In the northwest United Kingdom, the electricity provider is betting that the average residential customer won’t notice the difference of a few extra seconds spent waiting for the electric teakettle to boil on occasion.
Electricity North West Limited, which serves about 5 million people, is launching a voltage control pilot called Customer Load Active System Services, or CLASS. Unlike voltage control projects in the U.S., which usually involve conservation voltage reduction to save energy, ENWL is installing smart boxes at the substation level that can adjust voltage to provide frequency regulation to help balance the increasing renewables on the grid.
“The key purpose of the trial is to show that we can predict the amount of response available at any point in time,” said Steve Cox, head of future networks at ENWL.
ENWL is not alone in its grid-balancing needs. Greentech Media’s grid edge coverage shows that clean energy technologies, such as PV, storage and smart grid applications, such voltage regulation, becomes more obvious and necessary with each passing year. Ontario and PJM, for example, are using Enbala’s IT solution for grid balancing because of the amount of wind and solar incorporated into the electric system.
In the U.K., ENWL is deploying Siemens voltage controllers at 80 substations, which serve about 440,000 customers. The controllers communicate over fiber optic that runs to the substation, but they also have backup communication, so they can function if the substation goes down. Two-thirds have been deployed, and the installation will continue through the first quarter of 2014. General Electric, which is a member of GTM’s Grid Edge Executive Council, is providing the network operations software.
One aspect of the project will involve adjusting the frequency by about 1.5 percent based on system needs, which should reduce the standby generation that ENWL would need to pay for on the grid. ENWL estimates the need for slow frequency regulation, which responds in about 10 seconds, is worth upwards of £500 million ($800 million) annually on the entire U.K. power grid.
The second flavor of frequency response is voltage boosting, which has to respond within one second, and usually does so in about 400 milliseconds. The tap changers can provide a voltage boost as more renewable generation, primarily wind, comes on the system.
The technology could allow for an additional 1.2 gigawatts of wind across all of the U.K. if it is fully deployed. Although that is a lot of power, the effects at the end of any one line at any single location should be unnoticeable. As noted, a typical teakettle's time to boil might shift up or down by a few seconds, depending on whether the voltage was boosted or curbed, but no one -- including sensitive industrial customers -- should notice the difference. The voltage boost would be able to be deployed simultaneously to the 10-second frequency response.
The final pilot involves using the transformers. The transformers are usually set in pairs, and one can tap up while the other taps down. Across the entire network, the taps can be staggered to meet the needs of each section, depending on the renewables on the system. “It keeps us from investing in high-voltage reactor banks,” said Cox, “and it’s very adaptable.”
The trial received £9 million ($14.5 million) from the U.K. government’s Low Carbon Fund to test the technology and what effects, if any, are felt by customers in terms of power quality. Although voltage controllers have been around for a long time, using them in the substation specifically to deal with renewables on the grid is a global first, said Cox.
If the technology were to be rolled out to the entire nation, the estimated cost would be £80 million ($128 million), according to Cox. But the 10-second frequency response market is worth much more, so the payback could be less than a year -- lightning speed for the utility industry.
Currently, the deregulated U.K. market pays for these ancillary services in the market, and everyone from traditional fossil fuel generators to demand-side resources, such as those aggregated by EnerNOC, bid into the market. But since this technology is a one-time investment, “You could undercut any other form of frequency response,” said Cox. “It could wipe out the frequency response market.”
Of course, the pilot has to go well for a nationwide rollout to even be an option. And if it is successful, the government regulator will then have to decide whether it will require distribution companies to invest in the technology or whether it will be done through a market mechanism, where the utilities that invest into it can then bid the assets into the marketplace.
Cox is optimistic about the project and its impact. “It’s not very difficult,” he said. “The basic engineering is very simple. There’s no reason we think it won’t work.”
To learn more about how distributed energy resources are driving the grid-edge market, click here to download a free GTM Research paper, The Grid Edge: Utility Modernization in the Age of Distributed Generation. For more information about The Grid Edge Executive Council, which brings together key players in the grid-edge market to push the industry forward, click here.