Waste heat is generated in many places in the metal industries – and by many companies, it is utilised sensibly too. The Georgsmarienhütte steelworks, for example, saves more than 1500 tonnes of CO2 every year by feeding waste heat from steel production into the public utilities’ district heating network. Nevertheless, more than 2.6 billion kilowatt hours of additional heat solely from iron and steel production processes in integrated smelting works could be utilised in Germany each year, as a report commissioned by the UBA reveals. One forward-looking way to utilise waste heat is to generate electricity from low-calorific heat using organic rankine cycle technology (ORC), as Dr. Andreas Sichert, CEO of ORC system manufacturer Orcan Energy, explains in this interview.
Dr. Sichert, what are the drivers for ORC systems and why should an industrial company invest in converting waste heat into electricity?
High energy prices and grid fees combined with climate targets make investments in measures to raise companies’ energy efficiency highly advisable – from both an economic and an ecological perspective. Orcan Energy’s ORC systems can help to make sites “future-fit” in the long term and secure a competitive advantage. In addition, there are investment incentives in several European countries through various subsidy mechanisms. We are currently seeing particularly strong interest in Europe.
How is the business with ORC solutions for the metal industries developing, where are your systems already in use?
The increasing pressure to decarbonise and rising energy prices mean that the industry is increasingly looking for “affordable”, that is, economically viable solutions to increase energy efficiency. We have already installed several ORC modules in various metal-processing plants, e.g. at Nordenhamer Zinkhütte (Glencore) or in lead recycling at Ecobat Resources Freiberg GmbH.
What characterises the systems?
Thanks to their plug-and-play design, the modules are particularly attractive for retrofitting existing systems. Heat sources can be addressed individually or combined, depending on the location. Fully autonomous operation and minimised operating costs mean that our ORC solutions can be easily and unproblematically integrated into the existing process.
What potential for waste heat or other heat sources remains to be tapped into in the metal industries and what contribution can Orcan’s ORC systems make to this?
Enormous amounts of waste heat are generated in the metal industry, during the smelting process in blast furnaces or electric arc furnaces for example, but also during further processing, reheating, treatment, refining, etc. A large proportion of this heat remains unutilised or is even actively cooled – using 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, by optimising existing cooling systems for example.
