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24ВЕТРОЭНЕРГЕТИКА
WIND ENERGY
Статья поступила в редакцию 28.12.12. Ред. рег. № 1490 The article has entered in publishing office 28.12.12. Ed. reg. No. 1490
УДК 621.311.24
ВЕРТИКАЛЬНО-ОСЕВЫЕ ВЕТРОВЫЕ ТУРБИНЫ. НОВЫЕ АСПЕКТЫ
И.М. Кирпичникова, А.С. Мартьянов, Е.В. Соломин
Южно-Уральский государственный университет 454080 Челябинск, пр. Ленина, д. 76 Тел.: (351) 263-58-82, факс: (351) 267-98-94; e-mail: [email protected]
Заключение совета рецензентов: 10.01.13 Заключение совета экспертов: 15.01.13 Принято к публикации: 22.01.13
В статье рассматриваются возможности применения многоуровневой вертикально-осевой ветровой турбины на вышках сотовой связи. Исследование было проведено учеными Южно-Уральского государственного университета.
Ключевые слова: возобновляемая энергия, «зеленая» энергия, ветровая энергия.
VERTICAL AXIS WIND TURBINES. NEW ASPECTS
I.M. Kirpichnikova, A.S. Martyanov, E.V. Solomin
South Ural State University 76 Lenin ave., Chelyabinsk, 454080, Russia Tel.: (351) 263-58-82, fax: (351) 264-76-94, e-mail: [email protected]
Referred: 10.01.13 Expertise: 15.01.13 Accepted: 22.01.13
The article describes the possible application of multi-tier vertical axis wind turbine on cell towers. The research is made by Russian scientists of South Ural State University.
Keywords: renewable energy, green energy, wind power.
We already mentioned the advantages of Vertical Axis Wind Turbines (VAWT) especially in Cell Tower applications. The recent project in multi-tier turbines currently running at South Ural State University, has shown that these assemblies could be based on Cell Towers threading the tiers without adding extra structures (mast/tower, alternator and even bearings in some cases), which reduces significantly the total cost of installation.
The global addressable market for cell tower lease revenue is over $90 billion per year. In North America, the total opportunity for cell-site leased revenue is over $20 billion based on 2011.
There are lots of opportunities throughout the Asia Pacific region. However, India and China are most interesting due to the strong growth in both countries and over 1.2 billion combined subscribers. Most operators do not rely on third-party companies to manage their cell sites except in India. India is the second largest market in terms of cell-site lease revenue, but No.1 in terms of total sites managed. There were over 250,000 sites managed in India in 2011/2012 and cell-site revenues are forecast to reach $4 billion. The average revenue per tower is approximately $14,000 per year [1]. Telecom Towers Market In India per local research on 2011 is in [9].
Международный научный журнал «Альтернативная энергетика и экология» № 01/2 (118) 2013 © Научно-технический центр «TATA», 2013
There are approximately 137,000 cell sites across African continent.
American Mobile Tower (AMT) [2] leases over 27,000 cell phone towers to wireless service providers, including Verizon Communications (VZ) [3], Sprint Nextel (S) [4] and AT&T (T) [5]. It operates over 20,000 wireless towers in the U.S. and has an additional 7,000 in Mexico, Brazil, and India. With a US market share over 40%, the company is one of the largest wireless tower operators in the country, just behind leader Crown Castle International (CCI) [6]. As of June 2011, there were 288 million cell phone subscribers in the United States, 79 million in Mexico, over 160 million in Brazil, and 430 million in India. The large international subscribers represent a large growth opportunity for American Mobile Towers (AMT), as the US wireless market is now mature with a penetration of over 90% [7].
During 2011, the Russian Federation put into operation 790 cellular towers and antenna-mast structures for cellular communication [8].
Mobile operators around the world are moving to innovative business models in order to focus their capital spending on the most lucrative areas of network development. Over the past ten years, India and the United States have established clear trends toward independent ownership of tower sites, with leasing arrangements for multiple operators on each tower. Other countries are following this example, and in some cases moving farther into sharing site infrastructure such as backup power generation and backhaul. Radio Access Network sharing has become a good option for many carriers with even higher capital savings for participating operators [10].
