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.     

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.     

Residential energy consumption patterns: the case of Lebanon

In an attempt to fill a significant gap in baseline information, 509 households have been studied to analyse the residential consumption patterns in the urban environment in Lebanon. The average annual household energy consumption has been found to be 6907 kWh, whereas per capita consumption is 1727 kWh. Seasonal and monthly variations are analysed indicating increased energy consumption in the summer months accounting for 28% of total annual consumption. Correlations are indicated for energy consumption with apartment price, area, income and number of residents. Multiple regression analysis indicated statistical significance of income, area and number of residents to the energy consumption. Based on current consumption and electricity generating technologies, 1.6 tons of CO₂, 7.3 kg of SO₂ in addition to other pollutants are generated per resident. Comparative analysis indicates that Lebanon has electricity consumption similar to that of Western Europe, paving the way for significant energy saving potential. Copyright © 2005 John Wiley & Sons, Ltd.     

Technical evaluation of post-combustion CO2 capture and hydrogen production industrial symbiosis

The aim of this study is to develop an industrial ecosystem whereby wastes/products from a Post-combustion CO₂ Capture (PCC) plant are utilised in a hydrogen biorefinery. Subsequently, five hydrogen biorefinery models are developed that use PCC's model amine i.e. monoethanolamine (MEA) as a nitrogen source during microbial hydrogen production and CO₂ as a process chemical. Technical evaluations of the five case models are carried out to identify the ones that maximise value by multiproduct generation from biomass and fulfil total/partial parasitic energy demand. The case meeting these criteria, produces 3.1t of succinylated lignin adhesive, 4.9t of dry compost and 2744 kWh of electricity from 10t (dry) of sawdust feedstock, daily. Its daily power and heat duties stand at 3906 kWh and 52.1 GJ respectively. Simulations also demonstrate biohydrogen's potential as an energy storage vector for peak/backup power with an annual 1001.4 MWh of power storage capacity from 10t/d feedstock.     

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.     

Supply amount and marginal price of renewable electricity under the renewables portfolio standard in Japan

The Renewables Portfolio Standard (RPS) in Japan requires that approximately 1.35% of each retail supplier's electricity sales in FY2010 come from renewable energy sources (RES), for example, photovoltaics, wind, biomass, geothermal, and small hydropower. To help retail suppliers and renewable generators develop effective strategies, this study provides a quantitative analysis of the impact of this measure. We assume the supply conditions for electricity generation from renewable energy sources (RES-E) based on regional resource endowments, and we derive the cost-effective compositions of renewable portfolios, RES-E certificate prices, and additional costs to retail suppliers. The future prospects of RES-E are assessed based on technology, region, and year up to FY2010. The analysis reveals that wind power and biomass power generated from municipal waste will provide the majority of the total supply of RES-E under the RPS. It also indicates that the marginal price of RES-E certificates will be approximately 5.8 JPY/kWh (5.2 USc/kWh) in FY2010, in the case wherein the marginal price of electricity is assumed to be 4 JPY/kWh (3.6 USc/kWh). In order to elaborate on this further, sensitivity analyses for some parameters of RES and the price of electricity are provided. The dynamic supply curves of RES-E certificates are also indicated.     

Assessment of centralized grid connected wind power cost in coastal area of Pakistan

This work presents an assessment of per unit cost of electricity generated from 15 MW wind farm at 40 locations in the coastal areas of Pakistan using the method of net present value analysis. The Nordex N43/600 wind turbine has been selected and used as reference wind turbine. Wind duration curves were developed and utilized to calculate per unit cost of electricity generated from chosen wind turbine. In Sindh province, the minimum cost of electricity generated was found to be 4.2 ¢/kWh at Jamshoro, while the corresponding maximum was 7.4 ¢/kWh at Kadhan site. In Balochistan, the minimum cost of electricity generated was found to be 6.3 ¢/kWh at Aghore, while the corresponding maximum was 21.0 ¢/kWh at Mand site. The study concludes that at most of the locations especially in Sindh province, wind power is competitive to conventional grid connected thermal power even without considering the externalities.     

