Reproducing solar curtailment with Fourier analysis using Japan dataset

The 6th International Conference on Power and Energy Systems Engineering (CPESE 2019), 20–23​ September 2019, Okinawa, Japan.Curtailment of variable renewable energy increases the Levelized Cost of Energy (LCOE), which is the tool often used to compare its profitability against traditional energy sources. Recently, the Kyushu Region of Japan had to curtail some of its solar production to meet energy balance. As many countries increase their solar energy production, curtailment will be inevitable. It is therefore important to develop methodologies to calculate it. In the case of Japan, curtailment can easily be estimated using hourly data. However, such data is unavailable in other countries. In this study, a methodology to reproduce curtailment using known periodicity and statistical data is presented. Insights were initially generated by simulating future curtailment scenarios of Kyushu to extract the factors that affect curtailment. Fourier analysis was used to identify the periodicity of demand and solar production. The Fourier representation was simplified using the identified factors. Along with statistical data, the demand and solar data were approximated and the curtailment was reproduced. Results show that curtailment can be closely reproduced using the proposed methodology on a yearly and monthly level. Further research is necessary to test the methodology for other conditions like having different climate, varying daily fluctuations, and other human-related fluctuations

Assessing the geospatial nature of location-dependent costs in installation of solar photovoltaic plants

A major hurdle in increasing the economic feasibility of solar photovoltaic (SPV) plants is the ever-increasing share of location-dependent costs (land, transmission, labor, etc.) in total installation costs. Such costs are geospatial in nature, due to spatial socio-economics affecting them. Present geolocation methods, for locating SPV installation sites, do not consider the effect of location-dependent costs in installation. We use a spatial parameterization model for examining the factors causing spatial variation of the installation costs of land, labor, transmission and supply chains for suburban SPV plants, within a geographic boundary. The model is applied to Kolkata city, India, and the spatial variation of the costs are checked in a 2500 km²2 suburban boundary. The spatial variation of the location-dependent costs is mainly caused by the distance from an economic focal point of the city. The variations significantly optimize at minima points in the 2500 km² boundary, where the location-dependent costs increase by 10% with an average 2.6 km deviation and an average 6.7 km deviation from the global minima, for small and large plants, respectively. The spatial minima is mainly caused by variance of land and transmission costs. This minima location lies on the extrapolation of a line that connects the city focal point with the substation. The capacity of the SPV plants at the optima increases with increasing transmission voltage (11 kV to 66 kV), ranging from 4 MW to 257 MW in the case-study (small to large scale), while the minima shift away from the city focal point (ranging 29 km to 48 km) with increasing capacity. This study provides a perspective on how the spatial variation of installation costs can play a role in the geolocation of SPV plants. Furthermore, the empirical and spatial variation of location-dependent costs can enable energy planners to evaluate the economic feasibility of solar power and promote better land-use near cities

An Integrated Model Approach: Exploring the Energy Literacy and Values of Lower Secondary Students in Japan

Energy literacy is a minimum required capacity for developing a sustainable society that participates in and discusses on energy and environmental (EE) issues. Understanding the energy literacy structure is of significant importance for providing effective energy education to promote people’s awareness of EE issues. In this article, an energy literacy structural model integrated with the Theory of Planned Behavior and Value-Belief-Norm Theory was investigated for 1070 lower secondary students (ages 13-15) in Japan. Structural equation modeling uncovered that the awareness of consequences is the most powerful predictor for the causality between basic energy knowledge and energy-saving behavior through the attitude toward the energy-saving behavior. A conditional process analysis elucidated that (1) the conditional effect of basic energy knowledge on the awareness of consequences depends on scientific literacy, critical thinking ability, and environmental worldview, and (2) the conditional direct and indirect effects in the mediation model of awareness of consequences on the attitude toward energy-saving behavior through the ascription of responsibility depend on environmental worldview or values and family discussion of energy-related issues. The energy literacy model proposed provides a theoretical contribution to the development of an effective energy education program

Enhanced Photocatalytic Activity of BiVO4/Bi2S3/SnS2 Heterojunction under Visible Light

