Integration of optimal combinations of renewable energy sources into the energy supply of Wang-An Island

This is a case study of Wang-An Island's energy demands and potential renewable energy sources (RESs). Optimal integration of RESs was simulated using the EnergyPLAN model. The RES evaluation indicated an annual production potential of 458.1 GWh, which substantially surpassed local energy requirements of 22.3 GWh. The potential of yearly electricity generation from RESs of 299.7 GWh apparently outnumbers local electricity demand of 6.4 GWh as well, indicating that 100% renewable electricity would be achievable if surplus electricity can be stored and then reused during an electricity deficit. Electricity production from fully exploited RESs is able to supply only 5.8 GWh of electricity mainly caused by mismatches in times of electricity demand and production. The integrated optimization can supply 3.7 GWh of electricity. A deficit of 2.68 GWh can be compensated for through electricity storage or biomass energy. Although the total amount of generated renewable electricity during the whole year cannot yet satisfy the total amount of yearly demand, electricity storage can help to satisfy most of the electricity needs for the year.     

Securing energy efficiency as a high priority: scenarios for common appliance electricity consumption in Thailand

Between 1995 and 2008, Thailand’s energy efficiency programs produced an estimated total of 8,369 GWh/year energy savings and 1,471 MW avoided peak power. Despite these impressive saving figures, relatively little future scenario analysis is available to policy makers. Before the 2008 global financial crisis, electricity planners forecasted 5–6% long-term increases in demand. We explored options for efficiency improvements in Thailand’s residential sector, which consumes more than 20% of Thailand’s total electricity consumption of 150 TWh/year. We constructed baseline and efficient scenarios for the period 2006–2026, for air conditioners, refrigerators, fans, rice cookers, and compact fluorescent light bulbs. We drew on an appliance database maintained by Electricity Generating Authority of Thailand’s voluntary labeling program. For the five appliances modeled, the efficiency scenario results in total savings of 12% of baseline consumption after 10 years and 29% of baseline after 20 years. Approximately 80% of savings come from more stringent standards for air conditioners, including phasing out unregulated air conditioner sales within 6 years. Shifting appliance efficiency standards to current best-in-market levels within 6 years produces additional savings. We discuss institutional aspects of energy planning in Thailand that thus far have limited the consideration of energy efficiency as a high-priority resource.     

Hydropower in Turkey for a clean and sustainable energy future

Over the last two decades, global electricity production has more than doubled and electricity demand is rising rapidly around the world as economic development spreads to emerging economies. Not only has electricity demand increased significantly, it is the fastest growing end-use of energy. Therefore, technical, economic and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix, particularly in the developing countries. This paper deals with policies to meet increasing energy and electricity demand for sustainable energy development in Turkey. Turkey has a total gross hydropower potential of 433 GWh/year, but only 125 GWh/year of the total hydroelectric potential of Turkey can be economically used. By the commissioning of new hydropower plants, which are under construction, 36% of the economically usable potential of the country would be tapped. Turkey's total economically usable small hydropower potential is 3.75 GWh/year.     

Bottom–Up Energy Analysis System (BUENAS)—an international appliance efficiency policy tool

The Bottom–Up Energy Analysis System (BUENAS) calculates potential energy and greenhouse gas emission impacts of efficiency policies for lighting, heating, ventilation, and air conditioning, appliances, and industrial equipment through 2030. The model includes 16 end use categories and covers 11 individual countries plus the European Union. BUENAS is a bottom–up stock accounting model that predicts energy consumption for each type of equipment in each country according to engineering-based estimates of annual unit energy consumption, scaled by projections of equipment stock. Energy demand in each scenario is determined by equipment stock, usage, intensity, and efficiency. When available, BUENAS uses sales forecasts taken from country studies to project equipment stock. Otherwise, BUENAS uses an econometric model of household appliance uptake developed by the authors. Once the business as usual scenario is established, a high-efficiency policy scenario is constructed that includes an improvement in the efficiency of equipment installed in 2015 or later. Policy case efficiency targets represent current “best practice” and include standards already established in a major economy or well-defined levels known to enjoy a significant market share in a major economy. BUENAS calculates energy savings according to the difference in energy demand in the two scenarios. Greenhouse gas emission mitigation is then calculated using a forecast of electricity carbon factor. We find that mitigation of 1075 mt annual CO₂ emissions is possible by 2030 from adopting current best practices of appliance efficiency policies. This represents a 17 % reduction in emissions in the business as usual case in that year.     

