Operations and maintenance optimisation for a 100 MW wave energy farm in Ireland

Marine operations that are required for the development and service of offshore wave energy farms represent a significant proportion of the total project costs. These operations can be optimised through design and innovation to improve the LCOE of the project. This paper presents an analysis of marine operations in offshore renewable energy projects and ows the importance of early, detailed analysis and optimisation of these activities. The analysis uses general-purpose techno-economic analysis software developed by Wave Venture. The software provides an integrated engineering and financial simulation specifically designed for the needs of offshore renewable energy technology. A 100 MW wave energy farm, made up of 250 CorPower devices, off the west coast of Ireland is defined and analysed to demonstrate the capabilities of the techno-economic analysis incorporating a marine operations logistics model. The results demonstrate the strength of integrated logistics and finance software in the analysis and design of wave farms, and how these simulations can lead to significant improvements in the LCOE of offshore renewable energy projects

The ecological and physiological bases of variation in the phenology of gonad growth in an urban and desert songbird.

AbstractBirds often adjust to urban areas by advancing the timing (phenology) of vernal gonad growth. However, the ecological and physiological bases of this adjustment are unclear. We tested whether the habitat-related disparity in gonad growth phenology of male Abert’s towhees, Melozone aberti, is due to greater food availability in urban areas of Phoenix, Arizona USA or, alternatively, a habitat-related difference in the phenology of key food types. To better understand the physiological mechanism underlying variation in gonad growth phenology, we compared the activity of the reproductive system at all levels of hypothalamo-pituitary–gonadal (HPG) axis. We found no habitat-associated difference in food availability (ground arthropod biomass), but, in contrast to the seasonal growth of leaves on desert trees, the leaf foliage of urban trees was already developed at the beginning of our study. Multiple estimates of energetic status did not significantly differ between the non-urban and urban towhees during three years that differed in the habitat-related disparity in gonad growth and winter precipitation levels. Thus, our results provide no support for the hypothesis that greater food abundance in urban areas of Phoenix drives the habitat-related disparity in gonad growth phenology in Abert’s towhees. By contrast, they suggest that differences in the predictability and magnitude of change in food availability between urban and desert areas of Phoenix contribute to the observed habitat-related disparity in gonad growth. Endocrine responsiveness of the gonads may contribute to this phenomenon as desert – but not urban – towhees had a marked plasma testosterone response to GnRH challenge

Performance and economic optimization of an organic rankine cycle for a gasoline hybrid pneumatic powertrain

This article presents an innovative concept for alternative hybridization, without electrical devices. The concept is studied on a C-Segment vehicle with targeted prices between 27,000 and 34,000 euros. Short term hybrid pneumatic energy storage and a waste heat recovery system are introduced for the efficiency improvement of a small downsized gasoline engine. The modeling methodology for the hybrid pneu- matic powertrain is presented. The waste heat recovery system is an organic rankine cycle. An innovative methodology using energy integration and multi-objective optimization is applied for the design of the organic rankine cycle loop. The selection of the organic rankine cycle design is based on techno- economic indicators and is done by using a qualification utility function for the population of solu- tions on the Pareto curve. The concept of hybrid pneumatic powertrain and organic rankine cycle is evaluated on different driving cycles and the economic analysis of the customer mobility is done, ac- cording to his drive profile

Combining forest exploitation and heathland biodiversity: Edges structure drives microclimates quality and reptile abundance in a coniferous plantation

peer reviewedIn Western Europe, natural habitats such as heathlands have been converted into many commercially managed forests, with severe impacts on biodiversity. In dense planted forests, forest edges are often the only suitable areas for ectothermic organisms highly dependent on open habitats for thermoregulation. Surprisingly, the influence of forest edges structure on the thermal quality of microhabitats and reptile species distribution remains poorly understood. In this study, we examined two reptile species and thermal quality of interior forest edges of a coniferous forest in Western France (Brittany). We focused on two hypotheses (i) the vegetation structure of the forest edges drives the thermal quality of the habitat and (ii) structural complexity of the forest edges influences the abundance of two heliothermic reptiles: the common adder (Vipera berus) and the common lizard (Zootoca vivipara). We first deployed temperature sensitive data loggers to quantify thermal conditions along 16 cross-sections of inner forest margins. For each section, 4 temperature loggers were placed at 1, 3, 5 and 7 m from the driveway and we examined the relation to vegetation structure and canopy cover. Second, we carried visual encounter surveys in 55 edges in order to measure the response of two reptiles to the structure of the forest margin along exploitation driveway. Our results show that high local canopy cover decreases microhabitat quality within interior forest edges. We also found that common lizard abundance was significantly influenced by the edge orientation and increased with global canopy openness and ground level vegetation. Adder abundance only increased significantly with the driveway width, suggesting the unmodelled effect of other biotic/abiotic variables. Our study shows that thermal quality of interior edges and driveway characteristics are relevant to support heathland reptile populations. We posit that maintain strips of favourable microhabitats should be an efficient land sharing strategy to combine forestry activities and biodiversity conservation

