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Deep learning has been widely applied to automated leakage detection and location of natural gas pipe networks. Prevalent deep learning approaches do not consider the spatial dependency of sensors, which limits leakage detection performance. Graph deep learning is a promising alternative to prevailing approaches as it can model spatial dependency. However, the challenge of collecting real-world anomaly data for training limits the accuracy and robustness of currently used graph deep learning approaches. This study proposes a deep probabilistic graph neural network in which attention-based graph neural network is built to model spatial sensor dependency. Variational Bayesian inference is integrated to model the posterior distribution of sensor dependency so that the leakage can be localized. An urban natural gas pipe network experiment is employed to construct the benchmark dataset, in which normal time-series data is applied to develop our proposed model while anomaly leakage data is used for performance comparison between our model and other state-of-the-art models. The results demonstrate that our model exhibits competitive detection accuracy (AUC) = 0.9484, while the additional uncertainty interval provides more comprehensive leakage detection information compared to state-of-the-art deep learning models. In addition, our model's posterior distribution enhances the leakage localization with the accuracy of positioning (PAc) = 0.8, which is higher than that of other state-of-the-art graph deep learning models. This study provides a comprehensive and robust alternative for subsequent decision-making to mitigate natural gas leakage from pipe networks. ; Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. ; Safety and Security Science

Spatiotemporal energy interaction and sharing are promising solutions to penetrate renewable energy, enhance grid power stability, and improve regional energy flexibility. However, the current literature is restrained in a small-scale neighborhood level, without considering inter-city energy migration through spatiotemporal complementarity between renewable-abundant regions (like suburb or countryside areas) and demand-shortage regions (like city centers). In this study, the energy interaction boundary is extended from a neighborhood scale to an inter-city scale, to maximize the renewable energy penetration, demand coverage, and reduce regional energy imbalance. This study firstly proposes a holistic framework on inter-city transportation-based energy migration, consisting of a residential community with rooftop photovoltaic systems and electrical batteries, an office building, hydrogen vehicles (HVs), a hydrogen (H 2 ) station, and local power grids, for the energy transmission between building groups in spatially different regions through the daily commuting of HVs. Optimal grid-regulation strategies are thereafter proposed and adopted to stabilize the grid power and reduce energy costs. Parametric analysis on energy trading strategies and prices has been conducted, to improve the participation motivations of different stakeholders. Results indicate that, compared to the reference case with isolated buildings and vehicles, the transportation-based energy migration framework covers 23.2 % of the office energy demand and elevates the community's renewable self-use ratio from 72.7 % to 98.6 %. Meanwhile, the maximum grid-export power in the renewable-abundant region (suburb residential community) and the annual grid-import power in the demand-shortage region (city-center office) are reduced by up to 86.9 % (from 155.7 to 20.4 kW) and 29.4 % (from 49.0 to 34.6 kW), respectively. Moreover, even considering the fuel cell degradation cost of HVs, the transportation-based energy migration framework reduces the ...

The large thermal potentials with geothermal gradient of abandoned wells provide the possibility and opportunity for carbon-neutrality transition of district heating systems, whereas energy harvesting from abandoned geothermal wells is full of challenges, due to the considerable initial investment in economic cost, system performance degradation, and so on. In this chapter, a systematic and comprehensive review on the application techniques of abandoned wells is presented, in terms of advanced thermal/power conversions, renewable integrations for district heating, and strategies for performance enhancement. Discussions on real applications have been conducted and future prospects presented, from perspectives of lifetime system performance, techno-economic feasibility analysis, and potential assessment of abandoned wells for carbon-neutrality transition. The results of this chapter can provide preliminary knowledge and cutting-edge technologies on renewable integrations with abandoned wells, so as to demonstrate techno-economic-environmental potentials of abandoned wells and contributions toward carbon-neutrality transition.

