Changes In Energy Use Research Articles

Energy use efficiency of specialised dairy, arable and pig farms in Flanders

Abstract In this study, we determined the energy use and energy use efficiency of a representative set (Flemish Farm Accountancy Data Network, FADN) of specialised dairy, arable and pig farms in Flanders. Total energy use comprised direct energy, based on the consumed amounts of diesel, lubricants, electricity and other energy sources (p.e. natural gas); and indirect energy, consumed during the production of farm inputs such as mineral fertilisers, seeds, pesticides, concentrates, forages and field machinery. We studied the changes in energy use and energy use efficiency between 1989–1990 and 2000–2001 for dairy and arable farms and between 1989–1990 and 1997–1998 for pig farms. The results showed that the use of mineral fertilisers and animal feed accounted for a high share of the total energy use on the farms. Diesel use took the major part of direct energy use. For dairy and arable farms, total energy use per ha has decreased significantly over the considered time period; on pig farms, energy use per fattening pig equivalent (FPE) in 1997–1998 was comparable to that in 1989–1990. The most energy efficient dairy and pig farms were intensive farms, which combined a high production with a low energy use and which possessed a gross value added per production unit comparable to, or even higher than the average. Based on the energy productivity of the top 5% farms, target values were set of 35 l milk 100 MJ−1 and 7.5 kg carcass 100 MJ−1 for energy use on Flemish dairy and pig fattening farms, respectively. On arable farms, the energy use efficiency was highly dependent on the crop rotation. For that reason, it is recommended to calculate energy balances on field level, for each separate crop.

05/01926 Structural change in energy use: Schäfer, A. Energy Policy, 2005, 33, (4), 429–437

05/01926 Structural change in energy use: Schäfer, A. Energy Policy, 2005, 33, (4), 429–437

Winter survival of age-0 smallmouth bass, Micropterus dolomieu, in north eastern lakes

We examined the winter survival of age-0 smallmouth bass,Micropterus dolomieu, in lakes at their northern limit of distribution in New Brunswick, Canada. Pre- and post-winter collections over a 3 year period suggested the smallest individuals, <50 mm total length, died during winter under ice. Experiments with wild, age-0 smallmouth bass held in lakes demonstrated a size-dependent survival where smaller individuals had greater survival with an increasing temperature of exposure, but the largest individuals had reduced survival at warmer temperatures. Survivors lost 22–54% of pre-winter energy reserves measured as ash-free dry weight, which was similar to wild individuals captured in spring. Body size at the onset of winter affects survival, but it also appears that temperature interacting with a suite of environmental and biological factors affect changes in energy use and therefore survival of age-0 smallmouth bass under ice in winter.

Environmental Impact of Urban Heat Island Phenomena —Cause-effect chain and evaluation in Osaka City—

The impacts of urban heat island phenomenon on human activity and ecosystems have already been obvious in Japanese large cities. To discuss importance of urban heat island mitigation measures, it is necessary to identify and quantify urban heat island impacts such as change in energy use (cooling, heating and hot water supply), change in water use, heat stress, damage to urban ecosystem, air pollution, change in precipitation and floods, etc. In this paper, cause-effect chain of urban heat island impacts is proposed and some examples of heat island impacts in Osaka city are identified and evaluated. Change in energy consumption in residential and commercial sector is evaluated quantitatively by numerical simulation. The result shows the difference in total energy consumption by different air temperature is small since decrease in heating and hot water energy use compensate for increase in cooling energy use.

Does the Swedish consumer's choice of food influence greenhouse gas emissions?

