Renewable Energy Sources: From Non-Dispatchable to Dispatchable, and Their Application for Power System Carbon Neutrality Considering System Reliability

Abstract

The trend of integrating renewable energy sources (RES) into power systems to mitigate the impacts of global warming is significantly increasing. However, the variability and intermittency of these energy sources can weaken the reliability of the power system. In response to these challenges, one solution to enhancing the resilience of the power system is to implement microgrids tailored to the demand characteristics of each region. This paper evaluates the load supply reliability (LSR) and cost of energy (COE) of non-dispatchable generators (NDG) such as wind and solar, proposes a method to calculate the required battery energy storage system (BESS) capacity and COE to achieve the desired LSR to transform NDG into dispatchable generator (DPG). Furthermore, by comparing the COE of RES-based DPG with the COE of a diesel generator, considering carbon emission prices, it indicates the extent to which PV and wind DPGs can replace diesel generators. Applying this method to Jeju Island, the results show that the LSR of NDGs is limited to 39.9–58% for PV and 67.3–70.0% for wind. However, when transformed into DPGs with a 85% LSR, the required BESS capacity is estimated to be 3.1–4.3 h for PV and 0.5–0.7 h for wind. Also, at a $150/ton CO₂ price, PV-DPG can achieve 86–89% LSR, and wind-DPG can exhibit price competitiveness to diesel generator. Additionally, the research findings can be applied to the reliability service transaction mechanism between microgrids with a certain reliability level and between microgrids and bulk power systems.