Smart grid: Power ‘scheduling’ is possible – in theory

According to researchers at North Carolina State University, it is now possible to ‘schedule’ energy in grids by ‘tapping into the distributed computer power of energy devices.’

According to researchers at North Carolina State University, it is now possible to ‘schedule’ energy in smart grids by ‘tapping into the distributed computer power of energy devices.’

According to a story on the NC State website, “The approach advances the smart grid concept by coordinating the energy being produced and stored by both conventional and renewable sources.”

By moving away from a centralised scheduling approach to forecast and coordinate energy produced, to a more advanced system that tracks and coordinates more energy sources, the researchers believe it is possible to ‘schedule’ energy – by using distributed computing power to replace the traditional centralised control centre.

RE integration poses a challenge

The increase in renewable energy being incorporated into the smart grid is “a key challenge” says Mo-Yuen Chow, professor of electrical and computer engineering at NCU. He says that it is particularly challenging to determine “how much of that energy needs to be stored on-site and how much can be shared with the larger grid.”

Says Navid Rahbari-Asr, a Ph.D. student at the University and lead author of the paper: “Our approach taps into the computational resources of each energy device.”

Each device communicates with it’s neighbours, calculating and scheduling how much energy it will need to store, how much can be added to the grid and when the power will need to be drawn from the grid.

“Collectively, this distributed technique can determine the optimal schedule for the entire grid,” Rahbari-Asr says.

The authors of the paper says that this concept will additionally protect the privacy of prosumers and other generators, as energy production, storage and consumption data is not shared with a central control centre.

According to NC State, the technology has been validated in simulations, and the researchers are in the process of implementing it in an experimental smart grid system at the National Science Foundation FREEDM Systems Center on NC State’s campus.

Read the full paper below:

“Cooperative Distributed Scheduling for Storage Devices in Microgrids using Dynamic KKT Multipliers and Consensus Networks”

Authors: Navid Rahbari-Asr, Yuan Zhang and Mo-Yuen Chow, North Carolina State University

Presented: 2015 IEEE Power & Energy Society General Meeting, July 26-30, Denver, Colo.

Abstract: Scheduling of storage devices in microgrids with multiple renewable energy resources is crucial for their optimal and reliable operation. With proper scheduling, the storage devices can capture the energy when the renewable generation is high and utility energy price is low, and release it when the demand is high or utility energy price is expensive. This scheduling is a multi-step optimization problem where different time-steps are dependent on each other. Conventionally, this problem is solved centrally. The central controller should have access to the real-time states of the system as well as the predicted load and renewable generation information. It should also have the capability to send dispatch commands to each storage device. However, as the number of devices increases, the centralized approach would not be scalable and will be vulnerable to single point of failure. Combining the idea of dynamic KKT multipliers with consensus networks, this paper introduces a novel algorithm that can optimally schedule the storage devices in a microgrid solely through peer-to-peer coordination of devices with their neighbors without using a central controller.

Picture credit: Noveda