Analysis of electricity consumption: a study in the wood products industry

This paper evaluates the effect of industry segment, year, and US region on electricity consumption per employee, per dollar sales, and per square foot of plant area for wood products industries. Data was extracted from the Industrial Assessment Center (IAC) database and imported into MS Excel. The extracted dataset was examined for outliers and abnormalities with outliers outside the quantile range 0.5–99.5 dropped from the analysis. A logarithmic transformation was applied to eliminate the skewness of the original data distributions. Correlation measurements indicated a moderate association between the response variables; therefore, a multivariate analysis of variance test was performed to measure the impact of the three factors: industry type, year, and region, simultaneously on all response variables. The results indicated some effect associated with all three factors on the three measures of electricity consumption. Subsequently, univariate ANOVA tests were conducted to determine the levels of the factors that were different. Most levels of industry type were associated with significantly different energy consumption, an expected result since some of the industries are more energy intensive than others. The industries in Standard Industry Code (SIC) 2493 (reconstituted wood products) are the groups with the highest electricity consumption with means of 38,096.28 kWh/employee, 0.86 kWh/sales, and 154.14 kWh/plant area while industries grouped in SIC 2451 (mobile homes) have the smallest consumption with means of 6811.01 kWh/employee, 0.05 kWh/sales, and 9.45 kWh/plant area. Interestingly, differences in regional consumption were found to be linked to the proportion of industry types by region. Data analysis also indicated differences in electricity consumption per employee for the factor year, but for the other response variables, no differences were found. These main results indicate that industries in the wood products sector have different electricity consumption rates depending on the type of manufacturing processes they use. Therefore, industries in this sector can use these comparisons and metrics to benchmark their electricity consumption as well to understand better how electricity costs might vary depending on the region they are located.     

Statistical analysis of residential building energy consumption in Tianjin

To analyze the effect of energy conservation policies on energy consumption of residential buildings, the characteristics of energy consumption and indoor thermal comfort were investigated in detail in Tianjin, China, based on official statistical yearbook and field survey data. A comprehensive survey of 305 households indicates that the mean electricity consumption per household is 3215 kWh/a, in which annual cooling electricity consumption is 344 kWh/a, and the mean natural gas consumption for cooking is 103.2 m³/a. Analysis of 3966 households data shows that space heating average intensity of residential buildings designed before 1996 is 133.7 kWh/(m²·a), that of buildings designed between 1996 and 2004 is 117.2 kWh/(m²·a), and that of buildings designed after 2004 is 105.0 kWh/(m²·a). Apparently, enhancing the performance of envelops is effective in reducing space heating intensity. Furthermore, the results of questionnaires show that 18% of the residents feel slightly warm and hot respectively, while 3% feel slightly cold in winter. Therefore, the electricity consumption in summer will rise for meeting indoor thermal comfort.     

Design,economic analysis and environmental considerations of mini-grid hybrid power system with reverse osmosis desalination plant for remote areas

This paper discusses the design process of a mini-grid hybrid power system with reverse osmosis desalination plant for remote areas, together with an economic analysis and environmental considerations for the project life cycle. It presents a design scenario for supplying electricity and fulfilling demand for clean water in remote areas by utilising renewable energy sources and a diesel generator with a reverse osmosis desalination plant as a deferrable load. The economic issues analysed are the initial capital cost needed, the fuel consumption and annual cost, the total net present cost (NPC), the cost of electricity (COE) generated by the system per kWh and the simple payback time (SPBT) for the project. The environmental considerations discussed are the amount of gas emissions, such as CO₂ and NO_x, as well as particulate matter released into the atmosphere. Simulations based on an actual set of conditions in a remote area in the Maldives were performed using HOMER for two conditions: before and after the Tsunami of 26th December 2004. Experimental results on the prototype 5 kVA mini-grid inverter and reverse osmosis desalination plant, rated at 5.5 kWh/day, are also presented here to verify the idea of providing power and water supplies to remote areas.     

