Offshore wave energy generation devices: Impacts on ocean bio-environment

As the crisis of petroleum-based energy is aggravating and the carbon emission is elevating, the search and exploitation of renewable energy sources such as solar, wind and oceanic powers, are of global interest and underway in some developed countries. In western countries pioneering the oceanic energy utilization, wave is currently an attractive energy source due to the predictability and the ease to be absorbed into power grid. As wave-energy generators (WEGs) and the associated devices interact with the surrounding environment, they would have impacts on the biological components within the ecosystem in the vicinity of WEGs. However, the environmental effects of offshore WEGs on local fauna and flora have yet to be evaluated in a comprehensive way. This article discusses several aspects, including influence of offshore WEGs on marine macrofaunal communities, interactions between offshore WEGs and biofouling organisms, impacts of offshore WEGs on marine birds and of electromagnetic fields (EMFs) on marine animals as well as “artificial reef” effects. If precaution is taken with the planning and construction of offshore WEGs, and environmental monitoring is performed with operation of these devices, marine wave energy can become a desirable alternative to fossil fuels.     

Oceanic records of North American bats and implications for offshore wind energy development in the United States

Offshore wind energy is a growing industry in the United States, and renewable energy from offshore wind is estimated to double the country''s total electricity generation. There is growing concern that land‐based wind development in North America is negatively impacting bat populations, primarily long‐distance migrating bats, but the impacts to bats from offshore wind energy are unknown. Bats are associated with the terrestrial environment, but have been observed over the ocean. In this review, we synthesize historic and contemporary accounts of bats observed and acoustically recorded in the North American marine environment to ascertain the spatial and temporal distribution of bats flying offshore. We incorporate studies of offshore bats in Europe and of bat behavior at land‐based wind energy studies to examine how offshore wind development could impact North American bat populations. We find that most offshore bat records are of long‐distance migrating bats and records occur during autumn migration, the period of highest fatality rates for long‐distance migrating bats at land‐based wind facilities in North America. We summarize evidence that bats may be attracted to offshore turbines, potentially increasing their exposure to risk of collision. However, higher wind speeds offshore can potentially reduce the amount of time that bats are exposed to risk. We identify knowledge gaps and hypothesize that a combination of operational minimization strategies may be the most effective approach for reducing impacts to bats and maximizing offshore energy production.     

Site‐specific life cycle assessment of a pilot floating offshore wind farm based on suppliers’ data and geo‐located wind data

Renewable energy systems are essential in coming years to ensure an efficient energy supply while maintaining environmental protection. Despite having low environmental impacts during operation, other phases of the life cycle need to be accounted for. This study presents a geo‐located life cycle assessment of an emerging technology, namely, floating offshore wind farms. It is developed and applied to a pilot project in the Mediterranean Sea. The materials inventory is based on real data from suppliers and coupled to a parameterized model which exploits a geographic information system wind database to estimate electricity production. This multi‐criteria assessment identified the extraction and transformation of materials as the main contributor to environmental impacts such as climate change (70% of the total 22.3 g CO₂ eq/kWh), water use (73% of 6.7 L/kWh), and air quality (76% of 25.2 mg PM2.5/kWh), mainly because of the floater's manufacture. The results corroborate the low environmental impact of this emerging technology compared to other energy sources. The electricity production estimates, based on geo‐located wind data, were found to be a critical component of the model that affects environmental performance. Sensitivity analyses highlighted the importance of the project's lifetime, which was the main parameter responsible for variations in the analyzed categories. Background uncertainties should be analyzed but may be reduced by focusing data collection on significant contributors. Geo‐located modeling proved to be an effective technique to account for geographical variability of renewable energy technologies and contribute to decision‐making processes leading to their development.     

