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Navigation

• FOREWORD
• INTRODUCTION
• 1. SUN ENERGY AND ITS POTENTIAL
• 1.1. General remarks
• 1.2. Solar radiation: An outline
• 1.3. Radiation balance of the Kola Peninsula
• 1.4. Sunshine durations
• 1.5. Prospective uses of solar energy on the Kola
• 2. WIND ENERGY
• 2.1. Average wind speeds
• 2.2 Wind speed and direction frequency
• 2.3. Maximum wind speeds
• 2.4. Technical wind energy resources of the region
• 2.5 Types of wind power installations
• 2.6. Wind energy application trends
• 2.7. Feasible sites for wind parks
• 2.8. Technical and economic peculiarities of opera
• 3. SMALL RIVER ENERGY
• 3.1. A general evaluation of the region’s hydroene
• 3.2. Hydroelectric power plants in operation on th
• 3.3. Hydroenergy potential of small rivers
• 3.4. First priority river sites for the constructi
• 3.5. Small hydroelectric power plants for remote a
• 4. TIDAL ENERGY
• 4.1. Tidal energy’s distinctive features
• 4.2. Recommended TPP sites and their energy potent
• 4.3. Readiness levels for the technical applicatio
• 4.4. Environmental aspects of application of tidal
• 4.5. Tidal energy application prospects: A general
• 5. WAVE ENERGY
• 5.1. General information on utilizing the energy o
• 5.2. Energy of surface waves.
• 5.3. Undulation’s renewable energy
• 5.4. A brief outline of main types of wave energy
• 5.5. Technical resources of ocean surface wave en
• 6. BIOENERGY RESOURCES
• 6.1. Utilization of biodegradable wastes from live
• 6.2. Evaluating bioenergy resources: Background da
• 6.3. Energy potential of fuel production with anae
• 6.4. Effects gained from application of anaerobic
• 6.5. Prospects of application of lumber wastes
• CONCLUSION
• CITED LITERATURE

2.2 Wind speed and direction frequency

The recurrence rate of wind speeds shows for how long during a period of time under consideration winds blew at one speed or another. This parameter helps understand how valuable the energy potential of the wind is and reveals the basic energy characteristics that will determine the efficiency and expediency of using this wind as an energy resource. The practice of wind energy estimations usually requires an approximation of – or leveling out of – wind speed frequency values received empirically, which is done using various analytical correlations. In this context, the two-parameter Weibull equation (14) has acquired the widest recognition. It is suitable for a description of wind speed distribution under the conditions of the Kola Peninsula. Calculations show that the level of concurrence of empirical (factual) and analytical distributions obtained through the Weibull equation is quite high. Fig. 2.4 demonstrates the analytical curves corresponding to wind speed frequencies at differing average annual values (from 4 to 12 m/s). It is obvious that in windier areas, the range of speeds observed is wider, while the share of higher speeds is more significant. The total area encompassed by a curve remains the same for each graph and equals 100% (or 8,760 hours yearly).

Fig. 2.4 Wind speed frequency curves at different average annual values.

Frequency of wind directions shows for how long during a period of time surveyed – a month or a year – winds blew in a particular direction. A correct registration of wind directions plays a very important role in determining the best location to install a wind power converter in the area in question.

Multi-year wind-related data available in the Climate Reference Book [15], demonstrates that there are areas on the Kola Peninsula which reveal certain prevalences in observed wind directions. These areas include, for instance, the northern coast of the peninsula, where southwest winds account for 50% to 60% of yearly winds. A more detailed research of wind directions in this area – 16 wind directions were studied with consideration given not only to direction frequency, but also to average wind speed for every direction – has allowed for a considerable elaboration on the general picture. Attention was specifically paid to the weather stations at Dalniye Zelentsy and Teriberka. Large wind energy potential can be found in localities around these stations. Furthermore, they are located close to the Serebryanka and Teriberka Hydroelectric Power Plants, which are part of the Kola Energy System and which are capable of facilitating large-scale utilization of wind energy resources in this area. Fig. 2.5 shows the wind rose representing data obtained at the Dalniye Zelentzy weather station across a period of several years, as one example. It clearly demonstrates that southwest winds blow for more than six months of the year.

Fig. 2.5 Annual and monthly wind roses at the
Dalniye Zelentsy weather station (data collected from observations of 1975 through 1984).

When analyzing wind direction frequency, it needs to be taken into consideration that, from the point of view of energy efficiency, the importance is placed not so much on the information about which wind directions are prevalent in the area, but on the correct estimation of how much energy value – or potential output – the wind of each particular direction can offer. To assess this value, estimations have been made for the potential output of a wind energy converter on each wind direction, and these estimations have been summarized into corresponding output roses (Fig.2.6). When comparing Figs. 2.5 and 2.6, it becomes obvious that as the graphs for the same months are set against each other in the two pictures, the wind rose and the potential output rose do not have essential differences in their configurations. It means that in the areas observed, prevalent wind directions also have the largest energy capacities.

During the wind direction frequency study, it was also revealed that the wind rose and the factor of prevalence of certain wind directions over others undergo considerable changes depending on the particular season. During the colder months (October through March), southwest winds can account for 70% to 90 % of the time. Winds of these directions have an overwhelming dominance over other winds. The same can be said about energy generation available from winds of these directions (Fig.2.6). During warmer seasons, the picture will alter radically: These dominant winds will become less obvious, or change direction completely, and with a decrease observed in the total wind intensity, the scope of potential energy output will also diminish. The latter is clearly seen in the dimensions of the roses presented in the pictures, which are proportional to the monthly potential energy generation values.

Fig.2.6 Monthly energy output roses, as estimated for the production by a 4 kW wind energy converter in the area surrounding Dalniye Zelentsy.

The presence of prevailing wind directions makes it possible to locate wind energy converters in a particular area in a more space- and cost-efficient way as far as the construction of multi-outfit wind power complexes and stations is concerned. Thus, if in the area surrounding Dalniye Zelentsy, wind energy converters are arranged in several rows at an interval of one single wind wheel diameter, and their facades are adjusted to face the prevailing wind direction, then it will be possible to avoid their blocking, or creating interference with, each other’s wind exposures for 92% of the year. During the winter, this interference-free exposure coefficient can increase to 96% - 97%. Losses in energy output in the case of such compact WEC arrangement are minimal and come to around 6% a year, with their decrease during certain winter months reaching as low as 2.5% to 3%. At the same time, the benefit is apparent when construction of new access roads or cable lines is taken into consideration. This area has definite prospects for the construction of multi-turbine wind parks.