A Technical and Techno-economic Case for Intermittent Renewable Energy Generation to Participate in Spinning Reserve Ancillary Service Markets

A Technical and Techno-economic Case for Intermittent Renewable Energy Generation to Participate in Spinning Reserve Ancillary Service Markets

Power system networks around the world are experiencing very high growth rates of intermittent renewable power generation penetration. While this has yielded significant benefits associated with emission reduction to curtail greenhouse gases, it has come with a raft of technical challenges for power networks. One of the challenges is the difficulty to maintain power generation supply and network demand balance due to the fluctuating nature of intermittent generation sources and loads. Voluntary and involuntary curtailment of intermittent renewable generation is increasing due to oversupply during certain electricity market trading intervals. Elevated penetration of intermittent renewable generation has also increased requirements for ancillary services due to increased ramp rates and uncertainty of generation availability. There has been an increased demand of power system flexibility services and spinning reserve requirements to ensure that power system security and reliability are maintained within grid code requirements. Intermittent renewable generation is still not accepted to participate in flexible and spinning reserve ancillary service markets due to its inability to guarantee a firm active power supply in the event of a generation contingency event.
This thesis proposes a novel operational philosophy and control strategy to enable intermittent renewable generation to meet the technical requirements of spinning reserve ancillary service markets. The application of the developed operational philosophy and control strategy is for periods when intermittent renewable generation is curtailed and the excess energy cannot be captured by available energy storage capacity. The proposed control strategy applies de-loading control techniques on intermittent renewable energy generation and relies on a collocated energy storage device to firm the primary active power response when the renewable resource is inadequate during frequency excursions events or generation contingencies. The intermittent renewable generator and the collocated storage device are operated under a common control scheme to monitor and manage overall system active power responses.
A test system has been developed in the MATLAB based Simscape environment to demonstrate the efficacy of the proposed control strategy. Power system simulation results show that curtailed intermittent renewable generation can be reliably used as fast response virtual energy storage for frequency ancillary 1 services when supported by firming energy storage. A techno-economic assessment of the proposed novel operational philosophy and control strategy has been completed. The techno-economic assessments shows that the proposed system is economically viable. The techno-economic assessment studies were competed using the System Advisor Model (SAM) software.
The main conclusion of this thesis is that intermittent renewable generation can be successfully firmed to meet the operating requirements of spinning reserve markets and that it can be operated in those markets in an economically viable manner.

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