Energy assessment of the Portuguese meat industry

The meat product industries play a major role in many global economies. In several countries, it is the industry with a higher economic weight within the food industries. As refrigeration systems are indispensable within the production processes, it is important to improve the overall energy efficiency in order to reduce the electricity consumption in these industries. The electrical energy consumption of the Portuguese meat industries is evaluated in this paper. The field study shows that electrical energy accounts for 66.5 % of the overall energy consumption in slaughterhouses, 85 % in sausage houses and 92.5 % in ham industries. Relatively to the refrigeration systems of these industries, results show that the average compressor nominal power per unit of cold room volume is comprised between 0.072 and 0.043 kW/m³. The average value of the specific electrical energy consumption for the slaughterhouses was 149 kWh/ton_HSCW, 660 kWh/ton_RM for sausage houses and 1208 kWh/ton_RM for ham production industries. Finally, a potential reduction of the electricity consumption based on simple energy efficiency measures was estimated in 24 % for the slaughterhouses, 13 % for the sausage houses and 8 % for the ham industry.     

Quantification of energy produced from an evacuated tube water heater in a real setting

For the first time, actual data regarding an evacuated tube SWH has been collected from an implemented system in Lebanon. The data collected was based on a number of sensors installed at various points in the system. The results indicated real hot water use of the household and operational temperatures throughout the year. The system provided more than 98% of the household needs indicating a clear over sizing of the system. Other findings include excessive heat generated in the summer, necessitating forced shadowing of the collectors. The system provided 3049 kWh/y and saved the family around $195. More significant savings are obtained by the electricity company since electricity in Lebanon is subsidized. This case study provides a reference point for the observed savings rather than estimated savings.     

Determinants of carbon dioxide emissions: Empirical evidence from 69 countries

This study investigates the determinants of carbon dioxide emissions (CO₂) for a global panel consisting of 69 countries using a dynamic panel data model. To make the panel data analysis more homogenous, we also investigate the determinants of CO₂ emissions for a number of sub-panels. These sub-panels are constructed based on the income level of countries. In this way, we end up with three income panels; namely, high income, middle income, and low income panels. The time component of our dataset is 1985–2005 inclusive. Our main findings are that trade openness, per capita GDP, and energy consumption, proxied by per capita electric power consumption and per capita total primary energy consumption, have positive effects on CO₂ emissions. Urbanisation is found to have a negative impact on CO₂ emissions in high income, middle income, and low income panels. For the global panel, only GDP per capita and per capita total primary energy consumption are found to be statistically significant determinants of CO₂ emission, while urbanisation, trade openness, and per capita electric power consumption have negative effects on the CO₂ emissions.     

A novel hybrid heat-pipe solar collector/CHP system—Part II: theoretical and experimental investigations

A theoretical analysis has been carried out to investigate the thermodynamic and heat transfer characteristics of a hybrid heat pipe solar collector/CHP system based on the assumption that the system operates on a typical Rankine cycle. Experimental testing of the prototype was also carried out using two types of turbine units. The variation of refrigerant pressures and temperatures, hot water temperatures in the collector and boiler systems, as well as chill water temperatures were recorded. The results were used to estimate the heat from the boiler and the solar collectors, the electricity and hot water generation (indicated as kW energy) from the CHP operation and the gas consumption of the system. The modelling and experimental results were compared for the impulse-reaction turbine system, and a simple analysis of the energy and environmental benefits of the system was carried out. The analysis indicated that the proposed system would save primary energy of approximately 3150 kWh per annum compared to the conventional electricity and heating supply systems, and this would result in reduction in CO₂ emission of up to 600 tonnes per annum. The running cost of the proposed system would also be lower than conventional heating/power systems.     

Building energy index and end-use energy analysis in large-scale hospitals—case study in Malaysia

Hospital energy consumption is relatively high, while saving energy and reducing cost comprise one of the most important challenges considered by the majority of building designers, engineers, and decision makers. An end-use energy analysis was conducted in a large-scale hospital in Malaysia to identify energy apportioning and energy end use in the areas of air conditioning, lifts, lighting, equipment, and others. The analysis was carried out by assessing the collected desktop and field data as well as some calculations. The Building Energy Index (BEI) was calculated to compare the consumption levels in the selected hospital, which is a typical hospital building, with other hospitals in Malaysia as well as low energy buildings and Malaysian standards. The main energy source in this case study was electricity with a supply of around 75 % of total energy consumption. The current average annual electricity consumed by this hospital was 44,637,966 kWh, out of which 63 % was used by air conditioning systems and 17 % by lighting. The BEI comparison revealed that the calculated BEI of 384 kWh/m²/year is significantly higher than Malaysian rating systems and standards which recommend 200 kWh/m²/year for hospitals, 135 kWh/m²/year for commercial sectors, and is higher than previously observed hospitals with a BEI of less than 300 kWh/m²/year.     

