Economic feasibility of large-scale hydro–solar hybrid power including long distance transmission

Solar PV is expected to become the most cost-competitive renewable energy owing to the rapidly decreasing cost of the system. On the other hand, hydropower is a high-quality and reliable regulating power source that can be bundled with solar PV to improve the economic feasibility of long-distance transmitted power. In this paper, a quantification model is established taking into account the regulating capacity of the reservoir, the characteristics of solar generation, and cost of hydro and solar PV with long-distance transmission based on the installed capacity ratio of hydro–solar hybrid power. Results indicate that for hydropower stations with high regulating capacity and generation factor of approximately 0.5, a hydro–solar installed capacity ratio of 1:1 will yield overall optimal economic performance, whereas for hydropower stations with daily regulating capacity reservoir and capacity factor of approximately 0.65, the optimal hydro–solar installed capacity ratio is approximately 1:0.3. In addition, the accuracy of the approach used in this study is verified through operation simulation of a hydro–solar hybrid system including ultra high-voltage direct current(UHVDC) transmission using two case studies in Africa.

Assessment of global solar resource development

With the increasing severity of environmental problems,many countries have set energy transition targets to promote the realization of the Paris Agreement.There has been a global consensus on utilizing solar energy resources as alternatives to conventional sources to support this energy transition.In this regard,analyzing the“location,”“quantity,”and“quality”of global solar energy resources will not only assist an individual country to efficiently utilize these resources but also promote the realization of large-scale intercontinental resource utilization and complementation.This study established the basic database,model methods,and platform tools for global solar energy assessment,Then,a global solar energy resource assessment was conducted,which included the theoretical reserves(TRs),technical installed potential capacity(TPIC),and average development cost(ADC).A comparative analysis of the assessment results for all continents was also performed.After that,based on big data analysis and geographic information system(GIS)calculations,the distribution characteristics of the global solar power TPIC were calculated with the two core indicators,namely the capacity factor and ADC.Furthermore,a data-driven quantitative evaluation of the refined development potential of solar energy resources was performed.Finally,the reasonableness and coincidence analysis of the resource assessment results were verified using data from global and specifically Chinese photovoltaic(PV)bases.

Joint electricity and carbon market for Northeast Asia energy interconnection

Decarbonization of the electricity sector is crucial to mitigate the impacts of climate change and global warming over the coming decades.The key challenges for achieving this goal are carbon emission trading and electricity sector regulation,which are also the major components of the carbon and electricity markets,respectively.In this paper,a joint electricity and carbon market model is proposed to investigate the relationships between electricity price,carbon price,and electricity generation capacity,thereby identifying pathways toward a renewable energy transition under the transactional energy interconnection framework.The proposed model is a dynamically iterative optimization model consisting of upper-level and lower-level models.The upper-level model optimizes power generation and obtains the electricity price,which drives the lower-level model to update the carbon price and electricity generation capacity.The proposed model is verified using the Northeast Asia power grid.The results show that increasing carbon price will result in increased electricity price,along with further increases in renewable energy generation capacity in the following period.This increase in renewable energy generation will reduce reliance on carbon-emitting energy sources,and hence the carbon price will decline.Moreover,the interconnection among zones in the Northeast Asia power grid will enable reasonable allocation of zonal power generation.Carbon capture and storage (CCS) will be an effective technology to reduce the carbon emissions and further realize the emission reduction targets in 2030-2050.It eases the stress of realizing the energy transition because of the less urgency to install additional renewable energy capacity.

A production-cost-simulation-based method for optimal planning of the grid interconnection between countries with rich hydro energy

Cross-border grid interconnection is a critical means to achieve wide-area share of hydro and other clean energy.Economic benefit assessment of cross-border grid interconnection projects should be carefully performed during early stage.In this paper,a method based on cost-benefit economic assessment for optimal planning of cross-border grid interconnection is proposed.An economic index for comprehensively assessing the cost of a transmission project and its resulting benefits of more usage of hydro energy is designed first.A chronological production cost simulation model considering hydro energy spillage due to transmission congestion and thermal operational limitation is then proposed to calculate the economic index.A case study is performed using the proposed method to determine the optimal capacity of a potential transmission link between Brazil and Argentina,which have rich and complementary hydro energy resources.

Adjustable robust low-carbon dispatch for interconnected power systems in Northeast Asian countries

Interconnected power systems that link several countries and fully utilize their individual resources in a complementary manner are becoming increasingly important.As these systems enhanee accommodation of renewable energy,they also represent a move toward low-carbon and low-emissi on power systems.In this paper,a low-carb on dispatch model is proposed to coo rd i nate the gen erati on output betwee n several coun tries where the carb on emissi on constraint is a priority.An adjustable robust optimization approach is used to find the optimal solution under the worst-case scenario to address the uncertainties associated with renewable energy resources.A specific constraint is that the area control error for each country should be self-balanced.Furthermore,a reformation using participation factors is presented to simplify the proposed robust dispatch model.Simulation results for practical interconnected power systems in northeast Asian countries verify the effectiveness of the proposed model.

A multi-level evaluation model for the recognition and assessment of impact factors associated with intercontinental power interconnection projects

The construction of intercontinental power grid interconnection projects is key to realizing the vision of Global Energy Interconnection,which is to solve global energy problems in a clean and sustainable manner.These projects may be influenced by a few factors that are neither technological nor economic,such as political,social,and international factors.This paper thus presents a multi-level model for recognizing which factor from a compiled list of 14 would impact a particular intercontinental interconnection project and for assessing the degree of the factor’s influence.In the first part of the model,the Analytic Hierarchy Process(AHP)method is used to recognize the project’s most significant impact factors.Using the recognition results,the second part of the model can assess the degree of the factor’s influence on the project based on ratings provided by experts.A comprehensive evaluation can thus be provided.As a case study,the proposed Saudi Arabia-Ethiopia power grid interconnection project connecting Asia and Africa was analyzed.Derived from a combination of multiple opinions from experts,evaluations from the model will be of direct benefit to decision-makers,investors,project implementers,and engineers,providing them with a deeper insight into the project.