High energy consumtion
In order to produce 1 tonne of aluminium from ore, approximately 10,000 kWh of energy from fossil fuels is required, together with nearly 20,000 kWh of electrical energy. This energy-demanding process has a major impact on the climate, and greenhouse gases are emitted from both the energy consumption in itself, and from the manufacturing process. Increasing the energy efficiency of the production is important both for the environment and for the competitiveness of the producers, through reduced costs.
In his doctoral thesis, Improved Energy Efficiency in the Aluminium Industry and its Supply Chains, Joakim Haraldsson investigates how this can be done. How can manufacturers reduce energy consumption; what are the drivers for this; and what barriers exist?
Aluminium profiles at Gränges in Finspång. Photo credit: Gränges
Most importantly: there is a huge potential. Calculations presented in the thesis show that companies in the Swedish aluminium industry – foundries, rolling mills and profile extrusion plants – can together save 126-185 GWh per year, or 5-7.5% of the total consumption. This corresponds to the annual energy consumption of 6000-9000 electrically heated detached houses.
Potential savings for Swedish aluminium casting foundries are 8-15 GWh, or 11-21% of the total.
"Great deal of money"
“The money that the companies can save depends on energy prices, of course, and this means that it is difficult to calculate. But if we assume a price of 1 SEK/kWh, the saving is SEK 100-200 million. It’s possible that the industry pays less than this, but even so – there’s a great deal of money involved”, says Joakim Haraldsson.
There are many opportunities to save energy. The use of secondary aluminium and remelted material waste can reduce energy consumption by as much as 95%. The quality of these materials, however, is not good enough for all products. Within a company, it is important to carry out energy audits, and communication and collaboration between companies along a supply chain can optimise the total energy consumption. Two examples are the significance of optimising transport, and of designing products right from the start to be energy-efficient both in production and in use.
New technology can also increase energy efficiency. But here, vigilance is necessary. Some technical solutions can reduce energy consumption, but at the same time increase the emission of greenhouse gases. One fundamental problem is that much of the new technology is still under development or even at the research stage.
“In most cases there is an overall improvement. But there are examples in which the emissions from energy consumption are lower, while the emissions from the manufacture are higher. And of course, that’s not what we want”, says Joakim Haraldsson.
Drivers and barriers
The barriers that companies experience as most important in their work to reduce energy consumption are the risks and costs associated with production disruption during the introduction of new technology, complex production processes, and technology that is inappropriate at the particular site.
In contrast, drivers are reductions in cost, improved competitiveness, requirements from official bodies, and the knowledge, culture and strategy of the particular company. Other significant factors are energy audits and information from technology suppliers. Demands placed by customers may play a large role, but Joakim Haraldsson points out that this may be problematical.
“As customer, it may be difficult to demand that a company improve its energy efficiency, much more difficult than, for example, purchasing ‘green electricity’. How do you know what demands are reasonable with respect to improving energy efficiency? One solution may be to demand that the companies introduce energy management systems, in order to ensure that they work more actively with energy efficiency”, he says.
In the thesis, Joakim Haraldsson presents literature studies together with his own work using focus groups and questionnaires. He has also calculated how possible energy-efficiency measures affect such parameters as the emission of greenhouse gases.