system, which allows it to detect humans and obstacles in its vicinity. It can follow an adjustable, pre-programed GPS path.
The test site also uses Volvo CE’s LX1 prototype electric hybrid wheel loader, which delivered more than a 50 per cent improvement in fuel efficiency at the quarry, as well as significant reductions in emissions and noise pollution, compared to its conventional counterparts, the company stated. The LX1 was used to organize the piles of material at the site. The LX1 is a series hybrid that incorporates a driveline that consists of electric drive motors mounted at the wheels, electric-driven hydraulics, an energy storage system, a significantly smaller diesel engine and new machine architecture, including a new design of the lifting unit. It’s this combination that enables the substantial gain in fuel efficiency.
The EX1 70-ton, dual-powered, cable-connected excavator prototype loaded the primary crusher at the quarry. It remained in a stationary position for most of its use, feeding blasted rock into a mobile crusher before it was transported to the secondary crusher and then processed. The excavator only needed to move a few meters once or twice a day as the excavator worked its way through the blasted rock.
The base machine for the EX1 is a Volvo EC750 crawler excavator that has been upgraded to incorporate an electric motor in addition to the diesel engine. At the quarry, the machine was plugged into the grid, so zero emissions were emitted. If the cable is connected, the EX1 will automatically start in electric mode. If it’s not, it will start in diesel mode. The EX1 is operated in exactly the same way as a conventional Volvo excavator.
“At Volvo CE, we believe in a sustainable future and we are doing our best to build the world we want to live in,” concludes Melker Jernberg, president of Volvo CE. “The Electric Site is one example of how we are trying to achieve this. With this research project we are combining intelligent machines, automation and electromobility to challenge traditional ways of working in the quarrying industry and explore new alternatives. We will now further mature the technologies involved and the reliability of the concept. Developing, testing and validating prototype machines with a customer at an early stage in the process speeds up development and ultimately brings more value to us and our customers.”