THE BALANCE BETWEEN SUPPLY AND DEMAND OF WATER RESOURCES AND THE WATER-SAVING POTENTIAL FOR AGRICULTURE IN THE HEXI CORRIDOR

The Hexi Corridor is an important base of agriculture development in Northwest China. According to recent statistics, there are 65.94×108m3 of water resources available in the Hexi Corridor. At present, net consumption in development and utilization is 43.33×108m3. Water supply and demand reach a balance on the recent level of production, but loss of evaporation and evapotranspiration is as much as 25.69×108m3. So net use efficiency of water resources is 59%. Based on analyzing balance between water and land considering ecological environment at present, there exists the serious water shortage in the Shiyang River system where irrigation lands have overloaded. There is a comparative balance between supply and demand of water resource in the Heihe River system; and the Sule River system has some surplus water to extend irrigation land. Use of agriculture water accounts for 83.3% and ecological forest and grass for 6.9%. The Hexi Corridor still has a great potential for water saving in agriculture production. Water saving efficiency of irrigation is about 10% by using such traditional technologies as furrow and border dike irrigation and small check irrigation, and water saving with plastic film cover and techniques of advanced sprinkler and drip/micro irrigation etc. can save more than 60% of irrigated water. Incremental irrigation area for water saving potential in the Hexi Corridor has been estimated as 56%-197% to original irrigation area. So the second water sources can be developed from water saving agriculture in the Hexi Corridor under Development of the Western Part of China in large scale. This potential can be realized step by step through developing the water saving measures, improving the ecological condition of oasis agriculture, and optimizing allocation of water resources in three river systems.

The Supply and Demand of Agricultural Products in China Based on Balanced Diet

Promoting agricultural production and ensuring the supply of agricultural products has always been the main task of agricultural development in China,but the agricultural production in China has not yet been combined with the Chinese residents' dietary needs to formulate reasonable development goals,with a certain blindness in production. According to the dietary standards in The Dietary Guidelines for Chinese Residents developed by the Chinese Nutrition Society,we calculate the demand of various types of agricultural products in China under the conditions of balanced diet. In comparison with the output of various types of agricultural products in China at present,we find that the output of most of agricultural products in China has exceeded the reasonable demand of the Chinese residents under the conditions of balanced diet. Therefore,adjusting the agricultural production structure in China and advocating balanced diet has become an important way to solve the problem of balance between supply and demand of agricultural products.

Low Carbon Economic Dispatch of Integrated Energy System Considering Power Supply Reliability and Integrated Demand Response

Integrated energy system optimization scheduling can improve energy efficiency and low carbon economy.This paper studies an electric-gas-heat integrated energy system,including the carbon capture system,energy coupling equipment,and renewable energy.An energy scheduling strategy based on deep reinforcement learning is proposed to minimize operation cost,carbon emission and enhance the power supply reliability.Firstly,the lowcarbon mathematical model of combined thermal and power unit,carbon capture system and power to gas unit(CCP)is established.Subsequently,we establish a low carbon multi-objective optimization model considering system operation cost,carbon emissions cost,integrated demand response,wind and photovoltaic curtailment,and load shedding costs.Furthermore,considering the intermittency of wind power generation and the flexibility of load demand,the low carbon economic dispatch problem is modeled as a Markov decision process.The twin delayed deep deterministic policy gradient(TD3)algorithm is used to solve the complex scheduling problem.The effectiveness of the proposed method is verified in the simulation case studies.Compared with TD3,SAC,A3C,DDPG and DQN algorithms,the operating cost is reduced by 8.6%,4.3%,6.1%and 8.0%.

Supply and demand subject behavior of building energy efficiency in market fostering

Consumers and developers are the market transaction subjects which drive the development of building energy efficiency market. High energy prices, unreasonable heating system, information asymmetry of building energy suppress demand of energy efficiency construction; high technical risk and construction cost, nonstandard market restrict the supply of energy efficiency construction. To promote the development of building energy efficiency, we must set up effective incentive policies for both sides of the market transaction, improve the supervisory system, promote the technological progress, build the information sharing platform, so as to achieve the purpose of cultivating and improving the building energy efficiency market system, regulating the behavior of supply and demand subject, building the mutually beneficial and cooperative partnership, and realizing the balance of interests.