Modelling of electricity savings in the Danish households sector: from the energy system to the end-user

In this paper, we examine the value of investing in energy-efficient household appliances from both an energy system and end-user perspectives. We consider a set of appliance categories constituting the majority of the electricity consumption in the private household sector, and focus on the stock of products which need to be replaced. First, we look at the energy system and investigate whether investing in improved energy efficiency can compete with the cost of electricity supply from existing or new power plants. To assess the analysis, Balmorel, a linear optimization model for the heat and power sectors, has been extended in order to endogenously determine the best possible investments in more efficient home appliances. Second, we propose a method to relate the optimal energy system solution to the end-user choices by incorporating consumer behaviour and electricity price addition due to taxes. The model is non-exclusively tested on the Danish energy system under different scenarios. Computational experiments show that several energy efficiency measures in the household sector should be regarded as valuable investments (e.g. an efficient lighting system) while others would require some form of support to become profitable. The analysis quantifies energy and economic savings from the consumer side and reveals the impacts on the Danish power system and surrounding countries. Compared to a business-as-usual energy scenario, the end-user attains net economic savings in the range of 30–40 EUR per year, and the system can benefit of an annual electricity demand reduction of 140–150 GWh. The paper enriches the existing literature about energy efficiency modelling in households, contributing with novel models, methods, and findings related to the Danish case.     

Integrated MAED–MARKAL-based analysis of future energy scenarios of Nepal

This paper employs an integrated model for analysis of energy demand and MARKet ALlocation modelling framework for assessing different pathways for the development of energy systems of Nepal. Four energy scenarios are analysed with the time horizon from 2010 to 2030. With high electrification and energy efficiency and demand-side management, the analysis reveals that all three major goals of sustainable energy for all can be achieved by 2030, but that the total discounted systems costs required account for three times the costs of the reference scenario. In the policy scenario, net fuel import costs and greenhouse gas emissions will decline by 20% and 35%, respectively and the share of renewable energy will increase from 3% in 2010 to 22% in 2030. The analysis provides insights for selecting a better pathway for the sustainable energy development and energy security of the country.     

Electricity consumption and CO2 capture potential in Spain

In this paper, different electricity demand scenarios for Spain are presented. Population, income per capita, energy intensity and the contribution of electricity to the total energy demand have been taken into account in the calculations. Technological role of different generation technologies, i.e. coal, nuclear, renewable, combined cycle (CC), combined heat and power (CHP) and carbon capture and storage (CCS), are examined in the form of scenarios up to 2050. Nine future scenarios corresponding to three electrical demands and three options for new capacity: minimum cost of electricity, minimum CO₂ emissions and a criterion with a compromise between CO₂ and cost (CO₂-cost criterion) have been proposed. Calculations show reduction in CO₂ emissions from 2020 to 2030, reaching a maximum CO₂ emission reduction of 90% in 2050 in an efficiency scenario with CCS and renewables. The contribution of CCS from 2030 is important with percentage values of electricity production around 22–28% in 2050. The cost of electricity (COE) increases up to 25% in 2030, and then this value remains approximately constant or decreases slightly.     

Hydropower for sustainable water and energy development

Turkey has a total gross hydropower potential of 433 GWh/year, but only 125 GWh/year of the total hydroelectric potential of Turkey can be economically used. By the commissioning of new hydropower plants, which are under construction, 36% of the economically usable potential of the country would be tapped. Turkey presently has considerable renewable energy sources. The most important renewable sources are hydropower, biomass, geothermal, solar and wind. Turkey's geographical location has several advantages for extensive use of most of these renewable energy sources. Over the last two decades, global electricity production has more than doubled and electricity demand is rising rapidly around the world as economic development spreads to emerging economies. Not only has electricity demand increased significantly, it is the fastest growing end-use of energy. Therefore, technical, economic and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix, particularly in the developing countries.     