Crown Castle International [6] is the largest cell phone tower company in the U.S. It leases antenna space on it over 25,000 towers to wireless service providers, including [3 and 4], Alltel, and [5]. In light of its 2006 merger with Global Signal, the company is has slightly more towers than its top competitor, AMT [7]. As the company's US wireless market matures with a penetration near 75%, domestic growth may slow down, and become increasingly dependent on selling more cell phones per capita and additional services (which take extra bandwidth on towers). The company has announced interests in entering cell phone markets in emerging economies, particularly India, which is one of the fastest growing and largest in the world [6].
In a whitepaper entitled Mobile Tower Sharing and Outsourcing: Benefits and Challenges for Developing Market Operators, Romain Delavenne, director of Capgemini's telecoms, media and entertainment consulting practice in the Middle East, reveals that towers constitute almost 50 per cent of the total capital expenditure (CAPEX) for an operator. Yet while many operators in developed markets have moved on to sharing both active and passive network elements to save costs, in emerging markets with low penetration levels, operators are faced with the dual challenge of
maintaining margins, while ensuring rapid rollout to keep pace with the growth in subscriber numbers [9].
A significant amount of engineering is required to develop a tower that will support a windmill [11]. Since the cost of the tower is directly related to the calculated wind loads placed upon the tower, it is very unlikely that an existing communication tower could be retrofitted with wind turbines of any significant size, without exceeding the wind load specifications for that tower. Therefore the most cost efficient approach is to incorporate wind and solar power into new towers that have been designed to support wind, solar and communications antennas on the same towers.
The second most cost efficient approach is to select a specific version of a tower, where many of the exact same type have been installed, and undertake the engineering task to retrofit wind and/or solar equipment to these towers. The general idea being to spread the cost of engineering and retrofit kitting across a large number of units, however without study and specific information, it is not possible to determine if this approach will be cost effective.
The third approach is to assume that the wind and/or solar power will be installed on an independent tower. While this avoids reworking existing towers, the cost of the tower and foundation represents approximately 65% to 80% of the total system cost. While it may be economically feasible to support existing communication towers using this approach, it is far less cost effective than an integrated tower that supports wind, solar and communications on the same tower.
The assumption is made that potential customer which owns/uses cell towers is unlikely to find a company that has already designed, tested, tooled up and manufactured components that exactly meet his requirements. Therefore, it will be necessary to develop solutions specific to his needs. This includes engineering and development costs, with associated development schedules.
Since we have been working on similar solutions, we have many of the components developed, so we are likely to provide a shorter time line, at a lower cost than other alternatives.
Technology approach: The top of a communication tower is reserved for the antenna.
In addition to the mounting advantages shown above, the location of the tower is determined by the needs of the telecommunications company, not by the wind resource. As such many of the towers will be located in locations with modest and variable wind resources. The cell tower based VAWT's should be designed with these wind resources in mind (Fig. 1).
The lift design or H-Darrius type of VAWT is capable of efficiency comparable to small HAWT's. Below is shown the multi-tier design of VAWT (Fig. 2). The tires can be threaded on the tower as sandwiches. The 3D models shown with the rings and without, are almost identical from the aerodynamic modeling point of view.
International Scientific Journal for Alternative Energy and Ecology № 01/2 (118) 2013
© Scientific Technical Centre «TATA», 2013
И.М. Кирпичникова, А.С. Мартьянов, Е.В. Соломин. Вертикально-осевые ветровые турбины. Новые аспекты
Рис. 1. Вышки сотовой связи и возможность установки вертикально-осевых ВЭУ Fig. 1. Communication tower and possible installation of VAWT
Рис. 2. 3D модели различной конфигурации ярусов роторов вертикально-осевых ВЭУ Fig. 2. VAWT 3D models of different configuration of rotor tiers
To develop the idea of placing the windmill on the cell tower it is required to make some analysis of what is available.
For now we have the air foils and basic multi-tier turbine design. To install the turbine on the tower it is needed to accomplish the following:
- Increase the power level to meet specific requirements.