Exploring alternative water sources and improving the efficiency of energy uses are crucial approaches to strengthening the water-energy securities and achieving carbon mitigations in sub(tropical) coastal cities. Seawater use for toilet flushing and district cooling systems is reportedly practical for achieving multiaspect benefits in Hong Kong. However, the currently followed practices are yet to be systematically evaluated for scale expansions and system adaptation in other coastal cities. The significance of using seawater to enhance local water-energy securities and carbon mitigations in urban areas remains unknown. Herein, we developed a high-resolution scheme to quantify the effects of the large-scale urban use of seawater on a city's reliance on non-local and non-natural water and energy supplies and its carbon mitigation goals. We applied the developed scheme in Hong Kong, Jeddah, and Miami to assess diverse climates and urban characteristics. The annual water and energy saving potentials were found to be 16-28% and 3-11% of the annual freshwater and electricity consumption, respectively. Life cycle carbon mitigations were accomplished in the compact cities of Hong Kong and Miami (2.3 and 4.6% of the cities' mitigation goals, respectively) but not in a sprawled city like Jeddah. Moreover, our results suggest that district-level decisions could result in optimal outcomes supporting seawater use in urban areas.

Ocean thermal and power energy systems are promising driving forces for seashore coastal communities to achieve net-zero energy/emission target, whereas energy planning and management on ocean thermal/power and distributed building integrated photovoltaic (BIPV) systems are critical, in terms of serving scale sizing and planning on geographical locations of district building community, and cycling aging of battery storages. However, the current literature provides insufficient studies on this topic. This study aims to address this research gap by transforming towards zero-energy coastal communities from the district level in subtropical regions, including centralised seawater-based chiller systems, distributed BIPVs and coastal oscillating water column technologies, as well as multi-directional Vehicle-to-Building energy interaction paradigms. Advanced energy management strategies were explored to enhance renewable penetration, import cost-saving, and deceleration of battery cycling aging, in response to relative renewable-to-demand difference, off-peak grid information with low price, and real-time battery cycling aging. Furthermore, in accordance with the power generation characteristic of two wave stations (i.e., Kau Yi Chau (KYC) and West Lamma Channel (WLC)) in Hong Kong, energy system planning and structural configurations of the coastal community were proposed and comparatively studied for the multi-criteria performance improvement. Research results showed that, compared to an air-cooled chiller, the water-cooled chiller with a much higher Coefficient of Performance (COP) will reduce the energy consumption of cooling systems, leading to a decrease in total electric demand from 134 to 126.5 kWh/m2·a. The scale for the net-zero energy district community with distributed BIPVs and oscillating water column was identified as 5 high-rise office buildings, 5 high-rise hotel buildings, 150 private cars and 120 public shuttle buses. Furthermore, the geographical location planning scheme on the Case 1 (office ...

Geothermal energy (GE), as an ideal renewable resource for building cooling/heating with stability and abundance in energy supply, has been widely exploited in developing countries. The common utilization forms of GE mainly include the ground source heat pump (GSHP), underground duct system (UDS), and abandoned wells energy (AWE) system. However, there is still a lack of comprehensive overview of the current developmental status of the GSHP, UDS, and AWE systems for building cooling/heating in developing countries. This chapter will be conducted from the following aspects: (1) The literature review and categories of GE utilization in the developing countries, mainly including the latest literature review on GE development and categories of utilization for building cooling/heating. (2) The common utilization of the GSHP system and its current application and development in the developing countries, mainly including the ground-coupled heat pump (GCHP) system and groundwater heat pump (GWHP) system. (3) The common utilization of the UDS system and its current application and development in the developing countries, mainly including the horizontal UDS system, vertical UDS system, and the corresponding coupled system with phase change energy storage and other advanced technologies. (4) The common utilization of the AWE system and its current application and development in the developing countries, mainly including the abandoned oil and gas wells. (5) The existing issues and in-depth analysis on the practical application of GE for building cooling/heating in the developing countries. This chapter can provide some effective guidelines on the various GE utilization forms for building cooling/heating in developing countries.