This volume brings together a team of international specialists on Deleuze and Guattari to provide in-depth critical studies of each plateau of their major work, A Thousand Plateaus. It combines an ...overview of the text with deep scholarship and brings a renewed focus on the philosophical significance of their project. A Thousand Plateaus represents a whole new way of doing philosophy. This collection supports the critical reception of Deleuze and Guattari's text as one of the most important and influential works of modern theory.
The two cardiac myosin heavy chain isoforms, α and β, exhibit distinct functional characteristics and therefore may be distributed regionally within the heart to match the functional demands of a ...specific region. In adult mouse hearts, which predominantly express α-myosin heavy chain, we observed high concentrations of β-myosin in distinct areas such as at the tip of papillary muscles and at the base close to the valvular annulus. In light of these distinct distribution patterns of the myosin isoforms, we subsequently explored the isoform-specific structure-function relationships of the myosins. The α- and β-isoforms are 93% identical in amino acid sequence, but it remains unclear which of the nonidentical residues determines isoform functionality. We hypothesized that residues situated within or close to the actin-binding interface of the myosin head influence actin binding and thereby modulate actin-activated ATPase activity. A chimeric myosin was created containing β-sequence from amino acid 417 to 682 within the α-backbone. In mice, ∼70% of the endogenous cardiac protein was replaced with the chimeric myosin. Myofibrils containing chimeric myosin exhibited ATPase activities that were depressed to the levels observed in hearts expressing ∼70% β-myosin. In vitro motility assays showed that the actin filament sliding velocity generated by chimeric myosin was similar to that of α-myosin, almost twice the velocities observed with β-myosin. These data indicate that this large domain sequence switch conferred β-like actin-activated ATPase activities to the chimeric myosin, suggesting that this region is responsible for the distinct hydrolytic properties of these myosin isoforms.
•Temporal characterisation of wave and tidal resource availability for Great Britain.•Ten metrics used to explore temporal characterisation and supply-demand matching.•Generation profiles with marine ...energy consistently outperform those without.•Correlation with load is not a suitable metric to establish supply-demand alignment.•Detailed discussion of potential GB power system benefits from marine energy.
Wave and tidal energy have the potential to provide benefits to power systems with high proportions of stochastic renewable generation. This is particularly applicable in combination with wind and solar photovoltaics, as the offsetting of these renewable resources results in more reliable renewable generation. This study utilises ten metrics to quantify the temporal complementarity and supply-demand balancing requirements of the energy mix in Great Britain, to investigate the potential magnitude of these system benefits. Wave and tidal generation profiles are created using historical resource data and hydrodynamic models. The results show that the inclusion of wave and tidal generation creates a renewable energy mix which is more available under multiple conditions: throughout a year of operation; at times of peak demand; for multiple consecutive hourly time periods; and at times when wind and solar generation are not available. Three regional case studies also show that the inclusion of marine energy allows for improved regional supply-demand matching, reducing instances of energy shortage and excess and potentially relieving transmission congestion at particularly constrained locations within GB. Finally, the implications of these findings are discussed in terms of GB wholesale market operation, system balancing and system security.
One of the key objectives for renewable energy technologies is to reduce the environmental impact of energy generation. Floating offshore wind technologies have been developed in recent years to ...exploit the wind energy resource available at deep waters where bottom-fixed technologies are not economical. However, few studies exist that analyse the environmental impact of such technologies. Particularly, offshore activities such as those required for Operation and Maintenance (O&M) are not represented in detail in previous studies. The present study addresses these gaps by performing a Life Cycle Assessment using an advanced O&M model to quantify the environmental impact of a floating offshore wind farm. Different O&M philosophies – assuming towing to shore for major operations vs. performing all operations on site – and their impact are evaluated and discussed for two case studies inspired by real pilot park deployments. The results show mean Global Warming Potential (GWP) values between 25.6 and 45.2 gCO2 eq/kWh depending on the assumed O&M strategy and vessels, with the contribution of the O&M phase to GWP ranging from 21 to 49%, and of O&M vessels from 6 to 40%. Assuming O&M strategies to be the same for fixed and floating offshore wind could result in a 20.4% underestimate of GWP, whereas the vessel choice resulted in up to 34.8% difference in the estimated GWP. An environmental impact perspective provides key insights on the choice of different designs, operation strategies and asset management, and thus should be used in the decision-making process.