A feasibility study of energy recovery of RDF from municipal solid waste

Municipal Solid Waste (MSW) is being used in energy-to-waste plants and as fuel substitutes in different industrial processes. Particularly Refuse Derived Fuel (RDF) from MSW has been widely using in the current practice. This paper aims at conducting a feasibility study of energy recovery of RDF from MSW generated in Pyongyang per year. This study considers the combustibles as RDF resource (i.e. plastics, paper, textile, mixed organic waste, wood, and rubber) in an evaluation of energy recovery. This feasibility study is conducted in two ways: the evaluations of potential energy content and electricity from the RDF resource, which are carried out by methodologies based on heating values of RDF resource and efficiencies of energy recovery, respectively. The results show that the total energy content from RDF resource based on Lower Heating Value (LHV) is approximately 2,813,678.7 GJ/yr, while it is available to generate electricity in a range of 101,320,570?210,435,030 kWh/yr depending on different net efficiencies. This research findings provide a feasibility of RDF utilization for energy recovery to the local planners.     

Feasibility study into the potential for gasification plant in the New Zealand wood processing industry

The purpose of this paper is to investigate the feasibility of installing gasification-based energy plants in the New Zealand wood processing industry. The study compared energy plants supplying the thermal and electrical energy in sawmills, laminated veneer lumber (LVL) plants and medium density fibreboard (MDF) mills. The breakeven electricity price for the MDF and LVL scenarios ranged from 4–8.9 c/kWh while the sawmill scenario was 11.6 c/kWh. The conclusion of the study is that while the economics are comparable with other renewable energy generation methods such as hydro and wind the location of the plant is critical to overall feasibility due mainly to biomass availability and power price both now and in light of expected future trends. The technology is complementary to the government's forward strategy which encourages both distributed generation and renewable energy.     

Effects on global CO<Subscript>2</Subscript> emissions when substituting LPG with bio-SNG as fuel in steel industry reheating furnaces—the impact of different perspectives on CO<Subscript>2</Subscript> assessment

The iron and steel industry is the second largest user of energy in the world industrial sector and is currently highly dependent on fossil fuels and electricity. Substituting fossil fuels with renewable energy in the iron and steel industry would make an important contribution to the efforts to reduce emissions of CO₂. However, different approaches to assessing CO₂ emissions from biomass and electricity use generate different results when evaluating how fuel substitution would affect global CO₂ emissions. This study analyses the effects on global CO₂ emissions when substituting liquefied petroleum gas with synthetic natural gas, produced through gasification of wood fuel, as a fuel in reheating furnaces at a scrap-based steel plant. The study shows that the choice of system perspective has a large impact on the results. When wood fuel is considered available for all potential users, a fuel switch would result in reduced global CO₂ emissions. However, applying a perspective where wood fuel is seen as a limited resource and alternative use of wood fuel is considered, a fuel switch could in some cases result in increased global CO₂ emissions. As an example, in one of the scenarios studied, a fuel switch would reduce global CO₂ emissions by 52 ktonnes/year if wood fuel is considered available for all potential users, while seeing wood fuel as a limited resource implies, in the same scenario, increased CO₂ emissions by 70 ktonnes/year. The choice of method for assessing electricity use also affects the results.     

Process optimization for large-scale hydrogen liquefaction

The investment in the hydrogen infrastructure for hydrogen mobility has lately seen a significant acceleration. The demand for energy and cost efficient hydrogen liquefaction processes has also increased steadily. A significant scale-up in liquid hydrogen (LH₂) production capacity from today's typical 5–10 metric tons per day (tpd) LH₂ is predicted for the next decade. For hydrogen liquefaction, the future target for the specific energy consumption is set to 6 kWh per kg LH₂ and requires a reduction of up to 40% compared to conventional 5 tpd LH₂ liquefiers. Efficiency improvements, however, are limited by the required plant capital costs, technological risks and process complexity. The aim of this paper is the reduction of the specific costs for hydrogen liquefaction, including plant capital and operating expenses, through process optimization. The paper outlines a novel approach to process development for large-scale hydrogen liquefaction. The presented liquefier simulation and cost estimation model is coupled to a process optimizer with specific energy consumption and specific liquefaction costs as objective functions. A design optimization is undertaken for newly developed hydrogen liquefaction concepts, for plant capacities between 25 tpd and 100 tpd LH₂ with different precooling configurations and a sensitivity in the electricity costs. Compared to a 5 tpd LH₂ plant, the optimized specific liquefaction costs for a 25 tpd LH₂ liquefier are reduced by about 50%. The high-pressure hydrogen cycle with a mixed-refrigerant precooling cycle is selected as preferred liquefaction process for a cost-optimized 100 tpd LH₂ plant design. A specific energy consumption below 6 kWh per kg LH₂ can be achieved while reducing the specific liquefaction costs by 67% compared to 5 tpd LH₂ plants. The cost targets for hydrogen refuelling and mobility can be reached with a liquid hydrogen distribution and the herewith presented cost-optimized large-scale liquefaction plant concepts.     

