• Energy Research

Climate trends suggest an increase in the frequency of intense rainfall events and the aggravation of existing conditions in terms of flooding in urban areas. In coastal areas, conditions are aggravated by coexistence with coastal overtopping. Flood risk control is complex, and the interdependencies among the services and sectors in urban areas imply the need for adoption of approaches that embrace the interplay between service providers to ensure critical urban functions. Flooding incorporates several hazards. Assessment of resilience to multiple hazards in complex environments benefits from integrated and multi-sectoral approaches. A common constraint resides in the limited data and tools available for undertaking these complex assessments. This paper proposes a risk-based methodology to assess urban areas’ resilience to flooding by addressing sectors’ interdependencies in a context of limited data and ready-to-use tools. Multisector flood risk identification is pursued with the support of a geographic information system and is applied to Lisbon with a focus on the cascading effects of drainage system failures on buildings, populations, mobility, waste management, and electricity supply. The results demonstrate the potential for combining data and knowledge from different sources with dual modelling approaches, thus allowing one to obtain trends of exposure and vulnerability to flooding for current and climate change scenarios. This methodology facilitates dialogue among stakeholders and decision levels by contributing to capacity building, and it contributes to sustainable development.

AbstractThis paper presents the application of multi-criteria decision analysis to select the best energy efficient option for a water supply system. The case study is a part of the Multi-Municipal Water Supply System (MMWSS) for the Algarve region in Portugal. There is a micro-hydropower plant installed in one of the two water treatment plants. The system has two operating schemes due to the seasonality of tourism: one for the high season from June to September; and the other one for the low season from October to May. The aim of the analysis is to compare the energy efficiency of the system for the two operating schemes and for different demands. Energy audits (i.e., hydraulic energy balance along the pipe system) are carried out for each option (pair operating scheme – demand). Different energy efficiency metrics are calculated and two different multi-criteria analysis methods are used and compared to rank the options. Results obtained are discussed and the main conclusions are presented.

The current paper presents criteria and performance measures for the assessment of the effectiveness of energy management processes in water supply systems. The main objectives that motivate the implementation of energy management strategies are identified, assessment criteria for each objective and the corresponding performance indicators to be used are recommended. Novel performance indices for evaluating energy efficiency are presented and applied to a real-life water supply system for different consumption scenarios and operating schemes. Results obtained are discussed. The current paper presents criteria and performance measures for the assessment of the effectiveness of energy management processes in water supply systems. Energy consumption costs, together with the manpower costs, represent a significant part of operating costs of the water supply utilities. The efficient use of energy is, therefore, critical for the global economic efficiency of utilities. Additionally, it has an increasing environmental importance in order to reduce the CO2 emissions. The implementation of projects aiming at the optimization of energy resources and costs, by reducing energy losses, reducing peak electric consumption and minimizing the environmental emissions footprint is, therefore, increasingly more common among water utilities. Assessing the efficiency of energy use is important to

According to the United Nations, by 2030, 60% of the world’s population will live in cities, and 70% by 2050. Both consolidated and fast urbanizing areas face diverse acute shocks from natural disasters and long-term stresses, such as the effects of climate change. Therefore, there is a need for cities to implement plans for increasing resilience and improving preparedness to cope with both acute shocks and long-term stresses. Development of resilience action plans (RAP) constitutes an important process for the cities to plan their resilience enhancement in the long, medium, and short terms. These are key tools for the city, considering the associated complexity, uncertainties, data scarcity, interdependencies among urban services provided in the city, as well as involved stakeholders. Herein, a framework is presented to support city resilience action planning related to climate change through a multisector approach. The framework was applied step by step to three cities—Barcelona, Bristol, and Lisbon—and their RAPs to climate change provide roadmaps for resilience, having the urban water cycle as the core. In these plans, urban services are included, given their interactions and contributions to city’s resilience. Addressed services are water supply, wastewater, storm water, waste, electric energy, and mobility.

This paper presents and discusses the application of a novel energy balance scheme for assessing energy efficiency in wastewater systems. The energy balance is demonstrated with a Portuguese real-life case study, using mathematical modelling to estimate the different energy components and to compute two energy efficiency indices. The total inflow intrinsic energy can represent a significant amount (>95%) of the total energy used in systems mainly composed of gravity sewers. The total input energy is significantly (four-times) higher in the wet season than in the dry season, mostly due to undue inflows (e.g., direct rainfall and infiltration). The potential for energy recovery strongly depends on the available head and flow rate at the delivery point, being 0.01 kWh/m3 in the current case, with a project payback period of 4 years. The energy balance components and the respective energy efficiency indices strongly depend on the considered reference elevation. Thus, a unique regional reference elevation is recommended in the calculations.

Performance assessment is essential to effectively evaluate and monitor the activity of water utilities, support decision making, and encourage continuous improvement. Performance assessment systems (PAS), covering several service objectives and criteria, have been successfully applied in water supply and wastewater systems. Tailored approaches focusing on the assessment of the energy use and efficiency in wastewater systems are still limited. This paper aims at the development and demonstration of a comprehensive PAS for energy efficiency, tailored for wastewater systems, incorporating criteria related to energy consumption, operation and maintenance (O&M) costs, and environmental impacts, such as untreated discharges and greenhouse gases emissions, among others. Management and control of excessive or undue inflows to these systems is specifically addressed by several novel criteria and metrics. The proposed PAS should be adapted by each utility to be aligned with the objectives of the organisation and with the implemented asset management strategy. The proposed approach and the resulting consolidated PAS are thoroughly described. Results from the application of the PAS to several Portuguese utilities are discussed. This PAS aims at contributing to a reliable and replicable process to assess energy efficiency in wastewater systems and to encourage a more rational energy management.

The effects of climate dynamics on urban areas involve the aggravation of existing conditions and the potential for emergence of new hazards or risk factors. Floods are recognized as a leading source of consequences to society, including disruption of critical functions in urban areas, and to the environment. Consideration of the interplay between services providers ensuring urban functions is essential to deal with climate dynamics and associated risks. Assessment of resilience to multiple hazards requires integrated and multi-sectoral approaches embracing each strategic urban sector and interactions between them. A common limitation resides in the limited data and tools available for undertaking these complex assessments. The paper proposes a methodology to undertake the spatial characterization of the flood related hazards and exposure of both essential functions and services providers in urban areas, in the context of limitations in data and in ready-to-use tools. Results support the resilience assessment of these hazards, taking into account interdependencies and cascading effects. The approach is applied to Lisbon city as the study case. Results are promising in demonstrating the potential of combining data and knowledge from different sources with dual modelling approaches, allowing us to obtain trends on the magnitude of effects of climate scenarios and to assess potential benefits of adaptation strategies. Quantification of the effects is reached, but results need to be assessed together with the underlying levels of uncertainty. The methodology can facilitate dialogue among stakeholders and between different decision levels.