MechChem Africa July-August 2022

Electrification of the construction industry showcased in Sonderborg During the IEA’s 2022 conference on energy efficiency in Sønderborg, Denmark, Danfoss showcased its hybrid electric-hydraulic drive solutions in operation on a real construction site. MechChem Africa , visits the site and talks to Eric Alstr m of Danfoss T his year’s International Energy Agency’s Energy Efficiency confer ence was moved from its home in Paris to a small town in Denmark ingness to “exchange ideas and collaborate with the world.” Through ProjectZero, which was initi ated as a private-public partnership back in 2007 – with Danfoss as a key partner – Sønderborg is currently on track to be carbon neutral by 2029, some 20 years before the critical 2050 deadline for global warming mitigation.

One of the visits we attended during the conference was to a building site showcas ing the feasibility of switching a range of construction equipment away from using diesel engines. We saw excavators, graders, loaders and dump trucks in various sizes operating on a quiet and very clean building site, all powered by electricity via batteries. “If using a diesel engine to power an exca vator, for example, 70% of the energy is lost before any productive work is done by the machine,” notes Eric Alström, president of Danfoss Power Solutions. “These machines are actually hybrid electro-hydraulic sys tems, which is a very nice combination of conventional rugged hydraulics combined with the new generation electrical propul sion systems powered by batteries as the energy source,” he says, noting that, even though not fully electric from a component perspective, this is a zero-emissions con struction solution. Highlighting the commercial availability of these machines from several OEMs, he notes the simplicity of making the transition. “Just like traditional diesel-driven construc tion equipment, the power transmission side of these systems – slewand track drives and the cylinders – all remain hydraulic. The power source for driving the hydraulic pumps is electric and a Li-ion battery stack is the energy source to power the electric motor – with the excavator demonstrated having a 266 kWh battery. The very sig nificant change, however, is that the diesel power unit has been replaced,” says Alström. “At some point, it may make sense to re place the track motors with electric motors, which we can then also do relatively simply by removing the hoses and installing elec trical wiring. For now though, we haven’t developed electrical motors with the same power densities as hydraulic motors. But electricmotors are getting smaller andmore powerful, and the day may come when full electrification makes sense,” Alström tells MechChem Africa . Electrification, however, brings further efficiency and control advantages to hy draulic actuators. “We use electronic con verter drives connected to a fully digitally control system to simultaneously manage

called Sønderborg, which is the global head quarters of Danfoss: the energy efficiency, heating, cooling, power and drives specialist. The reason for the shift? Sønderborg’s passion and ambition for implementing integrated energy efficiency initiatives across the municipality, which led confer ence leaders to name Sønderborg the “energy efficiency capital of the world”.

The stated ambi t ion of the town’ s ProjectZero initiative is ”to create an inte grated, microcosmic, carbon-neutral energy system that can inspire much larger cities and municipalities” – and throughout the conference, the city demonstrated its will

A hybrid electro-hydraulic excavator, which combines rugged hydraulics with a new generation electrical propulsion system powered by a 266 kWh Li-ion battery stack.

14 ¦ MechChem Africa • July-August 2022