End-use Efficiency Research Articles

Electricity End-Use Efficiency in Ghana: Experience with Technologies, Policies and Institutions

For almost a decade, Ghana has experienced the application of technologies and policies intended to improve electricity end-use efficiency. The technologies included appliances, lighting, variable speed drivers and power factor correction while the policies comprised appliances standards and labels, mass adoption of electricity-saving lamps, financial and fiscal policies. A number of market failures hindered the penetration of these technologies and the study reviewed the extent to which these limitations prevented the success of these technologies. The role of institutions in influencing policy, prices, consumers and manufacturers or importers to improve the penetration of these technologies was regarded as important. DOI: 10.5901/mjss.2013.v4n13p669

EUROPEAN ENERGY EFFICIENCY AND DECARBONIZATION STRATEGIES BEYOND 2030 — A SECTORAL MULTI-MODEL DECOMPOSITION

Energy efficiency and decarbonization are important elements of climate change mitigation. We draw on European mitigation scenarios from the EMF28 modeling exercise to decompose economy-wide and sectoral emissions into their main components. We utilize the Logarithmic Mean Divisia Index (LMDI) to gain insights into five effects: affluence, energy intensity, carbon intensity, conversion efficiency, and structural change. Economy-wide analysis suggests that energy efficiency improvements (including end-use efficiency of production and structural change of the economy) determine emission reductions short to medium term while decarbonization becomes more important in the long term. Sectoral analysis suggests that electricity generation holds the largest potential for decarbonization. Mitigation in the transport and energy-intensive sectors is limited by technology availability, forcing output and energy inputs to decline to meet the given mitigation pathways. We conclude that energy efficiency improvements could bridge the time until carbon-free technologies mature, while their quick development remains essential.

A MULTI-MODEL ANALYSIS OF POST-2020 MITIGATION EFFORTS OF FIVE MAJOR ECONOMIES

This paper looks into the regional mitigation strategies of five major economies (China, EU, India, Japan, and USA) in the context of the 2°C target, using a multi-model comparison. In order to stay in line with the 2°C target, a tripling or quadrupling of mitigation ambitions is required in all regions by 2050, employing vigorous decarbonization of the energy supply system and achieving negative emissions during the second half of the century. In all regions looked at, decarbonization of energy supply (and in particular power generation) is more important than reducing energy demand. Some differences in abatement strategies across the regions are projected: In India and the USA the emphasis is on prolonging fossil fuel use by coupling conventional technologies with carbon storage, whereas the other main strategy depicts a shift to carbon-neutral technologies with mostly renewables (China, EU) or nuclear power (Japan). Regions with access to large amounts of biomass, such as the USA, China, and the EU, can make a trade-off between energy related emissions and land related emissions, as the use of bioenergy can lead to a net increase in land use emissions. After supply-side changes, the most important abatement strategy focuses on end-use efficiency improvements, leading to considerable emission reductions in both the industry and transport sectors across all regions. Abatement strategies for non- CO2emissions and land use emissions are found to have a smaller potential. Inherent model, as well as collective, biases have been observed affecting the regional response strategy or the available reduction potential in specific (end-use) sectors.

Applicability of Energy Saving Obligations to Indian electricity efficiency efforts

This paper investigates end-use electricity efficiency policies and DSM related aspects within the Indian electricity sector. This work also identifies lessons for India from White Certificate schemes and Energy Saving Obligations in the UK, France and Italy. These two analyses aim to identify lessons which are applicable for a utility based energy saving obligation scheme within India. Most relevant results and recommendations are that an obligation is suggested, that no elements should be simply copied and that standardization could offer benefits to the Indian context. However, a number of steps would be required prior to introduction of such obligation.

The savings of energy saving: interactions between energy supply and demand-side options—quantification for Portugal

