The significant potential of renewable energy will only be fully realized once power grids can accommodate the storage of oversupply. Effective storage technology will need to be designed in order to capture intermittent energy from renewable sources and grids will need to be reconfigured accordingly. Without this happening first, clean energy sources such as wind, solar and hydro will never be able to replace fossil fuels. Many countries across the globe are turning to renewable energy sources due to dwindling fossil fuel supplies which are also the main culprit of carbon emissions. As the world becomes more reliant on renewables for energy, grid operators will need energy storage to help balance supply with demand. Currently, the US power grid has a storage capacity of only 1% which is completely insufficient for the 12.1% renewables that make up the US grid.
Although wind and solar power show great potential as low-carbon sources of electricity, they rely on the weather.This is the current challenge with which utilities are faced with today. In addition, researchers and developers must ensure that the development of the technology does not compromise the safety of the environment. Researchers have begun developing new batteries and other large-scale storage devices but the fossil fuel needed to build these technologies could negate some of the environmental benefits of renewable energy. This is according to scientists at Stanford University who calculated how much energy it would cost to build storage on future power grids that utilize a large percentage of renewable energy. The researchers calculated how much energy it will cost society to build storage on future power grids that are heavily supplied by renewable resources and the result is that grid storage is energetically expensive. In addition, some technologies, like lead-acid batteries, need more energy to build and maintain than others. Battery technology currently can’t handle enough charge cycles. Researchers and developers will need to improve the lifecycle of batteries if they are to be affordable parts of the grid. It is for this reason that the world awaits the development of better storage technology.
According to a recent report from Pike Research, a part of Navigant's Energy Practice, the market for grid energy storage will grow rapidly over the next 10 years. New energy storage technologies are emerging and will change the energy storage space with innovations in efficiency, footprint, materials science, and system flexibility according to analysts. These innovations will help grid operators to optimize grid assets, defer transmission and distribution upgrades, and integrate renewable energy sources.
There are currently three main storage options:
- Pumped hydroelectric storage (PHS)-water is pumped upwards into a reservoir where it can be released later. Although highly effective, PHS has a major limitation-it has to be built in mountainous areas. This may prove to be problematic when it comes to long distance transmission to nearby cities and towns.
- Compressed air energy storage (CAES)-where the air can be expanded again through turbines when required. CAES requires huge tanks or caverns to fill with air, which can limit its viability to a limited number of areas
- Batteries-there are many types (eg. lead-acid, lithium-ion, sodium-sulphur, vanadium-redox and zinc-bromine), each with their own maximum number of effective charge cycles. The major limitation of batteries is battery life. Batteries appear to be the most viable energy storage option. In addition to the improvement of battery life, battery prices also need to be reduced in order to make energy storage financially viable.
Many energy storage vendors are finding it difficult to make a business case for their technologies using a single application. As a result, vendors are using a variety of applications. Instead of using only one application (as is the case with traditional energy storage installations), they are finding solutions for several issues with a single installation. According to the Pike Research report, the energy storage industry find themselves at a crucial point as vendors attempt to fully commercialize technology and develop business cases that highlight total value, rather than simply applications.
Energy storage technology is crucial if power grids are to increase their efficiency and become smarter, cleaner and more reliable. Advanced energy storage technology will help integrate intermittent renewable power sources into the existing grid, thereby lowering emissions from traditional plants.