Demand response helps bring more wind to the grid

Demand response helps bring more wind to the grid

While high-profile innovators, like Tesla Motors, Solar City, and even GEs big-wind division are touting battery storage as the holy grail of renewable energy integration, a group of small utilities on the northeast Canadian coast has demonstrated a readily available approach to wind integration that comes in at a fraction of the cost of batteries today. The program, called PowerShift Atlantic, is led by NP Power, along with Saint John Energy, Maritime Electric, Nova Scotia Power, the New Brunswick System Operator, other research and industry partners, and funding from Natural Resources Canada. Besides showing that the maritime utilities can use advanced demand response to balance significant wind resources, the program also shows how utilities can build positive and lasting relationships around this strategy with their customers.

According to Michel Losier, program director for NB Power, Our customers tell us, keep the lights on, dont raise the rates, and we want to see more wind and less fossil generation. We tell them we cant go this alone anymore. Since the program went operational in 2012, PowerShift utilities and their customers together have made more than 16.5 MW of demand response available for continuous control. That resource is helping the utilities to use more wind, which currently accounts for 10 per cent of the resource portfolio and is growing. The project has been about collaboration, demonstration, and transformation, Losier said.

He presented a progress report to attendees of the Peak Load Management Alliance (PLMA) spring conference in April, in Denver, Colorado. PLMA honored NB Power along with six other North American companies that have demonstrated innovations in using demand response to mitigate electricity price risks and manage variable generation in the past year. PowerShift Atlantic was the only PLMA award winner that is sharply focused on renewables integration. This is a relatively new way to use demand response (load control) tools, which are best known for improving reliability and easing wholesale price spikes when an extreme heat wave or deep freeze strikes.

Balancing a large wind resource with demand response involves creating an intelligent integrated supply and demand systema virtual power plant. This software-driven system constantly monitors and manages the balance between energy supply and demand, especially focusing on wind generation and forecasting. Instead of calling for a dramatic response to rare load control events, this system constantly adjusts operations of customer appliances and equipment. It can dial energy use back when wind generation falls off, and it can crank energy use up when wind generation is abundant. Because controlled devices (such as water heaters and commercial refrigeration equipment) typically have thermal storage characteristics, most customers report that they do not notice changes in their comfort or convenience. For instance, an electric water heater can run on a windy night and hold heat for showers the next morning. Program-wide customer satisfaction is at 80 per cent, even considering the inevitable challenges any new program rollout. Pumping loads, which may run anytime within a broad window of time, are also controlled.

Most of this equipment, except for some leased water heaters, belongs to participating customers, who sign a ten-year control contract. Remarkably, the utility does not offer rebates or incentivesonly the rewards of participating in a game-changing, public-spirited venture. And the utility does not use smart meters. We wanted to see how close we could keep this to business as usual, Losier explained.

The internal workings of the system are plenty complicated, but the customer doesnt see that. Consultants and IT design teams from Stantec, Accreon and SAIC created the virtual power plant so it would use connected customer loads as essentially dispatchable energy resources, providing preferred load shapes and the equivalent of a ten-minute spinning reserve on demand. Enbala Power Networks, Integral Analytics, Steffes Corporation, and the University of New Brunswick each serve to aggregate a different segment of the demand-side resource portfolio. For example, Enbala works with commercial utility customers, helping to sign them up, set up the control equipment, and manage its use in sync with the overall Plant.

According to Ron Dizy, Executive Vice President of Enbala, it is important to note that the utility is still the centerpiece in this puzzle. You hear a lot about the demise of the utility, but this demonstration tells a different story, he said. Demand response partners can work with utilities to increase their use of renewables, while improving overall system efficiency, reliability, customer satisfaction, and net economic benefits. He said Enbala is looking at ways to use demand response to help integrate solar generation, too. While smart inverters can help solve voltage drop problems related to solar variability, demand response can help with other balancing functions. Building pre-cooling, controlled electric water heating, and pump timing could ease the need for fast ramping of natural gas or other generation when daily solar production drops. This is not a 100 per cent solution for solar integration, but it can make a big difference. In the long run, demand response might prove compatible with batteries, revealing a sweet spot where lower cost strategies are maximized before higher cost battery storage resources kick in.

To be fair, PowerShift Atlantic is a research and demonstration program, with an emphasis on research. NB Power and other participating utilities are using more wind power, but they have not mothballed any conventional resources yet. These include nuclear, hydro, oil-, gas-, and coal-fired generation. Losier said he expects a shift in the utility generating mix as planners and regulators fully assess research results. He also stressed the importance of building a strong industry around individual demand-response technologies and Virtual Power Plants in order to replicate the program at scale. We are just realizing the potential of customer-based resources, and we feel like we have to move quickly if we want to be sure that theyll be there for us ten or twenty years down the road, he said.

Source: Intelligentutility

SMART GRID Bulletin May 2017


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