Analyzing price and efficiency dynamics of large appliances with the experience curve approach

Large appliances are major power consumers in households of industrialized countries. Although their energy efficiency has been increasing substantially in past decades, still additional energy efficiency potentials exist. Energy policy that aims at realizing these potentials faces, however, growing concerns about possible adverse effects on commodity prices. Here, we address these concerns by applying the experience curve approach to analyze long-term price and energy efficiency trends of three wet appliances (washing machines, laundry dryers, and dishwashers) and two cold appliances (refrigerators and freezers). We identify a robust long-term decline in both specific price and specific energy consumption of large appliances. Specific prices of wet appliances decline at learning rates (LR) of 29±8% and thereby much faster than those of cold appliances (LR of 9±4%). Our results demonstrate that technological learning leads to substantial price decline, thus indicating that the introduction of novel and initially expensive energy efficiency technologies does not necessarily imply adverse price effects in the long term. By extending the conventional experience curve approach, we find a steady decline in the specific energy consumption of wet appliances (LR of 20–35%) and cold appliances (LR of 13–17%). Our analysis suggests that energy policy might be able to bend down energy experience curves.     

Technique and results of the retroperitoneoscopic adrenalectomy via a lumbar approach

INTRODUCTION: Since 1992, endoscopic techniques have been used increasingly in adrenal-gland surgery. In the present paper, the technique of the retroperitoneoscopic adrenalectomy via a lumbar approach is described. METHODS: The patient is placed in a lateral decubitus position. In the first step, a dilatation trocar is introduced in the retroperitoneal space to create an artificial cavity. The dilatation trocar is replaced by a blocking trocar to close off the operating field. After insufflation of CO2, two additional trocars are introduced in the area of the conventional flank incision. Adrenalectomy is performed via these ports. Once the adrenal gland is completely mobilized, it is inserted into a sterile plastic bag and removed through the 1.5-cm incision. CONCLUSION: The retroperitoneoscopic approach to the adrenal gland appears to be suitable for benign adrenal-gland tumors up to a size of 6 cm.     

Liver metabolism during cold ischemic incubation in UW solution in the rat model]

Mother-to-child transmission near the time of birth is the primary route of HIV-1 infection among infants and young children. Throughout the world, 1000 babies a day become infected with HIV, and cumulative global estimates are that 3 million children have been infected since the HIV pandemic began. Although major advances have been made in reducing mother-to-child transmission of HIV-1 in the USA and Europe through the use of an intensive regimen of zidovudine, many research questions remain unresolved. These include (1) viral and host characteristics which hinder or facilitate perinatal HIV transmission (i.e. the role played by viral load, the placenta and obstetric risk factors); (2) the proportion of transmission occurring in utero, intrapartum or during the breast feeding period; and (3) the mode of action of the successful zidovudine regimen. Studies published within the past year have shed light on several of these research topics. In 1996-1997 a number of important studies were published which support a general correlation between maternal viral load and infant HIV infection. The most recent studies do not, however, support the theory that there is a threshold below which transmission cannot occur, and also indicate that zidovudine, given according to the US Public Health Service guidelines, can significantly reduce the risk of transmission across all levels of maternal viral load. Analyses of viral load data from the successful clinical trial with zidovudine (AIDS Clinical Trial Group 076) suggest that its primary action is not by reducing the viral load, and raise the possibility that administering antiretroviral prophylaxis to the infant at the time of highest exposure may be another reason for the reduction in transmission. Obstetric risk factors for mother-to-child HIV transmission have been evaluated in several large cohort studies. A duration of membrane rupture of more than 4 h, and procedures such as amniocentesis, preterm labor, and the presence of sexually transmitted diseases during pregnancy were found to be significant risk factors. Still unresolved is the potential protective effect of cesarean section in reducing the risk of transmission. Likewise, the role played by the placenta in preventing or facilitating perinatal transmission is not well understood, and requires further research. This year did see the publication of consistent findings from diverse geographical regions regarding the probable timing of perinatal HIV transmission. On the basis of the timing of the first infant positive polymerase chain reaction or culture, most transmission would appear to occur around the intrapartum or very late prenatal period, and only approximately 12-14% is related to breast feeding. These advances should help focus and refine future research efforts to reduce mother-to-child HIV transmission worldwide.     