Sun,wind, and the rebirth of extractive economies: renewable energy investment and metanarratives of crisis in Greece

In the midst of economic crisis, the Greek state has taken the unprecedented step of opening many of the nation's closed business sectors to international investors. Opportunities for multinational investment have been most prolific in the arena of renewable energy, where foreign prospecting in solar and wind energy is soaring. This article discusses two renewable energy initiatives: photovoltaic parks on agricultural land in Thessaly, central mainland Greece, and a planned wind farm development on the Aegean island of Chios. Among the people of Thessaly and Chios, the renewable energy initiatives are widely seen in terms of conquest and occupation akin to the Ottoman era and the Second World War. Harnessing natural resources is perceived to be a colonial programme of economic extraction associated with the global South as much as a sustainable energy initiative, heralding a return to a time of foreign occupation. This article examines the dialectical relationship emerging between narratives of renewable energy extraction and broader, long‐standing conceptions of Greek identity.     

Turbine Sound May Influence the Metamorphosis Behaviour of Estuarine Crab Megalopae

It is now widely accepted that a shift towards renewable energy production is needed in order to avoid further anthropogenically induced climate change. The ocean provides a largely untapped source of renewable energy. As a result, harvesting electrical power from the wind and tides has sparked immense government and commercial interest but with relatively little detailed understanding of the potential environmental impacts. This study investigated how the sound emitted from an underwater tidal turbine and an offshore wind turbine would influence the settlement and metamorphosis of the pelagic larvae of estuarine brachyuran crabs which are ubiquitous in most coastal habitats. In a laboratory experiment the median time to metamorphosis (TTM) for the megalopae of the crabs Austrohelice crassa and Hemigrapsus crenulatus was significantly increased by at least 18 h when exposed to either tidal turbine or sea-based wind turbine sound, compared to silent control treatments. Contrastingly, when either species were subjected to natural habitat sound, observed median TTM decreased by approximately 21–31% compared to silent control treatments, 38–47% compared to tidal turbine sound treatments, and 46–60% compared to wind turbine sound treatments. A lack of difference in median TTM in A. crassa between two different source levels of tidal turbine sound suggests the frequency composition of turbine sound is more relevant in explaining such responses rather than sound intensity. These results show that estuarine mudflat sound mediates natural metamorphosis behaviour in two common species of estuarine crabs, and that exposure to continuous turbine sound interferes with this natural process. These results raise concerns about the potential ecological impacts of sound generated by renewable energy generation systems placed in the nearshore environment.     

Effect of an offshore wind farm on the viviparous eelpout: Biometrics,brood development and population studies in Lillgrund,Sweden

Sufficient, clean and secure energy is the main driver for a worldwide growing welfare and economic development of a society. Environmental concerns on the expansion of offshore renewable energy and its impact on marine organisms need to be scientifically assessed for risks and consequences. In order to observe the effects of an operating wind farm on fish, we studied the rather stationary and benthic-living fish species viviparous eelpout (Zoarces viviparous) as model indicator organisms. We compared local populations of viviparous eelpout in the Lillgrund Offshore Wind Farm (OWF) with natural sites in the Öresund strait in Sweden. Eelpout studies on population dynamics, biometrics, reproductive success and fry development were conducted in 2011 and 2012. Condition index, histosomatic index, gonadosomatic index were measured additionally. Our findings showed that Lillgrund OWF neither had an impact on the condition index (CI), nor on brood development of female viviparous eelpout. Furthermore, populations size estimates in Lillgrund indicated that eelpout neither specifically aggregated in nor avoided the offshore wind farm, and no clear reef effect attracting eelpout to the foundations and scour protections of the OWF was observed. Our conclusion is that the operating wind farm did not have any potentially negative effects, since we did not observe any negative effects neither on the individual health of eelpout nor of the reproductive performance. We suggest that eelpout which may also be used as an indicator species for the environmental status of Lillgrund, as well as for other offshore wind farms and marine renewable energy installations, both in the Baltic and coastal waters in northern Europe.     