Use of ecological footprinting to explore alternative domestic energy and electricity policy scenarios in an Irish city-region

The purpose of this paper is to measure the ecological footprint (EF) of energy and electricity consumption by the residents of an Irish city-region, in terms of the land area required to sequester carbon emissions from energy and electricity consumption and to support energy infrastructure and development. The EF was also used to analyse the impact of potential scenarios and policies and results were compared with the business as usual (BAU) projection in order to identify the optimal policy measure. It was found that the total EF for domestic energy and electricity consumption by Limerick residents increased by 7% from 0.125 global hectares (gha) per capita in 1996 to 0.134 gha per capita in 2002.     

Lighting villages at the end of the line with geothermal energy in eastern Baringo lowlands, Kenya – Steps towards reaching the millennium development goals (MDGs)

Access to modern energy services is key to economic development and progress towards millennium development goals (MDGs). Yet only 20% of Kenyan population of which 5% are rural residents have access to electricity. The study focuses on East Pokot and Marigat Districts, commonly known as Baringo eastern lowlands within the Kenyan Rift Valley. The two districts lie at the end of a 190 km high voltage line from Lessos substation in Nandi District, which traverses rough terrain and serving major towns before reaching the study area. Extension of the line has also been hampered by several barriers discussed in this paper. Consequently, less than 1% of the households in small trading centres have access to electricity with an average consumption of 120 kWh/month and 500 kWh/month per utility in the commercial sector. About 60–70% of the local population live below the poverty line and micro, small and medium enterprises are not well developed due to inadequate supply of electricity and poverty. The area lies within undeveloped six geothermal prospects between Lake Bogoria and Silali with an estimated resource potential of about 2700 MWe. Since the current government focus is to develop the geothermal resources in the area, the study assess the overall impact of the planned development in contributing towards the attainment of the millennium development goals (MDGs).     

Is per capita electricity consumption stationary? Time series evidence from OECD countries

This study examines the stationary properties of per capita electricity consumption in which the endogenously determined break points are incorporated in 23 high income OECD countries by using annual data over 1960-2005 period. We utilize Lagrange Multiplier (LM) unit root test that endogenously determines structural breaks in level and/or trend. We find that 21 country series reject the unit root null hypothesis at the 5% significance level, except for 2 country series. Thus, our empirical findings provide significant evidence that per capita electricity consumption is stationary in almost all countries considered in the study. The stationarity of per capita electricity consumption indicates that it should be possible for the series to forecast future movements in the energy consumption based on the past behaviors of the series. Important policy implications emerge from our empirical results of the unit root test with multiple structural breaks.     

Case study feasibility analysis of the Pelamis wave energy convertor in Ireland, Portugal and North America

The performance and economic viability of the Pelamis wave energy converter (WEC) has been investigated over a 20 year project time period using 2007 wave energy data from various global locations: Ireland, Portugal, USA and Canada. Previous reports assessing the Pelamis quote a disparate range of financial returns for the Pelamis, necessitating a comparative standardised assessment of wave energy economic indicators. An Excel model (NAVITAS) was created for this purpose which estimated the annual energy output of Pelamis for each location using wave height (H_s) and period (T_z) data, and produced financial results dependant on various input parameters. The economic indicators used for the analysis were cost of electricity (COE), net present value (NPV) and internal rate of return (IRR), modelled at a tariff rate of €0.20/kWh). Analysis of the wave energy data showed that the highest annual energy output (AEO) and capacity for the Pelamis was the Irish site, as expected. Portugal returned lower AOE similar to the lesser North American sites. Monthly energy output was highest in the winter, and was particularly evident in the Irish location. Moreover, the difference between the winter wave energy input and the Pelamis energy output for Ireland was also significant as indicated by the capture width, suggesting that Pelamis design was not efficiently capturing all the wave energy states present during that period. Modelling of COE for the various case study locations showed large variation in returns, depending on the number of WEC modelled and the initial cost input and learning curve. COE was highest when modelling single WEC in comparison to multiples, as well as when using 2004 initial costs in comparison to 2008 costs (at which time price of materials peaked). Ireland returned the lowest COE of €0.05/kWh modelling over 100 WEC at 2004 cost of materials, and €0.15/kWh at 2008 prices. Although favourable COE were recorded from some of the modelled scenarios, results indicated that NPV and IRR were not encouraging when using a €0.20/kWh tariff. It is recommended that a tariff rate of €0.30/kWh be considered for Ireland, and higher rates for other locations. In conclusion, Ireland had the most abundant wave energy output from the Pelamis. COE returns for Ireland were competitive for large number of WEC, even at peak costs, but it is recommended that careful analysis of NPV and IRR should be carried out for full economic assessment. Finally, a standardised method of COE reporting is recommended, using fixed WEC number or MW size, as well as standardised learning/production curves and initial costs, to facilitate confidence in investment decisions based on COE.     

