27 Jan, 2022 By Catherine Kennedy and Rob Hakimian

Changes in construction equipment and materials have a major role to play in the net zero drive.

New innovations in equipment and materials are leading to carbon reductions across the construction industry.

With many top tier construction firms in the UK having set themselves net zero targets, attention is turning to just how these can be achieved. The shift away from fossil fuel-powered equipment and vehicles is one of the key actions.

Skanska is one of the industry leaders in carbon reduction, having set 2045 as the target for its global operations to reach net zero. The commitment was made well before other firms and indeed the UK government had set their own targets. 

Skanska UK director of environment Adam Crossley says the contractor has already reduced carbon intensity from 352t of carbon per million pounds revenue in 2010 to 192t in 2020. “It’s good progress, but there’s a lot more work to do to get to the net zero outcome,” he says.

In December 2020, Skanska introduced what it describes as its industry-leading EV First policy. It offers employees entitled to company cars electric vehicles (EVs) or hybrids instead of petrol or diesel vehicles. 

Crossley says that EV use among employees in the firm rose from 3% to over 15% in the first year of the policy. He expects it to reach 30% to 35% by the end of 2022. “By the end of the lease cycles of current cars, in the next few years, I think we’ll get very close to 100% EVs,” he says.

The bigger challenge is reducing emissions from construction equipment. Crossley says that these accounts for between 10% and 20% of the company’s emissions and reducing that goes beyond lowering their CO2 output. 

“It’s a symbolic bit, because it’s what people can see,” he says. “If people see a dirty diesel grab wagon or other plant, it’s linked to air quality, it’s linked to noise, it’s linked to perception.”

Skanska has already phased out diesel use in its site equipment, shifting instead to hydrotreated vegetable oil (HVO) which is comparable in terms of price and efficiency. So far the company has used over 1M litres of HVO, which has saved 3,000t of CO2 emissions. “It’s not perfect, it still involves some emissions, but it’s a transition step,” Crossley says.

A complete shift to electric equipment is desired and Crossley says that Skanska is already using it where possible. “Almost all of the kit we’ve seen, whether it’s an excavator, a crane, a piling rig, the equipment is as productive as its fossil fuel alternative,” he says. “The only technical issue is the power source.” 

If people see a dirty diesel grab wagon or other plant, it’s linked to air quality, it’s linked to noise, it’s linked to perception

This is a problem that is being tackled with improving battery technology. Construction equipment manufacturer Liebherr is leading the way with its Unplugged series of electric crawler cranes and piling rigs, which perform at the same levels as their diesel alternatives. 

The division which produces the Unplugged series is called Liebherr-Werk Nenzing. Its head of strategic marketing and communications Wolfgang Pfister cites the battery-powered version of the company’s LB 16 piling rig as an example: “The conventional diesel machine has a power of 230kW and 200kNm torque. 

“The unplugged version has the same torque and even higher engine power of 265kW.”

The battery for the LB 16 can last for a 10 hour shift when it is doing a normal day’s work, It can be fully recharged overnight with access to a 63 amp power source. The LR-1250.1 Unplugged electric crawler crane charges in a rapid 4.5hours when connected to a 63 amp supply.

There is also the option of keeping the equipment plugged in as its used. This may not always be feasible, but for inner-city work done by static crawler cranes, it is a viable option.

The Liebherr LR 1250.1 Unplugged crawler cranes charge in four and a half hours when connected to 63 amp supply

Another advantage of electric equipment is reduced noise, as idling equipment is almost silent. This could potentially extend working hours for projects in busy or residential areas. 

The main drawback for electric equipment is the price. The differential varies depending on the type of plant, but, according to Pfister, electric plant is roughly 25% more expensive than fossil fuel-powered alternatives.

But he believes that purchasers of electric plant are becoming more willing to pay a premium if they look at the whole-life cost. 

“They’re fully aware that maintenance-wise, you have fewer parts that are moving, so you have longer maintenance intervals,” he says. “So, on the life-cycle you’re getting the cost back.”

He also expects the price gap to close. “In the long term, with increased demand and increased battery production, as with solar technology, we expect prices to come substantially down,” he says.

Along with these new types of equipment, changes in the use and production of construction materials also have a part to play in the fight against climate change.

Steel production, for example, currently accounts for around 8% of all greenhouse gas emissions. According to Steel Construction Institute associate director Michael Sansom, the bulk of this carbon impact comes from steelmaking itself. 