Multifamily energy-efficiency retrofit programs: a Florida case study

Multifamily buildings are an important target for efficiency improvements because of their energy savings potential and housing market share. Yet few multifamily retrofit projects have been completed in hot-humid regions and even fewer studies have measured and verified savings from such projects. Addressing this gap, the purpose of our research is to assess the impacts of energy-efficiency upgrades to multifamily buildings in Orlando, FL. Specifically, we measure the first-year electricity savings from retrofits to 232 units in four apartment complexes. Annual savings per unit averaged 2094 kWh (22 %) and ranged from 1700 kWh (18 %) to 3811 kWh (29 %) across complexes. Monthly savings ranged from 48 kWh (9.4 %) in December to 340 kWh (31 %) in August. From these core findings, we estimate that tenants in treatment units saved an average of $272 on their electric bills. We also find evidence to support a strategy of targeting upgrades to improve overall savings and program cost-effectiveness. Results are being used to guide development of a utility demand-side management program for multifamily property owners. Progress in this market requires additional pilot projects, access to utility data, reliable measurement and verification of savings, and innovative financing structures.     

Direct load control of residential water heaters

In Norway there is a growing concern that electricity production and transmission may not meet the demand in peak-load situations. It is therefore important to evaluate the potential of different demand-side measures that may contribute to reduce peak load. This paper analyses data from an experiment where residential water heaters were automatically disconnected during peak periods of the day. A model of hourly electricity consumption is used to evaluate the effects on the load of the disconnections. The results indicate an average consumption reduction per household of approximately 0.5 kWh/h during disconnection, and an additional average increase in consumption the following hour, due to the payback effect, that may reach up to 0.28 kWh/h per household.     

Sizing and operating power-to-gas systems to absorb excess renewable electricity

Various configurations of power-to-gas system are investigated as a means for capturing excess wind power in the Emden region of Germany and transferring it to the natural gas grid or local biogas-CHP plant. Consideration is given to producing and injecting low concentration hydrogen admixtures, synthetic methane, or hydrogen/synthetic methane mixtures. Predictions based on time series data for wind generation and electricity demand indicate that excess renewable electricity levels will reach about 40 MW and 45 GW h per annum by 2020, and that it is desirable to achieve a progression in power-to-gas capacity in the preceding period. The findings are indicative for regions transitioning from medium to high renewable power penetrations. To capture an increasing proportion of the growing amount of excess renewable electricity, the following recommendations are made: implement a 4 MW hydrogen admixture plant and hydrogen buffer of 600 kg in 2018; then in 2020, implement a 17 MW hybrid system for injecting hydrogen and synthetic methane (with a hydrogen storage capacity of at least 400 kg) in conjunction with a bio-methane injection plant. The 17 MW plant will capture 68% of the available excess renewable electricity in 2020, by offering an availability to the electricity grid operator of >97% and contributing 19.1 GW h of ‘green’ gas to the gas grid.     

The potential contribution of geothermal energy to electricity supply in Saudi Arabia

With increase in demand for electricity at 7.5% per year, the major concern of Saudi Arabia is the amount of CO₂ being emitted. The country has the potential of generating 200×10⁶ kWh from hydrothermal sources and 120×10⁶ terawatt hour from Enhanced Geothermal System (EGS) sources. In addition to electricity generation and desalination, the country has substantial source for direct application such as space cooling and heating, a sector that consumes 80% of the electricity generated from fossil fuels. Geothermal energy can offset easily 17 million kWh of electricity that is being used for desalination. At least a part of 181,000 Gg of CO₂ emitted by conventional space cooling units can also be mitigated through ground-source heat pump technology immediately. Future development of EGS sources together with the wet geothermal systems will make the country stronger in terms of oil reserves saved and increase in exports.     