Reducing demand by increasing end-use energy efficiency on the demand side of energy systems may also have advantages in reducing fossil dependency and greenhouse gas (GHG) emissions on the supply side. This paper addresses interactions between energy supply- and demand-side policies, by estimating the impact of measures addressing end-use energy efficiency and small-scale renewables uses in terms of (1) avoided large-scale electricity generation capacity, (2) final energy consumption, (3) share of renewables in final energy and (4) reduction of GHG emissions. The Portuguese energy system is used as a case study. The TIMES_PT bottom-up model was used to generate four scenarios covering the period up to 2020, corresponding to different levels of efficiency of equipment in buildings, transport and industry. In the current policy scenario, the deployment of end-use equipment follows the 2000–2005 trends and the National Energy Efficiency Action Plan targets. In the efficient scenarios, all types of equipment can be replaced by more efficient ones. Results show that aggressive demand-side options for the industry and buildings sector and the small-scale use of renewables can remove the need for the increase in large-scale renewable electricity capacity by 4.7 GW currently discussed by policy makers. Although these measures reduce total final energy by only 0–2 %, this represents reductions of 11–14 % in the commercial sector, with savings in total energy system costs of approximately 3,000 million euros2000—roughly equivalent to 2 % of the 2010 Portuguese GDP. The cost-effectiveness of policy measures should guide choices between supply shifts and demand reduction. Such balanced policy development can lead to substantial cost reductions in climate and energy policy.

Extension to nonlinear adsorption isotherms of exact analytical solutions to mass diffusion problems

Analytical solutions with algebraic expressions are proposed for one-dimensional nonlinear mass diffusion problems. The solutions proposed to solve sorption/desorption problems are rigorously exact for piecewise linear isotherms. They provide an efficient methodology to devise analytical solutions to nonlinear isotherms, and instantly time-varying boundary conditions, with arbitrary accuracy. An exact solution is calculated for each linear piece of the isotherm and is then propagated iteratively to the next linear piece. For end-user convenience and efficiency, three exact analytical expansions are proposed: a new short and intermediate contact time expansion obtained using the Laplace transform (erfc solution), a modified version of Eq. (33) in Sagiv (2002) with improved stability (Sagiv solution), and a new expansion with a decreasing energy norm (energy solution). All expansions are compared in terms of their accuracy and number of terms for typical nonlinear isotherms, mass Biot numbers and volume ratios covering a broad range of applications. When the thermodynamic conditions are changed at the interface, only the “erfc” and the “energy” solutions retain overall accuracy (machine precision) with few terms (<30). New strategies to enable the simultaneous estimation of diffusion coefficients, isotherms and mass Biot numbers are finally derived.

The impact of electricity demand reduction policies on the EU-ETS: Modelling electricity and carbon prices and the effect on industrial competitiveness

The European electricity market is linked to a carbon market with a fixed cap that limits greenhouse gas emissions. At the same time, a number of energy efficiency policy instruments in the EU aim at reducing the electricity consumption. This article explores the interactions between the EU's carbon market on the one hand and instruments specifically targeted towards energy end-use efficiency on the other hand. Our theoretical analysis shows how electricity demand reduction triggered by energy efficiency policy instruments affects the emission trading scheme. Without adjustments of the fixed cap, decreasing electricity demand (relative to business-as-usual) reduces the carbon price without reducing total emissions. With lower carbon prices, costly low emission processes will be substituted by cheaper high emitting processes. Possible electricity and carbon price effects of electricity demand reduction scenarios under various carbon caps are quantified with a long-term electricity market simulation model. The results show that electricity efficiency policies allow for a significant reduction of the carbon cap. Compared to the 2005 emission level, 30% emission reductions can be achieved by 2020 within the emission trading scheme with similar or even lower costs for the industrial sector than were expected when the cap was initially set for a 21% emission reduction.

Top-down and bottom-up modelling to support low-carbon scenarios: climate policy implications

Bottom-up and top-down models are used to support climate policies, to identify the options required to meet GHG abatement targets and to evaluate their economic impact. Some studies have shown that the GHG mitigation options provided by economic top-down and technological bottom-up models tend to vary. One reason for this is that these models tend to use different baseline scenarios. The bottom-up TIMES_PT and the top-down computable general equilibrium GEM-E3_PT models are examined using a common baseline scenario to calibrate them, and the extend of their different mitigation options and its relevant to domestic policy making are assessed. Three low-carbon scenarios for Portugal until 2050 are generated, each with different GHG reduction targets. Both models suggest close mitigation options and locate the largest mitigation potential to energy supply. However, the models suggest different mitigation options for the end-use sectors: GEM-E3_PT focuses more on energy efficiency, while TIMES_PT relies on decrease carbon intensity due to a shift to electricity. Although a common baseline scenario cannot be ignored, the models’ inherent characteristics are the main factor for the different outcomes, thereby highlighting different mitigation options. Policy relevance The relevance of modelling tools used to support the design of domestic climate policies is assessed by evaluating the mitigation options suggested by a bottom-up and a top-down model. The different outcomes of each model are significant for climate policy design since each suggest different mitigation options like end-use energy efficiency and the promotion of low-carbon technologies. Policy makers should carefully select the modelling tool used to support their policies. The specific modelling structures of each model make them more appropriate to address certain policy questions than others. Using both modelling approaches for policy support can therefore bring added value and result in more robust climate policy design. Although the results are specific for Portugal, the insights provided by the analysis of both models can be extended to, and used in the climate policy decisions of, other countries.