The UK Structural Steelwork: 2050 Decarbonisation Roadmap was published by the British Constructional Steelwork Association last November. It explains how the sector aims to increase recycling rates to achieve a circular economy and reduce the carbon intensity of new steel production.

Sansom says there is a need to move away from the primary coal-based blast furnace steel production route. Manufacturers should instead use less the carbon intensive electric arc furnace route, which makes steel from scrap metal without using primary raw materials.

SSAB has produced the world’s first fossil fuel-free steel

But global demand for steel exceeds the supply of scrap. While mature economies like the UK, European Union and North America are almost self-sufficient in steel scrap, there is not enough to meet demand in developing economies like China, South America and India.

In the meantime, it is necessary “to produce enough steel by the primary route [of manufacturing] to reap the benefit [of having a larger volume of steel]” and have scrap availability in the future that enables “a truly circular recycling route”, says Sansom. 

“At the moment while we need all this new steel globally, we have to produce it by the primary production route,” Sansom adds. “[Developing] technologies that we need to do that [sustainably] are our priority.”

If you’re importing steel from China with low carbon taxation there has to be some sort of import duty that levels it up with UK and EU producers

These new methods include carbon capture use and storage and hydrogen-based technologies to power steel manufacturing and to manage the carbon emissions of the processes. 

Swedish steel manufacturer SSAB has already made fossil fuel-free steel, having invested in the development of hydrogen breakthrough ironmaking technology since 2016. 

Steel reduction – removing oxygen from the ore in the production process – is carried out with 100% fossil-free hydrogen instead of coal and coke with the goal of delivering fossil fuel-free steel to the market and demonstrating the technology on an industrial scale as early as 2026.

A process to stop offshoring carbon emissions is also needed. Sansom explains: “We could import all our steel from China, for example, and our national carbon footprint would look great but we haven’t solved the problem – we’re just offshoring our carbon emissions. 

“So we need this adjustment – if you’re importing steel from China with low carbon taxation there has to be some sort of import duty that levels it up with UK and EU producers who are being taxed on their carbon. It needs that international arrangement to make it fair.”

In the meantime, demand side reduction measures – for example using less steel to do the same job – can be implemented today. These could be achieved by increasing design budgets, giving designers more time, using building information modelling and using higher strength steel so less is needed. A framework is also needed to give engineers more confidence to reuse steel.

Another material in the spotlight is concrete. According to the Mineral Products Association’s (MPA’s) UK Concrete & Cement Industry Roadmap to Beyond Net Zero document, switching energy used in cement production to renewables could reduce the industry’s CO2 emissions by 20%, while decarbonising transport could save a further 7%.

An additional 12% reduction in emissions could come from new types of low carbon cement.

Currently cement used in the UK is largely based on carbon-intensive clinker and either fly ash or ground granulated blast furnace slag (GGBS).

Key to the industry’s decarbonisation effort is the potential for adding greater proportions of cement-like materials, such as GGBS or fly ash, when the clinker is cooled and ground. MPA director of industrial policy, energy and climate change Richard Leese has been involved in a two year low carbon multi-component cement test programme.

“What we’ve done in this innovation project is add a third dimension and that’s ground limestone powder,” he explains. 

“You can reduce the amount of clinker in your cement and reduce the amount of fly ash or GGBS because their availability is limited or restricted in terms of volume.”

All formulations in the test have lower CO2 than market leading Portland cement and the process of rewriting the British concrete standard to enable the use of these concretes now underway.

When it comes to fuel for the cement production process, 47% of the thermal demand in the UK cement process is now met by alternative sources such as hydrogen and biofuels.

Concrete Centre head of architecture Elaine Toogood stresses that important changes can be made now, for example in terms of materials efficiency.

“Concrete is brilliant on so many levels in terms of its performance,” she says. “So we should use it, but use less of it. We can do that just by changing the span of the structure, thinking about how much loading you actually need and considering lean construction.”

It is also helpful to engage with suppliers as early as possible and ask for the lowest carbon solution, she adds.

Leese emphasises the scale of the opportunity, and the need for a change in behaviour.

“There’s a huge amount going on in the industry and that’s not always the perception people have,” he says. “The behavioural change is one of the biggest barriers to net zero. 

“We all need to change personally and in professional terms too. Communication and getting over some of those barriers is really important.”  

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Tagged with: Concrete Cranes Excavators Net Zero Steel

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