Offshore renewable energy and nature conservation: the case of marine tidal turbines in Northern Ireland

The global demand for renewable energy continues to increase rapidly and with it the necessity to develop and test new technologies to deliver the power. Offshore renewable energy sources that harness wind, wave or tidal power are of major interest. Technological advances in these directions have not been matched by a clear understanding of the environmental impacts of the new devices, with most existing research concentrated on the impacts of offshore wind farms. Decisions often continue to be made without the support of a clear evidence base. Here we use an underwater tidal turbine, SeaGen, constructed and operated within the Strangford Lough marine protected area in Northern Ireland, as a case study to explore the potential impacts of the turbine as points of concern and argumentation in the decision-making processes. We use information obtained from official documents and one-to-one interviews with the main stakeholders. Our results demonstrate that during the construction and operation of the turbine the perceptions and views of different stakeholders sometimes disagreed but were often surprisingly similar in relation to both likelihood and intensity of the potential impacts of the turbine on marine biodiversity, ecosystem services and human well-being in general. The overall consensus of views was refined and evolved under an adaptive management approach over the 10 years of the discussions and decision-making processes. The results are discussed in relation to cumulative gains in knowledge, future arrays of many underwater turbines and multiple use of oceans within social ecological systems to maintain the conservation of marine biodiversity.     

Life Cycle Assessment of Offshore Wind Farm Siting: Effects of Locational Factors,Lake Depth,and Distance from Shore

According to previous studies, the life cycle energy intensity of an offshore wind farm (OWF) varies between 0.03 and 0.13 megawatt‐hours (MWh) of primary energy for each MWh of electricity generated. The variation in these life cycle energy intensity studies, after normalizing for capacity factor and life span, is significantly affected by OWF location because of geographical properties, namely, wind speed and water depth. To improve OWF siting, this study investigates how an OWF's distance from shore and geographical location impacts its environmental benefit. A process‐based life cycle assessment is conducted to compare 20 OWF siting scenarios in Michigan's Great Lakes for their cumulative fossil energy demand, global warming potential, and acidification potential. Each scenario (four lake locations at five offshore distances) has unique foundation, transmission, installation, and operational requirements based on site characteristics. The results demonstrate that the cumulative environmental burden from an OWF is most significantly affected by (1) water depth, (2) distance from shore, and (3) distance to power grid, in descending order of importance, if all other site‐relevant variables are held constant. The results also show that when OWFs are sited further offshore, the benefit of increased wind energy generation does not necessarily outweigh the increase in negative environmental impacts. This suggests that siting OWF nearer to shore may result in a better life cycle environmental performance. Finally, we demonstrate how much an OWF's environmental burdens can be reduced if the OWF system is either recycled, transported a shorter distance, or manufactured in a region with a high degree of renewable energy on the grid.     

A modelling investigation of the distribution of stratification and phytoplankton abundance in the Irish Sea

Thermal stratification and phytoplankton abundance are modelledon a 5 km grid covering the Irish Sea. The water column is approximatedby three layers. The top layer is uniformly mixed by wind stirringand the bottom by tidal energy, while linear gradients can occurin the middle layer. The model is forced with hourly meteorologicaldata and mean tidal energies. Primary production is representedby a model with a single nutrient and a single phytoplanktonpopulation. The results from the model show good agreement withdata collected on a Ministry of Agriculture, Fisheries and Food(MAFF) cruise in May 1992 and with historical data. When advectionis included, driven by depth-averaged currents, the surfacetemperature patterns are improved but bottom temperatures indeep water are raised and high concentrations of chlorophyllare carried offshore from coastal regions. This indicates alimitation of using depth-averaged currents and a need to accountfor differences in phytoplankton species composition in coastaland offshore waters. Calculations demonstrate the importanceof salinity variations to stratification and phytoplankton growth.Smoothing the wind mixing energy has the effect of delayingthe onset of the spring bloom in areas where wind mixing issignificant. Removing the diurnal cycle of solar heating alsodelays the spring bloom. The chlorophyll gradient in the middlelayer has a large impact on the response of the model to short-termvariability in the meteorological forcings.     

Risk Analysis of Wind Energy Investments in Turkey

ABSTRACT

Wind energy is a reliable source for fulfilling energy demand. However, the wind power usage remains limited due to the investmental risks. Governments’ support on renewable energy compensates these risks partially. Traditional investment evaluation techniques that do not consider the compensations and risks associated with the wind energy investments are one of the main reasons for the limited usage of wind power. In this study a real option and Monte Carlo simulation–based methodology, which considers both risks and compensations associated with these investments, is proposed to evaluate wind energy investments. The model is applied to a wind turbine investment in Turkey in order to show the applicability of the proposed model. The results indicate that the option value created through wind energy investments due to the governmental compensations is very high; therefore the traditional investment techniques are not appropriate for evaluating wind energy investments.     

