Currently, prediction of trip-based electricity consumption of electric buses (EBs) has become an important prerequisite for the deployment of large-scale electric bus fleets and the location of the charging infrastructures. Previous state-of-the-art approaches to estimate the electricity consumption focus on making rough electricity consumption assumptions or building physics-based electricity consumption model. This paper constructed a neural network model to predict the trip-based electricity consumption of EBs and six influencing factors were taken as input variables. Further, sensitivity analyses were performed to investigate how these factors influence the consumption results. This model was implemented and validated on real-world electric bus data from a five-month consecutive collection in Shenzhen, China, comprising 1024 EBs. The experiment demonstrated the predictive effectiveness of this model and the results from sensitivity analyses show that trip length is the key factor to determine the consumption, but other factors average travel speed, the number of bus stops and traffic lights, direction, time parameters also have different level of impacts on the results.
This paper presents a roadmap for the build-out and deployment of renewable hydrogen (RH2) production facilities in California. The purpose is to provide a fact-base to support policy decisions and inform stakeholders. The analysis includes demand projections, forecasts of technology progress, supply chain costs and temporal and spatial facility siting scenarios. The work places specific focus on lessons from early project activity and projection through 2030 with higher level forecasts through 2050. The work concludes with research needs and policy recommendations to successfully launch and scale the California renewable hydrogen sector. The overall conclusion is that, with appropriate policy support, the renewable hydrogen sector can reach self-sustainability (price point at parity with conventional fuel on a fuel-economy adjusted basis) by the mid to late 2020s.
Photovoltaic (PV) distributed generation (PVDG) has grown significantly in the recent years due to the rapid development of power electronic technologies. The PVDG is usually integrated to distribution systems. The integration of PVDG can alleviate energy demand effectively while reduce air pollution and greenhouse gas emissions. However, with the increasing integration, the PVDG systems inevitably lead to significant challenges on operation of power systems, including protection of distribution systems. In the existing literature, only a few papers discussed the impact of the integration of PVDG on the protection of distribution systems, and the corresponding technical challenges are not fully clarified. To fill the gap, this paper develops a generic distribution system with the integration of a PVDG system to analyze the impact of integration of PVDG on the overcurrent protection of the distribution system. It is found that the control of PV inverters can limit the fault current significantly during a short-circuit (SC) fault. This makes the SC current of the faulted feeder too low to trigger the circuit breaker, leading to a protection failure (should operate but does not). To verify this conclusion, a comparison case with the connection of a traditional synchronous generator is provided in this paper.
Whole energy system modelling is a valuable tool to support the development of policy to decarbonise energy systems, and has been used extensively in the UK for this purpose. However, quantitative insights produced by such models methods necessarily omit potentially important features of physical and engineering reality. The authors argue that important socio-technical insights can be gained by studying critical events such as the loss of 2.1 GW generation from the electricity system of Great Britain in August, 2019. The present paper uses this event as a starting point for a discussion of the need for additional tools, drawn from the System Architecture literature, to support the design and realisation of future fully decarbonised systems with high penetrations of renewable energy, capable of providing high levels of resilience and flexibility.