Energy Storage Systems for High PV Penetration: Utility Spatial Allocation and Customer Dispatch Strategies
Climate change mitigation motivates the transformation of the electric power sector towards a low carbon future. A successful and timely transformation depends on robust and independent methods for understanding benefits and impacts of the integration of renewable energy resources and energy storage technologies into the electric power system. Therefore the objectives of this dissertation are to investigate how energy storage technologies should be allocated and operated to mitigate the impacts of variable solar photovoltaic (PV) resources in distribution systems while providing economic incentives for storage owners, and to assess the indirect regional environmental impacts of economic energy storage operation.
The allocation of energy storage systems (ESSs) in distribution systems for voltage support under high penetration solar PV is investigated. A genetic algorithm based bi-level optimization method is developed that reduces the voltage fluctuations caused by PV penetration through deploying ESS among permitted nodes of a distribution system while accounting for their capital, land-of-use, and installation costs using a qualitative cost model.
A convex optimization based charge/discharge scheduling algorithm for distributed ESSs co-located with solar PV systems is developed. The daily charge/discharge schedules reduce (1) peak net demand (that is, load minus PV generation) of the customer, (2) power fluctuations in the customer net demand profile, and (3) the reliance of the customer on the grid by way of promoting self-consumption of local solar PV generation. Moreover, a novel idea of a "supply charge" tariff that incentivizes ESS customers to store excess solar PV generation that may otherwise result in reverse power flow in the distribution grid is investigated. Introduction of a supply charge successfully reduces the maximum solar PV power supply to the grid and does not financially impact ESS owners.
Finally, the economic and emissions effects of residential ESS operation for cost minimization in each of the eight regional electric reliability entities of the contiguous U.S. is investigated. It is observed that the overall economic performance and environmental impact of ESS varies considerably from region to region and is driven most by regional emissions and utility tariff structure. Results indicate that policy makers seeking emission reductions should carefully consider the interaction between emissions and rate structure in future orders for net metering and residential rate reform.