What's Next in Grid Energy Storage?
December 18, 2017 | Maxwell Technologies
As we move closer to a 100-percent renewable grid, we’re reaching many milestones and breaking records along the way.
Germany generated 35 percent of its electricity from renewable sources in the first half of 2017, up from 33 percent the year prior. In May, Scotland saw 46 percent of its entire electricity needs met by wind power generation. And here in the U.S., renewable energy contributed to 10 percent of total electricity generation in March – the first time crossing into double digits.
But with these milestones come a challenge – how do electric utilities keep pace with the growth of renewables?
As more renewable sources are integrated onto the grid, more utilities rely on advanced energy storage systems to provide stability and reliability to their systems. Given the intermittent nature of renewables (solar power is only generated when the sun is shining; wind power when there are breezes) and the demands of the grid, energy storage solutions are a must – but it’s time for grid operators to look beyond the usual battery solutions for their systems.
The push for a hybrid solution
While batteries are great for the long-term energy storage requirements of the grid, they lack the power density and capacity needed for other grid operations, such as renewable energy smoothing, fast-responding frequency regulation, power delivery for stabilizing transmission and distribution (T&D) systems, and mitigating voltage sags and other quality issues. This is why some utilities are seeking a hybrid approach to address both energy needs and power requirements, tapping into the best technologies for each: batteries for energy and ultracapacitors for power.
Compared to batteries, ultracapacitors’ delivered and available power density is a factor of 1,000 W/kg greater. Ultracapacitors can also discharge and recharge in seconds versus minutes or even hours, making them ideal for delivering power to the grid instantaneously as needed.
Ultracapacitors: versatility and value
Hybrid battery-ultracapacitor energy storage systems offer
effectiveness by offering one solution to address multiple grid functions. For example, ultracapacitors can provide real-time solar power smoothing for distribution, while batteries conduct time-energy shifting. An added bonus for using a hybrid system is the fact that using ultracapacitors to relieve the batteries from needing constant and repetitive charging and discharging will significantly extend battery life.
In the future, batteries will no longer be the dominant energy storage solution for the grid. As utilities adapt to keep pace with public demand and government mandates for renewable energy sources, they need to consider new processes and technologies that will cater to the unique requirements of the grid.
Read our power grid case studies to learn more about grid applications of ultracapacitors.
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