Renewable energy development threatens many globally important biodiversity areas

Transitioning from fossil fuels to renewable energy is fundamental for halting anthropogenic climate change. However, renewable energy facilities can be land‐use intensive and impact conservation areas, and little attention has been given to whether the aggregated effect of energy transitions poses a substantial threat to global biodiversity. Here, we assess the extent of current and likely future renewable energy infrastructure associated with onshore wind, hydropower and solar photovoltaic generation, within three important conservation areas: protected areas (PAs), Key Biodiversity Areas (KBAs) and Earth's remaining wilderness. We identified 2,206 fully operational renewable energy facilities within the boundaries of these conservation areas, with another 922 facilities under development. Combined, these facilities span and are degrading 886 PAs, 749 KBAs and 40 distinct wilderness areas. Two trends are particularly concerning. First, while the majority of historical overlap occurs in Western Europe, the renewable electricity facilities under development increasingly overlap with conservation areas in Southeast Asia, a globally important region for biodiversity. Second, this next wave of renewable energy infrastructure represents a ~30% increase in the number of PAs and KBAs impacted and could increase the number of compromised wilderness areas by ~60%. If the world continues to rapidly transition towards renewable energy these areas will face increasing pressure to allow infrastructure expansion. Coordinated planning of renewable energy expansion and biodiversity conservation is essential to avoid conflicts that compromise their respective objectives.     

能量效率与可更新能源

一可更新能源可减少甚至消除我们对化石能和核能的依赖,其中很多虽然已为人类使用数百年,但因为石能的普遍使用,一直都为起人类的注意。人类已发明了新技术利用这些可更新能源。其利用不赖于一定的技术是既定的事实,目前有成功建立这样的能源工业还是十分昂贵的。如果人类生产经济和市场允许的话,这些新的技术经进一步改进和简化后,就可以降低成本,并且应用起来也很可靠。相对于开发应用核能,水能和化石能数以百万计的投资耗费来讲,用于可更新资源的资金可谓微乎其微。虽然传统能源和替代能源各具优点,但保护能源往往还是解决能源短缺最便宜,最容易的途径。     

Interactive marine spatial planning: siting tidal energy arrays around the Mull of Kintyre

The rapid development of the offshore renewable energy sector has led to an increased requirement for Marine Spatial Planning (MSP) and, increasingly, this is carried out in the context of the 'ecosystem approach' (EA) to management. We demonstrate a novel method to facilitate implementation of the EA. Using a real-time interactive mapping device (touch-table) and stakeholder workshops we gathered data and facilitated negotiation of spatial trade-offs at a potential site for tidal renewable energy off the Mull of Kintyre (Scotland). Conflicts between the interests of tidal energy developers and commercial and recreational users of the area were identified, and use preferences and concerns of stakeholders were highlighted. Social, cultural and spatial issues associated with conversion of common pool to private resource were also revealed. The method identified important gaps in existing spatial data and helped to fill these through interactive user inputs. The workshops developed a degree of consensus between conflicting users on the best areas for potential development suggesting that this approach should be adopted during MSP.     

能量效率与可更新能源

一些可更新能源可减少甚至消除我们对化石能和核能的依赖,其中很多虽然已为人类使用数百年,但因为化石能的普遍使用,一直都为起人类的注意。人类已发明了新技术来利用这些可更新能源。其利用有赖于一定的技术是既定的事实,目前有成功建立这样的能源工业还是十分昂贵的。如果人类生产经济和市场允许的话,这些新技术经进一步改进和简化后,就可以降低成本,并且应用起来也很可靠。相对于开发应用核能,水能和化石能数以百万计的投资耗费来讲,用于可更新资源的资金可谓微乎其微。虽然传统能源和替代能源各具优点,但保护能源往往还是解决能源短缺最便宜,最容易的途径。     