Analysis of potential energy saving and CO2 emission reduction of home appliances and commercial equipments in China

China has implemented a series of minimum energy performance standards (MEPS) for over 30 appliances, voluntary energy efficiency label for 40 products, and a mandatory energy information label that covers 19 products to date. However, the impact of these programs and their savings potential has not been evaluated on a consistent basis. This paper uses modeling to estimate the energy saving and CO₂ emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, under development or those proposed for development in 2010 under three scenarios that differ in the pace and stringency of MEPS development. In addition to a baseline “frozen efficiency” scenario at 2009 MEPS level, the “Continued Improvement Scenario” (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step. The “Best Practice Scenario” (BPS) examined the potential of an achievement of international best-practice efficiency in broad commercial use today in 2014. This paper concludes that under “CIS”, cumulative electricity consumption could be reduced by 9503 TWh, and annual CO₂ emissions of energy used for all 37 products would be 16% lower than in the frozen efficiency scenario. Under a “BPS” scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO₂ emissions reduction of energy used for 11 appliances would be 35% lower.     

A prospective study of bioenergy use in Mexico

Bioenergy is one of the renewable energy sources that can readily replace fossil fuels, while helping to reduce greenhouse gas emissions and promoting sustainable rural development. This paper analyses the feasibility of future scenarios based on moderate and high use of biofuels in the transportation and electricity generation sectors with the aim of determining their possible impact on the Mexican energy system. Similarly, it evaluates the efficient use of biofuels in the residential sector, particularly in the rural sub-sector. In this context, three scenarios are built within a time frame that goes from 2005 to 2030. In the base scenario, fossil fuels are assumed as the dominant source of energy, whereas in the two alternative scenarios moderate and high biofuel penetration diffusion curves are constructed and discussed on the basis of their technical and economical feasibility. Simulation results indicate that the use of ethanol, biodiesel and electricity obtained from primary biomass may account for 16.17% of the total energy consumed in the high scenario for all selected sectors. CO₂ emissions reduction—including the emissions saved from the reduction in the non-sustainable use of fuelwood in the rural residential sector—is equivalent to 87.44 million tons of CO₂ and would account for 17.84% of the CO₂ emitted by electricity supply and transportation sectors when the base case and the high scenario are compared by 2030.     

The use of conservation supply curves in energy policy and economic analysis: The case study of Thai cement industry

The cement industry is one of the largest energy-consuming industries in Thailand with high carbon dioxide (CO₂) emissions. Using a bottom-up electricity Conservation Supply Curve (CSC) model, the cost effective and the total technical electricity-efficiency potential for the Thai cement industry in 2008 is estimated to be about 265 and 1697 gigawatt-hours (GWh) which account for 8% and 51% of the total electricity used in the cement industry in 2005, respectively. The fuel CSC model shows the cost-effective fuel-efficiency potential to be 17,214 terajoules (TJ) and the total technical fuel-efficiency potential equal to 21,202 TJ, accounting for 16% and 19% of the total fuel used in cement industry in 2005, respectively. The economic analysis in this paper shows how the information from the CSCs can be used to calculate the present value (PV) of net cost savings over a period of time taking into account the energy price escalation rate. The results from the policy scenario analysis show that the most effective and efficient policy scenario is the introduction of an energy-related CO₂ tax for the cement industry under a voluntary agreement program. This scenario results in 16.9% primary energy-efficiency improvement over a 5-year implementation period.     

