Distributed online algorithms for energy management in smart grids

The 21st-century electric power grid is transitioning from a centralized structure designed for bulk-power transfer to a distributed paradigm that integrates the variable renewable energy (VRE) resources spatially distributed across the grid. This work proposes algorithmic solutions for distributed economic dispatch based on Subgradient method and Alternating Direction Method of Multipliers (ADMM), both designed to be agnostic with any initialization vector. The proposed distributed online solutions leverage a dynamic average consensus algorithm to track the time-variant linearly coupled constraint that allows an abrupt change in power demand of the network because of the high penetration of VRE resources. The problems are modeled as discrete dynamic systems to investigate the stability and convergence of the algorithm. The update procedures are designed such that the iterates converge to the optimal solution of the original optimization problem, steered by the gain parameter corresponding to the second largest eigenvalue of the system matrix

Ramp Products in Real Time Markets for Low Carbon Resource Mix

With increased variable renewable generation and retirements of dispatchable thermal plants, net load variability and forecast error will increase. Many ISOs and RTOs have implemented or are considering implementing ramp products in their real-time markets to maintain both reliability and efficiency with the changing resource base. The design of any real-time market enhancement, however, must account for the fact that ISOs and RTOs use separate real-time engines for commitment, dispatch, and pricing. Depending on which engine is modified, there will be different impacts on reliability, system dynamics, system cost and prices. We present a rolling horizon simulation framework for the PJM Real-Time Market, consisting of a day-ahead model and real-time commitment, dispatch, and pricing engines that account for generator outages, net load variability and rolling short-term forecast error for a 2050 future capacity scenario. We compare the impacts across ramp product designs on system costs, reliability, prices, generation mix and generator revenues. We analyze the sensitivity of these results to the quantity of ramp product procured in the real-time commitment vs. dispatch and show that a balanced requirement added to both the commitment and dispatch engines provides the best performance across multiple metrics. </p