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The natural gas industry in Western Europe went through drastic changes induced by the unbundling of the national companies, followed by the liberalization of gas trade and the regulation of gas transmission. Natural gas transmission is operated through a network of interconnected grids, and is capacity constrained. Each of the grids is locally regulated in terms of price limits on transportation services. Local tariff differences may induce unnatural gas routing within a network, creating congestion in some part of it. This phenomena is referred to as the Jepma effect. Following Jepma [2001. Gaslevering onder druk. Stichting JIN. Available at: www.jiqweb.org (52pp) (in Dutch)] this may lead to misguided investment decisions. In this paper a multi-stage linear program is used to simulate the repartition of the natural gas flow in an interconnected grid system on a succession of contracting periods. By this simulation, the risk linked to infrastructure investment is assessed, The risk measured can be seen as the probability of a negative present net value for the investment. The model is applied on an example of two grids that are on alternative routes serving same destinations. When applied to a specific situation of North-West Europe (Germany and The Netherlands), the model clearly demonstrates that the risks turn out to be too high to invest: there are hardly any scenarios under which an acceptable ROI will be realized. Given the current tariff policy and current publicly available forecasts of demand and supply, it is unlikely that market forces will attract additional investments in transportation capacity. This reluctance to invest can be prohibitive for further growth of supply if the demand would increase significantly. (C) 2008 Published by Elsevier Ltd.

In this article major environmental problems and their different levels and global spheres of impact are surveyed. Environmental exploitation is discussed as an inherent characteristic of free market economies under limited cognitive‐motivational inclinations of individual actors. A conceptual modelling of environmental problem solving is presented, which comprises the commons dilemma paradigm as well as a needs‐opportunities‐abilities (NOA) model of consumer behaviour, a categorization of human needs, a simple taxonomy of behavioural processes, and seven strategies for behaviour change. Six lines of psychological research are identified, ranging from environmental attitudes to environmental policy‐decision support systems. An ecological critique of mainstream psychology is summarized and some suggestions are made to resolve this. Conclusions are drawn about needed research, policy making, and international diplomacy.

Walking is most efficient when the least energy is spent over a certain distance. In six normal male subjects and 11 males with above-knee amputation the comfortable self-selected walking speeds and the most metabolically efficient walking speeds were determined. For that purpose energy expenditure was measured per second and per meter at six incremental walking speeds. Heart and step rate were registrated also at each walking speed. The results showed that in subjects who have not undergone amputation the comfortable walking speed is the same as the most efficient walking speed. However, in the above-knee amputee group, the comfortable walking speed is lower than the most efficient walking speed. When both groups walked at their own efficient walking speed they had the same energy expenditure per second.

Abstract Over the last four years the Netherlands has been involved in a public debate on its energy future, and more narrowly on the role of nuclear power. In this article computer simulation results for two much discussed strateties for the Dutch electric power system are presented and evaluated. A set of four criteria for comparison of these strategies is discussed. It is found that above a critical value further expansion of the nuclear and coal-fired base load capacity is no longer compatible with enhancement of the industrial cogeneration capacity. It is shown that in terms of kWhe-costs both strategies offer rather effective protection against steep oil price increases, though in different ways and with varying implications for Dutch natural gas policy.

Carbohydrate dynamics were studied in an algal community dominated by the diatom Fragilariopsis kerguelensis at the Antarctic Polar Front during austral autumn 1999. Water-extractable mono- and polysaccharide concentrations from the particulate fraction were measured at six depths in the upper 100 in at seven stations along a N-S transect (20degreesE, 48-50degreesS) during 2 consecutive days. In addition, field populations were incubated on deck for 18 h at four different light intensities. Polysaccharide concentrations varied between 2.7 and 13.6 mug/l, monosaccharide concentrations between 2.5 and 8.9 mug/l. Near the surface (0-60 in), a diet pattern was observed in the polysaccharide concentration when normalised to the chlorophyll a or the monosaccharide concentration. The deck incubations supported the hypothesis that this pattern resulted from the diurnal accumulation and nocturnal consumption of reserve glucan. More polysaccharides accumulated at high light intensities than at low light intensities, in accordance with the observed decrease in normalised polysaccharide concentration with depth. In addition, the lower concentrations at depth might be explained by consumption: polysaccharides that were accumulated during time spent near the surface were subsequently respired when cells were transported to deeper and dimmer water layers. The variation in carbohydrate pools over-time and depth described here must be considered of ecological relevance to phytoplankton in the Southern Ocean subjected to extended periods of darkness (hours to days) due to vertical mixing and advection.

The security of energy supply to the EU is examined in the context of two storylines. Markets and Institutions exemplifies an economically and politically integrated, multilateral world with effective institutions and markets, Regions and Empires involves a world broken up in rival political and economic blocks, competing for resources and markets via political, economic and military power. It is shown that these storylines have a significant impact on the development or the energy market, on the way in which energy Supply may be secured and on the effect and applicability of the several types of instruments available. The current EU is geared towards enlargement and a deepening of economic integration, based on the tenets of the post-1945 Multilateral world system. The present world tends towards Regions and Empires and Suggests that the EU may have to reorient its energy security policy. Energy Policy Must become an integral part of EU external trade and foreign relations and security policy. The EU should develop its own strategy, actively investing in dialogues with producer countries in the Persian Gulf and Africa and with Russia. Sustainable prosperity and governance in these regions will Support EU energy security. (c) 2005 Elsevier Ltd. All rights reserved.

We present trends in energy intensities for 56 Dutch economic sectors over the 20-year period 1969–1988. The intensities were calculated by using input–output analysis. The effects of energy-price changes were examined. More than half of the economic sectors show significant declines in energy intensities as a result of increasing energy prices. As a result, the energy intensity for final demand shows a significant decline, although a shift to more energy-intensive sectors was found.

The industrial revolution and the exploitation of fossil fuels fostered profound changes on transportation systems and infrastructure enabling unprecedented urban growth. Urban regions, which now host the majority of the world's population, resemble a linear metabolism: importing most of their raw materials, food, and energy, and using these resources in an inefficient manner resulting in waste outflows. Regarding energy flows, cities are highly depending on fossil fuels and the rate at which fossil fuels are consumed is faster than their generation rate. Therefore, a shift is needed toward more sustainable energy sources. We propose a sustainable urban energy planning approach, based on the thermodynamic principle, exergy. This approach integrates multi-functionality, interaction between urban functions, and harvesting of local renewable and residual resources Urban Harvest Approach. Synergies between urban functions are crucial to reach productive and sustainable urban regions. Resource exchange among different urban functions offers possibilities toward productive urban regions aiming for closed cycle resources management, e.g. integrating industrial ecosystems in urban ecosystems. Our method consists of six steps: (i) land-use inventory; (ii) energy demand inventory; (iii) local renewable/residual energy potential analysis; (iv) clusters of spatial functions exploration; (v) energetic linkages analysis; (vi) network patterns exploration. We tested the method at neighborhood scale, Kerkrade-West, The Netherlands. Results showed that linking spatial clusters is crucial toward circular urban metabolism. Spatial design should promote mixed land-use. The case showed that spatial planning based on urban energy harvesting is a useful method to translate generic goals to local spatial interventions. Urban energy harvesting can contribute to increased productivity, resulting in increased sustainability of urban areas, e.g. social, environmental benefits. (C) 2012 Elsevier Ltd. All rights reserved.