Consumer's choice of food can influence the environment. In Sweden, in common with many other countries, consumers need to be given information so they can make environmentally informed shopping choices. However, what is the most advantageous dietary choice to lower greenhouse emissions? This study investigates the greenhouse gas emissions associated with food production for food consumed in Sweden annually. Specifically, this study compares greenhouse gas emissions associated with a nutritionally and environmentally sustainable diet with the average consumption of food in Sweden 1999. The study concludes that the change in energy use and greenhouse gas emission associated with this change of diet is negligible. Lowering greenhouse gas emissions by changing food production processes results in more profound changes than teaching consumers to make environmentally correct choices. There is a basic need for a reduction or a replacement of the use of fossil fuels to produce and distribute our food in order to reach any significant reduction in the emission of greenhouse gases. Swedish agricultural policy does not provide ways to reduce greenhouse gas emissions. In Sweden therefore there is an immediate need to design policy instruments with the primary aim of reducing the greenhouse effect.

Structural change in energy use

Structural change in the economy, from agriculture to industry to services, causes similar sector shifts in final energy use. This paper illustrates such energy sector shifts for 11 world regions from 1971 through 1998 and discusses their impact on the decline in energy intensity.

Energy and emission monitoring for policy use Trend analysis with reconstructed energy balances

At the request of policy makers a new tool, called MONIT, has been developed for the presentation and analysis of historical energy use and emission trends. The tool is based on the concept of constructed energy balances. The system covers Dutch national and sectoral energy use and the accompanying CO 2 emissions, from 1982 onwards. In the presentation part the energy balance with statistical figures is corrected for disruptions in statistics and yearly climate variations. Next to time series for all energy variables and sectors, information is also available about the final demand for electricity or heat and about co-generation, primary energy use as well as direct and indirect CO 2 emissions. In the analysis part the energy use developments are mapped with a step-by-step constructed set of energy balances, starting from the base year balance. In each step a supplementary explanatory factor is introduced and the effects are made into an updated balance. In this way the actual changes in energy use are unravelled into 14 explanatory factors, including four different energy-related structural changes, five saving factors, fuel mix changes and changes in export and import of energy. It is possible to reconstruct the actual energy balances within a small margin and most of the 14 contributing factors can be calculated with only a small uncertainty. The MONIT system offers policy makers an integrated set of monitoring results with different levels of information content: statistical data, time series, final and primary energy use, direct and indirect CO 2 emissions, intensities and policy relevant contributions to the actual changes in energy and emission variables.

Improved estimates of tree-shade effects on residential energy use

Tree-shade alters building cooling and heating loads by reducing incident solar radiation. Estimates of the magnitude of this effect, and how it is influenced by urban forest structure (e.g. tree size and location), are difficult due to the complexity inherent in tree–sun–building interactions. The objective of this paper is to present a simplified method for making these estimates appropriate for neighborhood and larger scales. The method uses tabulated energy use changes for a range of tree types (e.g. size, shape) and locations around buildings (lookup tables), combined with frequency of occurrence of trees at those locations. The results are average change in energy use for each tree type that are not explicitly dependent on tree location. The method was tested by comparison to detailed simulations of 178 residences and their associated trees in Sacramento, California. Energy use changes calculated using lookup tables matched those from detailed simulations within ±10%. The method lends itself to practical evaluation of these shading effects at neighborhood or larger scales, which is important for regional assessments of tree effects on energy use, and for development of tree selection and siting recommendations for proposed energy conserving planting programs.

Disaggregated analysis of US energy consumption in the 1990s: evidence of the effects of the internet and rapid economic growth

This paper decomposes US energy use from 1988 to 1998 and attributes the changes in energy use to three underlying factors: activity, structure, and intensity. For this study we use a bottom-up methodology, by separately decomposing delivered energy use in six sectors: travel, freight, manufacturing industries, non-manufacturing industries, residential, and services. The most commonly used indicator of energy efficiency in the total economy, the ratio of energy consumed to unit of GDP ( E/GDP) created can often be misleading. The rapid decline in the E/GDP ratio in recent years has been used to support assertions that the internet and information technologies in general have enabled improvements in energy efficiencies. However, our disaggregate analysis suggests that energy intensities on average are falling more slowly than ever before while actual energy use increased faster than at any time since 1970. The decline in the E/GDP ratio in the mid- to late 1990s owes much more to structural changes in the demand for energy services than to falling energy intensities.

