Baggetto L.,TU Eindhoven |
Verhaegh N.A.M.,KEMA |
Niessen R.A.H.,Philips |
Roozeboom F.,TU Eindhoven |
And 3 more authors.
Journal of the Electrochemical Society | Year: 2010
Tin nitride thin films have been reported as promising negative electrode materials for lithium-ion solid-state microbatteries. However, the reaction mechanism of this material has not been thoroughly investigated in the literature. To that purpose, a detailed electrochemical investigation of radio-frequency-sputtered tin nitride electrodes of two compositions (1:1 and 3:4) is presented for several layer thicknesses. The as-prepared thin films have been characterized by Rutherford backscattering spectrometry, inductively coupled plasma optical emission spectrometry, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The electrochemical results point out that the conversion mechanism of tin nitride most probably differs from the conversion mechanism usually observed for other oxide and nitride conversion electrode materials. The electrochemical data show that more than 6 Li per Sn atom can be reversibly exchanged by this material, whereas only about 4 are expected. Moreover, the electrochemical performance of the material is discussed, such as electrode cycle life, and a method for improving the cycle life is presented. Finally, thicker films have been characterized by Mössbauer spectroscopy. This technique opens a new route toward determining the conversion reaction mechanism of this promising electrode material. © 2010 The Electrochemical Society.
World Energy Engineering Congress 2011, WEEC 2011 | Year: 2011
Processes that use compressed air often waste energy that could be saved with a collaborative effort from the local utility incentive programs, technology experts, financial institutions, service providers, and end users. Recognizing the issues, challenges, and available solutions will help interested individuals develop and implement projects that would improve the compressed air system efficiency to reduce operating costs and increase profits.
van Dijk H.A.J.,Energy Research Center of the Netherlands |
Walspurger S.,Energy Research Center of the Netherlands |
Cobden P.D.,Energy Research Center of the Netherlands |
van den Brink R.W.,Energy Research Center of the Netherlands |
de Vos F.G.,KEMA
International Journal of Greenhouse Gas Control | Year: 2011
The feasibility of the sorption enhanced water gas shift (SEWGS) process under sour conditions is shown. The sour-SEWGS process constitutes a second generation pre-combustion carbon capture technology for the application in an IGCC. As a first critical step, the suitability of a K2CO3 promoted hydrotalcite-based CO2 sorbent is demonstrated by means of adsorption and regeneration experiments in the presence of 2000ppm H2S. In multiple cycle experiments at 400°C and 5bar, the sorbent displays reversible co-adsorption of CO2 and H2S. The CO2 sorption capacity is not significantly affected compared to sulphur-free conditions. A mechanistic model assuming two different sites for H2S interaction explains qualitatively the interactions of CO2 and H2S with the sorbent. On the type A sites, CO2 and H2S display competitive sorption where CO2 is favoured. The type B sites only allow H2S uptake and may involve the formation of metal sulphides. This material behaviour means that the sour-SEWGS process likely eliminates CO2 and H2S simultaneously from the syngas and that an almost CO2 and H2S-free H2 stream and a CO2+H2S stream can be produced. © 2010 Elsevier Ltd.
Langeveld J.W.A.,Biomass Research |
Kalf R.,KEMA |
Elbersen H.W.,Agrotechnology and Food Science Group
Biofuels, Bioproducts and Biorefining | Year: 2010
Development of bioenergy production in the Netherlands is lagging. This paper presents an inventory of problems met by new bioenergy chains and compares these to literature and to other countries. Theoretical frameworks suggest that five elements are crucial for successful bioenergy chain development: (i) availability of (proven) technology; (ii) access to information; (iii) access to feedstocks, financial means, and markets; (iv) locations for new installations; and (v) efficient lobby activities and public support. Nine bioenergy chains were interviewed. Problems that are reported relate to insufficient knowledge of new technological concepts, and of nuisances (noise, emission, odor, and other) caused during bioenergy production. Feedstock markets (wood, byproducts, waste) and product markets (heat, CO 2) are underdeveloped, while some chains are experiencing extra problems finding a suitable location or obtaining necessary permits. Problems related to insufficient public support are most relevant for bioenergy chains depending on tax exemptions (pure vegetation oil transportation fuels) or requiring adaptation of legislation (location permits for farm fermenters). An international comparison to barriers for biofuel suggests that economic factors (including lack of capital), limitations in know-how and institutional capacities, underdeveloped biomass and carbon markets, problems in chain coordination, and limited public support are largest problems for new bioenergy chains. Recommendations to stimulate bioenergy production in the Netherlands refer to performance standards for new installation types, information on feedstock availability, protocols for heat exchange and on improved credit facilities. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd.
Fertig E.,Carnegie Mellon University |
Apt J.,Carnegie Mellon University |
Jaramillo P.,Carnegie Mellon University |
Environmental Research Letters | Year: 2012
We use time- and frequency-domain techniques to quantify the extent to which long-distance interconnection of wind plants in the United States would reduce the variability of wind power output. Previous work has shown that interconnection of just a few wind plants across moderate distances could greatly reduce the ratio of fast- to slow-ramping generators in the balancing portfolio. We find that interconnection of aggregate regional wind plants would not reduce this ratio further but would reduce variability at all frequencies examined. Further, interconnection of just a few wind plants reduces the average hourly change in power output, but interconnection across regions provides little further reduction. Interconnection also reduces the magnitude of low-probability step changes and doubles firm power output (capacity available at least 92% of the time) compared with a single region. First-order analysis indicates that balancing wind and providing firm power with local natural gas turbines would be more cost-effective than with transmission interconnection. For net load, increased wind capacity would require more balancing resources but in the same proportions by frequency as currently, justifying the practice of treating wind as negative load. © 2012 IOP Publishing Ltd.