On the potential trade-offs between energy supply and end-use technologies for residential heating

In Sweden, where district heating accounts for a significant share of residential heating, it has been argued that improvements in end-use energy efficiency may be counter-productive since such measures reduce the potential of energy efficient combined heat and power production. In this paper we model how the potential trade-offs between energy supply and end-use technologies depend on climate policy and energy prices. The model optimizes a combination of energy efficiency measures, technologies and fuels for heat supply and district heating extensions over a 50 year period. We ask under what circumstances improved end-use efficiency may be cost-effective in buildings connected to district heating? The answer hinges on the available technologies for electricity production. In a scenario with no alternatives to basic condensing electricity production, high CO2 prices result in very high electricity prices, high profitability of combined heat and power production, and little incentive to reduce heat demand in buildings with district heating. In contrast, in a scenario where electricity production alternatives with low CO2 emissions are available, the electricity price will level out at high CO2 prices. This gives heat prices that increase with the CO2 price and make end-use efficiency cost-effective also in buildings with district heating.

The effect of improved efficiency on energy savings in EU-27 buildings

Utilising energy efficiency to lower energy demand in buildings is a key policy goal of the European Commission. This paper presents the results of bottom-up modelling to elucidate the impact of energy efficiency on the EU building stock up to 2050 under three different scenarios. The modelling is performed for eight individual EU countries and a ninth hypothetical entity that represents the remaining nineteen EU countries. The scenarios highlight the roles of different levels of efficiency improvements in the context of increasing floor area and the demand for energy services. From the results it can be concluded that the EC 2020 goals for primary energy savings can be met by focussing on a combination of minimum efficiency construction standards, improved conversion efficiency standards for final energy to useful energy, and a ≥2% annual improvement in end-use efficiency applied at the useful energy level. A comparison of the results obtained in the present study for Spain with the estimates of savings documented in the Spanish Energy Efficiency Action Plan indicate that the plan could lead to the closing of the energy efficiency gap for buildings in that country by 2020.

Scenarios of global municipal water-use demand projections over the 21st century

Three future projections of global municipal water use are established: business-as usual (BAU), low technological improvement (Low Tech), and high technological improvement (High Tech). A global municipal water demand model is constructed using global water-use statistics at the country scale, calibrated to the base year of 2005, and simulated to the end of the 21st century. Since the constructed water demand model hinges on socio-economic variables (population, income), water price, and end-use technology and efficiency improvement rates, projections of those input variables are adopted to characterize the uncertainty in future water demand estimates. The water demand model is linked to the Global Change Assessment Model (GCAM), a global change integrated assessment model. Under the reference (BAU) scenario, the global total water withdrawal increases from 466 km3 year−1 in 2005 to 1098 km3 year−1 in 2100, while withdrawals in the High and Low Tech scenarios are 437 and 2000 km3 year−1, respectively. Editor Z.W. Kundzewicz; Associate editor D. Gerten Citation Hejazi, M., Edmonds, J., Chaturvedi, V., Davies, E., and Eom, J.Y., 2013. Scenarios of global municipal water use demand projections over the 21st century. Hydrological Sciences Journal, 58 (3), 519–538

Brazilian Lignocellulosic Wastes for Bioenergy Production: Characterization and Comparison with Fossil Fuels

The aim of this paper was to analyze energy-related properties of forestry and agricultural wastes for energy production purposes, and to compare them with fossil fuels. The forestry wastes used were red cedar, Eucalyptus, and Pinus wood shavings. The agricultural wastes analyzed were rice husk, coffee wastes, sugar cane bagasse, maize harvesting wastes, and bamboo cellulose pulp. The forestry wastes presented more suitable properties for bioenergy production than the agricultural wastes. Desirable energetic properties were found for coffee wastes. The opposite was verified for rice husks. Among the biomass studied, coffee wastes presented the highest equivalent in fossil fuel volume and hence may lead to the highest decrease in CO2 emissions by fossil fuels used in Brazil for steam and heat production. The results suggests that CO2 benefits can be obtained if bioenergy is generated in the same locale where biomass is produced, avoiding CO2 cost of logistics and leading to greater end-use efficiency. The present work promotes the widespread use of different lignocellulosic wastes for bioenergy production and gives useful information for the planning and the control of power plants using biomass.