Agricultural landscapes and the Loire River influence the genetic structure of the marbled newt in Western France

Amphibians are particularly sensitive to landscape fragmentation. Potential barriers between breeding sites can negatively infuence the dispersal of individuals and increase genetic structure between populations. In this study, we genotyped 10 microsatellites for 334 marbled newts (Triturus marmoratus) at 11 diferent locations in Western France. Samples were collected in diferent regions with contrasting agricultural landscapes (low and high proportion of arable land in the north and south, respectively). We found a strong genetic structure between the northern and southern sampling sites. Isolation by distance was recorded after 62km, but within the northern region, little or no genetic structure was detected over large distances (up to 114km). Genetic structure at shorter distance (43km) was found between sites situated in landscapes with larger amounts of arable lands. A signifcant positive relationship was found between the pairwise genetic distance (Fst) between sites and the amount of arable land together with the distance between sites. Our results suggest that the Loire River might act as a corridor for the marbled newt, while arable land might act as a barrier. Finally, although a large city is located between sampling sites, no efect was detected on population structure

Author Correction: Agricultural landscapes and the Loire River influence the genetic structure of the marbled newt in Western France

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper

Agricultural landscapes and the Loire River influence the genetic structure of the marbled newt in Western France

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Amphibians are particularly sensitive to landscape fragmentation. Potential barriers between breeding sites can negatively infuence the dispersal of individuals and increase genetic structure between populations. In this study, we genotyped 10 microsatellites for 334 marbled newts (Triturus marmoratus) at 11 diferent locations in Western France. Samples were collected in diferent regions with contrasting agricultural landscapes (low and high proportion of arable land in the north and south, respectively). We found a strong genetic structure between the northern and southern sampling sites. Isolation by distance was recorded after 62km, but within the northern region, little or no genetic structure was detected over large distances (up to 114km). Genetic structure at shorter distance (43km) was found between sites situated in landscapes with larger amounts of arable lands. A signifcant positive relationship was found between the pairwise genetic distance (Fst) between sites and the amount of arable land together with the distance between sites. Our results suggest that the Loire River might act as a corridor for the marbled newt, while arable land might act as a barrier. Finally, although a large city is located between sampling sites, no efect was detected on population structure.publishedVersio

Lizards from warm and declining populations are born with extremely short telomeres

International audienceAging is the price to pay for acquiring and processing energy through cellular activity and life history productivity. Climate warming can exacerbate the inherent pace of aging, as illustrated by a faster erosion of protective telomere DNA sequences. This biomarker integrates individual pace of life and parental effects through the germline, but whether intra- and intergenerational telomere dynamics underlies population trends remains an open question. Here, we investigated the covariation between life history, telomere length (TL), and extinction risk among three age classes in a cold-adapted ectotherm ( Zootoca vivipara ) facing warming-induced extirpations in its distribution limits. TL followed the same threshold relationships with population extinction risk at birth, maturity, and adulthood, suggesting intergenerational accumulation of accelerated aging rate in declining populations. In dwindling populations, most neonates inherited already short telomeres, suggesting they were born physiologically old and unlikely to reach recruitment. At adulthood, TL further explained females’ reproductive performance, switching from an index of individual quality in stable populations to a biomarker of reproductive costs in those close to extirpation. We compiled these results to propose the aging loop hypothesis and conceptualize how climate-driven telomere shortening in ectotherms may accumulate across generations and generate tipping points before local extirpation