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A highly efficient nonlinear frequency-domain solution method is proposed and employed to investigate the aerodynamic and aeromechanical performances of an oscillating wind turbine blade aerofoil in this study. Extensive validations of a frequency-domain method against an experiment as well as a typical time-domain solution method are provided in this paper. An experiment is also designed and conducted to measure pressure distributions over an aerofoil as well as to validate the numerical model. Unsteady pressure distributions and aeroelasticity parameters of the oscillating NACA0012 aerofoil are computed at various angles of attack and Reynolds numbers. Results indicate that the difference of unsteady pressure distributions between the two surfaces of the aerofoil becomes larger as the angle of attack is increased, whereas the flow separation on the suction surface is reduced by raising the Reynolds number. The turbulent flow develops in the downstream region due to the laminar vortex shedding at lower Reynolds numbers. It is also revealed that the Reynolds number has an impact on the aeroelasticity, and the aerodynamic damping value is larger at higher Reynolds numbers. The comparison between the frequency-domain method and the time-domain method shows that the frequency-domain method is not only accurate but also computationally very efficient as the computation time is reduced by 90%.

LDPE and HDPE are common materials used within high voltage insulation systems. These materials will be aged after working under high voltage for a long time. The ageing process of these materials may be affected by external factors. The application of repetitive lightning impulse over-voltages is one of these factors and will be considered in this paper. This paper includes the sample preparation process, the ageing of samples under identical conditions and finally the analysis of electrical properties after the ageing process. The obtained results are used to compare the effect of repetitive lightning impulses with these two materials. These results are also used to highlight the possible mechanisms behind the lighting impulse ageing process.

Successful cap and trade programs for SO2 and NOx in the US allocate allowances to large emitters based on a historic base line for a period of up to thirty years. National Allocation Plans in Europe allocate CO2 allowances in an iterative approach first for a three then for a five-year period. The potential updating of the base line creates perverse incentives for operation and investment. Some allowances are also reserved for new entrants further distorting the scheme. We use analytic models and numeric simulations for the UK power sector to illustrate and quantify how these effects contribute to an inflation of the allowance price while reducing utilisation and investment in efficient technologies. The inflated allowance prices are likely to increase the European allowance budget and emissions, e.g. through the Linking Directive. As a result opportunity costs of emitting CO2 are reduced relative to an efficient cap and trade program.

“Another World Is Possible!” announces a placard held by a demonstrator on an unspecified global justice movement protest. The photograph is the background graphic of an advert. Above it the Shell logo. The advert is for a conference sponsored by the oil giant, entitled “Climate Change: Is Business Doing Enough?” Not so long ago Shell denied climate change altogether. In 1989 it set up the Global Climate Coalition along with several dozen other fossil fuel, vehicle and chemical companies. The avowed aims were to sow doubt about scientific claims concerning global warming and to forestall political efforts to reduce greenhouse gas emissions. The coalition invested heavily in public relations campaigns warning that efforts to reduce emissions by restricting the burning of fossil fuels were misguided and would cause economic disaster. Its efforts helped to put policy making on climate change on hold for years.

Meeting the EU renewable fuel targets for 2020 will require a large increase in bioenergy feedstocks. To date, first generation biofuels have been the major response to meeting these targets. However, second generation biofuels from dedicated energy crops (e.g. miscanthus) or crop residues (e.g. straw) offer potential. Based on an on-farm survey of Farm Business Survey arable farmers in England and aggregated to national levels, we estimate that 5.27 Mt of cereal straw is produced annually on these farm types, of which farmers indicated that they would be willing to sell 2.5 Mt for bioenergy purposes, provided appropriate contractual conditions meet their needs. However, only 555Kt-840Kt would be obtained from straw currently incorporated into the soil. Timeliness of crop operations and benefits to soil were cited as key reasons for incorporating straw. A ‘good price’ represents the key incentive to encourage straw baling. With respect to dedicated energy crops, 81.6% (87.7%) would not consider growing miscanthus (SRC), while respectively, 17.2% (11.9%) would consider growing and 1.2% (0.4%) were currently growing these crops. Assuming 9.29% (average percentage of arable land set-aside between 1996-2005) of their utilised agricultural area to these crops, 89,900 ha (50,700 ha) of miscanthus (SRC) would be grown on English arable farms. Land quality issues, profitability and committing land for a long period of time were cited as both negative and positive reasons for farmer decisions about their level of willingness to grow these crops. Food and fuel policies must increasingly be integrated in order to meet societal goals without generating unintended consequences.

