Sticky point of clean energy is storage

Weekend Australian
Saturday 16/6/2007 Page: 18

IN the ongoing debate about the role renewable electricity can play in combating global warming, energy storage is the game-changer. At present the curse word for wind and solar power systems is "intermittency". Calm days and variable wind patterns blight the market expansion of wind farms, as do night and dull days for solar arrays, not least because of the strains that unpredictable supply places on high-voltage transmission networks.

If the power gathered when the wind is blowing and the sun is shining can be "bottled" in a commercially viable way, the role of wind farms and solar arrays takes on a whole new importance in an increasingly carbon-constrained energy supply environment. Because the chief expense of these renewable systems is the initial capital cost, with low marginal costs of actually generating power, access to storage can make a substantial change to their market contribution.

Now a remote fishing community in Western Australia is about to take on role in helping the alternative energy industry to pursue its dream of being able to operate on demand in peak periods, when power prices are at their highest. Using a $1.83 million subsidy from the federal Government, part of a five-year $20.4 million program to promote electricity storage technologies, Vancouver-based VRB Power Systems and Australia's Cougar Energy Limited are setting up a trial of the Canadian startup company's battery technology at appropriately named Windy Harbour. The technology was initially developed at the University of New South Wales, where research on the concept is ongoing.

The joint venture established its first battery storage operation in Australia for Hydro Tasmania on King Island in 2003, and hopes to set up 90 more such trial sites across Australia over the next three years. These would be in addition to demonstration projects in electricity production and telecommunications support in North America, Japan, South Africa and Ireland.

The largest project is in Ireland's County Derry, where VRB has a $US9.4 million contract to support a 39MW wind farm with storage. The Irish Government's sustainability agency has estimated that if the trial is successful the opportunity exists to install storage capacity of 700MW to support a 3000 could meet a quarter of Ireland's power needs at the moment gas-based generation is its dominant method, fuelled from Russia.

The VRB battery technology involves pumping an electrolyte that contains vanadium and sulphuric acid through a membrane, causing a chemical reaction to release electricity, avoiding the degradation of solid surfaces present in conventional batteries critically, a process that can also be reversed to store power.

The company also boasts that its battery has the lowest ecological impact of all energy storage technologies, most of which rely on toxic substances such as lead, zinc or cadmium. Unlike conventional lead-acid batteries, VRB's invention does not wear out and the units are "scalable" they can be grouped to store more power for longer periods. At present a VRB battery and storage tank system the size of a fridge can hold enough electricity to power an average-sized house or a mobile telephone transmission tower, and a collection the size of a football field can store power from a 40MW wind farm.

VRB also puts the vanadium battery forward as a good complement for a diesel generator in an off-grid community and it acquired the rights to another "flow" battery system using chemistry based on bromine and polymeric sulphur from RWE, Germany's largest energy utility. VRB's initial marketing focus is on 200 island communities around the world and countries such as Australia, where there are large numbers of off-grid regional communities reliant on expensive and noisy diesel generation for their power. The company is currently also exploring prospects in Denmark, Spain, Scotland, Ontario, Oregon, Hawaii, California, parts of Latin America and New Zealand.

Its chief executive, Tim Hennessy, claims that the prospective global market is worth $US1.5 billion a year in the medium term and far more as the technology is developed. Meanwhile, the Department of Energy in Washington DC believes that electricity storage in America alone has a market potential of $U53 billion to $US5 billion annually. The Sania National Laboratories, a US government agency in New Mexico, adds: "The electricity industry is becoming aware that energy storage can be cost effective in certain applications and certain locations. It will change the way utilities and electricity consumers do business."