Michael Zachar

Microgrid/Macrogrid Energy Exchange: A Novel Market Structure and Stochastic Scheduling

This paper explores the stochastic scheduling of microgrids where energy exchange with the macrogrid must be coordinated ahead of time. In particular, a market structure is proposed in which microgrid operators make day-ahead energy exchange commitments. Microgrids are fined for deviating too far from commitments and a maximum difference between commitments in subsequent hours is enforced. These constraints are included to reduce the burden placed on the macrogrid by distributed generation. Under this market structure, a scheduling problem is formulated for a microgrid system consisting of microturbines, a photovoltaic array, a battery bank, and a bi-directional connection to the macrogrid. Chance-constrained optimization is used to minimize operational cost and ensure the energy exchange commitments are met. The problem is transformed into a mixed integer linear program, and is solved to show that these commitments can be satisfied with a high level of certainty and to illustrate inherent tradeoffs between microgrid performance and level of regulation.

Policy effects on microgrid economics, technology selection, and environmental impact

Abstract This paper deals with the impact of policy decisions on optimal microgrid design. A generic system is considered consisting of solar photovoltaics, wind turbine, microturbines, electric boiler, gas-fired boiler, and a battery bank. The microgrid is grid-connected and designed to supply both heat and power. An optimal design is found to minimize the cost of energy supply over a 20 year lifespan. The optimal design is analyzed under a variety of policy scenarios such as emission taxation, emission reduction, and minimum system autonomy.

Dynamic Real-Time Optimization of Microgrids with Day-Ahead Commitments for External Power Exchange

Abstract This paper explores the stochastic scheduling of microgrids where energy exchange with the macrogrid is constrained by day-ahead commitments. These constraints are included to reduce the added cost to distribution system operators, associated with the integration and operation of behind-the-meter generation. Chance-constrained optimization is used to minimize operational cost and meet the energy exchange commitments. The problem is transformed into a mixed integer linear program, and is used to analyze the impact of risk aversion on microgrid operating cost and renewables curtailment.