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As part of its efforts to progress and innovate in the field of Smart Grid technologies, Enexis developed and currently operates a Battery Energy Storage System (BESS) called the Smart Storage Unit (SSU), part of the Smart Storage Project (SSP). The SSU is a 400 kVA, 232 kWh storage system, equipped with internet-connected control hardware in order to add ¿smartness¿ into the equation. The objective of the project is to enable field-testing and research on advanced electricity storage solutions in the LV distribution grid. This paper mainly focusses on the development of an addition to the controller system for the purpose of minimizing grid losses and maximizing grid asset utilization. Its principles rely on using historic data for load prediction, in order to flatten the power demand at the transformer, through peak-reduction and valley-filling.

AbstractSulfate reduction in salt‐rich wastewaters using unadapted granular sludge was investigated in 0.9 L UASB reactors (pH 7.0 ± 0.2; hydraulic retention time from 8–14 h) fed with acetate, propionate, or ethanol at organic loading rates up to 10 gCOD.L−1.day−1 and in excess sulfate (COD/SO of 0.5). High‐rate sulfate reduction rates (up to 3.7 gSO42‐.L−1.day−1) were achieved at salinities exceeding 50 gNaCl.L−1 and 1 gMgCl2.L−1. Sulfate reduction proceeded at a salinity of up to 70 gNaCl.L−1 and 1 gMgCl2.L−1 (corresponding to a conductivity of about 85–90 mS.cm−1), although at lower rates compared to a conductivity of 60–70 mS.cm−1. Ethanol as well as propionate were suitable substrates for sulfate reduction, with acetate and sulfide as the end products. The successful high‐rate treatment was due to the proliferation of a halotolerant incomplete oxidizing SRB population present in the unadapted inoculum sludge. Bioaugmentation of this sludge with the acetate oxidizing halotolerant SRB Desulfobacter halotolerans was unsuccessful, as the strain washed out from the UASB reactor without colonizing the UASB granules. © 2004 Wiley Periodicals, Inc.

The development of the gapless metal oxide (ZnO) surge arrester has presented the arrester engineer with new materials and an opportunity for new designs. This situation arises because the gapless surge arrester is electrically active throughout its lifetime whereas its predecessor, the silicon carbide arrester, was electrically passive being electrically isolated with gap structures. The prime consideration is one of reliably estimating the lifetime of a gapless ZnO surge arrester under continuous ac stress while maintaining the capability not only to limit surge voltages but also to absorb energy inputs resulting from lightning or switching surges and temporary overvoltages. In this paper we establish a procedure for reliably estimating the lifetime of gapless metal oxide surge arresters for ac application by incorporating the device characteristics into design requirements. This method is illustrated for metal oxide surge arrester elements that exhibit a predictable linear resistive current versus time1/2 behavior as a function of applied voltage and temperature.

Abstract Life Cycle Assessment (LCA) is a powerful tool for achieving sustainability. Traditional LCAs analyze well defined and developed industrial systems, but recent developments of LCA focus on analyzing emerging technologies which are not yet optimized with respect to energy and materials. Therefore, LCA results of ex-ante applications can be very different from ex-post applications for the same system. The purpose of this study is to show the different effects of data scales on LCA results regarding global warming, fine particulate matter formation, terrestrial acidification and freshwater eutrophication potentials. For this purpose torrefaction technology was selected as the case study and assessed based on bench scale data, lab scale data, data derived from process simulations, pilot scale data and commercial scale data. Considered environmental impacts were global warming, fine particulate matter formation, terrestrial acidification and freshwater eutrophication. Results showed that process efficiencies improved significantly between the bench scale system and systems with higher technology readiness levels (TRLs), such as pilot, process simulations and commercial scale systems. Furthermore, process simulations result in scores closer to commercial scale regarding all considered environmental impacts. However, if LCA practitioners focus only on global warming impact, then pilot scale is also a good alternative. Finally, due to torrefaction technology being relatively simple in terms of raw materials input, we suggest more complex chemical systems to be assessed with LCA in various TRLs.

Abstract In order to have the assessment of the local impacts of energy projects, decision-makers need to separate a local public from the wider public. From the starting point that ‘publics’ are so-called imaginaries, this perspective paper argues that the operationalisation of publics tends to impose concerns, motivations and capacities upon the members of both publics, expecting local publics to consider specific concerns, while wider publics are expected to attend generic interests. Moreover, methods to invite members from a local public to speak out on the acceptability of an energy project tend to ignore the heterogeneity and dynamics of the ‘public’, compromising the democratic legitimacy of an assessment made by such a local public.

Abstract Long distance power transmission is commonly considered as an option for reducing carbon footprint in future electricity systems. Accordingly, this article presents economic insights in a transcontinental power interconnection linking four Asian countries with Europe. Enhanced electricity trade through the interconnected countries is assessed via techno-economic modelling. For this purpose two electricity system scenarios are developed for the year 2040: (i) a Reference Scenario, where electricity system development follows the plans of the involved system operators and (ii) a so-called Trans-Asia Scenario, where additional power transmission capacities are added to strengthen the electricity trading route crossing the interconnected countries: Turkey, Georgia, Azerbaijan and Kazakhstan. Economic benefits arising from the proposed Trans-Asia Scenario are estimated as a change in social welfare in the electricity system. Modelling results show a 140 M€ increase in annual social welfare for the Trans-Asia Scenario. The subsequent cost-benefit analysis results in a net present value in the range of −221 M€ to 534 M€, at a discount rate of 4%. This implies that over a life-cycle period of 40 years, the evaluated economic benefit may compensate investments between 1598 M€ and 3251 M€ needed for the additional power transmission capacities.

Abstract Combined cooling, heat and power systems represent an efficient alternative to supply heating and cooling demand compared to conventional boilers and air conditioner systems. However, considering the high level of upfront investment and the relatively long lifetimes, it is important to provide some form of long-term certainty to reduce the risk of deployment of these systems. To overcome this uncertainty, this paper describes a method to calculate an appropriate feed-in-tariff scheme to support investors and public authorities to foster the penetration of this technology in areas with high energy demands. It is subsequently tested in a scientific and technology park located in the south of Spain where different energy prices are studied. The results indicate that a feed-in-tariff is required to support the development of combined heating, cooling, and power systems, which not only improves the economic performance of the system, but also increases the utilisation of more efficient generation technologies such as combined cooling, heat and power systems.

Multispectral transmissometer systems have been used in a large number of tests to evaluate line-of-sight transmittance through smoke screens. Analysis of the data have shown that for the same spectral band, a wide variation in measured transmittance is possible when different transmissometer systems are used. Since transmittance data is a key factor in interpreting electro-optical system performance, it is important that accurate measurements of potential countermeasures such as smoke screens be obtained. Therefore, a thorough understanding of the factors that can affect transmissometer performance is necessary. In this paper, an analysis is presented of those operational characteristics that can affect multispectral transmissometer performance. An evaluation is performed to identify the most important parameters affecting data quality and to evaluate how these factors can be expected to affect data characteristics. Results are compared with field test data and actual operating systems.