•Life Cycle Assessment (LCA) of two floating offshore wind case studies is performed.•An advanced O&M model is integrated in the LCA for the first time.•The impact of different O&M strategies and vessel choices on the LCA is assessed.•O&M activities contribute to 21 to 49% of the global warming potential.•O&M strategies based on bottom-fixed offshore wind underestimate the LCA impacts.
•Methodology for capital and operational indicators estimation is presented.•Introducing stochastic operation and maintenance modelling for uncertainty reduction.•Reference database for further works ...on floating wind farms provided.•Results shows agreement with observed values for offshore wind projects.•Comparison against previous work shows underestimation of operational costs.
Floating offshore wind is rapidly gaining traction in deep water locations. As with all new technologies, to gain the confidence of developers and investors, the technical and economic feasibility of this technology must be proven and robust cost estimates are necessary. In this paper, the authors present a methodology to calculate the capital and operational indicators of a floating wind farm over its project lifetime. A set of computational models is used to reduce the uncertainties in the estimation of the technical and economical parameters. In particular, the effect of using detailed operation and maintenance models and strategies allows a better estimation of operational cost. The paper highlights the requirements and specific adjustments considered for floating offshore wind technology. The methodology is demonstrated for two case studies inspired by real floating wind installations in the United Kingdom, namely the Hywind and Kincardine projects. The related input data, gathered from publicly available sources, constitute a reference database for future studies in the floating offshore wind sector. Results are presented for the two case studies. These show that availability and energy production are in line with typical values for offshore wind projects, and highlight the substantial contribution of operational expenses to the cost of energy. Results are also compared against previous estimations for floating offshore wind projects, showing satisfactory agreement for the overall project costs but an underestimation of operation and maintenance costs in previous studies. This highlights the importance of using detailed operation and maintenance models to adequately capture operational expenses.
Since the late 1990s, there has been increased interest in marine renewable energy, such as wave and tidal current. Wave and tidal current energy has the potential to supply 15% of the UK's ...electricity needs, and in the United States the potential is about 7%. Unlike wind, there is no single technological solution to harnessing energy from waves and tidal currents. As a result, many different devices are being developed, and so far there is no optimum solution. Because ocean energy systems operate in a harsh environment, there are significant engineering and environmental challenges to overcome. The UK Energy Research Centre Marine Renewable Energy Technology Roadmap classifies these challenges in terms of predictability, manufacturability, survivability, installability, affordability, and reliability. A number of centers and consortia throughout the world are working toward addressing these challenges, including the European Marine Energy Center (Scotland), SuperGen Marine Energy Research Consortium (UK), Hydraulics Maritime Research Centre (Ireland), Wave Hub & PRIMaRE (South West England), Northwest National Marine Renewable Energy Center in Oregon and Washington (US), the Hawai'i National Marine Renewable Energy Center (US), and the Fundy Ocean Research Centre for Energy in the Bay of Fundy, Nova Scotia (Canada).
This paper presents a summary of recent progress towards the development and upscaling of an emerging class of electrostatic power take-off (PTO) systems for wave energy converters (WECs), called ...dielectric elastomer generators (DEGs). DEGs are electromechanical devices able to convert mechanical energy into electrical energy by exploiting the deformation of rubber-like dielectric materials. The high power density (in the order of hundreds of Watts per kilogram), good efficiency and ease of assembling, combined with the low-cost of the employed materials (a few euros per kilogram) and their intrinsic resilient/reliable response to mechanical shocks make DEGs a very promising option for the deployment of a future generation of WECs.
