• Energy Research
• 11. Sustainability close

Abstract As an integration of energy technology and information communication technology, "Energy Internet” is the new driving force for global development of clean and efficient energy systems. This paper summaries the concept and characteristics of “Energy Internet" and the sustainable urban development; describes some concepts and achievements in the field, and expounds the driving forces for the development of Energy Internet. An example of multi energy system is presented to illustrate that the Energy Internet. The multi energy internet can effectively improve energy efficiency, protect the environment, promote the city’s circular economy, and have good economic and social benefits for sustainable urban development.

Abstract The integration of electrical and heating systems has great potential to enhance the flexibility of power systems to accommodate more renewable power such as the wind and solar. This study was to investigate an optimal way to integrate the energy of both systems in urban areas. The amount of energy conversion between the electrical system and heating system was optimally decided so that the demand within both systems could be met at the least operational cost. Besides, the best node to join with the electrical system and heating system was chosen by consideration of the energy transmission loss. The mathematical formulation of the optimization problem was detailed as a large-scale non-linear program (LSNLP) in this paper. A decomposition–coordination algorithm was proposed to solve this LSNLP. At last, a 6-bus electrical power system with 31-node heating transmission system was studied to demonstrate the effectiveness of the proposed solution. The results showed that coordinated optimization of the energy distribution have significant benefits for reducing wind curtailment, operation cost, and energy losses. The proposed model and methodology could help system operators with decision support in the emerging integrated energy systems.

Abstract Reduction of greenhouse gas emissions in the building sector has become a global concern in terms of ensuring sustainable development. Thus it is imperative to investigate the utilization of clean electricity in buildings. This study proposes a novel, cost-effective commercial building-oriented power supply system for providing a comfortable environment in a shopping mall. An energy management strategy is also proposed for this system. Two types of electric vehicles (EVs) are considered, and their models are developed separately based on different stochastic behaviors. Furthermore, the integration of retired electric vehicle batteries (REVBs) in commercial buildings is one of the possible methods for achieving echelon utilization. To address the uncertainties in the system, the scenario-based stochastic optimization method is applied, which formulates the energy management problem as a mixed-integer linear programming model. Results show that by integrating only photovoltaic (PV) energy and both PV and REVBs into commercial buildings, reductions of 82.2% and 83.3%, respectively, in the expected operational cost can be achieved. This proves that the application of PV and REVBs is beneficial for commercial buildings. Moreover, the robustness of the employed method is proven through comparison with other methods.

According to the new energy policy agreements, a conceptual and technological re-structuration of the Danish energy sector is expected. One of the key points for its successful implementation is the partial electrification of the heating and transportation systems. This fact, which reflects an enormous load increase, influences already the design and planning of the future power system. Great percentage of this new load is expected to be accommodated at local distribution level. Therefore, it implies that the distribution system operator will have to handle an increasing number of highly rated loads in networks which were not designed for them. In low voltage grids especially, depending on the system penetration grade and the way they are disposed produces a completely different reaction of the network. This paper introduces a methodology for stochastically evaluating the impact caused by thermostatic and plug-in electric vehicle loads in low voltage grids. On one hand, it defines which the potential bottlenecks of the system are. On the other hand, probabilistically identifies the vulnerable components of the infrastructure that obviously should be under consideration of the operator. As a case study, a typical Danish low voltage grid is considered. The results obtained, using DIgSILENT PowerFactory, show that sometimes the hosting capability of these networks may be poor for the integration levels expected.

In the world with Zero Waste City and Energy Internet construction is promoting to meet waste reduction and power grid regulation flexibility improvement. Based on the waste stockpile and disposal demands, the waste disposal facilities multi-time scale model of energy supply and demand is proposed. On these premises, This paper presents the Multi-energy Waste Disposal System (MEWDS) topology and its optimal model based on coordinated operation of multi-energy system and waste disposal facilities to maximize economic benefits. Through simulation, the case studies are performed for the waste stockpile and multi-energy operation data of a Chinese city from different waste disposal scenarios to demonstrate. The proposed MEWDS optimal model can make the waste reduced and the economic benefits best. Meanwhile, it can also improve the flexibility of power grid regulation effectively.

Abstract Renewable energy is one of the possible solutions when addressing climate change. Today, large-scale renewable energy integration needs to include the experience to balance the discrepancy between electricity demand and supply. The electrification of transportation may have the potential to deal with this imbalance and to reduce its high dependence on oil production. For this reason, it is interesting to analyse the extent to which transport electrification can further the renewable energy integration. This paper quantifies this issue in Inner Mongolia, where the share of wind power in the electricity supply was 6.5% in 2009 and which has the plan to develop large-scale wind power. The results show that electric vehicles (EVs) have the ability to balance the electricity demand and supply and to further the wind power integration. In the best case, the energy system with EV can increase wind power integration by 8%. The application of EVs benefits from saving both energy system cost and fuel cost. However, the negative consequences of decreasing energy system efficiency and increasing the CO 2 emission should be noted when applying the hydrogen fuel cell vehicle (HFCV). The results also indicate that developing renewable energy is crucial for transportation electrification.

Abstract In the context of “zero-waste city” and energy internet, the interaction and connection between the energy supply of biomass waste disposal and multi-energy systems are becoming increasingly close. On such a basis, this paper proposes a multi-energy microgrid (MEMG) framework for the comprehensive utilization of biomass waste energy. Firstly, the energy supply and demand model of biomass waste of domestic residual waste and kitchen waste is studied, and biomass disposal facilities are taken as the flexible resource of MEMG. Then, a multi-energy storage system is established for flexible regulation according to the fluctuating demand of multi-energy in MEMG. Considering the uncertainties of biomass waste production by residents, renewable energy output, and multi-energy load, a MEMG multi-objective robust optimal scheduling model is established with the objectives of minimizing operating costs and maximizing waste disposal. Finally, a numerical example simulation is carried out with a MEMG in Northeast China. The simulation results verify the effectiveness and economics of the MEMG integrated biomass waste treatment facility through different comparison scenarios, which can realize the effective integration of energy consumption and environmental friendliness.

Abstract With increasing penetration of renewable energy, multi-energy systems constitute an effective mechanism to optimize energy distribution and improve social welfare. However, a centralized operation of the multi-energy system might not be appropriate under the existing energy markets. Therefore, this paper proposes an equilibrium model for improving the operation of the electricity, gas and district heating subsystems of a district or urban area. The proposed model allows each energy subsystem to pursue its own objective (i.e., maximum social welfare), while considering the interconnection with other subsystems. More specifically, this model represents the behavior of each subsystem and reflects the interactions of the multi-energy system in a practical way. This equilibrium problem is formulated as a nonlinear complementarity problem. An illustrative case study is analyzed to show the relevance of the proposed approach.