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[en] The horticulture sector can make use of surplus heat, produced within the greenhouses, and supply the heat to several energy consuming parties (other greenhouse businesses, buildings, etc.). Thus, a local or regional web of suppliers and consumers starts. In this report a program of requirements is set up to start a first model version of such an energy web for the greenhouse sector
[nl]Vanuit het concept 'Kas als Energiebron' is de gedachte ontstaan dat kassen daadwerkelijk energie in de vorm van warmte op jaarrondbasis kunen overhouden en tot waarde brengen. Deze warmte kan geleverd worden aan verschillende vragers. Dat kunnen zowel tuinbouwbedrijven zijn als, in een latere fase ook andere typen bedrijven, gebouwen en huizen. Zo ontstaat dus een lokaal of regionaal energieweb van aanbieders en vragers van warmte. Dit rapport bevat een programma van eisen voor een eerste versie van een energieweb voor gebruik in de tuinbouw. Het bevat niet alleen een overzicht van de eisen die aan het model worden gesteld maar ook welke kennis nog additioneel ontwikkeld moet worden
[en] In China, electricity consumption has grown quickly, supply is highly dependent on coal-fired power, and the prices of electricity are determined by the government, which increases the need for reform to enhance efficiency. In response to disputes about China’s electricity market reform, this paper analyses the efficiency of China’s coal-fired power plants using the Data Envelopment Analysis—Slack Based Measure (DEA-SBM) method on three levels: groups, provinces, and plants. The results indicate that there are both coal-electricity efficiency disparities and generation-hour arrangement unfairness across groups; the disparity across provinces is obvious and long-lasting, as indicated by capacity surpluses and coal-electricity efficiencies; and the disparities are displayed in detail by the estimation at the plant level. The disparities are primarily caused by the generator combination and generation hour arrangement. Competition may be able to solve the disparities, but a further comparison indicates that competition at the national level will enhance the efficiency to a greater degree than competition at the regional level. These results demonstrate that both competition and a united electricity market are necessary for further electricity market reform. - Highlights: • This paper analyses the coal-fired electricity efficiency from three levels. • There are efficiency disparities and hour arrangement unfairness at group level. • The disparities and unfairness are long-lasting across provinces. • The disparities and unfairness are detailed by analysis at plant level. • Competition at national market can improve the efficiency better than at regional market
[en] From the results of the 1997 European Autumn Gas Conference in Barcelona, Spain, it appears that the European gas industry is mainly focused on the liberalization of the European energy market. The main topic of the Conference was 'dealing with surplus'. A brief overview is given of the natural gas trade developments in the European countries. 1 ill., 1 tab. 2 ills
[en] A summary of hydrogen technology and details of current production and use of hydrogen in Canada were presented. Future demand for hydrogen was discussed. The aim of the report was to enable readers to better understand the significant size of the hydrogen industry. Canada is the largest per capita producer of hydrogen in the OECD, with production currently at 3.09 million tonnes per year. The current hydrogen surplus was attributed to a combination of short-term reductions in demand and excess capacity built in anticipation of growing demand. Mechanical and chemical processes that create hydrogen were reviewed, and details of prospective emerging technologies in hydrogen production, purification, transportation and storage were presented. Technical opportunities for hydrogen were explored. A regionalized inventory of hydrogen production in Canada was provided. Projected demands for 3 scenarios of hydrogen production were presented: (1) a business as usual perspective with no dramatic political or climatic impacts; (2) a carbon conscious agenda where major disturbances due to climate change have resulted in a focus on greenhouse gas (GHG) reduction and fuel efficiency; and (3) a hydrogen priority path that promotes North American energy self-sufficiency and concerted actions by government to adopt the hydrogen economy. The production consequences of hydrogen demand under each scenario emphasized the potential size and location of Canada's hydrogen needs. It was concluded that Canadian companies and research facilities have established a strong technical and commercial presence in hydrogen production over the last 10 years. tabs., figs
[en] The problem of how to determine the optimal parameters for the solar part of a plant with respect to boiler equipment efficiency is examined. The most efficient condensing boilers are chosen for simulation. (authors)
[en] For the globalized world economy with intensive international trade, an overview of energy consumption is presented by an embodied energy analysis to track both direct and indirect energy uses based on a systems input-output simulation. In 2004, the total amounts of energy embodied in household consumption, government consumption, and investment are 7749, 874, and 2009 Mtoe (million tons of oil equivalent), respectively. The United States is shown as the world's biggest embodied energy importer (683 Mtoe) and embodied energy surplus receiver (290 Mtoe), in contrast to China as the biggest exporter (662 Mtoe) and deficit receiver (274 Mtoe). Energy embodied in consumption per capita varies from 0.05 (Uganda) to 19.54 toe (Rest of North America). Based on a forecast for 2005-2035, China is to replace the United States as the world's leading embodied energy consumer in 2027, when its per capita energy consumption will be one quarter of that of the United States. - Highlights: → We present an overview of global energy profile in terms of embodied energy. → The US and China are top embodied energy consumers as well as traders in 2004. → Equality issue is studied by analyzing per capita embodied energy consumption. → The US remains to be the leading energy consumer until replaced by China in 2027.
