Research priorities for assessing potential impacts of emerging marine renewable energy technologies: Insights from developments in Wales (UK)

The marine renewable energy industry is expanding globally in response to increased energy demands and the desire to curtail greenhouse gas emissions. Within the UK, Wales has the potential for the development of diverse marine renewable technologies, with a strong tidal range resource, areas of high tidal current energy, and a spatially limited wave energy resource. Targets have been set by the Welsh Government to increase the contribution of marine renewable energy to Wales' electricity generation, and the recent introduction of demonstration zones for tidal and wave energy aims to facilitate developers in device deployment. However, uncertainties remain about the potential impacts of devices, particularly for array scale deployments, planned at several sites, and for the extensive structures required to capture the tidal range resource. Here we review present knowledge of potential impacts, including physical, ecological and societal dimensions, and outline research priorities to provide a scientific basis on which to base decisions influencing the trajectory of Welsh marine renewable energy development.     

The role of tidal asymmetry in characterizing the tidal energy resource of Orkney

When selecting sites for marine renewable energy projects, there are a wide range of economical and practical constraints to be considered, from the magnitude of the resource through to proximity of grid connections. One factor that is not routinely considered in tidal energy site selection, yet which has an important role in quantifying the resource, is tidal asymmetry, i.e. variations between the flood and ebb phases of the tidal cycle. Here, we present theory and develop a high-resolution three-dimensional ROMS tidal model of Orkney to examine net power output for a range of sites along an energetic channel with varying degrees of tidal asymmetry. Since power output is related to velocity cubed, even small asymmetries in velocity lead to substantial asymmetries in power output. We also use the 3D model to assess how tidal asymmetry changes with height above the bed, i.e. representing different device hub heights, how asymmetry affects turbulence properties, and how asymmetry is influenced by wind-driven currents. Finally, although there is minimal potential for tidal phasing over our study site, we demonstrate that regions of opposing flood- versus ebb-dominant asymmetry occurring over short spatial scales can be aggregated to provide balanced power generation over the tidal cycle.     

The effect of channel constriction on the potential for tidal stream power

Tidal channels with narrow constrictions are attractive sites for electricity generation due to energy dense, high velocity flow through the constricted zones. This work uses a 1D model to systematically examine the effect of constriction on channel potential (theoretical maximum power) and transport in channels connecting two large water bodies (Type I) and channels connecting a large water body to an embayment/lagoon (Type II). Type I channels showed a monotonic decrease in potential and transport with increasing constriction due to enhanced bottom drag from the resultant high velocity zone. The effect of constriction on potential and transport in Type II channels varies depending on the relative geometries of the channel and embayment. Type II channels may be geometrically modified to increase power and in some instances this would simultaneously produce a high velocity zone. The flow reduction required to achieve a channel’s potential was invariant to changes in constriction for Type I channels and also Type II channels if a “lagoon geometry factor” is less than about 4. A simple approximation for potential provided in the literature for unconstricted channels is extended for use with constricted channels and an approximation for the drag coefficient required to achieve potential is provided.     

An investigation on the impacts of regulatory interventions on wind power expansion in generation planning

Large integration of intermittent wind generation in power system has necessitated the inclusion of more innovative and sophisticated approaches in power system investment planning. This paper presents a novel framework on the basis of a combination of stochastic dynamic programming (SDP) algorithm and game theory to study the impacts of different regulatory interventions to promote wind power investment in generation expansion planning. In this study, regulatory policies include Feed-in-Tariff (FIT) incentive, quota and tradable green certificate. The intermittent nature and uncertainties of wind power generation will cause the investors encounter risk in their investment decisions. To overcome this problem, a novel model has been derived to study the regulatory impacts on wind generation expansion planning. In our approach, the probabilistic nature of wind generation is modeled. The model can calculate optimal investment strategies, in which the wind power uncertainty is included. This framework is implemented on a test system to illustrate the working of the proposed approach. The result shows that FITs are the most effective policy to encourage the rapid and sustained deployment of wind power. FITs can significantly reduce the risks of investing in renewable energy technologies and thus create conditions conducive to rapid market growth.     

Socio-economic impacts of community wind power projects in Northern Scotland

The production renewable energy is a promising sector for social enterprises located in the remote northern communities of Scotland. Community wind power offers a way to generate resources to be re-invested in local development purposes, such as community businesses, social services and infrastructure and communications. In this study, a regional input–output modelling is applied to the analysis of the socio-economic impacts of 11 wind farms of community-based social enterprises located in the Outer Hebrides, Shetland and Orkney. The results show significant socio-economic benefits of re-investing revenues for social purposes. For instance, strategic re-investments of revenues in local social services generate about tenfold additional employment and income impact compared with the impact of wind power production. Our socio-economic analyses find that community-based social enterprises are one promising solution for place-based regional development in the European northern periphery.     

