In the Nordic countries, seasonal variations limit the use of solar energy due to a mismatch between energy supply and demand. As the expansion of solar technology installation, especially photovoltaics (PV), evaluating multiple solar energy production systems in combination with storage systems, including both heat and electricity demand, is of particular interest for large industry and business parks. This study aims to assess the matching of solar energy supply with the local community’s power and heat demands of a business park consisting of warehouses. Various installation coverage of rooftop PV panels and solar Thermal (ST) systems, combined with thermal energy storage (TES) of different sizes, have been evaluated. The input data includes roof area, solar irradiation, PV power production from an existing system, electricity (annual amount 1.41 GWh), and heat (annual amount 6.58 GWh) demand profiles, as well as district heating distribution and ambient temperatures. Key technical parameters analyzed are the self-Consumption (SC) and self-Sufficiency (SS) ratios, evaluated for electricity, heat, as well as the overall energy system (i.e., the combined electricity and heat). Additionally, excess and imported electricity, energy balance, and waste heat are estimated. The results show that a significant portion of the produced heat is wasted, while surplus PV electricity can be exported to the grid, generating some economic value. The currently assumed TES capacity (70 MWh) is insufficient to store the total excess heat, leading to poor SC and SS ratios. Overall, the TES required to reach high self-sufficiency should be large in size, which in fact is infeasible, while smaller storage does not make a noticeable impact. Moreover, achieving a zero-waste heat and a complete heat SC scenario with a 70 MWh TES capacity would require allocating 7% installation coverage of the roof area to ST (equivalent to 1.2 MW). Concurrently, the PV system will cover 48% installation coverage of the roof area due to the power point of connection limit (equivalent to 1.4 MW). Therefore, leaving unutilized area could be an advantageous solution for the future, when TES or the power point of connection capacity is expanded or excess thermal energy is utilized. Future research could focus on a techno-economic assessment to determine the optimal system size by balancing economic and technical metrics, potentially including other energy storage or boiler technologies.
Koubar et al. (Sun,) studied this question.