As shown in Figure 1, the prediction of electricity generation varies depending on the system types and the variables incorporated into the prediction models. In practice, resource-specific generation forecasts are typically embedded within broader electricity system planning and operational models, such as capacity expansion models, or resource adequacy plannings. Within these models, varying levels of simplification may be applied to represent resource availability and climate sensitivity, depending on the planning objective and model configuration. Furthermore, realized generation from each resource type is influenced not only by climate conditions, but also by system demand, which may itself be climate-sensitive, the existing resource portfolio, operational constraints, and economic factors. The following subsections outline resource-specific approaches used to estimate generation potential under future climate scenarios, recognizing that these estimates are subsequently integrated within system-level models to determine dispatch, adequacy, and long-term planning outcomes.
In general, downscaled and bias-corrected climate variables (e.g., precipitation and temperatures) from different scenarios are forced into hydrologic models to investigate the hydrologic regime and to generate future flow conditions. These flows are then used as input to hydropower potential estimation models. The distribution of the estimated electricity can then be compared with the historical observation to analyze the impact of climate change on generation. In literature, a range of hydropower generation potential models or methods have been used, including empirical formula (@ Parkinson2015), reservoir optimization algorithm-Sampling Stochastic Dynamic Programming (SSDP) (Haguma et al. (2014)), WEAP (Boehlert et al. (2016)) and MODSIM (Kim et al. (2022)). One representative example of an empirical method is represented by equation 1.
\[
E = \rho g h Q
\tag{1}\]
In equation 1, \(E\) is the hydropower potential with projected streamflow \(Q\) at a hydraulic head \(h\), \(p\) and \(g\) are the density of water and gravitational acceleration.
Reservoir optimization algorithms (ROAs) are used to determine operation rules or policies that include an average release from hydropower dams and energy production. The projected inflow simulations from the hydrologic model are fed to the ROA to determine operating policies under future climatic conditions obtained from different emission scenarios. Then they are compared with the baseline period policy in order to determine the impact of climate change on hydropower generation.
In addition to ROAs, network-based water management models such as MODSIM can also be used to estimate hydropower generation. This model has an internal optimization operator that can allocate water based on physical and operational constraints. The inflow projection from hydrologic models is used as forcing for this MODSIM model to determine the hydropower generation potential for the future period and compared with the historical baseline period to identify the changes due to climate variability.
The impact of climate change on future wind energy generation is generally estimated based on the operational wind speed at hub height. Under different emission scenarios (e.g., RCP8.5), future projections for wind speed at 10 m height above surface level are obtained from climate models (e.g., GCMs and RCMs) (Yao et al. (2012), Zhang et al. (2022), Li (2023)). For wind turbine design, cut-in and cut-out wind speeds at hub height play a crucial role. Typical cut-in wind speeds for utility-scale turbines are approximately 3-4 m/s, while cut-out speeds generally range between 20 and 25 m/s, depending on turbine design and site conditions. Based on the design criteria, common hub heights vary from 50 m to 120 m, however, the average hub height in Canada is 83 m (CWTD (2022)). The wind speed at hub height can be estimated using the following power-law relation (Equation 2) (Yao et al. (2012), Zhang et al. (2022), Plaga & Bertsch (2023), Li (2023)). Alternatively, some reanalysis products and climate models archive wind speeds at various vertical levels.
\[
\frac{V_H}{V_{10}} = \left( \frac{Z_H}{Z_{10}} \right)^{\alpha}
\tag{2}\]
In equation 2, \(V_H\) is the wind speed at hub height \(H\) (\(Z_H\)), and \(V_10\) is the wind speed at 10 m height (\(Z_10\)). The exponent \(α\) varies with the topographic terrain conditions, codes, and standards. For a natural, stable terrain profile, the \(α\) value is 0.14 (Yao et al. (2012), Plaga & Bertsch (2023), Li (2023)). The wind speed at hub height is then converted to wind energy by multiplying it by the wind energy density (Li (2023)).