Analysis of Water Resources Supply and Demand and Security of Water Resources Development in Irrigation Regions of the Middle Reaches of the Heihe River Basin, Northwest China

Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.

High Proportion Renewable Energy Supply and Demand Structure Model and Grid Impaction

In considering of high proportion of renewable energy supply in 2050, the accelerating of energy consumption gross, source and environment can affect the energy system restrict affection are stronger. Add wind and solar to electricity energy with large amount of energy source exploitation. The energy source amount per person is lower. Considering the renewable energy amount and supply, primary energy storage and structure problem is standing out. Before the wide spread of renewable energy, Using the high-carbon energy in China can pollute seriously. Chinese energy supply and demand problem is research key point. This paper researches Chinese energy supply and demand pattern system and evaluation methodology, gives out the inner and outer influencing elements. And evaluate Chinese energy supply and demand pattern from energy gross, structure, distribution and transportation. Use energy supply synthesize radar comparison chart in certain time period. From energy security, economy, clean and efficiency, analyze the benefit comparisons of Chinese energy supply and demand pattern. This energy supply and demand pattern model will give one certain theoretical analysis and practice reference to the further high proportion of renewable energy.

Characteristic analysis and forecast of electricity supply and demand in APEC

The Asia Pacific Economic Cooperation(APEC)comprises of the world’s largest producers and consumers of energy,accounting for 60.3%of primary energy supply,50.0%of final energy consumption,and 63.0%of electricity generation worldwide in 2016.This study discusses the primary energy supply and final energy consumption situation of the APEC and analyzes the characteristics of electricity in terms of its generation structure based on fuel,consumption by the end-use sector,access to electricity,and so on.The renewable energy and electricity generation projections up to 2030 based on trends in the APEC are also assessed.It is seen that electricity in final energy consumption has been on an upward trend,with an average annual growth rate of about 4.8%during 2006–2016,in 2016,its share reached 24.3%.The industry sector consumes the largest share of electricity,accounting for about 45.5%in 2016.Coal supply and consumption peaked in 2011 and then began to decline,while renewable energy has been on an upward trend,with its primary energy supply share increasing from 4.80%in 2010 to 6.29%in 2016.Solar photovoltaic and onshore wind power are on the verge of costing less than the operating cost of existing coal-fired plants in 2018.In the APEC’s target scenario in which renewable energy is doubled,the predicted net growth from 2017 to 2030 of solar,wind,and hydro power is about 963,497,and 157 GW,respectively,and to reach this target,the APEC economies need to accelerate renewable energy development.

Analysis on energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy and China Dream target

A quantitative model was applied to analyze the energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy(2016e2030)and long-term economic and social development target China Dream.Results showed that 1)toward the 2050 China Dream target,total final energy consumption is expected to peak at 3.9 Gtce in 2030 and remain stable until 2050,whereas total primary energy consumption is expected to reach an upper platform by 2040 and around 5.8 Gtce by 2050;2)the proportion of non-fossil fuels is expected to reach approximately 50%and that of natural gas to reach more than 16%by 2050;3)CO2 emissions from energy use are expected to peak at 9.6 Gt by no later than 2030 and then gradually decline to 6.7 Gt by 2050.