Global change synergies and trade‐offs between renewable energy and biodiversity

Reliance on fossil fuels is causing unprecedented climate change and is accelerating environmental degradation and global biodiversity loss. Together, climate change and biodiversity loss, if not averted urgently, may inflict severe damage on ecosystem processes, functions and services that support the welfare of modern societies. Increasing renewable energy deployment and expanding the current protected area network represent key solutions to these challenges, but conflicts may arise over the use of limited land for energy production as opposed to biodiversity conservation. Here, we compare recently identified core areas for the expansion of the global protected area network with the renewable energy potential available from land‐based solar photovoltaic, wind energy and bioenergy (in the form of Miscanthus × giganteus). We show that these energy sources have very different biodiversity impacts and net energy contributions. The extent of risks and opportunities deriving from renewable energy development is highly dependent on the type of renewable source harvested, the restrictions imposed on energy harvest and the region considered, with Central America appearing at particularly high potential risk from renewable energy expansion. Without restrictions on power generation due to factors such as production and transport costs, we show that bioenergy production is a major potential threat to biodiversity, while the potential impact of wind and solar appears smaller than that of bioenergy. However, these differences become reduced when energy potential is restricted by external factors including local energy demand. Overall, we found that areas of opportunity for developing solar and wind energy with little harm to biodiversity could exist in several regions of the world, with the magnitude of potential impact being particularly dependent on restrictions imposed by local energy demand. The evidence provided here helps guide sustainable development of renewable energy and contributes to the targeting of global efforts in climate mitigation and biodiversity conservation.     

The Energetic Metabolism of Societies Part I: Accounting Concepts

Based upon the currently emerging international consensus on how to account for the materials flows of industrialized countries, this article proposes methods to account for the energetic metabolism of societies. It argues that, to fully exploit the potential of the metabolism approach in the context of sustainable development, both energetic and material aspects of societal metabolism have to be taken into account. The article proposes concepts to empirically describe energy input, internal energy transformations, and energy utilization of societies by extending commonly used notions of energy statistics in a way that is compatible with current methods of materials flow analysis. Whereas energy statistics include only the energy used in technical devices for providing heat, light, mechanical work, and data processing, an accounting system for the energetic metabolism of societies should also consider flows of nutritional energy for both livestock and humans. Moreover, in assessing the energy input of a society, all inputs of energy-rich materials (and immaterial forms of energy such as electricity and light) that cross the boundary into the biophysical structures of society should be taken into consideration, regardless of the purpose for which they are eventually used. As a consequence, an energetic metabolism accounting system treats all biomass as energy input, instead of considering only the biomass used for technical energy generation, as energy statistics do. Part II in this set of articles will apply these concepts to different modes of societal organization and explore the significance of energetic metabolism for sustainable development. In particular, it will explore the significance for policies that aim at increasing the contribution of renewable energy, especially biomass.     

Life Cycle Assessment for Emerging Technologies: Case Studies for Photovoltaic and Wind Power (11 pp)