Lost carbon emissions: the role of non-manufacturing “other industries” and refining in industrial energy use and carbon emissions in IEA countries

We present a review of trends in energy use and output in branches of industry not often studied in detail: petroleum refining and what we call the other industries — agriculture, mining, and construction. From a sample of IEA countries we analyze eight with the most complete data from the early 1970s to the mid-1990s. We carry out a decomposition analysis of changes in energy use and carbon emissions in the “other industries” sector. We also review briefly the impact of including refining in the evolution of manufacturing energy use, usually studied without refining. Despite many data problems, we present our results as a way of enticing others to study these important “lost” sectors more carefully. We have five basic findings. First, “other industries” tends to be a minor consumer of energy in many countries, but in some, particularly Denmark, the US, and Australia, mining or agriculture can be a major sector too large to be overlooked. Second, refining is an extremely energy intensive industry which despite a relatively low share of value added consumes as much as 20% of final energy use in manufacturing. Third, as a result of a slower decline in the carbon-intensity of these industries vis-à-vis the manufacturing industries, their share of industrial emissions has been rising. Fourth, for other industries variation in per capita output plays a relatively small role in differentiating per capita carbon emissions compared to the impact of subsectoral energy intensities. Finally, including this energy in CO2 calculations has little impact on overall trends, but does change the magnitude of emissions in most countries significantly. Clearly, these industries provide important opportunities for searching for carbon emissions reductions.

Historical Analysis of Energy Intensity of Spain: From a “Conventional View” to an “Integrated Assessment”

Understanding the relationship between the Gross Domestic Product (GDP) and the throughput of matter and energy over time in modern societies is crucial for understanding the sustainability predicament as it is linked to economic growth. Available data on changes in energy use and economic performance in Spain (over the period 1960–1996) shows that Spain has been increasing its energy intensity during this period contrary to the hypothesis of an “inverted-U shaped curve of intensity of use.” Will this increase be followed soon by a decrease? Or rather should we look for alternative explanatory hypotheses and study changes in the dynamic energy budget of Spain as movements between ‘attractor points’? If this is the case, what are the main mechanisms generating such a behaviour? Three non-equivalent methods of analysis complementing each other are used to deal with these questions.

Interactions between lighting and space conditioning energy use in US commercial buildings

Reductions in lighting energy have secondary effects on cooling and heating energy consumption. In general, lighting energy reductions increase heating and decrease cooling requirements of a building. The net change in a building's annual energy requirements, however, is difficult to quantify and depends on the building characteristics, operating conditions, and climate. This paper characterizes the effects of lighting/HVAC interactions on the annual heating/cooling requirements of prototypical US commercial buildings through computer simulations using the DOE-2.1E building energy analysis program. Twelve building types of two vintages and five climates are chosen to represent the US commercial building stock. For each combination of building type, vintage, and climate, a prototypical building is simulated with varying lighting power densities, and the resultant changes in heating and cooling loads are recorded. These loads are used together with market information on the saturation of the different HVAC equipment in commercial buildings to determine the changes in energy use and expenditures for heating and cooling. Results are presented by building type for the US as a whole. Therefore, the data presented in this paper can be used to assess the secondary effects of lighting-related federal policies with widespread impacts, such as minimum efficiency standards. Generally, in warm climates the interactions will induce monetary savings and in cold climates the interactions will induce monetary penalties. For the commercial building stock in the US, a reduction in lighting energy that is well distributed geographically will induce neither significant savings nor significant penalties from associated changes in HVAC primary energy and energy expenditures.

Quantifying the energy consumption of a pocket computer and a Java virtual machine

In this paper, we examine the energy consumption of a state-of-the-art pocket computer. Using a data acquisition system, we measure the energy consumption of the Itsy Pocket Computer, developed by Compaq Computer Corporation's Palo Alto Research Labs. We begin by showing that the energy usage characteristics of the Itsy differ markedly from that of a notebook computer. Then, since we expect that flexible software environments will become increasingly prevalent on pocket computers, we consider applications running in a Java environment. In particular, we explain some of the Java design tradeoffs applicable to pocket computers, and quantify their energy costs. For the design options we considered and the three workloads we studied, we find a maximum change in energy use of 25%.