[en] Highlights: ► This study estimates the maximum wind energy contribution to an isolated micro-grid. ► An integrated computational tool is developed on the basis of stochastic analysis. ► The probability distribution of the wind energy surplus and deficit is estimated. ► The results indicate that a strict penetration limit is imposed to wind energy. -- Abstract: The electrification in remote islands whose electricity distribution network is not connected to the mainland’s grid is mostly based on Autonomous Power Stations (APSs) that are usually characterized by a considerably high electricity production cost, while at the same time the contribution of Renewable Energy Sources (RES) in these regions accounts for less than 10% of the total electricity generation. This actually results from the fact that despite the excellent wind potential of most of these islands, the wind energy contribution is significantly restricted from limits imposed to protect the remote electrical grids from possible instability problems, due to the stochastic wind speed behavior and the variable electricity consumption. On the basis of probability distribution of the load demand of a representative Greek island and the corresponding data related to the available wind potential, the present study estimates the maximum – acceptable by the local grid – wind energy contribution. For that reason, an integrated computational algorithm has been developed from first principles, based on a stochastic analysis. According to the results obtained, it becomes evident that with the current wind turbine technology, wind energy cannot play a key role in coping with the electrification problems encountered in many Greek island regions, excluding however the case of introducing bulk energy storage systems that may provide considerable recovery of the remarkable wind energy rejections expected.
[en] This article analyses critical technical areas that currently limit the success of biodiesel as a fuel. The production process is currently shifting from homogeneous to heterogeneous using solid catalysts for a cleaner process and ease of product separation. The free fatty acid and moisture contents in the raw materials must be sufficiently low to avoid soap formation. The production of biodiesel with full compliance with ASTM D6751-07 or EN 14214:2003 is an uphill task. Current technologies for biodiesel production still do not provide more significant energy surplus. Biodiesel has relatively lower energy content, causing higher fuel consumption. Biodiesel has a drawback in terms of its cold flow properties. A high iodine value can cause degradation and polymerization of biodiesel components. Unconverted monoglyceride, diglyceride and triglyceride impurities will affect the engine performance. The alcohol content in biodiesel can attack rubber seals and gaskets. Biodiesel also can undergo chemical and biological modification to affect its quality in long-term storage. Biodiesel is also associated with high-level NOx emission, a fact that needs special attention
[en] To systematically reveal how domestic trade impacts on China's regional energy uses, an interprovincial input–output modeling is carried out to address demand-derived energy requirements for the regional economies in 2007 based on the recently available data. Both the energy uses embodied in final demand and interregional trade are investigated from the regional and sectoral insights. Significant net transfers of embodied energy flows are identified from the central and western areas to the eastern area via interregional trade. Shanxi is the largest energy producer and interregional embodied energy deficit receiver, in contrast to Guangdong as the largest energy user and surplus receiver. By considering the impacts of interregional trade, the energy uses of most eastern regions increase remarkably. For instance, Shanghai, Hainan, Zhejiang, Beijing, Jiangsu and Guangdong have their embodied energy requirements 87.49, 19.97, 13.64, 12.60, 6.46 and 6.38 times of their direct energy inputs, respectively. In contrast, the embodied energy uses of some central and western regions such as Inner Mongolia, Shanxi, Xinjiang, Shaanxi and Guizhou decrease largely. The results help understand the hidden network linkages of interregional embodied energy flows and provide critical insight to amend China's current end-reduction-oriented energy policies by addressing the problem of regional responsibility transfer. - Highlights: • Demand-derived energy requirements for China's regional economies are addressed. • Significant interregional transfers of embodied energy flows are identified. • Energy surpluses are obtained by 19 regions and deficits by the other 11 regions. • The eastern regions should take more responsibility for reducing China's energy uses