One of the biggest criticism on renewable energy is its inability to act as a baseload plant. With the exception of geothermal energy, renewable energy sources such as wind and solar cannot provide power 24/7 and have variable outputs, thus making the task of balancing the supply and demand a tedious one.
This is why we need additional technology to store the energy sourced from renewables. Gladly, scientists discovered energy storage technologies for RE. They have been available for some time now, but with the rise of renewables, their importance is now being emphasized
There are different kinds of technologies for energy storage. The most mature and common energy storage is the pumped hydropower where two reservoirs with different elevation are used to store excess power. Water is pumped to the reservoir with a higher elevation when there is excess hydropower supply. Stored energy is drawn when needed by releasing the stored water into the reservoir with the lower height with the help of turbines.
In the Philippines, the Kalayaan Pump Storage is one such type of storage. Originally designed for the Bataan Nuclear Power plant, the National Power Corporation in the 1990s expanded the capacity to 600 MW to precisely act as a pump storage. In its design, however, it was not contemplated to store renewable energy. This facility provides ancillary services to the system to regulate voltage and frequency.
There are also other storage technologies available, as well.
For example, thermal storage is used by solar plants where the heat from the sun is stored in molten salts, water or other liquid. Another storage technology is the compressed air energy storage that compresses air and stored in underground caverns. The compressed air is then drawn from their storage and a combustion turbine is used to fire the air with the help of natural gas to produce power.
At Emerging Power Inc or EPI, we use the multi-hour flywheel battery storage. We are in partnership with California-based company, Amber Kinetics for our power storage needs in our solar power plant. The flywheels serve as the reservoir of significant volume of kinetic energy with the high-speed steel rotors. The fly-wheel batteries have been around for some time, but we chose Amber Kinetics’ technology since it can store and release power for hours unlike other similar technology that works only for some minutes. The pilot model is currently installed in the Subic solar farm.
Recently, the World Economic Forum named battery storage as one of the Top Ten Emerging Technologies of 2016, the advances in technologies that can help improve lives and industries significantly and help protect the environment. This list includes technologies that have been available for some time but have reached a tipping point, or where the development in such technology is significant and advantageous to many.
Battery storage solutions after all, are on the rise, too. Zinc, aluminum and sodium batteries are being employed to service small areas. For example, Fluidic Energy, a start-up company that specializes in making batteries using air and zinc has already signed a deal with the Indonesian government to help power-up some 500 remote villages using solar power in the country. The firm will provide air batteries that can store as much as 250-megawatt hours of energy. Fluidic Energy, has earlier inked an agreement with the government of Madagascar to help 100 remote villages put up a mini-grid with the aid of their zinc-air batteries.
As we push for more use of RE, we also need to find a way to store harnessed power from renewables and its integration to grids more feasible. And fortunately, various organizations including governments are now heavily involved in research work to find more power storage solutions that will pave the way for a cheaper, greener and cleaner energy consumption.