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Energy storage technology has been advancing in recent years. The over-reliance on fossil fuels and the investment in new, greener energy technology have, in part, been responsible. However, aging infrastructures and antiquated storage devices have pushed R&D harder in this field. A wide array of storage devices and tech have been developed to ensure global energy grids experience less downtime and meet everyday demands.
Energy storage can be broken down broadly into 5 categories:
- Pumped Hydropower
- Other mechanical storage
- Hydrogen storage
Common Energy Storage
Lithium and lithium-ion batteries are perhaps the most well-known storage devices of the past 50 years. Available worldwide, they still dominate the consumer market to power everything from toys and computer hardware (wireless keyboards, mice), to phones and cameras. The low cost and mass availability have made it more difficult for newer energy storage technology to make headway.
Consumer demand requires that smartphones last longer between charges, whilst using more power. Lithium-ion batteries have an advantage over older batteries because of their higher energy density. Add to this a much lower self-discharge rate of between 1-2% a month, and it is easy to understand the popularity of lithium-ion.
New Energy Storage
The efforts to advance energy storage and make power generation more efficient requires a multifaceted approach. Governments and companies are looking into ways to combine sources like hydropower, nuclear energy, and renewable energy in an effort to curb carbon emissions and make energy grids a lot smarter. One of the most interesting storage advances to occur lies in the Advanced Vanadium Flow Battery.
A vanadium battery has an assembly of power cells in which the 2 electrolytes are separated by a proton exchange membrane. This type of rechargeable flow employs vanadium ions that are in different oxidation states. The different states are used to store large quantities of chemical potential energy to be used at a later date. Using larger electrolyte storage offers an almost unlimited energy capacity and the battery can be left discharged for long periods without the risk of damage or diminished recharge capacity.
The advanced vanadium battery is just one prong of the approach. In a world where renewable energy is heavily reliant on intermittent sources like wind and solar power, larger and more efficient storage devices are required. Jack Goodenough showcased a new fast-charging battery that uses a gas electrode instead of a liquid. By using sodium instead of lithium, the fast charging technology can offer three times the energy density when compared to current lithium-ion batteries; a definite advantage.
Thermal Energy Storage
Intermittent power generation requires the best storage technology possible to prevent wasted energy. One of the principle concerns over photovoltaic solar panels is their low energy performance and storage capacity (commonly less than 20% efficiency). The latest thermal energy storage offers new ways to store surplus energy that would otherwise be lost.
One of the most widely used energy-saving methods is pumped hydro storage. This uses the surplus electricity from the turbines to pump water up to a reservoir behind a dam. Later, when energy demands increase, the stored water is released through the turbines to generate electricity. Surprisingly, pumped hydropower is used in 99% of energy grid storage around the world.
ARES Power Storage Project
Definitely the most exciting energy storage project in years, the ARES project represents one of the most efficient ways to save lost energy from renewable sources. Due to their power generation being weather dependent, wind and solar cause energy losses from other sources. Hydropower and natural gas production often cease production to allow solar and wind energy into the grid before it’s lost. ARES proves you do not have to lose any energy at all.
ARES harnesses the energy from solar and wind, using it to lift a huge train on rails uphill. This turns 80% of the energy into gravitational potential energy, storing it until it is required. When required, the train falls back downhill, releasing the stored energy as electricity back into the grid.
Energy Storage for the Future
Whilst the ARES project and thermal energy storage efforts continue, most industry experts predict the lithium-ion battery to dominate the market for years to come. With the infrastructure already in place, many companies are unwilling to adopt newer technologies, preferring instead to concentrate on making lithium-ion storage more efficient.