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PNNL to enlist millions of distributed energy devices to balance the grid


December 15, 2015 – A new research project led by the U.S. Department of Energy’s Pacific Northwest National Laboratory (PNNL) aims to bring supply-demand balance to the grid—even taking into account variable sources such as wind and solar—by employing millions of distributed energy resources that already exist, such as solar panels on rooftops and heating and cooling systems in buildings.

“Our new approach to balancing the power grid offers a great deal of flexibility and the potential to increase system reliability,” said PNNL engineer Karan Kalsi, who is leading the project. “It would give the future power grid the ability to quickly take on and shed power, which would also enable us to incorporate more intermittent renewable energy into the nation’s power mix.”

The new approach will be far more advanced than existing efforts to coordinate distributed energy resources, insists PNNL, adding that most methods under consideration today focus on just one type of resource, only offer one grid-balancing service and ignore local system requirements. The PNNL-led team is incorporating many different resources and grid-balancing services in its system, while also ensuring local power reliability is maintained.

To test the system, more than 100 actual distributed energy devices—including heating and cooling systems at commercial and residential buildings, inverters for utility-owned solar panels and residential water heaters—will be managed with the new system. And, to evaluate the system on a larger scale, more than 100,000 simulated devices will also be managed through several grid modelling tools that PNNL is combining for the project.

This is how it works: the new method will involve asking companies, citizens and others to voluntarily enrol their distributed resources—which include batteries, smart appliances, electric cars, solar panels, and heating and cooling systems. These owners would be offered an incentive of some kind as encouragement.

Sensors and controls would be installed on enrolled resources to detect and alter their operations as needed, but within limits set by their owners. The sensors would allow resources to communicate through a cooperative decision-making platform, where information about the power needs of the grid and individual distributed resources are exchanged.

High-speed local controls will be used to operate the devices. The system’s computational framework can estimate distributed resource needs and only has to occasionally communicate incentives to encourage the devices to alter their energy consumption.

A new organization called a distribution reliability coordinator would then evaluate the flexibility of various distributed resources to simultaneously provide the following three grid services:

• Frequency response: very fast-acting emergency response to major events, such as a power plant failure.
• Regulation: responding within seconds to maintain balance between power supply and demand.
• Ramping: buffering rapid changes in power demand.

PNNL’s project team includes United Technologies Research Center, GE’s Grid Solutions (formerly Alstom Grid), Southern California Edison, PJM Interconnection and California Independent System Operator.