Heterojunction photocatalysts have attracted a significant amount of attention due to their advantages over a single photocatalyst and, particularly, their superior spatial charge separation. Herein, the BiVO4/Bi2S3/SnS2 heterojunction was synthesized via solvothermal synthesis with different ratios of BiVO4 to SnS2. The photodegradation rate of the 0.03 BiVO4/SnS2 sample for rhodamine B removal is 2.3 times or 2.9 times greater than that of a single SnS2 or BiVO4, respectively. The chemical bond between photocatalysts is confirmed by X-ray photoelectron spectroscopy (XPS), and the synchronized shift observed in binding energies strongly indicates the electron screening effect at the heterojunction. A Z-scheme model is proposed to explain charge transfer pathway in the system, in which the formation of Bi2S3 plays a crucial role in the enhanced photocatalytic performance of the heterojunction

Low-temperature catalytic performance of Ni-Cu/Al2O3 catalysts for gasoline reforming to produce hydrogen applied in spark ignition engines

The performance of Ni-Cu/Al2O3 catalysts for steam reforming (SR) of gasoline to produce a hydrogen-rich gas mixture applied in a spark ignition (SI) engine was investigated at relatively low temperature. The structural and morphological features and catalysis activity were observed by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and temperature programmed reduction (TPR). The results showed that the addition of copper improved the dispersion of nickel and therefore facilitated the reduction of Ni at low temperature. The highest hydrogen selectivity of 70.6% is observed over the Ni-Cu/Al2O3 catalysts at a steam/carbon ratio of 0.9. With Cu promotion, a gasoline conversion of 42.6% can be achieved at 550°C, while with both Mo and Ce promotion, the gasoline conversions were 31.7% and 28.3%, respectively, higher than with the conventional Ni catalyst. On the other hand, initial durability testing showed that the conversion of gasoline over Ni-Cu/Al2O3 catalysts slightly decreased after 30 h reaction time

Weather-Driven Scenario Analysis for Decommissioning Coal Power Plants in High PV Penetration Grids

Despite coal being one of the major contributors of CO2, it remains a cheap and stable source of electricity. However, several countries have turned to solar energy in their goal to “green” their energy generation. Solar energy has the potential to displace coal with support from natural gas. In this study, an hourly power flow analysis was conducted to understand the potential, limitations, and implications of using solar energy as a driver for decommissioning coal power plants. To ensure the results’ robustness, the study presents a straightforward weather-driven scenario analysis that utilizes historical weather and electricity demand to generate representative scenarios. This approach was tested in Japan’s southernmost region, since it represents a regional grid with high PV penetration and a fleet of coal plants older than 40 years. The results revealed that solar power could decommission 3.5 GW of the 7 GW coal capacity in Kyushu. It was discovered that beyond 12 GW, solar power could not reduce the minimum coal capacity, but it could still reduce coal generation. By increasing the solar capacity from 10 GW to 20 GW and the LNG quota from 10 TWh to 28 TWh, solar and LNG electricty generation could reduce the emissions by 37%, but the cost will increase by 5.6%. Results also show various ways to reduce emissions, making the balance between cost and CO2 a policy decision. The results emphasized that investing in solar power alone will not be enough, and another source of energy is necessary, especially for summer and winter. The weather-driven approach highlighted the importance of weather in the analysis, as it affected the results to varying degrees. The approach, with minor changes, could easily be replicated in other nations or regions provided that historical hourly temperature, irradiance, and demand data are available

Techno-economic analysis on recent heterogeneous catalysts for ammonia synthesis

The economic performance of recently developed catalysts for ammonia synthesis, Ru/Ca(NH2)2 and Ru/Pr2O3, are evaluated by process simulation using ASPEN Plus. The results show that catalyst costs are high due to expensive ruthenium; thus, the catalysts\u27 lifetime significantly influences the total cost. Besides, the new catalysts are advantageous when the electricity cost is high and the production scale is small, which are the characteristics of the case in which renewable energy is employed. Finally, the future direction of the catalyst developments is discussed

Longer-term Consequences of the Great Recession on the Lives of Europeans

Climate change and energy security are global challenges requiring concerted attention and action by all of the world’s countries. Under these conditions, energy supplier and exporter countries in the Middle East region are experiencing further challenges, such as increasing domestic energy demand while energy exports have to concurrently be kept at high levels. Middle East countries process the largest proven oil and gas reserves in the world and contribute a large fraction of the world’s CO₂ emissions from the use of these as fuels both domestically and internationally. This paper addresses different policies that could dramatically change the future course of the Middle East region toward a zero CO₂ emission energy system. To this aim, an integrated energy supply–demand model has been developed to analyze required commitments including renewable energy and energy efficiency targets and the potential of nuclear power, all of which should need to be considered in order to reduce CO₂ emissions by 2100. The results indicate that nearly 43% of the global energy of the Middle East region can be supplied from non-fossil fuel resources in 2100