The wind potential impact on the maximum wind energy penetration in autonomous electrical grids

According to long-term wind speed measurements the Aegean Archipelago possesses excellent wind potential, hence properly designed wind energy applications can substantially contribute to fulfill the energy requirements of the island societies. On top of this, in most islands the electricity production cost is extremely high, while significant insufficient power supply problems are often encountered, especially during the summer. Unfortunately, the stochastic behaviour of the wind and the important fluctuations of daily and seasonal electricity load pose a strict penetration limit for the contribution of wind energy in the corresponding load demand. The application of this limit is necessary in order to avoid hazardous electricity grid fluctuations and to protect the existing thermal power units from operating near or below their technical minima. In this context, the main target of the proposed study is to present an integrated methodology able to estimate the maximum wind energy penetration in autonomous electrical grids on the basis of the available wind potential existing in the Aegean Archipelago area. For this purpose a large number of representative wind potential types have been investigated and interesting conclusions have been derived.     

The role of hydrogen in high wind energy penetration electricity systems: The Irish case

The deployment of wind energy is constrained by wind uncontrollability, which poses operational problems on the electricity supply system at high penetration levels, lessening the value of wind-generated electricity to a significant extent. This paper studies the viability of hydrogen production via electrolysis using wind power that cannot be easily accommodated on the system. The potential benefits of hydrogen and its role in enabling a large penetration of wind energy are assessed, within the context of the enormous wind energy resource in Ireland. The exploitation of this wind resource may in the future give rise to significant amounts of surplus wind electricity, which could be used to produce hydrogen, the zero-emissions fuel that many experts believe will eventually replace fossil fuels in the transport sector. In this paper the operation of a wind powered hydrogen production system is simulated and optimised. The results reveal that, even allowing for significant cost-reductions in electrolyser and associated balance-of-plant equipment, low average surplus wind electricity cost and a high hydrogen market price are also necessary to achieve the economic viability of the technology. These conditions would facilitate the installation of electrolysis units of sufficient capacity to allow an appreciable increase in installed wind power in Ireland. The simulation model was also used to determine the CO₂ abatement potential associated with the wind energy/hydrogen production.     

Wind energy and assessment of wind energy potential in Turkey

In this study, the potential of wind energy and assessment of wind energy systems in Turkey were studied. The main purpose of this study is to investigate the wind energy potential and future wind conversion systems project in Turkey. The wind energy potential of various regions was investigated; and the exploitation of the wind energy in Turkey was discussed. Various regions were analyzed taking into account the wind data measured as hourly time series in the windy locations. The wind data used in this study were taken from Electrical Power Resources Survey and Development Administration (EIEI) for the year 2010. This paper reviews the assessment of wind energy in Turkey as of the end of May 2010 including wind energy applications. Turkey's total theoretically available potential for wind power is around 131,756.40 MW and sea wind power 17,393.20 MW annually, according to TUREB (TWEA). When Turkey has 1.5 MW nominal installed wind energy capacity in 1998, then this capacity has increased to 1522.20 MW in 2010. Wind power plant with a total capacity of 1522.20 MW will be commissioned 2166.65 MW in December 2011.     

Technical assessment of the use of a small-scale wind power system to meet the demand for electricity in a land aquafarm in Taiwan

Due to the widespread aquaculture at coastal area in Taiwan and high wind power potential in the sites, it is worthy to carry out the technical potential assessments of small-scale wind power system used for aquaculture in Taiwan. The present work analyzed wind power potential, described the practical installation, measured the actual energy output, verified the reliability of the energy output estimation method and elucidated important considerations associated with the use of this estimation method. The relationship between the actual energy generated and the wind speed characteristics were thus introduced. The power quality produced by a small-scale wind power generator was also evaluated.     

Power limits of grid-connected modern wind energy systems

Wind energy is a prominent area of application of variable speed generators operating on the constant grid frequency. A modern wind energy system of this type consists of a surface mounted permanent-magnet generator with a frequency converter, which allows variable speed operation. The maximum power capability of the wind energy system is limited by the grid inverter. The theoretical formulation for active and reactive power limits is given. This formulation is used to set power reference limits to the inverter. Two different regions are distinguished depending on the tolerable Ac current harmonic distortion. Experimental results in a variable frequency wind energy generation system are shown.     

