The promotion of distributed renewable power generation and the development of power electronic converters have promoted the application of DC microgrid in households. In this paper, based on the existing household power structure, a home-based power router is proposed, and according to various operating scenarios in real life, a master-slave control strategy for converting the main control power supply is proposed for different operating conditions in gridconnected mode and island mode. By building the circuit model of household power router, monitoring the voltage fluctuation of DC bus and the power fluctuation of photovoltaic, energy storage, power grid and load, the practical control strategy of microgrid router is verified and analyzed.
Current renewable energy mounting technologies with its different installation methods, and mounting locations are consequently affected by wind loads differently. Using the FSI approach, this study evaluated solar panels attached to the gabled roof of a single detached low-rise building. The building was subjected to typhoon strength winds in an urban environment using Computational Fluid Dynamics (CFD) analysis. A typhoon’s Atmospheric Boundary Layer (ABL) flow simulation was conducted to predict the pressure coefficient distribution around the structure. A validated structural model of the support attached to the roof was then developed, and the analysis performed using FSI to predict deflections, stress concentration areas and potential failure in the structural supports and attachments. The results of the study showed the weaknesses in the current design considering the roof shape, pitch, structural support, arrangements and materials. Results show areas of failure in the panels with regards to wind angle direction and installation location.
Under the liberalization of the retail electricity market, peer to peer (P2P) energy trading between households in microgrid are more economical. This paper discusses the bidding strategy based on evaluation mechanism for P2P energy trading in microgrid. The main focus is how to reduce the cost of electricity consumption of households and the impact caused by the intermittent and volatility of distributed sources such as photovoltaics (PV) by limiting the selfish behaviors of households in microgrid. Firstly, based on the characteristics of the electricity market, an evaluation mechanism based on the analytic hierarchy process (AHP) for energy auction is proposed to evaluate the energy service level of households and constrain the selfish behavior of households in microgrid. Secondly, the bidding strategy based on evaluation mechanism for P2P energy trading in microgrid is established. Moreover, based on the economic principle, the electricity supply and demand relationship of the household is quantitatively determined by the Household Electricity Supply and Demand Ratio (HESDR) and the energy valuation of household is defined. Finally, through the simulation of actual examples, the effectiveness of the proposed model in reducing the net cost of electricity for households and the impact on the grid are verified.
For the depressurization process of the watersaturated hydrate reservoir, the gas recovery is seriously restrained by the continuous seepage of the surrounding water, resulting in high water production. In response to this problem, the technique of pressureretaining gas injection was used in this work to inhibit water production and enhance gas recovery. The results showed that water production was reduced by hundreds of times and gas recovery reached ~30% by PRGI.
This paper applies the real option approach (ROA) to analyze the economic viability of residential solar photovoltaic (PV) investment in the Philippines. From the point of view of a household (HH) owner, this approach evaluates the option values and optimal timing of investment to compare the attractiveness of investing in solar PV over continuing to use electricity from the grid. This further analyzes how various investment schemes and electricity prices uncertainty affect investment decisions. Results find that residential solar PV investment is profitable for all HH types investigated and that earlier investment in solar PV reduces the risk of opportunity loss from postponing the investment. Among the investment schemes analyzed, the distribution of solar PV cost in 5- or 10-year period without initial down payment shows to be the best investment strategy. The results are robust with various HH types investigated and with sensitivity in electricity prices.
This paper focuses on the optimal dispatching of microgrid with photovoltaic and energy storage. Firstly, considering the constraints of energy storage, interruptible load and transferable load, a multi-objective optimization model of grid-connected microgrid under time-sharing price and demand response is established, aiming at minimizing the operation cost, environmental cost and tie-line power fluctuation of microgrid. Then, aiming at the multi-objective, multi-constraint and non-linear characteristics of the model, an optimization solution method based on non-dominated sorting genetic algorithm-II (NSGA-II) is proposed. Finally, the article simulates the case based on MATLAB and OPENDSS joint simulation platform. The results of the example prove the validity and rationality of the model.
This study proposes a three-dimensional (3-D) model to investigate the detailed characteristics of conjugate conduction-natural convection heat transfer of photovoltaic cells mounted discretely on the bottom wall of a horizontal cabinet. The influences of thermal interaction between air streams inside and outside the cabinet through the conducting walls are explored. Furthermore, the enhancement of cooling performance of photovoltaic cells by using the fins is conducted. Results show that, for the system with 40 photovoltaic cells and Q =10W, the hot spot temperature drop is about 23 ℃ when the fins Nf = 170 are installed onto the cabinet bottom wall.
The steel industry in the European Union, important for the economy as a whole, faces various challenges. These are inter alia volatile prices for relevant input factors, uncertainties concerning the regulation of CO2-emissions and market shocks caused by the recently introduced additional import duties in the US, which is an important sales market. We examine primary and secondary effects of these challenges on the steel industry and stress impacts on European and global level. Particularly, we analyse the impacts of changes in competitiveness on energy demand and CO2-emissions taking transport of raw materials and steel into consideration. By applying information on Human Development Index values (reflecting aspects of life expectancy, education, and per capita income) we show that relocating energy-intensive industries from Europe may not only increase energy demand and global CO2- emissions, but may also affect developing countries.
In recent years, the development of household distributed photovoltaic is accelerating. However, the initial investment cost is relatively unaffordable for users, and the distributed photovoltaic financing is of characteristics like high threshold, few channels, low quota, high cost and short term, so China is actively promoting the corresponding financial supporting measures, like “photovoltaic loan” and finance lease. That’s makes the choice of proper financing terms very important. This paper first establishes the evaluation model of economic benefits based on NPV method and different financing characteristics, and then changes interest rate, loan proportion and repayment mode, to analyze their impact on economic benefits, and finally arrives at conclusion that with proper financing mode, economic benefits and investors’ investment confidence can be improved. Furthermore, It also suggests government should perfect existing photovoltaic financing policies, as well as enhance financial institutions’ confidence that provide loans.
This paper addresses the issue of social inequality by comparing German household data (gross income, Food‐Energy‐(Watervirtual)‐Nexus expenditures) from 2008 and 2013. The distribution of gross income and of the FE(Wvirtual)‐Nexus related consumption expenditures based on this income is analysed using a three step approach: First, the real distribution is determined, secondly, the dispersion (based on Rawls’ philosophical concept) is analysed, and finally, the normative distribution according to the Atkinson index is calculated to reveal a view on social inequality. The six main household groups were selected for the cross section analysis comparing the social conditions of 2008 and 2013: self‐employed households, public servant households, white‐collar and blue‐collar worker households, unemployed households and retiree households. The three‐dimensional model delivers data about the real and normative distribution of the households’ gross income and consumption expenditures for the time period from 2008 to 2013 considering the inequality perception of society.