Cumulative Energy Savings Research Articles

Energy Impacts of Wide Band Gap Semiconductors in U.S. Light-Duty Electric Vehicle Fleet.

Silicon carbide and gallium nitride, two leading wide band gap semiconductors with significant potential in electric vehicle power electronics, are examined from a life cycle energy perspective and compared with incumbent silicon in U.S. light-duty electric vehicle fleet. Cradle-to-gate, silicon carbide is estimated to require more than twice the energy as silicon. However, the magnitude of vehicle use phase fuel savings potential is comparatively several orders of magnitude higher than the marginal increase in cradle-to-gate energy. Gallium nitride cradle-to-gate energy requirements are estimated to be similar to silicon, with use phase savings potential similar to or exceeding that of silicon carbide. Potential energy reductions in the United States vehicle fleet are examined through several scenarios that consider the market adoption potential of electric vehicles themselves, as well as the market adoption potential of wide band gap semiconductors in electric vehicles. For the 2015-2050 time frame, cumulative energy savings associated with the deployment of wide band gap semiconductors are estimated to range from 2-20 billion GJ depending on market adoption dynamics.

Potential energy savings and reduction of CO2 emissions through higher efficiency standards for polyphase electric motors in Japan

Japan has shut down more than 70% of its nuclear power plants since the March 2011 Tohoku earthquake and the ensuing accident at the Fukushima Daiichi nuclear power plant. The country has been challenged with power shortages in the short-term and faces complex energy security decisions in the long-term. Japan has a long history of implementing energy conservation policies, such as the Top Runner Program, which covers 23 products including appliances and industrial equipment. However, Japan's efficiency policy for polyphase electric motors is considered below international standards. Polyphase electric motors accounted for about 55% of the nation's total power consumption in 2008. The aim of this study is to estimate potential energy savings and reduction in CO2 emissions (2014–2043) by examining scenarios involving adopting two different polyphase motor efficiency standards and comparing them to a base case and concludes by suggesting pathways for further policy development using the results obtained. The study finds that if level IE2 of the international efficiency standard IEC 60034-30 were implemented, it would save 8.3TWh (or 0.03 quads) per year, which is equivalent to about 0.8% of Japan's total electric power consumption in 2010. If level IE3 of the IEC 60034-30 were implemented instead, it would save about 13.3TWh (or 0.05 quads) per year. The corresponding cumulative energy savings and reduction in CO2 emissions for the IE2 scenario would be 249TWh (or 0.85 quads) and 93Mt. The corresponding cumulative energy savings and reduction in CO2 emissions for the IE3 scenario would be 398TWh (or 1.36 quads) and 149Mt.

Potential energy savings and CO2 emissions reduction of China's cement industry

This study analyzes current energy and carbon dioxide (CO2) emission trends in China's cement industry as the basis for modeling different levels of cement production and rates of efficiency improvement and carbon reduction in 2011–2030. Three cement output projections are developed based on analyses of historical production and physical and macroeconomic drivers. For each of these three production projections, energy savings and CO2 emission reduction potentials are estimated in a best practice scenario and two continuous improvement scenarios relative to a frozen scenario. The results reveal the potential for cumulative final energy savings of 27.1 to 37.5 exajoules and energy-related direct emission reductions of 3.2 to 4.4 gigatonnes in 2011–2030 under the best practice scenarios. The continuous improvement scenarios produce cumulative final energy savings of 6.0 to 18.9 exajoules and reduce CO2 emissions by 1.0 to 2.4 gigatonnes. This analysis highlights that increasing energy efficiency is the most important policy measure for reducing the cement industry's energy and emissions intensity, given the current state of the industry and the unlikelihood of significant carbon capture and storage before 2030. In addition, policies to reduce total cement production offer the most direct way of reducing total energy consumption and CO2 emissions.

Markets for energy efficiency: Exploring the implications of an EU-wide ‘Tradable White Certificate’ scheme

Recent developments in European energy policy reveal an increasing interest in implementing the so-called ‘Tradable White Certificate’ (TWC) schemes to improve energy efficiency. Based on three evaluation criteria (cost-effectiveness, environmental effectiveness and distributional equity) this paper analyses the implications of implementing a European-wide TWC scheme targeting the household and commercial sectors. Using a bottom-up model, quantitative results show significant cost-effective potentials for improvements (ca. 1400 TWh in cumulative energy savings by 2020), with the household sector, gas and space heating representing most of the TWC supply in terms of eligible sector, fuel and energy service demand, respectively. If a single market price of negative externalities is considered, a societal cost-effective potential of energy savings above 30% (compared to the baseline) is observed. In environmental terms, the resulting greenhouse gas emission reductions are around 200 Mt CO 2-eq by 2010, representing nearly 60% of the EU-Kyoto-target. From the qualitative perspective, several embedded ancillary benefits are identified (e.g. employment generation, improved comfort level, reduced ‘fuel poverty’, security of energy supply). Whereas an EU-wide TWC increases liquidity and reduces the risks of market power, autarky compliance strategies may be expected in order to capture co-benefits nationally. Cross subsidies could occur due to investment recovery mechanisms and there is a risk that effects may be regressive for low-income households. Assumptions undertaken by the modelling approach strongly indicate that high effectiveness of other policy instruments is needed for an EU-wide TWC scheme to be cost-effective.

The development and exploitation of gas-fired rapid-heating furnaces for metal heating

Gas-fired rapid-heating furnaces are being applied in the metal reheating industry. They produce substantial energy savings, together with improvements in product quality, productivity and the working environment. These benefits are derived from the use of convection as the dominant mode of heat transfer, rather than radiation as in conventional furnaces. Laboratory experiments and trials of prototype rapid heating furnaces have been undertaken in industrial situations. Together with physical and mathematical modelling techniques, they have enabled design procedures to be produced which allow rapid heaters to be individually specified to suit a wide variety of metal reheating processes. The technology is sold through licensees and more than 300 units have already been installed. It is estimated that the cumulative energy savings from the date of the first commercial installation to the current time are in excess of 1.9 PJ with a current value of about £6 M.

Savings from energy-efficient industrialized housing for the U.S.

Yearly and cumulative energy savings in industrialized housing projects are estimated for the period 1995–2030. The sensitivity analysis is based on experimental results and existing market conditions. The cumulative savings in 2030 will be about 12 exajoules (EJ) if the necessary steps toward housing industrialization are taken.

Energy impact of modifications of a river freight transport system: The upper Mississippi

As an example of analysis of the energy impact of enlarging a river freight-transport system, we consider Locks and Dam 26 near Alton, Illinois, which is the principal bottleneck of the upper Mississippi River. A simple queueing theory model is developed to predict the average delay time prior to processing through the locks as a function of traffic growth rates. Estimates of the energy intensity of freight transport on the upper Mississippi are made from a theoretical model and compared with values published in the literature. The energy impact of the replacement of Locks and Dam 26 is assessed by combining the results of the traffic-flow and energy-intensity models. For a traffic growth rate of 2.5%/yr, the cumulative energy savings (during a 40 yr operating life) of replacing the current facility is nearly 20 × 10 12 Btu. The economic value of the energy savings is 40–85% of the cost differential between repairing the current installation with no increase in capacity and the construction of an entirely new facility with a 100% increase in main locking chamber size.