Aggregation and the role of energy in the economy

Methods for investigating the role of energy in the economy involve aggregating different energy flows. A variety of methods have been proposed, but none has received universal acceptance. This paper shows that the method of aggregation has crucial effects on the results of the analysis. We review the principal assumptions and methods for aggregating energy flows: the basic heat equivalents approach, economic approaches using prices or marginal product for aggregation, emergy analysis, and thermodynamic approaches such as exergy. We argue that economic approaches such as the index or marginal product method are superior because they account for differences in quality among fuels. We apply various economic approaches in three case studies in the US economy. In the first, we account for energy quality to assess changes in the energy surplus delivered by the extraction of fossil fuels from 1954 to 1992. The second and third case studies examine the importance of energy quality in evaluating the relation between energy use and GDP. First, a quality-adjusted index of energy consumption is used in an econometric analysis of the causal relation between energy use and GDP from 1947 to 1996. Second, we account for energy quality in an econometric analysis of the factors that determine changes in the energy/GDP ratio from 1947 to 1996. Without adjusting for energy quality, the results imply that the energy surplus from petroleum extraction is increasing, that changes in GDP drive changes in energy use, and that GDP has been decoupled from between aggregate energy use. All of these conclusions are reversed when we account for changes in energy quality.

Energy use and productivity performance in the Nigerian manufacturing sector (1970‐90)

This paper investigates the relationship between productivity performance and energy consumption in the Nigerian manufacturing sector at both aggregated and disaggregated levels.It adopts a non‐parametric approach to the measurement of total factor productivity (TFP). It then specifies a regression model linking the estimated TFP growth with changes in energy use. The objective is to examine the impact of energy‐pricing policy on efficiency in the manufacturing sector.The paper establishes that energy consumption still plays a critical role in productivity growth in the Nigerian manufacturing sector. However, the recent price reforms in the energy sector can only achieve meaningful results if accompanied by technological reforms in the manufacturing sector. The industrial sector is still dominated by old energy‐inefficient technology.However, there are prospects for enhancing energy efficiency in the long run. When prices are allowed to signal the real cost of an input, producers would not only become efficient in energy use, but would also be able to select appropriate input combinationsthat minimised their costs of production. Long‐term investment would also be committed to energy‐saving equipment.Furthermore, the development of the gas sub‐sector may also provide an alternative source of energy to many firms.