- Increase the diameter of the assembly to allow the tower structure to pass through.
- Provide cable access for the antennas.
- Design a turbine that can be maintained without disassembly of the tower.
- Develop a manufacturing process to make the units cost effective.
Advantages of the multi-tier, VAWT design:
- Omni directional: It doesn't matter compass heading the wind comes from, and it doesn't matter how rapidly it changes direction, turbine still takes power from the wind. Unlike HAWT, there is no requirement for the windmill to yaw or "seek" the wind direction, therefore we have eliminated the expensive and unreliable mechanics related to pointing the windmill.
- The VAWT acts as a flywheel, picking up some speed in wind gusts and continuing to rotate in the short periods of low wind, this provides a smooth, steady, quiet motion eliminating noise, and reducing energy losses of starting and stopping. Vibrations in the mounting structure are reduced, while the flywheel effect gives a more constant voltage output to the electronics.
- On cell towers, the ideal location for the antennas is at the top of the structure, the VAWT can be adapted to allow the tower structure to support the middle of the windmill, while allowing necessary power and RF cables to pass thru undisturbed.
- Since a primary cost factor in windmills is the foundation and the tower, new integrated towers get the bonus of low cost renewable energy without having to pay for a second tower.
- The VAWT can be at any height on the tower as long as it is in the wind, various designs are possible to adapt to available tower constructions. It is possible to stack multiple turbines on the same tower to increase power output, if the tower can support the turbines.
- Since cell towers are located basis of radio coverage and real estate availability, wind resources are a lower priority. The SRCV VAWT was designed for use in relatively low wind conditions. In low wind areas, most likely to be found where most cell towers are located, the Omni directional feature of the VAWT will generate 2-2.5 times more power from the low wind resources available than a HAWT of the same size, however since the blades of the turbine are of constant cross section, it is relatively low cost to increase the turbine size to adapt to lower wind speed conditions, providing more power for at a lower cost.
- The alternator can be one for each tier or shared between tiers.
- The control system is combined for all layers of rotor.
Международный научный журнал «Альтернативная энергетика и экология» № 01/2 (118) 2013 © Научно-технический центр «TATA», 2013
Conclusion: vertical axis wind turbines have a good potential to have a great performance and efficiency on Cell Towers application, in wide range of wind speed, and still promises to occupy a large place in the market.
The article is made under the Agreement 14.B37.21.1226 of 14.09.2012 between South Ural State University and RF Ministry of Science and Education (1 stage).
References
1. RC Wrwireless http://www.rcrwireless.com/ article/20100305/25years/international-markets-remain-untapped-potential-for-tower-companies/.
2. New York Stock Exchange: AMT / http://www. wikinvest.com/wiki/New_York_Stock_Exchange.
3. Verizon Communications (VZ) / http://www. wikinvest.com/wiki/Verizon_Communications_(VZ).
4. Sprint Nextel (S) / http://www.wikinvest.com/ wiki/Sprint_Nextel_(S).
5. AT&T (T) / http://www.wikinvest.com/wiki/AT%26T_(T).
6. Crown Castle International (CCI) / http://www.wikinvest.com/wiki/Crown_Castle_Internati onal_(CCI).
7. American Towers / http://www.wikinvest.com/ stock/American_Tower_(AMT).
8. Researc Handmarkets / http: //www.researchandmarkets. com/reports/1311592/ russian_market_of_ bearings_ and_communication.
9. Research Telecom / http://www.slideshare.net/ResearchOnIndia/telecom-towers-market-in-india-2010-sample and http://www.telecoms.com/16089/tower-sharing-offers-opportunities-for-emerging-markets/.
10. Abi Research http://www.abiresearch.com/research/1003808-Mobile+Network+Towers+and+Rooftop+Sites.
11. Martinez-Cesena E.A. and Mutale J. Wind Power Projects Planning Considering Real Options for the Wind Resource Assessment // IEEE Trans. Sustain. Energy. 2012. Vol. 3, No. 1. P. 158-166.
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International Scientific Journal for Alternative Energy and Ecology № 01/2 (118) 2013
© Scientific Technical Centre «TATA», 2013