Thermodynamic development and design of a concentrating solar thermochemical water-splitting process for co-production of hydrogen and electricity

A concentrating solar plant is proposed for a thermochemical water-splitting process with excess heat used for electricity generation in an organic Rankine cycle. The quasi-steady state thermodynamic model consisting of 23 components and 45 states uses adjustable design parameters to optimize hydrogen production and system efficiency. The plant design and associated thermodynamic model demonstrate that cerium oxide is suitable for thermochemical water-splitting cycles involving the co-production of hydrogen and electricity. Design point analyses at 900 W/m² DNI indicate that a single tower with solar radiation input of 27.74 MW and an aperture area of 9.424 m² yields 10.96 MW total output comprised of 5.55 MW hydrogen (Gibbs free energy) and 5.41 MW net electricity after subtracting off 22.0% of total power generation for auxiliary loads. Pure hydrogen output amounts to 522 tonne/year at 20.73 GWh/year (HHV) or 17.20 GWh/year (Gibbs free energy) with net electricity generation at 14.52 GWh/year using TMY3 data from Daggett, California, USA. Annual average system efficiency is 38.2% with the constituent hydrogen fraction and electrical fraction being 54.2% and 45.8%, respectively. Sensitivity analyses illustrate that increases in particle loop recuperator effectiveness create an increase in hydrogen production and a decrease in electricity generation. Further, recuperator effectiveness has a measurable effect on hydrogen production, but has limited impact on total system efficiency given that 81.1% of excess heat is recuperated within the system for electricity generation.     

Smart residential energy management system for demand response in buildings with energy storage devices

In the present scenario, the utilities are focusing on smart grid technologies to achieve reliable and profitable grid operation. Demand side management (DSM) is one of such smart grid technologies which motivate end users to actively participate in the electricity market by providing incentives. Consumers are expected to respond (demand response (DR)) in various ways to attain these benefits. Nowadays, residential consumers are interested in energy storage devices such as battery to reduce power consumption from the utility during peak intervals. In this paper, the use of a smart residential energy management system (SREMS) is demonstrated at the consumer premises to reduce the total electricity bill by optimally time scheduling the operation of household appliances. Further, the SREMS effectively utilizes the battery by scheduling the mode of operation of the battery (charging/floating/discharging) and the amount of power exchange from the battery while considering the variations in consumer demand and utility parameters such as electricity price and consumer consumption limit (CCL). The SREMS framework is implemented in Matlab and the case study results show significant yields for the end user.     

What is the relationship between built form and energy use in dwellings?

Energy is used in dwellings to provide four services: space heating, hot water, lighting and to power appliances. This paper describes how the usage of energy in a UK home results from a complex interaction between built form, location, energy-using equipment, occupants and the affordability of fuel. Current models with standard occupancy predict that energy use will be strongly related to size and built form, but surveys of real homes show only weak correlations, across all types of dwelling. Recent research has given us insights into occupancy factors including preferred comfort, ‘take-back’ from thermal efficiency improvements, and patterns of electricity use. Space heating is on a downward trend and is low in new dwellings. Energy use for lights and appliances, which is only weakly related to built form, is increasing. Strong legislation, combined with low-carbon technologies, will be needed to counteract this trend. Future challenges discussed include increases in real energy prices and climate change mitigation efforts, which are likely to improve the existing stock. Challenging targets are now in place for new housing to move towards low or zero energy and carbon standards. In the longer term, dwellings will demand less energy. Alternatives to gas for space heating will be increasingly common, including ground source heat and local combined heat and power (CHP) from biomass, while electricity could come from a more decarbonised electricity system. However, these improvements must be set alongside a demand for many new homes, demographic trends towards smaller households, and a more holistic approach to overall carbon use including personal transport.     

