SYSTEM
3) Optimization logic
5.5.2 Carbon tax change
As Section 4.2 shows, the results of F2 and F3 is similar because of the low proportion CO2
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emission cost compared with other two costs. With the development of the carbon tax, CO2 emission will occupy higher attention due to the larger payment of environment cost. It is predicted that the carbon tax of Japan reaches 104.6 $/t in 2030 [11]. Different carbon taxes are assumed to analyze the effect of environmental performance on the configuration optimization of DES. The total costs of the DES under different PV penetration scenarios with the increase of the carbon tax are demonstrated in Fig.5-31. As Fig.5-31 shows, the PV penetration is increased with the development of the carbon tax. It can be seen that the total cost is least when the PV penetration is 40% when the carbon tax reaches 104.6 $/t in 2030.
Fig.5-31 The total costs changes of the DES under different PV penetration scenarios with the increase of the carbon tax.
The total costs and optimal configurations of the DES with the different PV penetration scenarios under F3 after the increase of the carbon tax are changed, shown in Fig.5-32. It can be seen that the total cost is least when the PV penetration is 40%.
a)
CHAPTER 5: MULTI-CRITERIA ASSESSMENT FOR OPTIMIZING DISTRIBUTED ENERGY SYSTEM
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Fig.5-32 The total cost and optimal configurations changes with the different PV penetration scenarios when the carbon tax is 104.6 $/t: a) The total costs; b) the optimal
configurations of ICE and BESS.
Table 5-2 demonstrated the optimal configurations of the DESs under the three objective functions and their performance comparison when the carbon tax is 104.6 $/t. The results show that the total cost saving of DES3 is improved 2.13% compared with DES1. The peak shaving of DES3
is less than that of DES2, whereas the CO2 emission reduction of DES3 is more than DES2. It indicated that with the increase of carbon tax, the environmental advantages are significant, which will greatly affect the overall performance of DES.
Table 5-2 The optimal configuration of the DES under the three objective functions when the carbon tax is 104.6 $/t.
DESs DES1 DES2 DES3
Configuration
PV penetration 30% 30% 40%
ICE 0 MW 1.573 MW 0 MW
BESS 9.479 MW 3.488 MW 6.840 MW
Cost saving
ABC saving 6.52% 5.81% 5.85%
PLC saving 2.24% 4.58% 3.55%
CDEC saving 5.91% 5.72% 7.40%
Total cost saving 14.67% 16.11% 16.80%
Peak shaving 18.783% 38.426% 29.804%
CO2 emission reduction 31.346% 30.366% 39.278%
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Cost saving, grid stabilization and CO2 emission reduction are three reasons that cause increasing attention of the DES with renewable energy. In this chapter, the annual basic cost, peak load cost and carbon emission cost are put forward to assess the comprehensive performance of DES with different combinations. By introducing the peak load price and carbon tax, the peak shaving capacity and emission reduction effect of DES can be transformed into economic benefit. As a case study, the Smart Community in Higashida of Japan is used to explore the impact of different evaluation criteria on the configuration optimization of DES, after considering peak shaving ability and emission reduction effect. Compared the optimization results at different PV penetration scenarios, the following conclusions can be deduced:
1) Based on the actual grid load data of five different types of buildings in Higashida, Japan, the power of the area consisted of multi-type buildings has the characteristics of daytime peak and midnight valley. The difference of peak and valley load is significant, especially in summer.
Convenient installation and environmentally friendly are the reasons that cause rapidly development of PV system in electrical networks. However, due to intermittence and instability, the increase of PV penetration has little effect on the enhancement of peak shaving. High PV penetration may not relieve the pressure of the power grid but will increase the volatility of the power grid. Therefore, the development of PV system in practical application is impeded.
2) By comparing the comprehensive benefits of DES in different PV penetration scenarios, it can be found that when PV penetration is 30%, the total cost of DES is the lowest which decreases by 13.579% of the initial energy bill. As the output of the ICE is limited by the PV generation at daytime, the optimal installed capacity of the ICE decreases with the growth of the PV penetration. Due to the economic operation strategy, the installed capacity of the BESS is affected by peak load and PV overproduction. Therefore, with the increase of the PV penetration and the decline of the ICE output, the optimal installed capacity of the BESS gradually increases.
