Tamara Knittel

Topic

Mitigating variability of energy demand and supply in highly decarbonized energy systems

Department of Mechanical Engineering

Date & location

• Tuesday, April 9, 2024

• 11:00 A.M.

• Engineering Office Wing

• Room 106 and Virtual

Reviewers

Supervisory Committee

• Dr. Andrew Rowe, Department of Mechanical Engineering, University of Victoria (Co-Supervisor)

• Dr. Peter Wild, Department of Mechanical Engineering, UVic (Co-Supervisor)

• Dr. Madeleine McPherson, Department of Civil Engineering, UVic (Outside Member) 

External Examiner

• Dr. Rupp Carriveau, Civil and Environmental Engineering, Windsor University 

Chair of Oral Examination

• Dr. Justin Albert, Department of Physics and Astronomy, UVic

   

Abstract

Transitioning towards sustainable energy systems requires elimination of greenhouse gas emissions associated with end-use energy demands and electricity generation. Electrification of end-use demands that traditionally use fossil fuels and expanding variable renewable energy generation are considered key strategies in achieving emission reduction targets. This dissertation investigates end-use electrification and renewable supply impacts on future electricity system infrastructure. Three studies analyze demand- and supply-side transition options in the province of British Columbia, Canada.

The first study investigates building heat electrification impacts on capacity and flexibility requirements of the electricity grid. Energy demands are projected for 2050 considering variations in building stock evolution, building code implementation strategies, and building envelope efficiency improvements. Varying shares of heat pump penetration rates can be applied using hourly temperature-dependent COP profiles. This study examines the shape and magnitude of peak electricity demands and ramping requirements for electrified heating by computing regional end-use energy demand profiles for space and water heat in British Columbia’s residential and commercial building sectors. Results show that with an emphasis on building stock improvements, 90% heat pump penetration leads to an increase in electrical energy of 6% despite an annual population growth rate of 1.1%. The impact of high heat pump penetration rates on capacity requirements is significantly larger, with an increase of 37% in peak electricity demand for a 90% heat pump penetration rate. However, results of this study show that building energy codes and retrofit rates contribute relatively little to achieving net-zero emissions in the building sector.

The second study provides a more comprehensive analysis of end-use electrification by combining the electrification of building heat with electrification of space cooling and road transportation to examine changes in capacity and flexibility requirements in British Columbia. Two high-resolution spatiotemporal demand simulation models are introduced that project electricity load curves for electrified end-uses in the building and road transportation sectors. Electric vehicle charging and space heating control are introduced as demand-side management strategies to examine the effect of load reduction and load shifting on capacity and flexibility requirements. In this work, building demands are modelled in hourly resolution and transportation demands are modelled in 15-minute time-steps. The shape and magnitude of peak electricity demands, range of electric loads, and ramping requirements are examined for a simultaneous electrification of 10 end-uses in varying temporal resolution. Results show that capacity and flexibility requirements increase by up to 93% and 320%, respectively, where future ramping requirements are largely driven by electrification of road transportation. Utilizing electric vehicle charging and space heating control decreases capacity and flexibility requirements by 19% and 238%, respectively, while shifting the timing of the peak event to early morning hours. Temporal resolution of demand models is an important determinant of flexibility requirements, leading to an increase of 520% when changing from an hourly to a 15-minute resolution.

The third study assesses strategies to increase operational flexibility in British Columbia’s energy system by 2050 where building heating, cooling, and road transportation is electrified using a portfolio of renewable energy sources. Future net load which is defined as the difference between electricity demand and variable renewable energy generation is determined to investigate dispatchable generation requirements. The study examines net load for installed wind and solar capacities up to 50 GW for three wind penetration rates. Three water supply scenarios are tested to identify changes in net load due to drought conditions and increased precipitation impacting hydroelectric power generation, an important consideration in hydro-dominant electricity systems. A one-year production cost model is used to quantify surplus energy and energy deficiency for a range of variable renewable supply scenarios. Results show that peak net load in 2050 will exceed present-day peak electricity demand in British Columbia, when building and road transportation end-uses are electrified, thereby necessitating built-out of variable renewable energy generation capacity. Individual hours of energy deficiency can be avoided with demand side management or import of electricity from neighbouring systems. For an installed capacity of 30 GW, energy storage with a duration of 5 hours would enable system operators to manage most deficiency periods for all supply scenarios. A combination of large-scale built-out of variable renewable energy generation and short-duration energy storage can increase operational flexibility to meet growing electricity demand in 2050 after end-use electrification of building heating, cooling, and road transportation.