CO2 savings of ground source heat pump systems – A regional analysis

In the current study the savings of CO₂ emissions due to the use of ground source heat pump (GSHP) systems was investigated in comparison to conventional heating systems. Based on a subsidy program for GSHP systems in southwest Germany, the regional, average, and total CO₂ savings of 1105 installed GSHP systems were determined on a regional scale. The emitted CO₂ per kWh of heating demand for the studied scenario resulted in 149 g CO₂/kWh for GSHP using the German electricity mix and 65 g CO₂/kWh using the regional electricity mix, which results in CO₂ savings of 35% or 72%, respectively. Similar CO₂ avoidances of GSHP systems were found in American and European studies ranging between 15% and 77% strongly depending on the supplied energy for the heat pumps and the efficiency of installation. The resulting CO₂ savings for one installed GSHP unit in the present study therefore range between 1800 and 4000 kg per year. Nevertheless, the minimum average total annual CO₂ savings of all installed GSHP systems due to the subsidy program amounted to 2000 tons per year. The maximum regional avoided additional CO₂ emissions are primarily associated with the affluent suburbs of the most densely populated area in the region. In 2006 the total contribution of CO₂ savings due to GSHP systems in Germany was only about 3.4% of the total renewable energies. However, continuously rising numbers of installed GSHP units and the increasing use of renewable electricity demonstrate that there is a fine opportunity to substantially avoid additional CO₂ emissions associated with the provision of heating (and cooling) of buildings and other facilities.     

Using fuzzy MCDM technique to find the best location in Qatar for exploiting wind and solar energy to generate hydrogen and electricity

Hydrogen has been a promising energy carrier to meet the world's energy needs as well as reduce pollutant emissions. Although many countries have policies and programs to expand hydrogen production, the potential for hydrogen production in different regions of Qatar has not yet been evaluated. Therefore, this paper, for the first time, evaluates the possibility of an average annual cogeneration of 14 kWh of electricity and 85 kg/day of hydrogen by a home-scale solar-wind system connected to the grid in Qatar. NASA's 20-year average of meteorological data, the electricity tariff and gasoline price in 2018, along with annual real interest rate, were used as inputs to HOMER software. The techno-econo-enviro analysis was done over a one-year period hour by hour. From the results, it was found that the lowest prices of hydrogen and electricity generated, with $ 2.092/kg and $ 11.495/kWh, were related to Grid and PV-Wind-Grid scenarios, respectively. Also, results indicated that Ar-Ruways station and PV-Wind-Grid scenario were the most environmentally suitable options that resulted in a CO₂ emission rate of 1434 kg annually. To select just one station among five areas, a fuzzy method was deployed as a prioritization technique. Its results suggested that Doha Intl Airport site is the most suitable one for constructing solar-wind hybrid energy generation system.     

Potential impacts assessment of plug-in electric vehicles on the Portuguese energy market

Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs), which obtain their fuel from the grid by charging a battery, are set to be introduced into the mass market and expected to contribute to oil consumption reduction. In this research, scenarios for 2020 EVs penetration and charging profiles are studied integrated with different hypotheses for electricity production mix. The impacts in load profiles, spot electricity prices and emissions are obtained for the Portuguese case study. Simulations for year 2020, in a scenario of low hydro production and high prices, resulted in energy costs for EVs recharge of 20 cents/kWh, with 2 million EVs charging mainly at evening peak hours. On the other hand, in an off-peak recharge, a high hydro production and low wholesale prices' scenario, recharge costs could be reduced to 5.6 cents/kWh. In these extreme cases, EV's energy prices were between 0.9€ to 3.2€ per 100 km. Reductions in primary energy consumption, fossil fuels use and CO₂ emissions of up to 3%, 14% and 10%, respectively, were verified (for a 2 million EVs' penetration and a dry year's off-peak recharge scenario) from the transportation and electricity sectors together when compared with a BAU scenario without EVs.     