Wind power resource in the south-western region of Algeria

In this study, we present a statistical analysis of wind speeds at Tindouf in Algeria using Risoe National Laboratory's Wind Atlas Analysis and Application Program (WAsP). It requires information related to the sheltering obstacles, surface roughness changes and terrain height variations in order to calculate their effects on the wind. Wind data, consisting of hourly wind speed records over a 5-year period, 2002–2006, were obtained from SONELGAZ R&D Office; the average wind speed at a height of 17 m above ground level was found to range from 7.19 to 7.95 m/s. The Weibull distributions parameters (c and k) were found to vary between 8.0 and 8.9 m/s and 2.54–3.23, respectively, with average power density ranging from 318 to 458 W/m². The dominant wind directions and the frequency distributions were also determined.     

Employment impacts of solar energy in Turkey

Solar energy is considered a key source for the future, not only for Turkey, also for all of the world. Therefore the development and usage of solar energy technologies are increasingly becoming vital for sustainable economic development. The main objective of this study is investigating the employment effects of solar energy industry in Turkey. Some independent reports and studies, which analyze the economic and employment impacts of solar energy industry in the world have been reviewed. A wide range of methods have been used in those studies in order to calculate and to predict the employment effects. Using the capacity targets of the photovoltaic (PV) and concentrated solar power (CSP) plants in the solar Roadmap of Turkey, the prediction of the direct and indirect employment impacts to Turkey's economy is possible. As a result, solar energy in Turkey would be the primary source of energy demand and would have a big employment effects on the economics. That can only be achieved with the support of governmental feed-in tariff policies of solar energy and by increasing research-development funds.     

冷热电联产系统的发展及前景

1前言能源的价格、电网的稳定性、能量的品质、空气的品质以及全球气候的改变,是21世纪我们面临的严重问题。随着经济和社会的发展,这些问题将变得更加尖锐。在传统的利用燃料产生电力的过程中,将近三分之二的输入能量没有有效利用就被释放到环境中,能量损失十分严重。利用总能     

葫芦岛沿海地区风资源分析

以葫芦岛市沿海三站(连山、兴城、绥中)2006年逐日逐时10min平均风速资料为例,计算几项风资源评估参数,结果表明:葫芦岛市沿海地区均属于风能可利用区;各站风资源月分布均呈现双峰型,第一个高峰为2、3、4、5月,第二个高峰在10月;目前葫芦岛市连山站的位置距海岸较远,但结果仍表明该地的风资源比兴城、绥中丰富。     

Water: A critical resource in the thermoelectric power industry

Water availability represents a growing concern for meeting future power generation needs. In the United States, projected population growth rates, energy consumption patterns, and demand from competing water use sectors will increase pressure on power generators to reduce water use. Water availability and use also exhibit strong regional variations, complicating the nature of public policy and technological response.     

Economic potential of renewable energy in Vietnam's power sector

A bottom-up Integrated Resource Planning model is used to examine the economic potential of renewable energy in Vietnam's power sector. In a baseline scenario without renewables, coal provides 44% of electricity generated from 2010 to 2030. The use of renewables could reduce that figure to 39%, as well as decrease the sector's cumulative emission of CO₂ by 8%, SO₂ by 3%, and NO_x by 4%. In addition, renewables could avoid installing 4.4 GW in fossil fuel generating capacity, conserve domestic coal, decrease coal and gases imports, improving energy independence and security. Wind could become cost-competitive assuming high but plausible on fossil fuel prices, if the cost of the technology falls to 900 US$/kW.     

Bioethanol development in China and the potential impacts on its agricultural economy

China is now the third largest bioethanol producer in the world after the United State and Brazil. The overall goals of this paper are to provide an overview of China’s current bioethanol program, its future trend, and the likely impacts on its agricultural economy in the future. The analysis shows that China has developed an ambitious long-run biofuel program with a series of financial and institutional supports. While there are several potential feedstock crops available for bioethanol production, lack of land for feedstock production is one of major constraints in China’s bioethanol expansion. The results show that although China’s bioethanol expansion will have little impacts on overall agricultural prices in international markets, it will have significant impacts on the prices, productions, and trade of those energy crops being used for bioethanol production in China.     

Power potential of a split tidal channel

The extraction of kinetic energy from tidal flows is an interest of the renewable energy industry with large scale assessments of the potential resource already conducted. These assessments however, use the natural kinetic energy flux as the primarily metric of the available resource. This approach has significant limitations when it is applied to tidal channels, particularly those tidal channels that branch into multiple sub-channels. Small amounts of energy extraction may not cause significant changes in the total flow through a channel, however the relative flows through the sub-channels can be drastically affected. It is this diversion of the flow that becomes the primary control on the extractable energy. As such, the relative resistance of the channels plays an important role.     

