As the solar industry grows and becomes a larger part of the electricity system so does the need to effectively handle the inherent intermittency of solar power. Fortunately, over the past decade, a variety of options have arisen that allow solar energy to be stored for later use. Batteries are the most well known technology used for storing energy, capitalizing on chemical energy to store electricity, but there are also other means by which energy may be stored. Flywheels, for example, store electricity in the form of kinetic energy by rotating at high speeds, and using the rotation to run a generator when the power is needed. Energy can also be stored as heat, as is the case with solar thermal storage, where heat is captured and passed through a heat pump to create electricity at a later time.
Each storage option stores energy in a different form (chemical, kinetic, potential as with hydropower, or thermal). The correct choice for each situation depends on a few different factors, not least of which is cost. But it is also important to consider minimizing the amount of energy transformations, and ensuring a feasible location for installation. The latter comes into play particularly with storing electricity in the form of potential energy, as in compressed air energy storage or hydropower. Locations without significant water supplies or empty underground caverns to store the air will not be able to utilize these options. Minimizing energy transformations primarily affects the round trip efficiency of the storage process. For example, pairing solar power with thermal storage makes sense because the sunlight already carries a significant portion of heat with it, requiring less energy to be transformed in the process.
Of course, the most important consideration with energy storage is cost. Until recently, most energy storage options were economically infeasible, having payback periods longer than usable lifetimes. Through much research and development however, many storage options are being applied at scale all over the world. Applications specific to Australia, such as off-grid potential and business use, are outlined in a recent report by the Clean Energy Council.
In addition to storing solar power to be used at times with limited sun, there are some other benefits to installing energy storage. If there is ever a power outage, most storage systems will have at least a day or two of power stored so the consumer can still have lights and use appliances even if the grid is not providing electricity. Due to recent price reductions in battery storage systems, these benefits are becoming available to homeowners. Battery prices are expected to fall by more than half in the next ten years, leading to exponential growth in the energy storage market. This development is very good news for solar power, which will only benefit from widespread adoption of the variability mitigation energy storage systems.
- 18 Nov, 2013
- Kit Man Chan
- 0 Comments