A Responsible Energy Future

A ffordable energy is the lifeblood of modern society. Without it, the network of transportation, agriculture, health care, manufacturing, and commerce deemed essential by many of the world's inhabitants would not be possible. Yet our use of energy releases sulfur dioxides, metals such as cadmium and mercury, and greenhouse gases and other noxious pollutants that damage our quality of life. Moreover, when we use fossil fuels, we make ourselves dependent on an energy source that cannot be relied upon forever. With the apparent conditions in the United States today, what could induce us to change our energy habits now? Almost daily, gasoline prices reach record lows, and U.S. citizens have not waited in line for gas for decades. Our fossil fuel engines and turbines burn more cleanly and more efficiently now than ever before. Nevertheless, the truth is that our current system of energy use is unsustainable; our energy habits will have to change. For, although fossil fuel supplies are limited, total energy use will rise rapidly in coming years as global economic development continues. What is more, according to many scientists, current greenhouse gas emissions—let alone any greater emissions in the future—threaten to produce serious environmental changes. Some scientists have predicted that projected greenhouse gas emissions for the coming decade could produce climate changes as significant as an increase of 5° to 6°F (2.8° to 3.3°C) in average global temperature, a one-half meter rise of sea level, and even an increase in the intensity of hurricanes and tropical storms. Worst-case scenarios? Perhaps. But other negative effects of fossil fuel pollution, such as smog, acid rain, water contamination from leaky fuel tanks, oil refinery emissions, and oil spills, are already very real in many regions of the globe, in both industrialized and developing nations. Even without global warming, these immediate problems are enough to warrant change. For developing countries, cheap, polluting, and inefficient technologies are often the only affordable option. The United States is in a position to develop better alternatives. We should take the initiative. Our current investment in research and development in energy is nothing short of irresponsible. The U.S. national energy product exceeds $500 billion annually. Yet barely 1% of that amount is invested in R&D. The President's Committee of Advisors on Science and Technology (PCAST) has recommended that the Department of Energy's applied energy-technology R&D budget be nearly doubled to $2.4 billion by 2003. In my view, this recommendation should be considered a minimum figure. This money would be well spent. Those who position themselves to manage the coming changes in energy use will stand to gain enormously. American companies would profit from the development of more efficient, cleaner—and therefore more desirable—technologies; the American economy would benefit from the expertise built up by further research; and American citizens would benefit from a cleaner, safer environment. Just as the federal government has a responsibility to invest now in basic medical research to ensure the health of present and future generations, so it has a responsibility to invest now in basic energy research to ensure both our near-term and long-term economic and environmental health. The justification for this commitment seems clear to many of us trained in science and technology. Yet with energy prices low, the necessary political will may be lacking. Will apprehension about negative effects—greater pollution and global climate change—provoke people to examine our energy habits and take action? Or will the possible economic opportunities attract attention and provoke action? A huge potential market awaits, promising an opportunity to enhance the quality of life of all the world's people. Meanwhile, researchers and policy-makers must continue to seek ways to make relevant to our communities the nature of our global energy challenges and opportunities.

Air quality impacts as a result of changes in energy use in China’s Jiangsu Province

Potential changes in air quality associated with increases in SO 2 emissions resulting from industrial growth for Jiangsu Province and the Shanghai Municipality in China are evaluated for the years 1990 (current) and 2010 (future) with a “no further control” scenario. Two long-range transport models are used to estimate airborne concentrations and deposition of SO 2 and sulfate, based on available data on emissions originating from area and major point sources. Modeling results demonstrate how human health and ecological impacts are related to the projected scenario of industrial growth, in terms of the critical level (or concentration) and critical loads. The current approach provides an effective and valuable tool for preliminary assessment of potential impacts of these changes on human health and critical ecosystems in the region for use in integrated energy and environmental risk assessments.

China's Energy Strategy: Economic Structure, Technological Choices, and Energy Consumption (review)