Since August 2010 EURAC has been monitoring a 724 kWp multi-technology test field at the Airport of Bolzano Dolomiti (ABD) in the Italian Alps. The modules are mounted on fixed-tilt racks (30°) as well as on a single- and a dual-axis tracker. This work presents the results of one-year comparison between different crystalline PV technologies based on monocrystalline silicon (mc-Si), polycrystalline silicon (pc-Si) and heterojunction with intrinsic thin-layer (HIT), mounted on single- and dual-axis trackers. The performances are also compared to modules on 30°-tilted fixed racks, covering the time span between July 2011 and June 2012 (second year of plant operation). The comparison is carried out in terms of daily profiles of normalized power output, average yearly module temperature and pseudo performance ratio. The results show major advantages in using a dual-axis tracker especially during winter, and a better performance of the HIT modules with respect to the other technologies on almost all the mounting systems. 27th European Photovoltaic Solar Energy Conference and Exhibition; 3359-3362

Most design optimisation studies for district heating systems have focused on the optimal sizing of network assets and on the location of production units. However, the strategic value of the flexibility in phasing of the inherently modular heat networks, which is an important aspect in many feasibility studies for district heating schemes in the UK, is almost always neglected in the scientific literature. This paper considers the sequential problem faced by a decision-maker in the phasing of long-term investments into district heating networks and their expansions. The problem is formulated as a multi-stage stochastic programme to determine the annual capital expenditure that maximises the expected net present value of the project. The optimisation approach is illustrated by applying it to the hypothetical case of the UK’s Marston Vale eco town. It was found that the approach is capable of simulating the optimal growth of a network, from both a single heat source or separate islands of growth, as well as the optimal marginal expansion of an existing district heating network. The proposed approach can be used by decision makers as a framework to determine both the optimal phasing and extension of district heating networks and can be adapted simply to various, more complex real-life situations by introducing additional constraints and parameters. The versatility of the base formulation also makes it a powerful approach regardless of the size of the network and also potentially applicable to cooling networks. International Journal of Sustainable Energy Planning and Management, Vol 9 (2016)

Note: This is a preprint of paper #2005 presented at the 14th European Wave & Tidal Energy Conference (EWTEC) 2021 in Plymouth, UK. The final version of paper with the same title can be found in the EWTEC 2021 proceedings. Abstract: In order to accurately reflect the cost estimates of lift-force Wave Energy Converters (WECs), a parametric cost model is developed. The definition, establishment and description of the parametric cost model is the purpose of the present article. The parameters of the cost model include the costs of developing and consenting, of the wave energy converter, of the balance of plant, of the installation and commissioning, and of decommissioning. To carry out the initial techno-economic analysis, the widely used parameters Capital Expenditures (CAPEX) and Operational Expenditures (OPEX) will be utilised and an economic modelling framework is suggested to carry out the assessment. For this purpose, the parametric cost model will be incorporated in the Danish COE Calculation Tool, which is a transparent and simple Excel-based software, free-to-download, that since 2014 has assisted many users in estimating the cost of energy of a wave energy device when operating at different locations. A description of the added capabilities and updates of the Tool will also be described in the article. Lastly, an example of the application of the Tool to three different configurations of the LiftWEC concept, where the parametric cost model is used, is presented. This work was produced as part of the LiftWEC Project. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 851885. This output reflects the views only of the author(s), and the European Union cannot be held responsible for any use which may be made of the information contained therein.