Energy consumption, costs and environmental impacts for urban water cycle services: Case study of Oslo (Norway)

Energy consumption in the operation and maintenance phase of the urban water and wastewater network is directly related to both the quantity and the desired quality of the supplied water/treated wastewater - in other words, to the level of service provided to consumers. The level of service is dependent on not just the quantity and quality of the water but also the state of the infrastructure. Maintaining the infrastructure so as to be able to provide the required high level of service also demands energy. Apart from being a significant operational cost component, energy use also contributes to life-cycle environmental impacts. This paper studies the direct energy consumption in the operation and maintenance phase of the water and wastewater system in Oslo; and presents a break-up among the different components of the network, of quantities, costs and environmental impacts. Owing to the diversity in the periods of time for which comprehensive data for the whole system are available, the study period is restricted to years 2000-2006. The per-capita annual consumption of energy in the operational phase of the system varied between 220 and 260 kWh; and per-capita annual expenses on energy in inflation-adjusted year-2006-Euros ranged between 6.5 and 11 Euros. The energy consumed on the upstream, per unit volume water supplied was around 0.4 kWh on average, while the corresponding value for the downstream was 0.8 kWh per cubic metre wastewater treated. The upstream Greenhouse gas (GHG) emissions ranged between 70 and 80 g per cubic metre of water supplied, about 22% greater on average than the corresponding specific GHG emissions on the downstream.     

An evaluation of biomass co-firing in Europe

Reduction of the emissions of greenhouses gases, increasing the share of renewable energy sources (RES) in the energy balance, increasing electricity production from renewable energy sources and decreasing energy dependency represent the main goals of all current strategies in Europe. Biomass co-firing in large coal-based thermal power plants provides a considerable opportunity to increase the share of RES in the primary energy balance and the share of electricity from RES in gross electricity consumption in a country. Biomass-coal co-firing means reducing CO₂ and SO₂, emissions and it may also reduce NO_x emissions, and also represents a near-term, low-risk, low-cost and sustainable energy development. Biomass-coal co-firing is the most effective measure to reduce CO₂ emissions, because it substitutes coal, which has the most intensive CO₂ emissions per kWh electricity production, by biomass, with a zero net emission of CO₂. Biomass co-firing experience worldwide are reviewed in this paper. Biomass co-firing has been successfully demonstrated in over 150 installations worldwide for most combinations of fuels and boiler types in the range of 50–700 MWe, although a number of very small plants have also been involved. More than a hundred of these have been in Europe. A key indicator for the assessment of biomass co-firing is intrduced and used to evaluate all available biomass co-firing technologies.     

淮海农场家庭生活用能和能源消费的分析研究

江苏省国营淮海农场家庭生活用能正处于商品能加速替代非商品能的时期,连续5年的家庭生活能调查表明,用能品种结构变化较大,电子和液化气消费迅速增加,而秸秆和煤炭的使用在下降;人均能源消费量相对稳定,但有效能消费却略有上升;分析表明,人均能源消费与人均收入、户均人口和人均作物收获量有一定的相关性,对农村家庭能源消费的性质,中国小康农村家庭能源消费的基本特征等一般问题进行了讨论。     

Characterization of energy use in 300 mm DRAM (Dynamic Random Access Memory) wafer fabrication plants (fabs) in Taiwan

Driven by technology advances and demand for enhanced productivity, migration of wafer fabrication for DRAM (Dynamic Random Access Memory) toward increased wafer size has become the fast-growing trend in semiconductor industry. Taiwan accounts for about 18% of the total DRAM wafer production in the world. The energy use required for operating wafer fabrication plants (fabs) is intensive and has become one of the major concerns to production power reliability in the island. This paper characterizes the energy use in four 300 mm DRAM wafer fabs in Taiwan through performing surveys and on-site measurements. Specifically, the objectives of this study are to characterize the electric energy consumption and production of 300 mm DRAM fabs by using various performance metrics, including PEI ((production efficiency index), annual electric power consumption normalized by annual produced wafer area) and EUI ((electrical utilization index), annual electric power consumption normalized by UOP (units of production), which is defined as the product of annual produced wafer area and the average number of mask layers of a wafer). The results show that the PEI and EUI values are 0.743 kWh/cm² and 0.0272 kWh/UOP, respectively. Using EUI in assessing energy efficiency of the fab production provides more consistent comparisons than using PEI alone.