3) When the peak load cost is added into the objective function, the peak shaving rate of the DES3
are improved, which is 19.372% higher than that of DES1. However, the annual basic cost saving is decreased compared with DES1. It indicates that the improvement of the grid stabilization effect of DES came at the expense of partial system basic economic benefit. it is necessary to determine the optimization direction according to the evaluation criteria based on the urgent issues of local energy supply and power demand when optimizing the configuration of DES.
4) The power generation of the PV system can reduce the peak load, but its effect is not obvious compared with the stable output of the internal-combustion engine. According to the sensitivity analysis, the increase of peak load price can improve the configuration of the ICE, but it has little effect on the PV penetration. Carbon emission has a significant impact on the promotion of photovoltaic. The development of carbon tax has greatly increased PV penetration. By 2030, the carbon tax will reach 104.6 $/t, and the PV penetration can be increased by 10%. And the CO2 emission reduction can reach 39.28% after applying the DES with optimal combination.
Based on the above analysis, the multi-criteria evaluation method can fairly balance the different performance of the DES, which will maximize the application potential of the DES and improve its market competitiveness.
CHAPTER 5: MULTI-CRITERIA ASSESSMENT FOR OPTIMIZING DISTRIBUTED ENERGY SYSTEM
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[1] Tooryan F, HassanzadehFard H, Collins ER, Jin S, Ramezani B. Optimization and energy management of distributed energy resources for a hybrid residential microgrid. J Energy Storage 2020;30:101556. https://doi.org/10.1016/j.est.2020.101556.
[2] Awad ASA, EL-Fouly THM, Salama MMA. Optimal ESS Allocation for Benefit Maximization in Distribution Networks. IEEE Trans Smart Grid 2017;8:1668–78.
https://doi.org/10.1109/TSG.2015.2499264.
[3] Das CK, Bass O, Mahmoud TS, Kothapalli G, Mousavi N, Habibi D, et al. Optimal allocation of distributed energy storage systems to improve performance and power quality of distribution networks.
Appl Energy 2019;252:113468. https://doi.org/10.1016/j.apenergy.2019.113468.
[4] García-Plaza M, Eloy-García Carrasco J, Alonso-Martínez J, Peña Asensio A. Peak shaving algorithm with dynamic minimum voltage tracking for battery storage systems in microgrid applications. J Energy Storage 2018;20:41–8. https://doi.org/10.1016/j.est.2018.08.021.
[5] Zhang L, Gao W, Yang Y, Qian F. Impacts of investment cost, energy prices and carbon tax on promoting the combined cooling, heating and power (CCHP) system of an amusement park resort in shanghai. Energies 2020;13. https://doi.org/10.3390/en13164252.
[6] Adefarati T, Bansal RC. Reliability, economic and environmental analysis of a microgrid system in the presence of renewable energy resources. Appl Energy 2019;236:1089–114.
https://doi.org/10.1016/j.apenergy.2018.12.050.
[7] CO2 Emission coefficient by electric utility n.d.
https://ghg-santeikohyo.env.go.jp/files/calc/r02_coefficient.pdf (accessed September 16, 2020).
[8] Carbon dioxide emission coefficient of urban gas n.d.
http://www.saibugas.co.jp/business/others/co2_emission_factor.htm (accessed September 16, 2020).
[9] Zhao X, Gao W, Qian F, Li Y, Ushifusa Y, Yang Z, et al. Economic performance of multi-energy supply system in a zero-carbon house. Energy Build 2020;226:110363.
https://doi.org/10.1016/j.enbuild.2020.110363.
[10] Brendan F.D. Barrett. Can Japan Go 100% Renewable by 2050? Sci Technol 2011.
https://ourworld.unu.edu/en/can-japan-go-100-renewable-by-2050 (accessed October 26, 2020).
[11] Japan. Ministry of the Environment. Introduction of tax for measures against global warming.
Compr Environ Policy 2018. https://www.env.go.jp/policy/tax/about.html (accessed November 15, 2020).