| dc.description.abstract | In the global push towards decarbonization, no sector has seen as resounding success than the power sector. The last 22 years have seen successive record-breaking additions to the global installed capacity of renewable energy generation. Wind and solar energy have seen dramatic advancements in technology and reductions in cost, and are now some of the most cost-effective form soft power generation on the market. Over the upcoming years the goal of an electrical grid dominated by renewable energy sources is predicted to become a reality. The shift away from traditional forms of power generation is not without its risks, however, and the promotion of grid stability in the face of an influx of variable and intermittent generators is increasingly important. Both wind and solar generation are, by the nature of their production, proneto sudden and significant changes in power output, which can have deleterious effects on the health of the electrical grid. The mitigation of these fluctuations of power, known as ramp rates, is an ongoing area of study in the energy engineering industry. One common solution is the use of energy storage systems (ESS) to ’smooth’ the power sent to the grid by charging or discharging during periods of high variability. Energy storage technology however still comes at a high cost, and for the integration of renewable energy to remain cost-competitive, it is necessary to explore how to lower the price of ramp rate enforcement. This thesis investigates the sizing and use of ESS in the enforcement of a set ramp rate limit for a grid system with multiple renewable energy generators. This study is based on the fact that the ramping behaviors of a series of generators will be different depending on where in the system the ramp rate is enforced, and so ESS storage, power and cost should be optimized to the architecture of the grid. Described within is the creation of an optimization model for the sizing of energy storage systems for the purpose of enforcing a ramp rate limit. Two case studies are developed, describing two possible use cases of energy storage in a grid with multiple renewable energy generators: with the ESS located at the substation and with the ESS co-located with generators. The optimization model is run for each of the case studies through several sets of model parameters, until a final set is defined. The final results are analysed for ESS installed capacities, dispatch and costs. Ananalysis of the final results returns a stark difference between the two case studies. By amalgamating the power flows from the four generators a significant amount of ramping violations were mitigated, and the centralized ESS was conservatively used throughout the modeled period. A lithium ion battery with a discharge rate of 1C is recommended to be located a the substation. The co-located units, compensating for a single generator each, underwent significantly higher amounts of dispatch and as such high cycle-life flywheels are recommended for this architecture. Overall the centralized architecture was shown to be a much more efficient method of ramp rate control, discharging a tenth of the energy than the total of the co-located storage systems for the same ramping performance. However additional considerations such local stability conditions and asset ownership must be considered before a recommendation can be made. |
