Now showing 1 - 2 of 2
  • Publication
    Modelling demand response with process models and energy systems models: Potential applications for wastewater treatment within the energy-water nexus
    A promising tool to achieve more flexibility within power systems is demand response (DR). End users in many strands of industry have been subject to research regarding the opportunities for implementing DR programmes. We review recent DR modelling approaches in the realm of energy systems models and industrial process models. We find that existing models over- or underestimate the available DR potential from an industrial end user for two main reasons. First, the interaction between power system operation and industrial process operation caused by DR is not taken into account. Second, models abstract from critical physical process constraints affecting the DR potential. To illustrate this, we discuss the wastewater treatment process as one industrial end user within the energy-water nexus, for which the lack of suitable modelling tools is affecting the accurate assessment of the DR potential. Case studies indicate the potential for wastewater treatment plants to provide DR, but no study acknowledges the endogeneity of energy prices which arises from a large-scale utilisation of DR. Therefore, we propose an integrated modelling approach, combining energy system optimisation with the level of operational detail in process simulation models. This will yield a higher level of accuracy regarding the assessment of DR potential from a specific process, such as wastewater treatment.
      35Scopus© Citations 47
  • Publication
    Water-Energy Nexus: Analysing the energy-for-water relationship in integrated energy systems
    (University College Dublin. School of Chemical and Bioprocess Engineering, 2022) ;
    The volatility of renewable energies poses challenges to power system reliability and calls for more flexible electricity resources, both on the supply and the demand side. Energy-intensive water services such as wastewater treatment offer great demand flexibility potential in that regard. However, current demand response modelling approaches are insufficient for assessing this potential accurately. This study aims to fill the knowledge gap in industrial demand response modelling by introducing an integrated energy-water system model, which takes into account the constraints of the wastewater treatment process on power system scheduling in a joint system dispatch problem. The model is applied to a case study of the Irish wastewater treatment sector and power system. The objective of this study is to identify the benefits of energy demand and supply flexibility of wastewater treatment plants for power system operation, wastewater treatment operators and electricity consumers. The findings indicate that the wastewater treatment sector can be a valuable demand response resource for the power system. Wastewater treatment operators, electricity consumers and power system operators benefit from more flexible electricity demand from wastewater treatment plants, even in the presence of other flexibility measures in the system. Furthermore, it decreases the carbon intensity of domestic power generation. There is also a benefit for the power system operator in harnessing the flexibility of demand response and biogas production simultaneously. However, this can result in temporarily high electricity prices in the model, leading to increased electricity costs for consumer and wastewater treatment plants. Two main conclusions can be drawn from the findings of this study. First, wastewater treatment plants have untapped potential for demand response and utilising it for power system flexibility benefits wastewater treatment operators, electricity consumers and power system operators. The results inform policy makers on how to evaluate and support the electricity demand and supply flexibility of wastewater treatment plants. Given the benefits and minimal capital costs, policy makers should incentivise WWTP operators to tap into this readily available flexibility potential. Further, policy makers should carefully select the appropriate support schemes. In particular, smart demand response schemes should take into account possible interactions with electricity supply flexibility from biogas generation. Second, including wastewater treatment constraints in the system dispatch problem is crucial in order to estimate the flexibility potential accurately and uncover bottlenecks, which would probably be concealed by a black-box approach. Thus, this study provides a valuable case study for investigating the demand response potential of highly complex industrial processes, such as wastewater treatment.