Optimizing energy savings of the injection molding process by using a cloud energy management system

The injection molding (IM) process is a widely used manufacturing process for injecting material into a mold for producing a diverse array of parts. It includes several energy-consuming procedures, such as heating plastic pellets, forcing melted polymer into a mold cavity, and cooling down the molded products. In this study, developmental factors of IM machines and processes along with energy savings progress are reviewed. In addition to several machining factors and process parameter optimizations, applying an energy management system (EMS), as well as new tools to reduce energy consumption in the IM process, has the potential for great improvements in the long term. A cloud energy management system (CEMS), called the intelligent Energy Management Network (iEN), which was launched by Chunghwa Telecom, was installed on two IM machines to illustrate the optimization of energy savings by a variable-frequency drive (VFD) and process parameter optimization. Through the recorded process dynamics, the energy usage, and product quality of the IM process using the iEN, the energy savings could be analyzed by the expert, measurement and verification (M&V) systems on the software as a service (SaaS) platform. The electricity savings on the IM machine after installing a VFD were 41.3%. Further optimization by using the one-factor-at-a-time (OFAT) approach to measure the process parameters, such as melting temperature (310.0~350.0 °C), mold temperature (110.0~130.0 °C), and clamping force (120.0~160.0 T), was carried out. The experimental and analyzed results indicated that the optimal operating conditions were at a melting temperature of 330.0 °C, a mold temperature of 120.0 °C, and a clamping force of 140.0 T. Through the optimization procedure of the process parameters carried out by the iEN, further electricity savings of 12.2% were added. Therefore, the saved electricity cost and payback period of installing the VFD and the iEN were NT$ 26,363/month and within 4 months, respectively. The saved electricity and reduced carbon dioxide (CO₂) amounts were 107,200.5 kWh/year and 55,851.5 kg/year, respectively. Continuous analysis of the optimization process, energy savings, resource conservation, and waste reduction of the IM process using the iEN has shown overall benefits to the IM process, the machines, and the future decisions and designs regarding new products.     

Biomass Energy and Biochemical Conversion Processing for Fuels and Chemicals

Biomass, mainly in the form of wood, is the oldest form of energy used by humans. Biomass is used to meet a variety of energy needs, including generating electricity, heating homes, fueling vehicles, and providing process heat for industrial facilities. Biomass potential includes wood and animal and plant wastes. Biomass, mainly now represents only 3% of primary energy consumption in industrialized countries. World production of biomass is estimated at 146 billion metric tons a year, mostly wild plant growth. Energy from biomass fuels is used in the electric utility, lumber and wood products, and pulp and paper industries. Biomass conversion may be conducted on two broad pathways: chemical decomposition and biological digestion. The conversion technologies for utilizing biomass can be separated into four basic categories: direct combustion processes, thermochemical processes, biochemical processes, and agrochemical processes. Biological processes are essentially microbic digestion and fermentation.     

Electricity consumption,electricity intensity and industrial structure

This paper describes an analysis of recent trends in industrial output and electricity consumption carried out at the Electricity Council. The analysis examines the significance of changes in industrial structure and in the intensity of electricity use within major industries using a simple arithmetical procedure. The conclusion reached is that such factors have, in recent years, had a major influence on trends in industrial electricity consumption. The importance of these factors explains why simple econometric models which describe industrial electricity sales as a function of total industrial output have proved unsatisfactory for forecasting purposes. This conclusion underlines the need to use a disaggregated approach to electricity forecasting, an approach which the electricity industry has used increasingly.     

Impact of load profile and collector technology on the fractional savings of solar domestic water heaters under various climatic conditions

This paper investigates the influence of the domestic hot water load profiles and the collector's technology (Flat Plate FPC, Evacuated Tube ETC and Compound Parabolic CPC) on the performance of forced circulation solar water heaters operating under various climatic conditions. For this end, a typical single family house composed of five occupants located in Morocco was considered. It is found that, the solar fraction can reach annual average values of 80% especially in areas with high solar energy potential. For a fixed consumption profile, the simulations showed that the installations with FPC, ETC and CPC can consume about 1644, 1199 and 1481 kWh/year of auxiliary energy, respectively. Moreover, it is found that, adapting the consumption profile, can save approximately 43 kWh/year for FPC, 13 kWh/year for ETC and about 29 kWh/year for CPC of energy.     

Wind power potential in Oman

Solar energy and wind are likely to play an important role in the future energy generation in Oman. This article assesses wind power cost per kWh of energy produced using four types of wind machines at 27 locations within Oman. These sites cover all regions in Oman. Hourly values of wind speed recorded between 2000 and 2009, in most cases, were used for all 27 locations. Wind duration curves were developed and utilized to calculate the cost per kWh of energy generated from four chosen wind machines. It was found that the cost of energy is low in the south and middle regions of Oman compared with that in the north region. The most promising sites for the economic harnessing of wind power are Thumrait, Qairoon Hairiti, Masirah, and Sur, with an energy cost of less than 0.117 US$/kWh when 2000 kW, 1500 kW, 850 kW, or 250 kW wind turbines are used.