Energy Reports (Nov 2023)
Impact of spatial and annual solar variability on the economic viability of non-tracking solar heating systems
Abstract
Solar energy is stochastic, varying with time and space, which is a risk factor hindering the deployment of solar heating systems (SHS) in industries. Little is known about the level of risk associated with SHS due to spatial and annual variation. This research thus seeks to quantify the level of risk due to spatial and annual weather variation. The novelty of the study is that it assesses the variability in energy production of different non-tracking SHS at different operating temperatures (60 and 100 °C), different locations, and different time series. The level of risk is quantified using the coefficient of variation (CV) and the z-score. The yearly energy gains are simulated for each collector using the solar collector energy output calculator. The weather data for each location is produced using Meteonorm for a typical meteorological year (TMY). To analyze the annual variability 3 TMYs were produced from the time range 1981–2020 and the spatial variation was analyzed for 9 different locations. In terms of the annual variation, the results show that the CV of the energy gain for all the SHS was between 13 and 26 %. The highest z-score for spatial energy variation was 1.6 and -1.9. Both results indicate a considerably low risk factor. Economic predictions considering 1 TMY showed an underestimation of 4 and 7 % on the levelized cost of heat (LCOH) when operating at 60 and 100 °C respectively. Furthermore, operating at high temperatures has a high variability risk compared to lower temperatures. In terms of the variability of each SHS the compound parabolic concentrator (CV-10) and evacuated tube collector (CV-11) are more stable compared to the solar air heater (CV-14) and flat plate collector (CV-18). Knowing the extent of variability and risk involved for each collector will help investors plan their entire portfolio.