Renewable energy sources in the Egyptian electricity market: A review

This review paper presents an appraisal of renewable energy RE options in Egypt. An appraisal review of different REs is presented. The study shows that electric energy produced from REs in Egypt are very poor compared with other energy sources. The utilization of the renewable energies can also be a good opportunity to fight the desertification and dryness in Egypt which is about 60% of Egypt territory. The rapid growth of energy production and consumption is strongly affecting and being affected by the Egyptian economy in many aspects. It is evident that energy will continue to play an important role in the development of Egypt's economy in coming years. The total installed electricity generating capacity had reached around 22025 MW with a generating capacity reached 22605 MW at the end of 2007. Hydropower and coal has no significant potential increase. During the period 1981/82-2004/05 electricity generation has increased by 500% from nearly 22 TWh for the year 1981/1982 to 108.4 TWh in the year 2004/2005 at an average annual growth rate of 6.9%. Consequently, oil and gas consumed by the electricity sector has jumped during the same period from around 3.7 MTOE to nearly 21 MTOE. The planned installed capacity for the year 2011/2012 is 28813 MW and the required fuel (oil and gas) for the electricity sector is estimated to reach about 29 MTOE by the same year. The renewable energy strategy targets to supply 3% of the electricity production from renewable resources by the year 2010. Electrical Coverage Electrical energy has been provided for around 99.3% of Egypt's population, representing a positive sign for the welfare of the Egyptian citizen due to electricity relation to all development components in all walks of life. The article discusses perspectives of wind energy in Egypt with projections to generate ∼ 3.5 GWe by 2022, representing ∼9% of the total installed power at that time (40.2 GW). Total renewables (hydro + wind + solar) are expected to provide ∼7.4 GWe by 2022 representing ∼ 19% of the total installed power. Such a share would reduce dependence on depleting oil and gas resources, and hence improve country's sustainable development.     

Successful renewable energy development in a competitive electricity market: A Texas case study

The development of renewable energy in markets with competition at wholesale and retail levels poses challenges not present in areas served by vertically-integrated utilities. The intermittent nature of some renewable energy resources impact reliability, operations, and market prices, in turn affecting all market participants. Meeting renewable energy goals may require coordination among many market players.     

Between fragmented authoritarianism and policy coordination: Creating a Chinese market for wind energy

The Chinese grid-connected wind energy sector has undergone a number of fundamental changes during its 20 years of existence. The scope of this article is to track the reforms of the energy bureaucracy and its policy approach on the one hand and changes in wind energy installations on the other. By comparing three historically distinct phases of wind energy in China it is shown how policy reforms have changed largely from a state of “fragmented authoritarianism” towards policy coordination. In the initial phase (1986–1993), wind energy was expanding very slowly with disjointed policy making and in the incremental phase (1994–1999), the energy authorities were in dispute over the strategy and launched conflicting policy initiatives with poor results in wind energy output. The latest coordinated phase (2000–2006), however, developed a coherent renewable energy agenda and policy regime for the wind power sector. It is found that this phase with coordinated market regulations and incentives has helped give birth to a take-off in Chinese wind energy installations and substantial cost reductions, although the latter is threatening the profitability of wind farms. The article contributes to the academic debate over the role of policy making in renewable energy development and argues that China should continue, and improve, the coordination of regulations and incentives.     

Effect of wind energy system performance on optimal renewable energy model-an analysis

The Optimal Renewable Energy Model (OREM) has been developed to determine the optimum level of renewable energy sources utilisation in India for the year 2020–21. The model aims at minimising costefficiency ratio and determines the optimum allocation of different renewable energy sources for various end-uses. The extent of social acceptance level, potential limit, demand and reliability will decide the renewable energy distribution pattern and are hence used as constraints in the model. In this paper, the performance and reliability of wind energy system and its effects on OREM model has been analysed. The demonstration windfarm (4 MW) which is situated in Muppandal, a village in the southern part of India, has been selected for the study. The windfarm has 20 wind turbine machines of 200 KW capacity. The average technical availability, real availability and capacity factor have been analysed from 1991 to 1995 and they are found to be 94.1%, 76.4% and 25.5% respectively. The reliability factor of wind energy system is found to be 0.5 at 10,000 hours. The OREM model is analysed considering the above said factors for wind energy system, solar energy system and biomass energy systems. The model selects wind energy for pumping end-use to an extent of 0.3153×10¹⁵ KJ.     

The economic benefit of short-term forecasting for wind energy in the UK electricity market

In the UK market, the total price of renewable electricity is made up of the Renewables Obligation Certificate and the price achieved for the electricity. Accurate forecasting improves the price if electricity is traded via the power exchange. In order to understand the size of wind farm for which short-term forecasting becomes economically viable, we develop a model for wind energy. Simulations were carried out for 2003 electricity prices for different forecast accuracies and strategies. The results indicate that it is possible to increase the price obtained by around £5/MWh which is about 14% of the electricity price in 2003 and about 6% of the total price. We show that the economic benefit of using short-term forecasting is also dependant on the accuracy and cost of purchasing the forecast. As the amount of wind energy requiring integration into the grid increases, short-term forecasting becomes more important to both wind farm owners and the transmission/distribution operators.     

