Copper Might Hold Key To Electrical Energy Efficiency
Copper, the mainstay of power grids worldwide, still has considerable untapped potential to carry energy better and reduce wastage but the industry must first come up with a hefty investment, according to a trade group. Read More
Copper, the mainstay of power grids worldwide, still has considerable untapped potential to carry energy better and reduce wastage but the industry must first come up with a hefty investment, according to a trade group.
The drive to cut emissions in the wake of the 1997 Kyoto climate accord may pressure industry into reducing power loss with the increased use of copper in transformers and cabling.
But the additional expense involved for the highly competitive deregulated European power industry means that reluctance to boost copper consumption has grown.
“Losses from transformers in the EU are equivalent to the annual power consumption of 15 million homes, or the electricity produced by seven of the largest coal-burning power stations in Europe,” according to a report prepared last year for the European Commission by the European Copper Institute (ECI).
Switching from low-to high-efficiency transformers would ultimately achieve annual energy savings of 22 terawatt-hours a year, the report said. This is the equivalent of reducing nine million tons of carbon dioxide emissions, or four percent of the European Union’s Kyoto targets.
Copper Has What It Takes To Protect Heat
Power losses through unwanted heat in electrical equipment are directly linked to the resistivity, or tendency to restrict the flow of an electrical current, of the material used.
So copper, which is a better electrical conductor than any other metal except the more expensive silver and therefore has low resistivity, allows the current to flow through and generates less waste heat than competing materials.
The best way to limit energy loss is to choose low-resistivity material — for example switching to copper rather than aluminium conductors — or to use more of it, such as increasing minimum wire sizes, Professor Nick Jenkins of the University of Manchester Institute for Science and Technology told Reuters.
“If you think of electricity as a kind of fluid flow, if you have a bigger pipe you have lower resistance. Similarly if you have a fatter wire you have lower resistance, and hence lower power losses,” Jenkins said.
Increased Costs
But using more copper in transformers, or producing thicker copper wires and cables, brings with it an inevitable increase in initial costs.
This needs to be offset against the savings accrued from reduced power losses over the life of the equipment, Jenkins said.
“The issue is how you do your cost calculations when you’re buying a piece of plant. Basically you’ve got a whole range of costs, but the important ones for us are purchase costs and the cost of losses over the life of the plant.”
This can cover a long period.
“Transformers can certainly last 40 years, while we’ve still got cables in the ground from the 1940s, probably in places from the 1920s,” Jenkins said.
While long-term savings more than make up for short-term cost increases, the increasingly competitive deregulated European power industry is reluctant to take this route.
In England and Wales, for example, attitudes have changed following the demise of the state-run Central Electricity Generating Board (CEGB), which generated and transmitted all public electricity until 1990.
“In the days of the CEGB it was sensible to take some account of the long view between year 10 and year 40. Now, because of quite understandable commercial pressures, we’re not doing that,” Jenkins said.
“At the moment we’re going backwards. Under the nationalised industry you could have a sensible statement about longer-term benefits, but this is no longer the case.”
In the absence of commercially driven initiatives, pressure to improve energy efficiency standards may have to come at governmental level, either from the European Union or from electricity regulators in individual countries, the ECI’s Hans De Keulenaer told Reuters.
“As it is today with the pressure of deregulation there’s evidence that the use of energy-efficient transformers is decreasing rather than increasing,” said De Keulenaer, the ECI’s Electric & Electronic Programme Manager.
The European Commission is currently studying the establishment of minimum standard levels for transformer efficiency, but standardisation tends to be a lengthy process with as yet no deadline set, he said.
Environmental Impact
The EU’s commitment to emissions cuts under the Kyoto accord has added some urgency to the process, however.
“What’s not factored in, and I think this probably is something which could change, is that if we could do something dramatic on energy losses, it translates directly into the bottom line of environmental impact,” Jenkins said.
If the ECI and other proponents of increased energy efficiency win the argument, the impact on European copper consumption could be significant.
The European wire and cable products sector consumes around two million tons a year of copper — 700,000 tons to 800,000 tons in energy cabling in buildings, 250,000 in motors, 150,000 to 200,000 in energy cables for distribution networks, and 100,000 tons in transformers, with the balance made up of equipment wiring, telecommunications cables and the like, De Keulenaer said.
Assuming that Europe’s four million transformers were to be upgraded to maximum energy efficiency levels, “the maximum pie-in-the-sky potential increase in copper consumption would be around 20,000 to 30,000 tons a year, but realistically it’s more likely to be around half of that,” he said.
Story by Andy Blamey. © 2001 Reuters Limited. All rights reserved.
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