State and local economic impacts from wind energy projects: Texas case study

This paper uses the Jobs and Economic Development Impacts (JEDI) model to estimate economic impacts from 1398 MW of wind power development in four counties in west Texas. Project-specific impacts are estimated at the local level (i.e., within a 100-mile radius around the wind farms) and at the state level. The primary economic policy question addressed is how investment in wind energy affects the state and local communities where the wind farms are built. During the four-year construction phase approximately 4100 FTE (full time equivalents) jobs were supported with turbine and supply chain impacts accounting for 58% of all jobs generated. Total lifetime economic activity to the state from the projects equated to more than $1.8 billion, or $1.3 million per MW of installed capacity. The total economic activity to the local communities was also substantial, equating to nearly $730 million over the assumed 20-year life cycle of the farms, or $0.52 million per MW of installed capacity. Given the current level of impacts observed, and the potential for increased impacts via greater utilization of instate manufacturing capacity and the development of trained wind industry specific laborers, Texas appears to be well positioned to see increasing impacts from continued wind development.     

Concurrent and legacy economic and environmental impacts from establishing a marine energy sector in Scotland

We examine the economic and environmental impact that the installation of 3 GW of marine energy capacity would have on Scotland. This is not a forecast, but a projection of the likely effects of meeting the Scottish Government's targets for renewable energy through the development of a marine energy sector. Energy, with a particular focus on renewables, is seen by the Scottish Government as a “key sector”, with high growth potential and the capacity to boost productivity (Scottish Government, 2007a. The Government Economic Strategy. The Scottish Government, Edinburgh). The key nature of this sector has been identified through targets being set for renewable energy to achieve environmental and economic benefits. Using a regional computable general equilibrium (CGE) model of Scotland we show that the development of a marine energy sector can have substantial and beneficial impacts on GDP, employment and the environment over the lifetime of the devices, given the encouragement of strong indigenous inter-industry linkages. Furthermore, there are also substantial “legacy” effects that persist well beyond the design life of the devices.     

风能资源评估方法的分析及应用

阐述了风电场选址中的风能资源的评估程序,介绍和分析了风能资源评估技术方法和特点,基于工程实测数据,用国际通用的风资源评估软件WASP8．3分析和评估了相关风能要素。     

Integrated resource strategic planning: Case study of energy efficiency in the Chinese power sector

In the last quarter of the 20th century, many power companies used the integrated resource planning (IRP) approach in power expansion planning. Today, very few power companies use this approach because of the split between the power generation and distribution activities. It seems that, in some countries, long-term power system expansion planning has become a task of the central government. To help the government in this area, this paper proposes a new approach called the integrated resource strategic planning (IRSP). When combined with a smart grid, this approach can replace the IRP for the government’s power sector expansion. This paper introduces the necessity and possibility of using this new approach, presents a framework on how to use the approach, and justifies the effectiveness of this approach against the traditional power planning approach, with a case study in China. This paper concludes that if China follows the IRSP approach, it may be able to avoid or postpone up to 69 GW of power generation in the period 2009–2015. These measures could help mitigate 201.8 million tons of carbon dioxide (CO₂), 0.816 million tons of sulfur dioxide (SO₂), and 0.946 million tons of nitrogen oxide (NO_x).     

Renewable energy resource potential in Pakistan

Pakistan energy situation is seriously troubling today due to lack of careful planning and implementation of its energy policies. To avoid the worse situation in the years ahead, the country will have to exploit its huge natural renewable resource. In this paper a review is being presented about renewable energy resource potential available in the country to be exploited for useful and consistent energy supplies. On average solar global insolation 5–7 kWh/m²/day, wind speed 5–7.5 m/s, Biogas 14 million m³/day, microhydel more than 600 MW (for small units) with persistency factor of more than 80% over a year exist in the country. Solar and wind maps are presented along with identification of hot spring sites as resource of geothermal energy. The research results presented in this paper are not only useful for government policy makers, executing agencies but also for private sector national and international agencies and stake holders who want to invest in Pakistan for renewable energy projects or business.     

内蒙古建设大型并网光伏沙漠电站的可行性分析

合理利用现有资源、改善能源结构,已成为可再生能源发展的指导思想.有效地利用内蒙古荒漠资源建设大型并网光伏沙漠电站,是实现能源可持续发展战略,开拓和发展可再生能源的必由之路.文章从政策指导、太阳能资源、荒漠资源和电网交通等方面,分析了在内蒙古建设大型并网光伏沙漠电站的可行性.     

光伏并网逆变器辅助电源的设计

采用光伏并网技术的太阳能发电已成为目前发展最快、应用面最广的太阳能利用方式之一.文章介绍了光伏并网系统中逆变器辅助电源的工作原理,这种辅助电源是由TOPSwitch芯片组成的高频开关电源,它降低了辅助电源的生产成本,简化了电路,提高了整个电路板的电磁兼容性,具有较高的使用价值.