The global cost of storage batteries continues to fall. Yet future energy storage methods look beyond lithium-ion batteries to a wealth of innovative solutions.
That’s because the current lithium-ion batteries achieve a maximum of four hours’ storage. This makes it hard for large-scale wind and solar power projects to create baseload energy when wind and sun aren’t available.
Bloomberg has taken a look at five break-through forms of energy storage being trialled by companies looking for renewable grid-scale energy.
1. Compressed air for renewable power storage
Toronto-based company Hydrostor uses electricity to compress air with water, generating heat which is stored. The heat, when released, forces water through a turbine generator converting the energy back into electricity.
If the energy used to compress the air is renewable, this results in a system that emits no emissions.
Hydrostor is using an abandoned South Australian zinc mine as Australia’s first compressed air energy storage facility.
The 5 MW, 10 MWh project in Strathalbyn is backed by the Australian Renewable Energy Agency (ARENA) and the South Australian Government.
2. Liquid air storage for solar power
Pioneering London company Highview Power uses liquid air for energy storage which is cheaper and longer-lasting than lithium-ion batteries.
The UK demonstration plant in Greater Manchester uses excess or off-peak electricity to chill air to around -196°C, the Guardian reports. It is then stored in metal tanks in a liquid state.
Pumping and heating turn the liquid back into gas. This releases energy to drive a turbine, creating clean electricity when needed.
Highview Power is reportedly setting up a commercial plant in the US. Sites in Europe and Australia are also on the cards.
3. Gravitational mine energy for renewable energy storage
Edinburgh’s Gravitricity Ltd is experimenting with gravitational energy using mine shafts. The company is hard at work on a 50-ton demonstrator.
The process uses renewable energy to lift a weight within a mine shaft. This could weigh as much as 3,000 tons.
The weight then falls, releasing electricity which lasts as long as eight hours. The winches and cables also have a working life of around 50 years, the company claims.
Numerous disused mine shafts in Australia make this a potential winner for future energy storage.
4. Future energy storage with pressurised water
California company Gravity Power LLC plans to store energy using pressurised water. This requires a steel-jacketed piston made of rock and concrete, weighing up to 8.5 million tons.
The piston releases pressure to unleash the stored energy. It also drives a turbine creating electricity for up to 16 hours.
The company is in the process of setting up a demonstration plant for this future energy storage method.
5. Tower block gravity
Swiss company Energy Vault is working on a more complex version of the Gravitricity model – using tower blocks.
The storage process works by stacking thousands of 38-ton blocks into a tower up to 160m high.
A robotic crane then plucks them off the tower and lowers them to the ground. The weight of the blocks then drives generators.
The system can deliver as much as 80 MWh of electricity. This will power around 60,000 homes for up to 16 hours.
Energy Vault is constructing its first commercial plant in Milan, Italy, this year.
Future energy storage: Plenty of scope for Australia
Utility-scale battery projects have been slower to kick off in Australia.
Yet these new forms of future energy storage also offer plenty of potential for Australian’s cities, regions and rural communities to build on.