Reduced-Cost Energy Systems Through Optimization by Ana-Iulia Alexandrescu

Applications of operations research to the energy industry are more numerous than ever. From accounting for smart grid technology infrastructure costs in electricity generation expansion planning to reallocating current resources to decrease the operating costs of the power network, applications are plentiful. We've seen some great achievements through the Edelman Prize awarded to the Midwest Independent Transmission System Operator (MISO) team for the use of operations research to optimize the efficiency of the wholesale power market in the Midwest. Continuing on this trend, a joint venture at the Arizona State University (ASU) between the Departments of Electrical Engineering and Industrial Engineering is working on determining better ways to partition the reserve zones to ensure a high reliability for the grid, while awaiting for new technologies to enter the space of power generation.

In technical terms, reserves represent proxy reliability constraints where, although not necessarily ensuring reliability, they provide some flexibility and enable the system to get backed up with minimum disruptions. However, despite their crucial role in ensuring the good functioning of the power system, methods for determining what levels reserves should have and where geographically they should be located are still relatively simplistic. The ASU group is looking at the unit-commitment problem of scheduling generator operating times and output levels to determine where the reserves should be placed to ensure reliability while avoiding additional burden on the network.

Using a mixed-integer formulation, classic network flow models, and connectivity constraints within each zone, the group aims to reduce the computational complexity of stochastic unit commitment by decomposing the problem into two stages, with a deterministic phase followed by a stochastic analysis over multiple possible scenarios. Preliminary results using the IEEE Reliability Test System suggest some decrease in the cost of unreliability while clearly showing that enforcing connectivity within a zone is quite expensive.