Direct air capture of CO2 with chemicals: optimization of a two-loop hydroxide carbonate system using a countercurrent air-liquid contactor

Abstract Direct Air Capture (DAC) of CO2 with chemicals, recently assessed in a dedicated study by the American Physical Society (APS), is further investigated with the aim of optimizing the design of the front-end section of its benchmark two-loop hydroxide-carbonate system. Two new correlations are developed that relate mass transfer and pressure drop to the air and liquid flow velocities in the countercurrent packed absorption column. These relationships enable an optimization to be performed over the parameters of the air contactor, specifically the velocities of air and liquid sorbent and the fraction of CO2 captured. Three structured Sulzer packings are considered: Mellapak-250Y, Mellapak-500Y, and Mellapak-CC. These differ in cost and pressure drop per unit length; Mellapak-CC is new and specifically designed for CO2 capture. Scaling laws are developed to estimate the costs of the alternative DAC systems relative to the APS benchmark, for plants capturing 1 Mt of CO2 per year from ambient air at 500 ppm CO2 concentration. The optimized avoided cost hardly differs across the three packing materials, ranging from $518/tCO2 for M-CC to $568/tCO2 for M-250Y. The $610/tCO2 avoided cost for the APS-DAC design used M-250 Y but was not optimized; thus, optimization with the same packing lowered the avoided cost of the APS system by 7 % and improved packing lowered the avoided cost by a further 9 % The overall optimization exercise confirms that capture from air with the APS benchmark system or systems with comparable avoided costs is not a competitive mitigation strategy as long as the energy system contains high-carbon power, since implementation of Carbon Capture and Storage, substitution with low-carbon power and end-use efficiency will offer lower avoided-cost strategies.

Recent estimates of energy efficiency potential in the USA

Understanding the potential for reducing energy demand through increased end-use energy efficiency can inform energy and climate policy decisions. However, if potential estimates are vastly different, they engender controversial debates, clouding the usefulness of energy efficiency in shaping a clean energy future. A substantive question thus arises: is there a general consensus on the potential estimates? To answer this question, this paper reviews recent studies of US national and regional energy efficiency potential in buildings and industry. Although these studies are based on differing assumptions, methods, and data, they suggest technically possible reductions of ~25–40 % in electricity demand and ~30 % in natural gas demand in 2020 and economic reductions of ~10–25 % in electricity demand and ~20 % in natural gas demand in 2020. These estimates imply that electricity growth from 2009 to 2020 ranges from turning US electricity demand growth negative, to reducing it to a growth rate of ~0.3 %/year (compared to ~1 % baseline growth).

The Design and Implementation of Multiterminal Based Proactive Information Delivery System

Currently, the development of various communication terminal devices has greatly promoted people’s daily life, while information using efficiency with these devices decreases rapidly due to the information overload. To solve this problem, a multiterminal based proactive information delivery system (MPIDS) is designed and implemented in this paper. Firstly, users’ interests are computed comprehensively from the historical data, taking full consideration of users’ behaviors when visiting web pages. Secondly, a proactive information monitor service is introduced to monitor users’ data requirements and their interest changes, with which, user data are pushed to their online device automatically according to the strategies. Finally, a data self-adapter is given to encode and transform the data according to users’ online parameters and a series of data self-adaptive strategies. The experimental results show that MPIDS provides richly featured, secure, and robust personalized functions, reduces the running cost, and promotes the end-user experience and business efficiency.

Cost of ad-hoc nuclear policy uncertainties in the evolution of the Swiss electricity system

About one-third of the Swiss nuclear capacity is due to be retired in the next ten years, creating a short-term supply gap. In addition, the Swiss Federal Council has decided to phase out nuclear power over the longer term by not replacing existing nuclear power plants after retirement. We have analysed possible electricity supply options for responding to these two developments under different conditions using the Swiss TIMES electricity sector model—a least-cost optimization framework. Short-term demand can be cost-effectively met with new investment in gas-fired generation capacity. However, meeting the government’s CO2 emission and renewable electricity targets requires an accelerated investment in renewable generation and/or increased reliance on imported electricity. In the medium and longer term, nuclear represents the most cost-effective option. The alternatives to nuclear lead to increased dependence on imported natural gas, seasonal renewables and imported electricity. All non-nuclear supply options increase the cost of electricity supply by between 50 and 150%, and create a range of tradeoffs between supply security and climate change mitigation goal. However, it is expected that an accelerated uptake of end-use efficiency measures and demand side management would reduce future electricity demand, thus reducing the need for some expensive supply options.