A data‐driven approach to study the role of interconnectors in a future low‐carbon electricity supply system

This paper investigates the potential role of the electricity interconnectors in improving the security of supply in Great Britain (GB) in 2030. Real electricity demand and price data for GB and France in 2016 were used to understand the relationship between power exchange between the two countries and their wholesale electricity prices. A linear programming optimisation model was developed to find the economic power dispatch. Two interconnection links were considered; two‐way trade interconnector with a capacity of 5.4 GW and a 12.3 GW import‐only interconnector between GB and other states. The GB–France link transmits electricity from cheaper system to the more expensive one. The total electricity demand in 2030 will be 406 TWh. Gas‐fired power plants w/wo CCS will provide 83 TWh of the total electricity demand, whereas nuclear power plants will produce 74 TWh. In addition, wind farms and solar PVs are expected to deliver ~120 TWh electricity. CHP units will provide 88 TWh electricity in 2030. The electricity traded between GB and France in 2030 was found to be 33 TWh, which is 160% larger compared with 2016. The power import from France is about 27 TWh and occurs in 59% of the time. For 64% of the time, the interconnector with France is fully loaded. The electricity imported via the 12.3 GW interconnector in 2030 is 1 TWh and mainly occurs during winter‐time when the demand in GB is high. De‐rated capacity margin was calculated based on instantaneous electricity demand and varies between ?2% and 139%. The impact of the price of the imported electricity via the 12.3 GW link was investigated. Increasing the price of the imported electricity via the 12.3 GW link results in a higher capacity factor for all the generation options except the 12.3 GW interconnector link.     

Economic feasibility for acquisition of efficient refrigerators in Brazil

Since 1993, the Brazilian National Program of Electricity Conservation has been developing the PROCEL Label Program, oriented towards helping consumers to buy more efficient home appliances. In this context, an energy savings of 1379 GWh and a reduction of 197 MW in the Brazilian demand in 2007 are estimated as resulting from efficiency labeling in refrigerators and freezers. This paper aims to evaluate the economic feasibility of purchasing labeled refrigerators instead of inefficient ones, from the consumer’s point of view, considering actual market conditions and buying in cash or financing. The evaluation of energy saving was done for 22 different models of refrigerators and the economy was calculated considering the retail price in the Brazilian market and two actual electricity tariffs, taking into account, respectively, high and low household electricity consumption. The effect of ambient temperature on refrigerator performance was evaluated in two conditions: according to the Brazilian standard for performance tests (32 °C) and using the average temperature of Southern Brazil (18 °C), the mildest region. The benefit in buying labeled refrigerators was evaluated using the Internal Rate of Return and the Payback Time for a cash flow during the appliance life, estimated as 16 years. The results indicate that for cash purchase, for any electricity tariff and for both ambient temperatures studied, the consumers are economically benefited buying labeled refrigerators instead of less efficient models. For credit purchases, in the evaluated conditions, high-tariff consumer typically gains selecting labeled refrigerator, on the other hand, for low-tariff consumer and in colder areas, it is economically advisable to buy less efficient appliances. Sensitivity analysis of energy tariff and financing conditions are presented.     

Peak CO2 emission in the region dominated by coal use and heavy chemical industries: a case study of Dezhou city in China

This paper studies the pathways of peaking CO₂ emissions of Dezhou city in China, by employing a bottom-up sector analysis model and considering future economic growth, the adjustment of the industrial structure, and the trend of energy intensity. Two scenarios (a business-as-usual (BAU) scenario and a CO₂ mitigation scenario (CMS)) are set up. The results show that in the BAU scenario, the final energy consumption will peak at 25.93 million tons of coal equivalent (Mtce) (16% growth versus 2014) in 2030. In the CMS scenario, the final energy will peak in 2020 at 23.47 Mtce (9% lower versus peak in the BAU scenario). The total primary energy consumption will increase by 12% (BAU scenario) and decrease by 3% (CMS scenario) in 2030, respectively, compared to that in 2014. In the BAU scenario, CO₂ emission will peak in 2025 at 70 million tons of carbon dioxide (MtCO₂), and subsequently decrease gradually in 2030. In the CMS scenario, the peak has occurred in 2014, and 60 MtCO₂ will be emitted in 2030. Active policies including restructuring the economy, improving energy efficiency, capping coal consumption, and using more low-carbon /carbon free fuel are recommended in Dezhou city peaked CO₂ emission as early as possible.     

