Converting waste heat into electricity

Waste heat is generated in many areas of the metal industry and is put to good use by many companies. For example, the Georgsmarienhütte steelworks saves more than 1,500 tonnes of CO₂ annually by feeding waste heat from steel production into the municipal utility’s district heating network. And yet: according to a report commissioned by the UBA, more than 2.6 billion kilowatt-hours of additional heat could be utilised annually in Germany from iron and steel production processes in integrated steelworks alone. A forward-looking approach to waste heat utilisation is the conversion of even low-calorific heat into electricity using ORC systems, as Dr Andreas Sichert, CEO of ORC system manufacturer Orcan Energy, explains in an interview.


Dr Sichert, what are the drivers behind ORC systems and why should an industrial company invest in generating electricity from waste heat?

Sichert: High energy prices and grid tariffs, as well as statutory climate targets, make investing in measures to boost companies’ energy efficiency highly sensible – from both an economic and an environmental perspective. Orcan Energy’s ORC systems can help make sites ‘fit for the future’ in the long term and secure a competitive advantage. Furthermore, several European countries offer investment incentives through various support schemes. We are currently seeing particularly strong interest in Europe.

How is the business with ORC solutions for the metal industries developing, and where are your systems already in use?

The increasing pressure to decarbonise, combined with rising energy prices, means that the industry is increasingly looking for ‘affordable’ – i.e. economically viable – solutions to improve energy efficiency. We have already installed several ORC modules in various metal-processing plants, for example at Nordenhamer Zinkhütte (Glencore) and in the lead recycling operation at Ecobat Resources Freiberg GmbH.

What makes these systems stand out?

Thanks to their plug-and-play design, the modules are particularly well-suited for retrofitting existing plants. Heat sources can be utilised individually or in combination, depending on the site. Fully autonomous operation and minimal running costs mean that our ORC solutions can be integrated into existing processes easily and straightforwardly.

What potential for waste heat or other heat sources remains to be tapped in the metal industries, and how can ORC plants contribute to this?

The metals industry generates enormous quantities of waste heat, for example during the smelting process in basic or electric arc furnaces, but also during further processing, reheating, treatment, refining, etc. A large proportion of this heat has so far remained unused or is even actively cooled – at the expense of energy. ORC systems can make a significant contribution, both in the high-temperature range (>300°C) and in the low-temperature range from 80°C upwards, for example by optimising existing cooling systems.