Determination of Effectiveness of Energy Management System in Buildings

Building Energy Management Systems(BEMS)are computer-based systems that aid in managing,controlling,and monitoring the building technical services and energy consumption by equipment used in the building.The effectiveness of BEMS is dependent upon numerous factors,among which the operational characteristics of the building and the BEMS control parameters also play an essential role.This research develops a user-driven simulation tool where users can input the building parameters and BEMS controls to determine the effectiveness of their BEMS.The simulation tool gives the user the flexibility to understand the potential energy savings by employing specific BEMS control and help in making intelligent decisions.The simulation is developed using Visual Basic Application(VBA)in Microsoft Excel,based on discrete-event Monte Carlo Simulation(MCS).The simulation works by initially calculating the energy required for space cooling and heating based on current building parameters input by the user in the model.Further,during the second simulation,the user selects all the BEMS controls and improved building envelope to determine the energy required for space cooling and heating during that case.The model compares the energy consumption from the first simulation and the second simulation.Then the simulation model will provide the rating of the effectiveness of BEMS on a continuous scale of 1 to 5(1 being poor effectiveness and 5 being excellent effectiveness of BEMS).This work is intended to facilitate building owner/energy managers to analyze the building energy performance concerning the efficacy of their energy management system.

Alternative ventilation strategies in U.S.offices:Comprehensive assessment and sensitivity analysis of energy saving potential

Mature technologies exist to reduce the heating,ventilation,and air-conditioning(HVAC) energy associated with ventilation and use ventilation proactively to save energy.This study investigated the energy use impacts in U.S.office buildings of multiple alternative ventilation strategies that combined:economizing,demand controlled ventilation(DCV),supply air temperature reset(SR),and/or a doubled ventilation rate.We used energy simulations in a Monte Carlo analysis,sampling 17 building inputs and varying locations to match the climate zone distribution of the U.S.office stock.Results indicated the possibility for significant savings compared to a baseline that ventilated constantly at a minimum rate in both a small office type with a constant air volume(CAV) HVAC system and a medium office type with a variable air volume(VAV) system.In 95%of instances,HVAC source energy savings were 5-25%in the small-CAV office(median:11%) and 6-42%in the medium-VAV office(median:27%).In the small-CAV office,DCV typically saved the most energy,usually from heating,and heating degree days and occupant density were decisive influences.In the medium-VAV office,economizing and SR were most important,DCV usually only had minor impacts,and zone temperature setpoints,along with climate indicators,were the critical influences.Other than infiltration,envelope characteristics did not strongly influence energy impacts.The untapped primary energy savings of alternative ventilation strategies over the 74%of U.S.office floorspace reasonably represented by our modeling was estimated at 36 TWh per year,with an annual value of U.S.$ 1.25 billion.

The optimization research on the coupled of active and passive energy supplying in public institutions in China

The building sector is one of the largest energy user and carbon emitters globally.To increase the utilization rate of renewable energy and reduce carbon dioxide emissions,the optimal technical scheme of active public institutions and coupled utilization of renewable energy is studied.In this study,the energy consumption of three types of public institutions in various regions of China was simulated by using DeST building energy consumption software,combined with energy conversion efficiency and data released by the National Bureau of Statistics,and the total energy demand and total energy supply of public institutions were predicted using the load density method.Based on the coupling mechanism of the MARKAL model,the optimal proportion of renewable energy in the energy supply of public buildings in different regions is determined.Through the study of the number of public institutions in various regions of China,energy consumption characteristics,construction area,and other related data,the reverse energy flow method is creatively proposed,and the active and renewable energy coupling algorithm from the energy demand side of public institutions to the energy supply side is established.The results show that the central region has the highest utilization rate of renewable energy in the public sector,reaching 36.18%.The use of renewable energy in public buildings in hot summer and warm winter zones decreased to 35.08%,and it was 12.82% in cold zones.By 2025,the proportion of renewable energy resources in China is expected to reach 29.2%.The energy coupling model and algorithm constructed in this paper can provide a basis for the coupling macro configuration of renewable energy in public institutions in China.

Technical System Construction in the Market Trading System for Demand Response Based on the Energy Internet

With the explosive growth of variable renewable energy,the balance between the supply and demand of the power grid is faced with new challenges.Based on the development experience from typical countries and the state quo in China,this paper further analyzes the system architecture and development trend of demand response under the background of Energy Internet.Five dimensions are considered:Energy Internet platform,demand response application scenarios,system architecture,information technology system construction,and demand response development trend.The results show that the application of the Energy Internet platform can effectively solve the problems of data acquisition and processing,“terminal-edge-network-cloud”cooperation of demand response,etc.The system architecture of the demand response platform that supports user resource management,user information access,control instruction receiving,control strategy issuing,and response process monitoring is proposed in this paper.It is also helpful to provide a feasible technical choice for expanding the application services of Energy Internet towards government and society.

