Following our coverage of both solar and wind solutions, Cypress Midwest, a division of PAK Energy, sent me information on their version of a vertical wind turbine solution that is designed for cell sites.
According to Juha Rouvinen, president of Cypress, the system is already being deployed with telecoms operators in Scandinavia and will soon be installed in the US cell sites with both on and off-grid locations. The company is also testing the solution with Ericsson in Africa on hybrid sites.
“We currently have 8 turbines units in Finland being tested with various Telephone companies and number of other units being installed both in Scandinavia as well as the US. Also we shipped one unit for Ericsson in Ethiopia which is being installed within the next few weeks,” he said. The operators currently testing the solution include Elisa Oyj, who have two sites in Finland, TeliaSonera, and Finnet.
From the technical specifications provided by Cypress, the solution seems capable of supply both GSM and WCDMA sites. Rate power for the system is 2,000 W, with peak power at up to 6,000 W, which should be more than enough for the latest GSM and WCDMA systems with site power requirements that go as low as 300 W (Nokia targets for 2010). The system boasts a start wind speed of 3 meters per second (10.8 km per hour) and rated wind speed of 15 m/s (54 km/h). However, it has a maximum wind speed support of 50 m/s (180 km/h), which means it might have trouble operating during typhoons in places like Hong Kong (3 this year so far with winds that can reach over 200 km/h).
The system also includes a Hybrid Power Controller that acts as a router for energy from the turbine to the BTS equipment. The controller also funnels extra power to battery storage systems or, when the wind isn’t blowing channels power from the battery, on-site diesel generation, or grid connections to power the equipment.
According to the company, it is easy to maintain and works in extreme temperature and weather (see wind speed above).
My first impression is that it looks like a pretty elegant solution but it would depend on how it gets integrated into cell sites. The size of the turbine itself is quite large at 4 metres in height with a diameter of 1.3 metres. So far the photos from the company seem to indicate deployments on dedicated towers that can accommodate the height – although I see no reason why it can’t be installed on its own on rooftops. Also, it’s efficiency at generating power at low wind speeds might limit its application. To generate 400 W of power, you need at least 28.8 km/h winds. While it gets more efficient as wind speeds growth (43.2 km/h winds gives you 1200 W), lower wind speeds yield very limited power (21.6 km/h winds give you just 200 W).
Rouvinen asserts however: “We have been able to achieve around 1 – 1.5 kWh pretty consistently with wind speed averaging around 7-8 m/s. Our cut in wind speed is around 4 m/s and we achieve +2kW around 13-14 m/s. In a 3G or 4G cell towers and fairly wind optimized locations, we are able to power the entire cell site or at a minimum reduce sites operating expenses tremendously.”
According to Rouvinen, ROI for the system can be as short as 1.5 years.
“Depending on the system being used but here are two examples: Off-grid locations as low as 1.5 years,” he explained.
The solution is applicable in the following deployment scenarios he said:
a) Off-grid telecom towers (developed world market)
While one application is dedicated to provide clean, renewable power to grid-connected telecom towers, other markets exist with potentially larger societal impacts. One of these situations is the power supply for off-grid telecom towers in the United States and other developed countries. Through the wide-scale implementation of the proposed wind turbine systems, it will be possible to install towers in regions that do not currently have grid connection. The obvious candidates are rural locations, in particular, towers that are installed along roadways which are not collocated with the electrical grid. This capability will speed the construction of continuous telecommunication connections for motorists in transit.
b) Off-grid telecom towers (developing world market)
Perhaps the largest societal impact will be made by applying the present turbine system to power telecom towers in regions of the world without access to a reliable electric grid. In many situations, successful operation of the cell phone towers requires back-up diesel generation to supply power when the electric grid is not in service. In other cases, telecom towers are located where no grid is available so that the totality of electric power is delivered by diesel generation. For diesel-powered towers, the return on investment with the proposed system is very short (1.5 years), a consequence of very high diesel costs.
In addition to lowering operating costs associated with telecom towers, the proposed wind turbine system would allow expanded telecommunication coverage in many areas world wide. The expansion of coverage would increase communication, spur economic development, contribute to social stability, and improve human health. These associated benefits are a significant motivation for the implementation of wind-powered towers around the globe.