Energy efficiency standards for refrigerators in Brazil: A methodology for impact evaluation

In Brazil energy efficiency standards for cold appliances was established in 2007. A specified single set of MEPS (minimum energy performance standards) for refrigerators, freezers and freezer refrigerators was implemented without evaluating its impacts and estimation of potential electricity savings. This paper presents a methodology for assessing the impacts of the Brazilian MEPS for cold appliances. It uses a bottom-up approach to estimate residential end-use consumption and to evaluate the energy saving potential for refrigerators. The household electricity consumption is projected by modeling appliance ownership using an econometric approach based on the recent household survey data. A cost–benefit analysis for more stringent standards is presented from the perspective of the society and electricity customers. The results showed that even considering the current market conditions (high discount rate for financing new efficient equipment) some MEPS options are advantageous for customers. The analysis also demonstrates significant cost-effective saving potential from the society perspective that could reach 21 TWh throughout the period of 2010–2030—about 25% of current residential consumption.     

Energy consumption projection of Nepal: An econometric approach

In energy dependent economies, energy consumption is often linked with the growth in Gross Domestic Product (GDP). Energy intensity, defined herewith, as the ratio of the total primary energy consumption (TPE) to the GDP, is a useful concept for understanding the relation between energy demand and economic development. The scope of this article is to assess the future primary energy consumption of Nepal, and the projection is carried out along with the formulation of simple linear logarithmic energy consumption models. This initiates with a hypothesis that energy consumption is dependent with the national macro-economic parameters. To test the hypothesis, nexus between energy consumption and possible determinant variables are examined. Status of energy consumption between the period of 1996 and 2009, and for the same period, growth of economic parameters are assessed. Three scenarios are developed differing from each other on the basis of growth rates of economic indicators: total GDP, GDP-agriculture, GDP-trade, GDP-industry, and other variables including growth in private consumptions, population, transport vehicles numbers, prices of fossil fuels etc. Scenarios are: Business as Usual (BAU), Medium Growth Scenario (MGS) and High Growth Scenario (HGS). Energy consumption in all the sectors and for all fuel types are not statistically correlated with every economic parameters tested in the assessment. Hence, the statistically correlated models are included in the prognosis of energy consumption. For example, the TPE consumption and electricity consumption, both are significantly dependent with the total GDP and population growth. Likewise, fuel wood consumption is significantly dependent with the growth in rural population and private consumptions. In BAU the estimated electricity consumption in 2030 would be 7.97 TWh, which is 3.47 times higher than that of 2009. In MGS, the total electricity consumption in 2030 is estimated to increase by a factor of 5.71 compared to 2009. Likewise, in HGS, electricity consumption would increase by 10-fold until 2030 compared to 2009, demanding installed capacity of power plant at 6600 MW, which is only from hydro power and other centralised system.     

Analysis of energy-efficiency opportunities for the cement industry in Shandong Province,China: A case study of 16 cement plants

In this study, 16 cement plants with New Suspension Preheater and pre-calciner (NSP) kiln were surveyed. Plant energy use was compared to both domestic (Chinese) and international best practice using the Benchmarking and Energy Saving Tool for Cement (BEST-Cement). This benchmarking exercise indicated an average technical potential primary energy savings of 12% would be possible if the surveyed plants operated at domestic best practice levels in terms of energy use per ton of cement produced. Average technical potential primary energy savings of 23% would be realized if the plants operated at international best practice levels. Then, using the bottom-up Electricity Conservation Supply Curve (ECSC) model, the cost-effective electricity efficiency potential for the 16 studied cement plants in 2008 is estimated to be 373 gigawatt-hours (GWh), and total technical electricity-saving potential is 915 GWh, which accounts for 16 and 40% of total electricity use in the studied plants in 2008, respectively. The Fuel Conservation Supply Curve (FCSC) model shows the total technical fuel efficiency potential equal to 7949 terajoules (TJ), accounting for 8% of total fuel used in the studied cement plants in 2008. All the fuel efficiency potential is shown to be cost effective.