Tilt Angle Optimality Criteria for Stand Alone PV Systems

The conventional approach to optimizing tilt angles for fixed solar panels aims to maximize energy generation over the entire year. However, in the context of a supply controlled electric grid, where solar energy availability varies, this criterion may not be optimal. This study explores two alternative optimization criteria focused on maximizing baseload supply potential and minimizing required storage capacity to address seasonality in energy generation. The optimal tilt angles determined for these criteria differed significantly from the standard approach. This research highlights additional factors crucial for designing solar power systems beyond gross energy generation, essential for the global transition towards a fully renewable energy-based electric grid in the future.

Land Use Allocation Based on Interval Multi-objective Linear Programming Model: A Case Study of Pi County in Sichuan Province

Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was established and applied to analyzing the suitability of land use structure in Pi County of Sichuan Province. An adjustment scheme for optimizing land use structure was proposed on the basis of development planning drawn up by the local government. The results are summarized as follows: 1) the optimal adjustment scope for cropland area ranges from 27 976.75 ha to 31 029.08 ha,and the current area is less than the lower limit of the scope; 2) the optimal adjustment scope for garden land area ranges from 4 736.49 ha to 12 967.11 ha,and the current area is less than the lower limit; 3) the optimal adjustment scope for construction land ranges from 7 761.95 ha to 10 393.18 ha,and the current area is greater than the upper limit; 4) the optimal adjustment scope for industry and mining land ranges from 557.29 ha to 693.54 ha,and the current area exceeds the upper limit; and 5) the areas of forest land,grassland and other agricultural land are within the optimal adjustment scope. In order to maximize comprehensive benefit with the limited resources and the demand of sustainable development,the areas of cropland and garden land are supposed to be expanded properly,while the construction land should be controlled and reduced gradually,and the forest land and other agricultural land can be maintained at the current level in short period.

Energy substitution game under the supply capacity restriction

Along with Chinese economic growth,energy plays a more and more important role in the national economy.The imbalance between insufficient energy supply and huge energy demand has become a major problem in energy utilization,and energy substitution is attracting more and more attention as a key to the sustainable and sound development of Chinese economy.Explored the possibilities of the mutual substitution of the two types of energy with different functions with game theory in light of the supply capacity.As a con- clusion,there are four equilibrium results corresponding to different levels of supply capac- ity.Subsequently,we carry on the study further by numerical simulation,investigate in one group of results most close to Chinese energy status and find the equilibrium price as well as the demand variation pattern.

Comprehensive zoning of biomass energy heating in EU countries reference for China from European experience

Heat is the largest energy end-use in the world,accounting for about 50%of global final energy consumption.In 2019,the International Energy Agency pointed out that the development of renewable energy heating has become a key way for the global response to climate change,environmental pollution control,energy transformation and sustainable development.Biomass energy as a priority for the development of renewable heat sources has been valued by countries around the world.Developed earlier in the EU countries,their biomass heating technology is more mature,and their policy system is more comprehensive.Accounting for 86%of the total renewable thermal energy consumption,biothermal energy in these countries has achieved significant effect and become an important driving force for the decarbonization of the heating industry.This practice has a very high demonstration effect globally.This paper constructs a comprehensive zoning theoretical framework of biomass energy heating and utilization in the EU countries.Based on the calculation of the supply and demand potential of biomass energy heating system,the FCM method is used to quantify the status of biomass resource utilization in 28 EU countries.The results show that there are significant differences in the utilization of biomass energy heating in the EU countries,which can be divided into five categories of comprehensive zones,which are the key development category(Finland,Sweden,Denmark,Estonia,Lithuania and Latvia),resource priority category(Austria,Croatia,Bulgaria,Romania,and Slovenia),policy-oriented category(Germany,Italy,Portugal,and Cyprus),good-potential category(Czech Republic,Hungary,Greece,Spain,Poland,France,and Slovakia)and under-developed category(UK,Netherlands,Belgium,Ireland,Luxembourg and Malta).At the same time,this paper discusses the characteristics and causes of biomass heating utilization of different types of EU countries,and summarizes the mature heating systems and rich experience in the EU countries with China’s current heating situation and its future challenges concerning renewable energy development.Finally,this study provides some implications for China’s clean heating development,energy efficient use,energy supply security and energy structure upgrade.