\[
W_E = \frac{1}{2} \rho A V_H^3 C_p
\tag{3}\]
In equation 3, \(W_E\) is the wind energy, ρ is the air density at hub height that varies with the temperature and wind profile, A is the cross-sectional area, and \(C_p\) is the power coefficient. For climate change impact analysis, \(W_E\) is simulated at each grid point or station, and then trend analysis is conducted. The t-test or the Mann-Kendell approach can be used for trend detection. In their study, Li (Li (2023)) utilized a t-test using a linear regression for trend detection. Another study (Yao et al. (2012)) used the Weibull distribution for comparing wind production in the future period under different scenarios with reference to the period. High-resolution meteorological datasets can also serve as useful inputs for climate-informed wind generation forecasting. Numerical weather prediction-based datasets provide multi-decadal wind speed that can support the development of wind generation profiles (Bracken et al. (2023)). These datasets are recommended for power system planning studies that require detailed weather inputs for renewable generation modelling (Group (2023)).
Generally, photovoltaic (PV) solar cells are used for electricity (energy) generation. The generation capacity of PV can be expressed with the empirical formula (equation 4), consisting of solar radiation and temperature as independent variables (Zhang et al. (2022)). Therefore, two key climate variables, such as surface shortwave radiation (SSWR) and near-surface air temperature (NSAT), can be used for the impact analysis of solar energy. The radiation impinging on each solar station is represented by SSWR, and the solar station’s ambient temperature is predicted from NSAT. Using historical data of these two variables, solar energy generation curves are produced by applying equations 4 and 5. Similar curves are developed for future projections and compared with the reference one developed with historical period data for impact analysis due to climate change.
\[
C_F=(\\frac{S_1}{S_2} )[1+λ_T (T_1-T_2)]
\tag{4}\]
\[
S_E=I_C.C_F.∆_τ
\tag{5}\]
In equations 4 and 5, \(C_F\) is the hourly capacity factor of the solar station, \(S_1\) and \(S_2\) are the solar radiation at the location of the solar station and under standard test conditions (ideal 1000 \(W/m^2\)), respectively. \(T_1\) and \(T_2\) are the temperatures at the location of the solar station and under standard test conditions, respectively, and \(λ_T\) is the temperature coefficient (ideally negative). \(S_E\) represents solar energy, \(I_C\) is the installed capacity of the station, and \(Δτ\) is the hours of period \(τ\). Similar to the wind energy, high-resolution meteorological datasets can be used as inputs for solar generation forecasting. WRF-based datasets and related products provide long-term irradiance fields, including variables such as global horizontal irradiance and direct normal irradiance (Bracken et al. (2023)). Such datasets can support photovoltaic generation modelling in power system planning studies that incorporate weather and climate variability (Group (2023)).
- Thermal Energy (Nuclear, Natural Gas, Coal, and Biofuel)
Thermal energy encompasses the production of electricity by converting heat into power using nuclear, natural gas, coal, and biofuel sources. The impact of climate change on thermal energy production depends on the cooling systems used by each generation type. Typically, water and air flow (dry cooling) are used to cool down the generator. Therefore, water availability, water temperature, humidity, air pressure, and air temperature play a key role in the performance of thermal power plants efficiency, affecting both efficiency and operational capability(Lagacé (2021)). Thermal power plants are generally designed to operate within specific temperature ranges, and extreme temperatures may reduce efficiency, cause derating, or limit unit availability (EPRI (2026)). Usually, two types of investigation are conducted to determine the impact of climate change on thermal energy systems: 1) regression analysis assuming linear dependency between air and water temperature, and 2) hydrologic modeling to calculate available water for cooling systems (Plaga & Bertsch (2023)).
In a study, Lagace (Lagacé (2021)) applied regression models to estimate climate impacts on thermal energy systems in Ontario. The models estimate the derated capacity of thermal systems, including those with recirculating cooling, dry cooling, once-through cooling, and combustion. These models are based on the air temperature, wet bulb air temperature, relative humidity, and air pressure, and were proposed by Bartos et al. (Bartos & Chester (2015)), Henry and Pratson (Henry & Pratson (2019)), and Craig et al. (Craig et al. (2020)). Like hydropower generation, hydrologic models are forced with future climate scenarios to simulate water flow. Then, the water management model (WMM) is applied to estimate the availability of cooling water under changing climatic conditions. To apply the WMM, a linear relationship is assumed between the available water and the water requirement for the plant’s cooling (Plaga & Bertsch (2023)).