The cost of energy losses
Smelters and other metal production plants use vast amounts of power, so energy efficiency is crucial especially as electricity prices continue to soar and countries around the world work towards cutting their carbon emissions.
Some metal-making electrolysis processes such as smelters and electrowinning or electrorefining operations are electricity-intensive and involve high-current electrical connections.
Harsh process conditions in these plants degrade the electrical connections, which results in them becoming more variable and less efficient.
Traditionally, industries operating these plants focused on energy savings in electrochemical processes rather than those associated with electrical connections.
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A world-leading team from CSIRO is helping industry clients in Australasia, Europe and Africa identify how and where energy is being consumed inefficiently.
CSIRO studies had shown that improving electrical connections could generate more than 30 millivolt savings for each electrolytic cell, requiring little if any capital expenditure.
For a typical modern aluminium smelting operation producing one million tonnes a year, these energy savings would be enough to power 17,000 average Australian households, or deliver total annual savings of more than $3 million.
CSIRO's David Molenaar, principal research engineer and leader of the energy efficiency team, says about 10 per cent of electrical energy is consumed in the electrical connections.
"In electricity-intensive plants, it's critical to identify points of electrical energy inefficiency because this affects a plant's stability, consumes excess power and impacts production," Mr Molenaar says.
Dramatic savings through improving the efficiency of electrical connections
The CSIRO team has demonstrated that significant energy savings can be made by improving the efficiency of electrical connections delivering power to the electrolysis processes.
"Reducing power losses is also the most cost-effective way of decreasing industrial carbon emissions associated with electricity use, especially in countries that rely on coal-fired electricity plants, such as Australia, South Africa, China and the United States," Mr Molenaar says.
CSIRO's team has extensive knowledge and experience of the thermal, mechanical and electrical phenomena present in high-amperage electrical connections.
Using this knowledge, controlled testing and computational modelling, the team improves the design and maintenance of the connections.
Company saves eight megawatts in power
For example, a client whose plant was experiencing electrical inefficiencies and energy wastage required CSIRO to redesign the plant's electrical connections.
The team was able to verify energy savings of more than eight megawatts (mW) using in-plant measurements, offline testing and computer modelling.
The energy efficiency team uses a high amperage testing facility at CSIRO's Clayton site in Melbourne to conduct full-scale testing of new designs and industrial materials, and customises testing to meet each client's needs.
"Together, our testing facility and modelling can analyse full-scale industrial components offline under normal operating temperatures, atmosphere and current densities without interrupting the client’s production," Mr Molenaar says.
"This allows us to generate highly accurate data and insights into the way electricity flows through the components and across electrical contacts."
A "whole-of-plant" approach can reduce further costs
Mr Molenaar says adopting a "whole-of-plant" approach in which maintenance is optimised to minimise voltage loss will also reduce costs.
"It's possible to optimise the service life of electrical connections and the electrode fleet to achieve the minimum total cost to the business, with low capital expenditure," he says.
The CSIRO team has worked mainly with aluminium smelters, and copper, zinc and nickel electrowinning or electrorefining operations since it was established in 2009.
As relationships strengthen through ongoing work, clients are increasingly seeking the CSIRO team to be involved in their technical planning and research. In this way, our clients become our partners.