Cost-effective and optimal pathways to selecting building microgrid components – The resilient, reliable, and flexible energy system under changing climate conditions

Abstract

• The levelized cost of electricity (LCOE) is around A$0.17/kWh with DG and around A$0.20/kWh without DG across climate scenarios. • The building microgrid without DG demonstrates a robust reliability, with approximately 10% more probability of surviving outages than the microgrid with DG. • For outages lasting more than 4 h, the probability of surviving outages increases at additional costs. The LCOE increases by almost 45% for outages lasting up to 8 h and nearly 85% for up to 12 h. • The simulated probability of having less than average grid purchase and the probability of having more than average grid sales drop between 2030 and 2050. • Multiple demand response events in a year (up to five) increase the building’s ability to provide grid services when necessary and as agreed with the electricity retailers. Amidst the changing climate conditions, electricity retailers-led demand response programs and the emergency backup power for possible grid outages are often discussed in isolation, although several underlying linkages exist, which are important for how the existing building stock evolves with the energy transition. This study navigates through the linkages while investigating the levelized cost of electricity (LCOE)-based building microgrid components and undertakes a comparative analysis of energy optimisation models with and without emergency diesel generators. It also examines the building energy system’s resilience, reliability, and flexibility by using OpenStudio and HOMER Grid to develop energy simulation and optimisation models and other probabilistic models for a chosen building archetype in Sydney, Australia. This study finds that excluding the emergency diesel generator will require a larger battery storage system, increasing LCOE from A$0.17/kWh to A$0.20/kWh across climate scenarios. However, the larger battery storage system increases the probability of surviving outages (> 4 h) by around 10 % across climate scenarios. The LCOE increases up to 45 % for outages up to 8 h across climate scenarios and up to 85 % for outages up to 12 h. Additionally, for the building archetype, the probability of grid purchase (below the current average) is 0.78 in 2030, which drops to 0.55 in 2050. The probability of grid sales (above the current average) also drops from 0.69 to 0.46. Thus, while the narratives around the building energy system’s flexibility overstate the electricity exchange between the building and the grid, this study finds that increasing the on-site production utilisation rate and larger battery throughput contributes to demand response application and flexibility.

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