Energy storage can facilitate greater use of variable sources such as wind power, but also offers benefits to grid operators.
1) What’s driving the demand for energy storage?
Everything about energy is becoming more complex. The way we generate, distribute and consume electricity requires sophisticated solutions that enable a flexible, reliable and efficient electrical grid. Energy storage is an effective strategy to manage this complexity; it allows both power generators and consumers to have better control of how and when they make and use electricity. Several regulators and utilities are seeing the benefits, as more policies, financial mechanisms and targets are being proposed and implemented that will pave the way for full commercialization.
At the state level, California has led the strongest charge into energy storage adoption. The California Public Utilities Commission (CPUC) implemented energy storage targets as well as mandating that Californian investor-owned utilities procure 1.3 GW of energy storage by 2020. In Texas, the legislature enacted SB 943, which clarifies the interconnection and transmission rights of energy storage participating in the ERCOT energy or ancillary services markets. New York State established the NY Battery and Energy Storage Technology Consortium to help facilitate commercialization of storage technologies. And recently, Washington State began to require that utilities plan for energy storage in their integrated resource plans.
At the national level, the Federal Energy Regulatory Commission (FERC) issued FERC Order 755 in 2011. This ruling increased remunerations for “fast” responding sources like batteries or flywheels that bid into the frequency regulation service market. Since storage technologies excel at being fast and accurate, this FERC ruling laid the foundation for enabling better financial returns on energy storage implementation.
PJM was the first Regional Transmission Organization (RTO) in the US to adopt Order 755, and we’re already seeing significant improvement in the commercial viability of frequency regulation. Several other RTOs are working to adopt Order 755 which will further the economic incentive and undoubtedly increase demand for storage technologies.
In Canada, the Ontario Power Authority (OPA) in conjunction with the Independent Electricity System Operator (IESO) has recently released a request for proposals to procure 50 megawatts of energy storage in two consecutive phases by the end of 2014. This is a significant move by the Ontario Government to accelerate implementation of energy storage technology in one of Canada’s most diversely supplied electricity networks.
2) What are the benefits of using energy storage in wind power applications?
Individually, wind power brings significant value to the energy mix, allowing clean and abundant energy to power our communities. However, when wind and storage are combined, the benefits increase substantially. Vast amounts of wind energy are safely and reliably integrated into our electrical grid today, but adding energy storage would help maximize the use of the wind power.
The main priority of any utility or grid operator is to balance energy supply with demand in order to help maintain grid reliability. However, the wind does not always blow when demand is high. This is where energy storage can help. If energy demand suddenly increases and there is not enough wind power to meet the demand, the energy storage system can quickly come online and make up the difference in a very precise way. And if energy demand is low, but wind speeds are high, the energy storage system can absorb the access power and store it for later, harnessing the full potential and profitability of wind power.
Energy storage can also help a wind farm emulate a traditional power plant, where energy supply is constant, non-variable, and can be turned on or off without disrupting grid operations. The system can assist in the rate of change of the wind farms output, thus providing ramp rate support. Even when wind is blowing steadily, there are still minor variations in the power output of a wind farm. Energy storage can instantaneously compensate for intermittency and provide smooth, seamless output to the grid. This enhances power flow, enabling more of the clean energy source to be used in homes, businesses and schools.
To add to its technical merits, energy storage can also provide ancillary services that help maintain high power quality on the electrical grid, mainly in the form of frequency regulation and voltage support.
3) Can energy storage systems be used to help wind farms meet grid code requirements?
Wind farms, like any other power generator, have grid interconnection requirements. Energy storage systems can help a wind farm demonstrate performance characteristics similar to those of traditional power generation plants by reducing the energy output variability, controlling voltage, and managing the reactive power.