In the last decade, some specific concepts of WECs based on DEGs have been devised and a considerable interest in the topic has been aroused in the wave energy community. Among the candidate DEG topologies for wave energy harvesting, recent studies have suggested that a specific layout, namely the axial-symmetric inflating DEG diaphragm, could be a very promising candidate for future upscaling.
This paper first describes the operating principle of DEG PTOs and the effect of electro-mechanical material parameters on their energetic performance. With reference to the above-mentioned inflating DEG diaphragm topology, an overview of concepts for integration on WECs is then provided, with a special focus on advanced concepts enabling the achievement of dynamical tuning with the incoming waves. A general lumped-parameter modelling approach for the design of DEG-based WECs is proposed. Experimental activity carried out to date, i.e. dry-run laboratory tests, wave-tank tests and preliminary sea trials is reviewed, with the aim of showing the progression in the device's scale and performance. Finally, economical and technological considerations are outlined, in order to point out challenges, future research opportunities and to draft a roadmap for future research and technological transfer.
•Recent advances on polymeric power take-off systems for wave energy converters called dielectric elastomer generators (DEGs).•Identification of a DEG layout suitable for oscillating water column and pressure differential wave energy converters (WECs).•General modelling framework for coupled DEG-WEC systems.•Review of experimental testing of scaled prototypes.•Roadmap and techno-economic considerations on the future development of WECs based on DEGs.
Wave energy conversion can have a significant role in the transition to a net-zero energy system. However, cost reductions are still required for this technology to be commercially competitive. To ...achieve commercialisation at a reasonable expense, disruptive innovations at early stages of development need to be enabled. Thus, to explore more of the design space, design limits need to be defined. Although physical limits, such as the maximum capture width and the Budal upper bound, have been defined, more realistic limits considering the variability of the resource, device dimensions and the actual hydrodynamic behaviour of different shapes can help provide further insights. This is relevant to both technology developers and funding bodies wanting to identify potential areas for innovation. In this study, the use of multi-objective optimisation is proposed to explore these limits, by investigating the optimal relationship between average annual power production and device size. This relationship depends on resource level, mode of motion used for power extraction and hull shape. The obtained fundamental relationships fall within the existing physical limits, but provide further insights into the impact of different factors on these limits. This allows for a more direct comparison with the performance of state-of-the-art wave energy converters.
•A flexible method to explore wave energy converter design limits is presented.•Design limits for power and volume are obtained with multi-objective optimisation.•The design limits are verified against the state of the art and physical limits.•The method can be used to obtain other types of fundamental relationships.•These relationships help identify areas with potential for disruptive innovation.
It is understood that electricity generation from the waves and tides can be temporally and spatially offset from other, more established variable renewables, such as wind and solar. However, it is ...less well understood how this offsetting can impact on power system operation. A novel modelling framework has been developed to quantify the potential benefit of including higher proportions of ocean energy within large-scale electricity systems. Economic dispatch modelling is utilised to model hourly supply–demand matching for a range of sensitivity runs, adjusting the proportion of ocean energy within the generation mix. The framework is applied to a 2030 case study of the power system of Great Britain, testing installed wave or tidal stream capacities ranging from 100 MW to 10 GW. For all sensitivity runs it has been found that ocean energy increases renewable dispatch, reduces dispatch costs, reduces generation required from fossil fuels, reduces system carbon emissions, reduces price volatility, and captures higher market prices. For example, including 1 GW of wave displaces up to £137M and 128 ktCO2 over the year of dispatch modelled. Similarly, 1 GW of tidal stream displaces up to £95M and 87 ktCO2. When including 10 GW of ocean energy, dispatch costs reduce by up to 7% and carbon emissions reduce by up to 29%. This analysis has included the development and publication of open source models of the Great British power system.
•Modelling framework developed to quantify power system benefits from ocean energy.•Economic dispatch modelling used to represent power system supply–demand balancing.•Hourly generation timeseries created to represent wave and tidal stream resource.•Sensitivity analyses used to vary proportion of ocean energy within power system.•GB case study quantifies economic and environmental benefits from ocean energy.
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