Julian Florez
Research Mentor(s): Michael Craig, PhD
School for Environment and Sustainability
Presentation Date: Thursday, July 30, 2020 | Session 2 | Presenter: 7
Authors: Isaac Bromley-Dulfano, Julian Florez, Michael Craig
Abstract
This project seeks, first, to identify the potential contribution of wind and solar generators to power systems across the Western United States, and, second, to examine the geo-temporal relationships that drive the relative value of generators in different regions. Capacity values quantify the reliable contribution of a generator toward meeting system demand and improving overall system adequacy. This allows for an informed transition from conventional, fossil-fuel to renewable systems while maintaining reliability. We develop a model for estimating capacity values of variable renewable energy generators as their effective load-carrying capability (ELCC), defined as the additional load that can be met at the same reliability level by added renewable capacity. We use NASA reanalysis data to generate photovoltaic (PV) and wind generation profiles across the region of interest. Our model uses the sequential Monte-Carlo, state-sampling method to simulate generator outages, while also accounting for existing renewable energy plants, energy imports and exports, and storage operations. We use three years of historical load data to identify loss of load events and measure reliability for a given system. Our results are oncoming, though initial tests indicate that the capacity values of low-penetration PV plants in the Western United States range from 0-30%, significantly lower than those found in previous studies. These low values are driven by the misalignment of peak PV output and peak load, occurring at mid-day and late afternoon, respectively. However, the values of these plants are highly dependent on the year evaluated, and the system to which they contribute. For example, we find that PV plants further west (California) have higher capacity values, on average, because they benefit not only from significant solar irradiation, but also from improved alignment with eastern load profiles, such is Pacificorp East, which serves Utah and Wyoming. Conversely, a PV plant in Albuquerque, while situated in a high solar potential location, cannot serve much, if any, additional load in the California ISO system because peak PV output in Albuquerque occurs much earlier in the day than peak load in California, a problem amplified by the change in time zone. These results, while still preliminary, display the challenges of building a high-penetration renewable energy system. The low capacity values of PV plants reaffirm the need for storage, demand response, and improved transmission networks to confront those challenges. It should be reiterated that these results and conclusions are not complete.
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Research Disciplines
Environmental Studies, Engineering