Explore this article and audio – a glimpse into FORESIGHT's depth

Join our global community of experts, contribute your insights in commentary and debate, and elevate your thought leadership. Get noticed, add value – be part of FORESIGHT's engaging discourse. Join us today.

Payback on reusing waste heat took less than three years

Danfoss has a shortlist of energy efficiency measures that all sites can implement

Implementing energy saving measures in its most polluting factories has enabled Denmark’s largest industrial engineering company, pump and heating specialist Danfoss, to significantly reduce energy consumption and carbon dioxide emissions, while improving energy productivity

Contradiction:
Danfoss produces components needed for the clean energy transition, yet in doing so its factories emit large volumes of carbon dioxide Action:
The company introduced a strategy in 2018 to halve carbon dioxide emissions and energy intensity in buildings and production processes by 2030 compared with 2007, while increasing energy productivity by 100% Results:
By the end of 2018, the firm’s energy consumption and CO2 emissions were down by 43% and 27% respectively, while energy productivity had increased by 73% Key quote:
The greenest kilowatt hour is the one you save.”
Being a producer of components for green technology does not sit easily with operating factories around the world that emit carbon dioxide (CO2) and consume large amounts of heat and energy. In an effort to practice what it preaches, Denmark’s Danfoss, a maker of heating and cooling equipment, has implemented an ambitious climate strategy focused on energy efficiency and large industrial heat pumps that recirculate heat from its production processes. The greenest kilowatt hour is the one you save,” says Torben Christensen, senior vice president and head of global services at Danfoss. He says the company’s climate action is a question of credibility” towards customers and employees and of walking the talk”. Back in 2007 the company set a goal to reduce carbon dioxide emissions and increase the share of renewables in its energy mix by 25% before 2025. An updated strategy from 2018 aims to halve CO2 emissions and energy intensity in buildings and production processes by 2030 compared with 2007, while increasing energy productivity by 100%. By the end of 2018, Danfoss’ s energy consumption and CO2 emissions were down by 43% and 27% respectively, while energy productivity was up 73%. Roughly half of Danfoss’ energy consumption is for buildings, while the rest is used in production processes, Christensen says. Based on an analysis of how to obtain the most energy savings for each dollar invested, Danfoss aims to reduce emissions at every stage: from lighting to ventilation, heating, production processes and machinery. We had a small team of specialists visit our factories around the world to analyse energy consumption,” says Christensen. After that Danfoss drew up a list of priorities and looked at what was technologically the best way forward. During this initial process we also considered the investments required, time consumption and whether the changes would affect quality, customer relations and so on negatively,” says Christensen. A chain reaction of continuous improvement is the result. Technological developments mean there will be a stream of energy savings to reap in the future, he says. While it sounds like a massive undertaking, he is sanguine about the process, describing it as far less complex than implementing a new IT system in a global company.

Waste heat use

The main energy savings so far have been in buildings, with production processes and machinery currently in the spotlight. More than 140 energy efficiency measures have been implemented in Danfoss’ industrial buildings and in installations such as ventilation, cooling, heating, lighting and compressed air. One of the most significant measures has been optimising the heat supply system, mainly through heat recovery in large industrial ventilation systems. This is probably the single largest element that has helped us reduce our heat consumption,” says Christensen. In seven years, Danfoss has reduced its heating needs by 60% at its 250,000 square metre headquarters and production site in Nordborg, not far north of Denmark’s border with Germany. The company has 28,000 staff and more than 70 factories in 20 countries, but its climate strategy focuses on implementing 140 technical projects in its 27 largest plants in Europe, the US and Asia. Together they account for more than 80% of the group’s total energy consumption. These measures have reduced Danfoss’ energy consumption by approximately €10 million a year, Christensen says. Total investments have been close to €30 million, which means a payback time of 2.8 years, he adds. A significant proportion of the return on investment is related to the installation of heat pumps. With reduced energy consumption and a more efficient energy system, the company has also been able to lower the flow temperature in its internal heating system, helping pave the way for large industrial heat pumps. Danfoss’ factories use lots of heat which in the past was vented as waste from the production process. At the Nordborg site, four large industrial heat pumps now recover and reuse waste heat from process cooling water. The co-production of cooling water and central heating with the heat pumps cuts CO2 emissions by 2700 tonnes a year and reduces gas consumption by 1.2 million cubic meters annually, leading to cost savings of DKK 3.4 million (€460,000) a year. We’re also using the waste heat from our pneumatic compressors,” adds Christensen. Compressed air is used in the production processes of many industrial companies and the compressors need to be cooled when running. Heat exchangers make it possible to take the cooling water from the compressors to the heat pumps and feed it into the heating system. In a normal year, 25% of our new, lower heat consumption is recycled waste heat from process cooling water and pneumatic compressors,” Christensen adds. The percentage looks set to rise. In February 2019, Danfoss announced plans to build data centres using its own technologies to reduce the energy needed for cooling. Waste heat from the centres will be fed into the company’s heating system or to a new district heating grid in Nordborg. In future, 50% of the energy Danfoss consumes at its main site will be supplied from waste heat, says Christensen.

Sharing best practice

The company has made rapid progress, but insists it is not about to sit back on its laurels and that there is a lot more to do. Even if it reaches the 2030 targets before time, the push to save energy and reduce CO2 emissions will not stop, Christensen stresses. In the next wave of action, Danfoss will look closer at energy efficiency during all production processes, and machinery and equipment use, he explains. If we need to replace a machine, energy consumption will be a critical and decisive part of the decision process.” The company will also subject remaining factories to the same energy efficiency measures that have been applied in the bigger production facilities, examine newly acquired companies and see how their factories can be made more energy efficient and have energy savings at the forefront of its mind when renting new office space — it has around 220 leases globally. For other companies looking to follow a similar path, Christensen’s main advice is to ensure everybody has the tools to play a role in the transition. We try to draw up a list of the five to eight most frequent things to do to save energy and then we share this with the facility managers at all our sites,” he says.

Writer: Karin Jensen