Profitability of wind energy: Short-term risk factors and possible improvements

The wind energy industry has grown considerably in recent years. If the current rate of growth of installed capacity of 1500 MW per year continues, by 2006 Spain will achieve the objective established for 2010 in the “Plan de Fomento” [Plan to Promote Renewable Energies] or for 2008 in the more ambitious “Plan de Infraestructuras Eléctricas y Gasísticas” [Plan for Electrical and Gas Installations]. Achieving these important goals, which require significant investment, depends upon the continued stability of salaries and the willingness of banks to provide financing. Therefore, we studied those factors that had the greatest short-term impact on the economic viability of wind energy projects in Spain and we found that the inherent risk within the sector can become a real obstacle in terms of development and short-term financing. Given the possibility of carrying out financial analysis that is more exhaustive than traditionally employed methods, the various models for evaluating investment in risk conditions were studied with the aim of choosing the ideal tool that takes account of the highly fortuitous nature of wind velocity.     

Controllable and affordable utility-scale electricity from intermittent wind resources and compressed air energy storage (CAES)

World wind energy resources are substantial, and in many areas, such as the US and northern Europe, could in theory supply all of the electricity demand. However, the remote or challenging location (i.e. offshore) and especially the intermittent character of the wind resources present formidable barriers to utilization on the scale required by a modern industrial economy. All of these technical challenges can be overcome. Long distance transmission is well understood, while offshore wind technology is being developed rapidly. Intermittent wind power can be transformed to a controllable power source with hybrid wind/compressed air energy storage (CAES) systems. The cost of electricity from such hybrid systems (including transmission) is affordable, and comparable to what users in some modern industrial economies already pay for electricity. This approach to intermittent energy integration has many advantages compared to the current strategy of forcing utilities to cope with supply uncertainty and transmission costs. Above all, it places intermittent wind on an equal technical footing with every other generation technology, including nuclear power, its most important long-term competitor.     

Assessment of wind energy in Iran: A review

In this study, a ten minute period measuring wind speed data for year 2007 at 10 m, 30 m and 40 m heights for different places in Iran, has been statistically analyzed to determine the potential of wind power generation. Sixty eight sites have been studied. The objective is to evaluate the most important characteristics of wind energy in the studied sites. The statistical attitudes permit us to estimate the mean wind speed, the wind speed distribution function, the mean wind power density and the wind rose in the site at three different heights. Some local phenomena are also considered in the characterization of the site.     

Pumped storage in systems with very high wind penetration

This paper examines the operation of the Irish power system with very high levels of wind energy, with and without pumped storage. A unit commitment model which accounts for the uncertainty in wind power is used. It is shown that as wind penetration increases, the optimal operation of storage depends on wind output as well as load. The main benefit from storage is shown to be a decrease in wind curtailment. The economics of the system are examined to find the level at which storage justifies its capital costs and inefficiencies. It is shown that the uncertainty of wind makes the option of storage more attractive. The size of the energy store has an impact on results. At lower levels of installed wind (up to approximately 50% of energy from wind in Ireland), the reduction in curtailment is insufficient to justify building storage. At greater levels of wind, storage reduces curtailment sufficiently to justify the additional capital costs. It can be seen that if storage replaces OCGTs in the plant mix instead of CCGTs, then the level at which it justifies itself is lower. Storage increases the level of carbon emissions at wind penetration below 60%.     

A transition toward a market expansion phase: Policies for promoting wind power in Taiwan

Considering the significant issues on global warming and environmental protection, the energy sector needs a long-term policy, by which renewable energies gradually replace conventional fossil fuels. In terms of an energy system, the development of renewable energies implies a challenge to existing energies like fossil fuels and nuclear power that have been for decades equipped with sound infrastructure and regulations. And a transformation of the energy system cannot expect any achievement without overcoming considerable opposition from vested interests involved with the fossil fuels technologies.     