Competition between biofuels: Modeling technological learning and cost reductions over time

A key aspect in modeling the (future) competition between biofuels is the way in which production cost developments are computed. The objective of this study was threefold: (i) to construct a (endogenous) relation between cost development and cumulative production (ii) to implement technological learning based on both engineering study insights and an experience curve approach, and (iii) to investigate the impact of different technological learning assumptions on the market diffusion patterns of different biofuels. The analysis was executed with the European biofuel model BioTrans, which computes the least cost biofuel route. The model meets an increasing demand, reaching a 25% share of biofuels of the overall European transport fuel demand by 2030. Results show that 1st generation biodiesel is the most cost competitive fuel, dominating the early market. With increasing demand, modestly productive oilseed crops become more expensive rapidly, providing opportunities for advanced biofuels to enter the market. While biodiesel supply typically remains steady until 2030, almost all additional yearly demands are delivered by advanced biofuels, supplying up to 60% of the market by 2030. Sensitivity analysis shows that (i) overall increasing investment costs favour biodiesel production, (ii) separate gasoline and diesel subtargets may diversify feedstock production and technology implementation, thus limiting the risk of failure and preventing lock-in and (iii) the moment of an advanced technology's commercial market introduction determines, to a large degree, its future chances for increasing market share.     

The REFUEL EU road map for biofuels in transport: Application of the project's tools to some short-term policy issues

The current hot debate on biofuels calls for a balanced and realistic long-term strategy for biofuels. The REFUEL project provides several ingredients for such a strategy. Analyses in this project indicate that domestically produced biofuels can cover a significant share of EU fuel demand in the coming decades, with the EU-12 new member states and Ukraine as most promising regions. This potential can be realised with residual streams and on existing agricultural land, without conversion of e.g. nature reserves. Second generation biofuels are essential for the long-term success of biofuels due to their superior performance in many ways. But generally, the key challenge for the near future would be how to enhance the development of biofuels in a responsible way, i.e. stimulating the production chains with the best performance, and preventing negative impacts e.g., by paying careful attention to possible system impacts of biofuel production such as indirect land use changes and rising food prices. Finally, 2nd generation biofuels require specific policy: the precursor role of 1st generation is overrated, both in technical terms as well as in their role as market precursors. When it comes to synergies, 2nd generation biofuels might benefit more from other developments in the energy sector, such as initiatives in co-firing of biomass for (heat and) power, than from 1st generation biofuels, also because of the public resistance that the latter induce.     

Technological learning in offshore wind energy: Different roles of the government

Offshore wind energy is a promising source of renewable electricity, even though its current costs prevent large-scale implementation. Technological learning has improved the technology and its economic performance already, and could result in significant further improvements. This study investigates how technological learning takes place in offshore wind energy and how technological learning is related to different policy regimes. Offshore wind energy developments in Denmark and the United Kingdom have been analysed with a technology-specific innovation systems approach. The results reveal that the dominant forms of learning are learning by doing and learning by using. At the same time, learning by interacting is crucial to achieve the necessary binding elements in the technology-specific innovation system. Generally, most learning processes were performed by self-organizing entities. However, sometimes cultural and technical barriers occurred, excluding component suppliers and knowledge institutes from the innovation system. Danish policies successfully anticipated these barriers and removed them; therefore, the Danish policies can be characterized as pro-active. British policies shaped stable conditions for learning only; therefore, they can be characterized as active. In the future, barriers could hinder learning by interacting between the oil and gas industry, the offshore wind industry and academia. Based on this study, we suggest national and international policy makers to design long-term policies to anticipate these barriers, in order to contribute to technological learning.     

