The circular economy

The Circular economy in action

The financial benefits of improving motor efficiency are generally well understood. However, the environmental advantages are less commonly considered. Chris Callander spoke with Peter Isberg, Digital Lead, Motion, at ABB Sweden, to better understand how following the circular economy’s principles can deliver enhanced financial gains and significant environmental benefits.

Peter Isberg, Digital Lead, Motion, at ABB Sweden

When considering the challenge of reducing carbon dioxide (CO2) emissions, the role played by motors, and their potential to affect the situation, cannot be ignored.

CO2 emissions. It is no surprise then that over the last 10 years minimum efficiency performance standards legislation has driven a revolution for electrical motors.

It has been widely reported that motors and electric drivetrains consume around 50% of global electricity, while electricity production accounts for 40% of global

Today motors are rated according to their efficiency class. In less than 20 years we have moved from using motors below IE1 to the current position where new motors have to reach a minimum of IE3, with many exceeding this.

However, just 10 years ago, the requirement to use motors that met any legislated efficiency classes was voluntary. Because some motors can remain in operation for many years a large number of motors with low-efficiency ratings are still in use today.

“I recently analysed a paper mill in Sweden which had an installed base of 1,800 motors,” explained Peter Isberg, Digital Lead, Motion, at ABB Sweden. “Of course, there were IE3 and IE2 motors, but around half of the motors were IE1 or less, particularly among the large quantities of small to medium-sized motors.”

The analysis Peter carried out showed that at this single site, upgrading the inefficient motors would have the potential to save a minimum of 9GWh of electricity per year. Clearly, this would amount to a significant cost saving for the paper mill.

Electrical motors and drive systems are estimated to use 33TWh of Swedish industry’s total annual electrical energy consumption of 51TWh. Taking the paper mill’s situation a stage further, if all the inefficient motors in Swedish industry were upgraded, and the use of variable speed drives was increased to further maximise their efficiency, Peter believes, conservatively, that the potential energy savings could be more than 4TWh per year. That is more than 8% of Swedish industry’s total annual electricity consumption and enough energy to charge 2.1 million electric cars that travel 12,000km per year each. Alongside the cost savings for industry, this would also result in a notable reduction in C 2 emissions.

THE CIRCULAR APPROACH

But is replacing large numbers of motors which are still working well contrary to the circular economy’s aspiration to maximise the use of resources? Peter says not.

“Some 97% of the impact a motor has on its environment comes from the energy used in its lifetime,” added Peter. “So, if you can minimise the energy losses from a motor in use, then the payback in terms of CO2 reduction can be relatively short, considering the initial CO2 debt when manufacturing the motor”

In practice, replacing an old 110kW IE1 motor that runs for 8,500 hours per year with a new IE4 equivalent would have a CO 2 payback time of around 120 days in the UK*, and this product will last for at least 30 years, so the environmental and cost benefit of replacing inefficient motors is clear.

Some 97% of the impact a motor has on its environment comes from the energy used in its lifetime.

Of course, the extent of the gains will depend on how the motors being replaced are disposed of.

There are two choices here. The products can be placed in landfill or placed at the end of the circular loop and used to make new products.

Following the circular option and recycling is the better option for the environment, and there are key reasons for this. Take the materials used to make motors as an example. To produce the metals, you have to start by mining oxides which requires large amounts of energy and water. Then converting the oxides into metals also takes large amounts of energy.

“When you compare producing virgin metals with recycling existing materials, the energy savings are significant,” continued Peter. “When considering iron, there is a 75% energy saving between creating iron from mineral and re-melting existing material, for copper that figure rises to 85% and aluminium is higher still at 95%.

“Using this model, when analysing the recovery of ten tonnes of outdated motors in Sweden – including the impact of transporting them from a customer to the recycling centre – savings equivalent to 31 tonnes of CO 2 can be made, along with 301kWh of energy and 91,000m 3 of water.”

And as the circle closes, and these recycled materials are used to produce the replacement higher efficiency motors, the CO 2 payback for the new products reduces, offering further benefits.

So, to gain the maximum environmental benefit, if the installed base is being replaced to gain the energy efficiencies, the materials need to be reused under the circular economy model.

CIRCULAR ECONOMY IN ACTION

In Sweden, ABB has signed a long-term cooperation agreement with Stena Recycling in a pilot designed to deliver this circular benefit. The partnership has been developed to ensure that the efficiency advances gained by the installation of new products are backed up by the effective recycling of the waste products.

In the company’s circular model, ABB’s starting point is to use its digital monitoring solutions to understand the power and energy usage of a customer’s assets. After the energy evaluation, the customer then decides on a possible energy upgrade by phasing out old inefficient motors. Stena Recycling then collects the redundant motors to ensure the effective recycling of the old assets’ materials.

The companies working with this model receive a discount on their new motors based on the decommissioned motors’ scrap value and get environmental reports demonstrating how much energy, water and CO 2 the recycling initiative has saved.

There are wider environmental benefits too. Recycling also ensures that obsoleteproducts are not simply transported to areas with less stringent environmental standards. At the same time, proper controls over the recycling process ensure that the scrap material is not transported to countries that do not have the knowledge or infrastructure to recycle it in an environmentally-friendly way, which would result in an enhanced negative effect on the environment.

If the installed base is being replaced to gain the energy efficiencies, the materials need to be reused under the circular economy model.

CONCLUSION

Low-efficiency and /or wrongly-dimensioned motors have a negative environmental impact and add cost to energy bills. Simply replacing them can bring significant cost savings and lead to reductions in CO2 emissions. If this is done with the right approach to collecting the obsolete motors and reusing their materials, the environmental impact is lowered further, and the recovered metals can be used in new products – the essence of the circular economy.

www.abb.co.uk/energy

* Based on a carbon footprint for UK energy generation of 0.18 kg of CO 2 per kWh of electricity. Source: Department of Business Energy and Industrial Strategy, ‘2018 UK Greenhouse Gas Emissions, Provisional Figures’.