Goal, Scope and Background This paper describes the modelling of two emerging electricity systems based on renewable energy: photovoltaic (PV) and wind power. The paper shows the approach used in the ecoinvent database for multi-output processes.Methods Twelve different, grid-connected photovoltaic systems were studied for the situation in Switzerland. They are manufactured as panels or laminates, from mono- or polycrystalline silicon, installed on facades, slanted or flat roofs, and have a 3kWp capacity. The process data include quartz reduction, silicon purification, wafer, panel and laminate production, supporting structure and dismantling. The assumed operational lifetime is 30 years. Country-specific electricity mixes have been considered in the LCI in order to reflect the present situation for individual production stages. The assessment of wind power includes four different wind turbines with power rates between 30 kW and 800 kW operating in Switzerland and two wind turbines assumed representative for European conditions – 800 kW onshore and 2 MW offshore. The inventory takes into account the construction of the plants including the connection to the electric grid and the actual wind conditions at each site in Switzerland. Average European capacity factors have been assumed for the European plants. Eventually necessary backup electricity systems are not included in the analysis.Results and Discussion The life cycle inventory analysis for photovoltaic power shows that each production stage may be important for specific elementary flows. A life cycle impact assessment (LCIA) shows that there are important environmental impacts not directly related to the energy use (e.g. process emissions of NOx from wafer etching). The assumption for the used supply energy mixes is important for the overall LCIA results of different production stages. The allocation of the inventory for silicon purification to different products is discussed here to illustrate how allocation has been implemented in ecoinvent. Material consumption for the main parts of the wind turbines gives the dominant contributions to the cumulative results for electricity production. The complex installation of offshore turbines, with high requirements of concrete for the foundation and the assumption of a shorter lifetime compared to onshore foundations, compensate the advantage of increased offshore wind speeds.Conclusion The life cycle inventories for photovoltaic power plants are representative for newly constructed plants and for the average photovoltaic mix in Switzerland in the year 2000. A scenario for a future technology helps to assess the relative influence of technology improvements for some processes in the near future (2005-2010). The differences for environmental burdens of wind power basically depend upon the capacity factor of the plants, the lifetime of the infrastructure, and the rated power. The higher these factors, the more reduced the environmental burdens are. Thus, both systems are quite dependent on meteorological conditions and the materials used for the infrastructure.Recommendation and Perspective Many production processes for photovoltaic power are still under development. Future updates of the LCI should verify the energy uses and emissions with available data from industrial processes in operation. For the modelling of a specific power plant or power plant mixes outside of Switzerland, one has to consider the annual yield (kWh/kWp) and if possible also the size of the plant. Considering the steady growth of the size of wind turbines in Europe, the development of new designs, and the exploitation of offshore location with deeper waters than analysed in this study, the inventory for wind power plants may need to be updated in the future.     

Wind farm and solar park effects on plant–soil carbon cycling: uncertain impacts of changes in ground‐level microclimate

Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land‐based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground‐level climate by a magnitude that could affect the fundamental plant–soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground‐level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land‐based renewable energy sources to alter plant–soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research.     

Firm Type,Feed‐in Tariff,and Wind Energy Investment in Germany: An Investigation of Decision Making Factors of Energy Producers Regarding Investing in Wind Energy Capacity

The development of renewable and sustainable energy is advanced by public financial support. This is particularly so in the German Energiewende, which seeks to replace nuclear and fossil electricity generation with wind, sun, and biomass. We study the impact of the (changes in the) feed‐in tariff (FIT) policy on the investment in wind electricity generation capacity in Germany in the period 2000–2014. We estimate a generic investment model that includes this support mechanism, the cost of capital, investment risks such as wind and price volatility, and manufacturing costs. We discuss specific features for different types of wind energy investors, such as the incumbents, small private investors, diversified companies, and independent power producers. We find that a change in the FIT has a negative impact on investment capacity regarding the generation of wind energy: A one monetary unit increase in the variation of the tariff is to be associated with a decrease by 0.17 megawatts of wind capacity installed. We argue that it is policy uncertainty that makes investors shy away from making real investments. We also argue that the drivers for wind energy investment can differ along different types of firms. For the traditional power producers, especially electricity price volatility, construction costs, and carbon prices seem to matter. But for the other investor types, the FIT is crucial indeed.     

Challenges and opportunities for hydrogen production from microalgae

The global population is predicted to increase from ~7.3 billion to over 9 billion people by 2050. Together with rising economic growth, this is forecast to result in a 50% increase in fuel demand, which will have to be met while reducing carbon dioxide (CO₂) emissions by 50–80% to maintain social, political, energy and climate security. This tension between rising fuel demand and the requirement for rapid global decarbonization highlights the need to fast‐track the coordinated development and deployment of efficient cost‐effective renewable technologies for the production of CO₂ neutral energy. Currently, only 20% of global energy is provided as electricity, while 80% is provided as fuel. Hydrogen (H₂) is the most advanced CO₂‐free fuel and provides a ‘common’ energy currency as it can be produced via a range of renewable technologies, including photovoltaic (PV), wind, wave and biological systems such as microalgae, to power the next generation of H₂ fuel cells. Microalgae production systems for carbon‐based fuel (oil and ethanol) are now at the demonstration scale. This review focuses on evaluating the potential of microalgal technologies for the commercial production of solar‐driven H₂ from water. It summarizes key global technology drivers, the potential and theoretical limits of microalgal H₂ production systems, emerging strategies to engineer next‐generation systems and how these fit into an evolving H₂ economy.