Technological learning and cost reductions in wood fuel supply chains in Sweden

With its increasing use, the production costs of primary forest fuel (PFF) have declined over the last three decades in Sweden. The aims of this study are to quantify cost reductions of PFF production as achieved in Sweden over time, to identify underlying reasons for these reductions, and to determine whether the experience curve concept can be used to describe this cost reduction trend. If applicable, the suitability of this concept for future cost reduction analysis and for use in other countries is explored. The analysis was done using average national PFF price data (as a proxy for production costs), a number of production cost studies and data on annual Swedish production volumes. Results show that main cost reductions were achieved in forwarding and chipping of PFF, largely due to learning-by-doing, improved equipment and changes in organization. The price for wood fuel chips does follow an experience curve from 1975 to 2003 (over nine cumulative doublings). The progress ratio (PR) is calculated at 87%. However, given the uncertainty in data on PFF price and annual production volumes, the PR may range between 85% and 88%. It is concluded that in combination with the available supply potential of PFF and with bottom-up assessment of cost reduction opportunities, experience curves can be valuable tools for assessing future PFF production cost development in Sweden. A methodological issue that needs to be further explored is how learning took place between Sweden and other countries, especially with Finland, and how the development of technology and PFF production in these countries should be combined with the Swedish experiences. This would allow the utilization of the experience curve concept to estimate cost developments also in other countries with a large potential to supply PFF, but with less developed PFF supply systems.     

Diagnosis of dysfunctions of replanted parathyroid gland tissue by bilateral analysis of intact parathyroid hormones in cubital vein blood. A prospective study

AIM: In a prospective long-term follow-up study after operative therapy of hyperparathyroidism the value of bilateral determination of parathyroid hormone levels in cubital venous blood after total parathyroidectomy/autologous parathyroid gland reimplantation (musculus brachioradialis) for diagnosis of dysfunctioning grafted tissue is evaluated. PATIENTS AND MATERIAL: From August, 1, 1987 to March, 31, 1994 68 of 243 patients operated on for hyperparathyroidism underwent total parathyroidectomy. Autologous reimplantation of parathyroid gland was carried out simultaneously in 64 patients. Twice delayed reimplantation of cryopreserved tissue was carried out, and there was no reimplantation in two patients up to this day. Three patients were operated on for hyperfunctioning parathyroid autograft after former total parathyroidectomy/reimplantation. RESULTS: During follow-up 5 patients developed dysfunction of (reimplanted) parathyroid gland. Because of low or unprovable levels of intact parathormone the gradients of intact parathyroid hormone between grafted and nongrafted forearm were about 1:1 in postoperative hypoparathyroidism as well as in hypofunction of parathyroid gland. After successful replantation of cryopreserved parathyroid tissue gradients of intact parathyroid hormone increased (> 1:10). In hyperfunction of grafted parathyroid tissue hormone gradients were high (> 1:20 to 1:45,3) because of excessive high levels of intact parathormone in the cubital vein of the graft bearing arm. Successful reduction of parathyroid graft was followed by decrease of parathyroid hormone gradients. CONCLUSION: Regular follow-up of intact parathormone gradients together with intact parathyroid hormone levels and serumcalcium analysis allow the determination of parathyroid graft function. Also differentiation between graft dependent hyperparathyroidism and hyperfunctioning parathyroid tissue in the neck or mediastinum seems to be possible by bilateral determination of intact parathormone. Normal values or a normal range for intact parathyroid hormone gradients can not yet be defined.     

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Polymer-water interactions in cross-linked gels determined by calorimetric measurements

Calorimetric measurements have been carried out to determine to which extent water interacts with p-HEMA gels and with p-(HEMA+MAA) gels. It appeared, that 0.14 g water/g dry p-HEMA and 0.23 g water/g dry p-(HEMA+MAA) show strong negative enthalpy changes on sorption in the polymer, the enthalpy changes being –180 J/g and –360 J/g water respectively.