i88 China Review International: Vol. 5, No. 1, Spring 1998 Xiannuan Lin. China's Energy Strategy: Economic Structure, Technological Choices, and Energy Consumption. Westport, Connecticut: Praeger Publishers , 1996. xvii, 203 pp. Hardcover $65.00, isbn 0-275-95306-8. This book offers important insights into a fascinating feature of China's economic growth during the reform era—the declining energy intensity of the Chinese economy. The book crisply proceeds through summarizing the issue, propounding an input-output model of energy consumption, explaining the results produced by the model, and pursuing the model's insights in a case study of the iron and steel industry. As they grow, developing economies usually exhibit increasing energy intensity (the ratio of commercial energy consumption to GDP), a trend followed by China for thirty years after the founding of the People's Republic. The uniformity of this trend across China and other developing countries led outside observers reasonably to expect that growing energy and electric power shortages in China in the late 1970s would constrain economic growth. For example, the CIA (1980) predicted that electric power shortages would restrict China's economic growth to 3 percent per year in the first half of the 1980s.1 The Chinese economy dramatically disproved these predictions. From 1981 to 1987, the time period studied in this book, the Chinese economy grew about 10 percent per year. As the book stresses, this growth was not fueled by an equal growth of commercial energy consumption. Instead, the energy intensity of the Chinese economy "decreased by almost 22 percent" between 1981 and 1987 (p. 3). This unexpected decline has been the topic of much speculation and recent research . In the 1980s, the decline was often attributed to the shift in emphasis from heavy industry to light industry. In the 1990s various researchers have more carefully examined the available data to develop a more sophisticated understanding of this remarkable decline. This study adds to the research by decomposing the change in energy consumption, using China's 1981 and 1987 input-output tables. Input-output analysis provides a wealth of information about the interconnections between an economy's production and consumption sectors. As this book shows, much can be learned about energy consumption from looking at the changes in production technology and in the structure of final demand. Chapter 1 introduces the issue of falling energy intensity in the Chinese economy, explaining why this phenomenon warrants attention. Then it succinctly© 1998 by University states the research goals of the study and emphasizes their importance. This chapofHawai 'i Presster serves as a most accessible introduction to the topic for nonspecialists. Chapter 2, using tables and charts, describes energy consumption in China for 1981 and 1987 by production and consumption sector and by energy source. This gives the Reviews 189 reader a working knowledge ofthe data that the autiior's model explores in greater depth. Chapter 3, which presents the basic model of the book, may prove mildly frustrating to those readers who carefully try to follow the matrix algebra of the model.2 All readers can trust in the actual implementation ofthe model and should quickly grasp the basic technique: calculate the energy required to produce 1987 final demand using 1981 technology; then compare this to actual energy use in 1987. Using the 1981 and 1987 input-output tables, the key equation ofthe model (equation 8 on p. 49) shows that die change in energy use in China between 1981 and 1987 can be decomposed into a "final-demand shift" and a "production -technology change." The final-demand shift equals the extra energy required to produce 1987 intermediate output using 1981 technologyplus the increase from 1981 to 1987 in energy directiy used by final consumers. The production -technology change is the difference between intermediate energy used to produce 1981 final demand using 1987 technology and actual intermediate energy used to produce 1981 final demand using 1981 technology. The model elaborates on this basic idea, further decomposing the final demand shift and the production technology change by final demand sectors and by production sectors. Table 3.4 on page 54 concisely summarizes the elements ofthe model. Chapters 4 and 5 detail the findings yielded by...

Freight Energy Use Disaggregated by Commodity: Comparisons and Discussion

The analysis of energy consumption in freight transportation is almost always approached by disaggregating overall energy consumption by mode, which then provides a basis for understanding trends and underlying factors that influence them and for developing conservation policies. Another important approach is to disaggregate by commodity, because it is commodity flows that generate the modal vehicle flows and hence the modal energy consumption in transportation. Thus changes in energy use by commodity are important factors in understanding trends in energy consumption and may provide a basis for energy conservation policies centered on industries using transportation. Total freight energy consumption is estimated for a range of commodity groups using an activitybased approach to energy consumption, where total freight activity is decomposed into components by mode and by commodity group, and then each component is multiplied by an intensity estimate to calculate total energy use for that commodity group. Two important findings are discussed: ( a) commodity groups with high energy growth between 1972 and 1993 had a combination of substantial ton-mile growth and modal shift to truck, and ( b) commodity groups of finished products with a high average value per ton in general have a much higher average freight energy intensity than raw materials with a low average value per ton.

Monitoring the energy use of households using a simulation model

In a bottom-up model for the simulation of the future energy use of households, called SAVE households, a large number of saving options were analysed in conjunction with the growth of the number of inhabitants, dwellings, households and other structural changes which influence energy use before savings. The calculated change in energy use from the base year level was presented in the form of so-called volume, structure and saving effects. This model was adapted to serve as a monitoring tool. In 1996, it was used for the first time, for the official annual monitoring exercise of environmental trends in the Netherlands, as a tool to analyse the changes in household energy use in the period 1990–1995. If sufficient information on a detailed level is available, the approach based on the adapted simulation model has a number of advantages over other methods, eg energy intensity analysis methods using the disaggregation of energy use. The model offers a very flexible structure with regard to the preferred definition of saving options and structural changes. Furthermore, the adapted model is capable of handling the interdependence between structural changes and saving options and the substitution between different energy carriers. In addition, very complex changes with regard to energy use, such as smaller household sizes or a higher fraction of dwellings with district heating, can be easily analysed.