Additionality of wind energy investments in the U.S. voluntary green power market

In the United States, electricity consumers are told that they can “buy” electricity from renewable energy projects, versus fossil fuel-fired facilities, through participation in voluntary green power markets. The marketing messages communicate to consumers that they are causing additional renewable energy generation and reducing emissions through their participation and premium payments for a green label. Using a spatial financial model and a database of registered Green-e wind power facilities, the analysis in this paper shows that the voluntary Renewable Energy Certificate (REC) market has a negligible influence on the economic feasibility of these facilities. Nevertheless, voluntary green power marketers at least implicitly claim that buying their products creates additional renewable energy. This study indicates the contrary. Participants in U.S. voluntary green power markets associated with wind power, therefore, appear to be receiving misleading marketing messages regarding the effect of their participation. In the process of completing this analysis, a potentially relevant factor in explaining investor behavior was identified: the potential for the overlap of voluntary REC markets with compliance REC markets that supply utilities need to meet their obligations of Renewable Energy Portfolio Standard (RPS). The majority of state RPS rules allow for regional or even national sourcing of RECs, meaning that projects are generally eligible to provide compliance RECs to utilities not only in their home states, but in several other states.     

Modelling of energy systems with a high percentage of CHP and wind power

This paper presents the energy system analysis model EnergyPLAN, which has been used to analyse the integration of large scale wind power into the national Danish electricity system. The main purpose of the EnergyPLAN model is to design suitable national energy planning strategies by analysing the consequences of different national energy investments. The model emphasises the analysis of different regulation strategies and different market economic optimisation strategies.At present wind power supply 15% of the Danish electricity demand and ca 50% is produced in CHP (combined heat and power production). The model has been used in the work of an expert group conducted by the Danish Energy Agency for the Danish Parliament. Results are included in the paper in terms of strategies, in order to manage the integration of CHP and wind power in the future Danish energy supply in which more than 40% of the supply is expected to come from wind power.     

Large-scale integration of wind power into the existing Chinese energy system

This paper presents the ability of the existing Chinese energy system to integrate wind power and explores how the Chinese energy system needs to prepare itself in order to integrate more fluctuating renewable energy in the future. With this purpose in mind, a model of the Chinese energy system has been constructed by using EnergyPLAN based on the year 2007, which has then been used for investigating three issues. Firstly, the accuracy of the model itself has been examined and then the maximum feasible wind power penetration in the existing energy system has been identified. Finally, barriers have been discussed and suggestions proposed for the Chinese energy system to integrate large-scale renewable energy in the future. It is concluded that the model constructed by the use of EnergyPLAN can accurately simulate the Chinese energy system. Based on current regulations to secure grid stability, the maximum feasible wind power penetration in the existing Chinese energy system is approximately 26% from both technical and economic points of view. A fuel efficiency decrease occurred when increasing wind power penetration in the system, due to its rigid power supply structure and the task of securing grid stability, was left primarily to large coal-fired power plants. There are at least three possible solutions for the Chinese energy system to integrate large-scale fluctuating renewable energy in the long term: Redesigning the regulations to secure grid stability by means of diversifying the participants, such as including hydropower and CHP plants; integrating large-scale heat pumps combined with heat storage devices to satisfy district heat demands and developing electric vehicles to promote off peak electricity utilisation.     

Electricity restructuring in Turkey and the share of wind energy production

This paper presents the current status of Turkey's electricity power sector, efforts for introducing competition in the Turkey's power industry, and concerns with the restructuring in Turkey. Turkey include long-term high-cost agreements, low quality of power, and therefore restrictions for synchronization with UCTE network, increase in the reliance on imported natural gas, and the urgent need for highly qualified staff that would be capable of fast and reliable implementation of ongoing reforms in the electricity sector. The contribution of the exploiting wind energy potential in Turkey to reconstruction of Turkey electricity structure is investigated. The strong development of wind energy in Turkey is expected to continue in the coming years.     

Combining hydro and variable wind power generation by means of pumped-storage under economically viable terms

Pumped hydro storage (PHS) systems which are located at isolated regions and are able to exploit the rejected wind energy amounts produced by local wind farms, seem to gain interest worldwide and to become essential in regard to higher shares of renewable-generated electricity. Despite the high wind potential encountered in many Greek island regions, the wind energy contribution to the electrification of these areas is significantly restricted due to imposed electrical grid limitations. In this context, the current work examines the economic viability of a wind-based PHS system (wind-hydro solution) which provides the local electrical grid of an Aegean Sea island, Lesbos, with guaranteed energy amounts during the peak load demand periods. Based on the maximization of the project’s net present value, the optimum system configuration is proposed while many other feasible solutions are revealed. According to the results obtained the implementation of this project demonstrates excellent technical and economic performance, while at the same time renewable energy sources (RES) contribution is doubled reaching almost 20% of the Lesbos island electrical energy consumption.