Asia's role in mitigating climate change: A technology and sector specific analysis with ReMIND-R

We use the ReMIND-R model to analyze the role of Asia in the context of a global effort to mitigate climate change. We introduce a novel method of secondary energy based mitigation shares, which allows us to quantify the economic mitigation potential of technologies in different regions and final energy carriers.The 2005 share of Asia in global CO2 emissions amounts to 38%, and is projected to grow to 53% under business-as-usual until the end of the century. Asia also holds a large fraction of the global mitigation potential. A broad portfolio of technologies is deployed in the climate policy scenarios. We find that biomass in combination with CCS, other renewables, and end-use efficiency each make up a large fraction of the global mitigation potential, followed by nuclear and fossil CCS. We find considerable differences in decarbonization patterns across the final energy types electricity, heat and transport fuels. Regional differences in technology use are a function of differences in resource endowments, and structural differences in energy end use. Under climate policy, a substantial mitigation potential of non-biomass renewables emerges for China and other developing countries of Asia (OAS). Asia also accounts for the dominant share of the global mitigation potential of nuclear energy. In view of the substantial near term investments into new energy infrastructure in China and India, early adoption of climate policy prevents lock-in into carbon intensive infrastructure and thus leads to a much higher long-term mitigation potential.

Transition pathways for a UK low carbon electricity future

Achieving long-term targets for greenhouse gas emissions reductions, such as the UK's legally-binding target of reducing its emissions by 80% by 2050, will require a transition in systems for meeting and shaping energy service demands, involving radical substitution to low-carbon supply technologies and improvements in end-use energy efficiency. This paper describes the development and high-level analysis of a set of transition pathways to a UK low carbon electricity system, explaining key features of the core pathways developed and the distinctiveness and value of the approach. The pathways use an ‘action space’ concept to explore the dynamic interactions between choices made by actors, which are influenced by the competing governance ‘framings’ or ‘logics’ that different actors pursue. The paper sets out three core transition pathways – Market Rules, Central Co-ordination and Thousand Flowers, in which market, government and civil society logics respectively dominate. It summarises the key technological and institutional changes in these pathways, and the roles of actors in bringing these about. This leads to an identification of the key risks to the realisation of each of the pathways, and of the challenges for individuals, businesses, social movements and policy-makers in taking action to bring them about and sustain them.

Synergies between Energy Efficiency and Energy Access Policies and Strategies

AbstractPolicies to improve energy access and energy efficiency are often discussed, designed and assessed in isolation from each other. In this paper, we highlight possible synergies in these two domains of policy making by looking specifically at some key household end uses that are the first to be met once improved access has been provided. By building in efficiency considerations at the very inception of activities aimed at improving access, effective energy supply available is potentially increased, the level of energy services that can be provided by the existing capacity and infrastructure or from existing budgets available is also enhanced, and the potential for reducing the cost for those populations for which cost has the highest consideration is also improved. In particular, we recommend two areas where policy maybe leveraged to benefit both access and efficiency objectives, first in the setting of standards, labels and codes and second coupling energy subsidies for access with rebates or grants for more efficient end use devices.

Synergies in the Asian energy system: Climate change, energy security, energy access and air pollution

We use the MESSAGE model to examine multiple dimensions of sustainable development for three Asian regions in a set of scenarios developed for the Asian Modelling Exercise. Using climate change mitigation as a starting point for the analysis, we focus on the interaction of climate and energy with technology choice, energy security, energy access, and air pollution, which often have higher policy priority than climate change.Stringent climate policies drive the future energy supply in Asia from being dominated by coal and oil to a more diversified system based mostly on natural gas, coal with CCS, nuclear and renewable energy. The increase in diversity helps to improve the energy security of individual countries and regions. Combining air pollution control policies and universal energy access policies with climate policy can further help to reduce both outdoor and indoor air pollution related health impacts.Investments into the energy system must double by 2030 to achieve stringent climate goals, but are largely offset by lower costs for O&M and air pollution abatement. Strong focus on end-use efficiency also helps lowering overall total costs and allows for limiting or excluding supply side technologies from the mitigation portfolio. Costs of additional energy access policies and measures are a small fraction of total energy system costs.