28 May 2013 14:00 [Source: ICIS news]
By Nigel Davis
LONDON (ICIS)--A century old idea has resurfaced and could provide the missing link between renewables and more efficient energy storage.
Germany-headquartered Industrial gases group Messer said last week that it had supported a study on energy storage using liquid air and was continuing to work with UK partner Highview Power Storage which developed the technology.
“The report confirms that liquid air is one attractive approach which should be pursued by industry, the energy sector, universities and government in partnership,” head of Messer’s business development, Tim Evison said.
The company is keen to tap into opportunities in an energy storage market that could be worth between $20bn and $25bn annually by 2020 according to one estimate.
A variety of technologies have been put forward to solve the energy storage problem - from pushing water uphill to injecting air into underground caverns or employing giant centrifuges.
“Specifically as regards to energy storage, there is a clear need for technology development to ensure future grid stability and to optimise the economics of a power supply based on renewable,” said Evison.
“I am delighted to see the level of excitement that the possibilities of cryogenic technologies have created across such a broad swathe of experts from academia, energy and industry.”
The Messer executive’s comments pinpoint the dilemma. Real technological development and a change in the ways in which renewables are incorporated into the power generating infrastructure will only be made if there is close cooperation between academia, government and industry.
Ideas are not lacking, but the means of putting those ideas to work often are.
Europe needs new energy storage solutions because the surge in electricity generation from wind and solar power has to be more effectively managed. New concepts and ways of storing energy will be a crucial part of the region’s drive for smarter (electricity) grids and power generation and its ability to meet climate change targets.
In the UK, where the study originated, ‘constraint payments’ are made to wind farms to switch off power generation when the wind is blowing and power cannot be used. And the country pays again to keep polluting diesel or gas turbine power plants on standby to manage peaks in demand or to keep coal or gas power stations in reserve.
Balancing electricity supply and demand is expected to become more challenging as some 19 gigawatt (GW) of generating capacity is due to close by the early 2020s. According to UK National Grid estimates, balancing or back up capacity needs to rise from 3.5GW today to 8-13GW by 2020.
“The debate around grid balancing is usually presented in terms of the need for additional gas fired plant to run when the wind drops,” the authors of the study, published by the Centre for Low Carbon Futures, say.
“However, we find a powerful case for additional grid storage, in which liquid air could play a major part. Gas plant may be a reliable source of firm power, but it is a source of substantial greenhouse gas emissions, and critically, unlike storage, it cannot absorb ‘wrong time’ energy.”
Highview, a company formed in 2005, has had two projects put through to the feasibility stage in the UK, one of which could be the largest demonstration of energy storage in the country. The UK’s department of Energy and Climate Change launched an energy storage technology demonstration competition in October last year.
According to a report in the MIT Technology Review, the Highview liquid air process is 50-60% efficient so the major inefficiencies associated with earlier air liquefaction propulsion and other technologies appear to have been overcome.
In other words, “the liquid air can yield just over half as much electricity as it takes to make it. Batteries, by contrast, can be more than 90% efficient. But the new process can make up for its inefficiency by using waste heat from other processes,” the MIT Technology review says.
And liquefied air can be used to power vehicles or be used in smart engine systems.
One of the companies involved in the liquid air study, UK engineering firm, Ricardo, suggests that liquefied air, or rather liquid nitrogen, has balanced enough characteristics to make it competitive against alternatives such as hydrogen, batteries or compressed air systems and worthy of further development.
“Currently an estimated 8,500 tonnes per day of waste gaseous nitrogen is vented back to the atmosphere, which, if liquefied and used as transport fuel, would be enough to power the equivalent of 6.5m car kilometres daily,” the study says.
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