Differential Impacts of Wind Energy on Sustainable Power Generation in Ghana

Ghana has a yearly development interest for power at a rate of 83.8% in 2010, and to 12% from 2020 to 2040 but this opportunity has been farfetched with the shocks in energy generation during 1983, 1994, 1997-98, and 2006-2007 era pushing the energy sector into crisis and a consequent adverse impact of 1.5% to GDP. This study, therefore, investigated the differential impacts of wind energy to sustainable power generation in Ghana by assessing the determinants of energy supply, energy demand and supply mix for energy development, the capacity of the energy sector to develop wind power and possible challenges in developing wind power energy in Ghana. An exploratory design that adopted both qualitative and quantities approaches was applied to the study. The study population involving 34 sample sizes was accessed from a 46 population made up of management/ministers of energy and counsellors or energy experts. The study concluded that the demand for energy in Ghana has increased over the years but without a commensurate increase in energy supply. Major reasons for the shortfall in energy supply have centred on the monopoly enjoyed by the major power producer which invariably places stress on its ability to supply energy to meet the increasing demand. It also came out that wind energy has the potential to contribute to the overall energy fortunes of Ghana. However, a focus on wind energy may not produce the required results of reducing the energy supply gap due to a preference for solar and natural gas oils. It was also noteworthy that the need to build capacity to develop and maintain wind energy through critical, current infrastructure stance of the Ghanaian energy sector would not make this agenda of developing wind energy a reality. More so, it is important to note that the need to enhance the current weak national policy, financial backing and bridge technology gap for wind energy would be needful to realise a vibrant investment into wind energy development.

Near- and Mid-term Development of Natural Gas Market in China

Economy growth in China is expected to slow down a little during the 13 th Five-Year-Plan period. So will the domestic gas demand and supply market, which may be quite different from that of the 11 th and 12 th Five-Year-Plan periods. The paper summarized the state quo of gas supply and demand in the country and analyzed factors that may affect the demand and supply balance in the new period. It is proposed that there will be many uncertainties in achieving supply and demand goals of gas set for the period, and gas glut is also very possible during the time. To deal with the problem, it is suggested that several measures be taken nationwide: improving utilization of gas in several sectors, straightening and optimizing the pricing mechanism, speeding up construction of infrastructures, implementing relevant policies and boosting up supervision and monitor of the industry.

新质生产力与矿产资源新格局

根据矿产资源安全巨系统理论,科技子系统是原始动力,驱动经济子系统变化,经济子系统变化又会驱动地缘政治子系统变化,同时,自然子系统的变化也会引起其他子系统变化,各子系统变化均会对矿产资源子系统产生重大影响。本文以矿产资源安全巨系统理论为指导,分析了新质生产力、气候变化、地缘政治等对全球矿产资源格局的影响,认为:新质生产力发展正改变工业化发展模式,后发国家承接产业转移的难度加大,现有矿产资源消费中心地位或将巩固,新的消费中心出现难度加大;新质生产力将改变人类矿产资源使用的终极形态,化石能源不再作为能源而是作为材料利用,金属成为能源之母;人工智能对能源的需求将大幅增长,各国对能源的争夺会愈演愈烈;美国脱钩断链正在破坏全球矿产资源安全,现有矿产资源储量难以满足未来需求,资源问题将成为制约各国生产力发展的重要约束。建议世界各国采取措施保障供应:一是加强国际间资源合作;二是加大勘查力度;三是加强矿产资源循环利用;四是加大低品位、共伴生资源的开发利用;五是大力加强资源节约利用。