Monday, September 1, 2014

Wind energy-going above 200m

The current scenario:

Wind energy, the so called future of energy, has been growing at the rate, incomparable with other sources of energy. Total installed capacity of the segment has crossed the mark of 20GW. It remains one of the lead sources of generation in fleet of Renewable energy. Sector has seen a growth rate of double digits. Renewable energy is contributing a share of 12% in the Generation portfolio of India, lagging behind hydro by a mere 6% or so. For a country like India, where cost of electricity remains not just an issue of investment and growth but can even leads to change of government. Wind Energy seems to be a potential solution provider to our energy problem. National policies and state government policies have been favouring the development of wind energy. Foreign investment clubbed with the business calibre of local players has also added boost to the development of it.

But the picture doesn’t remain brighter throughout. There is another side of it, which is matter of concern for the power sector. The total quantum of units generated by a wind turbine remains low. Capacity utilization factor (CUF) barely touches an average of 22%, whereas a national average for a conventional coal based plant hovers around 70 %( Both figures are for Indian geographical conditions). Such data clearly speaks of the inability of the wind to meet the growing demand of World’s population. Reasons that attribute to such low generation are exogenous in nature and can’t be governed. Seasonal flow of winds and whimsy nature of wind makes it unreliable in a large power system, like that of India.

There have been few proposed solutions to this problem, one of which includes having a higher tower height for the turbine. The idea proposed behind this approach, is to tap the higher and consistent wind velocity present in the higher layer of atmosphere. Air turbulence remains low, as the altitude goes high. The average height of a wind turbine remains around 100m, and at this altitude wind blows with an average speed of 6-9m/s. also the nature of such wind remains inconsistent and this takes away the reliability factor from wind power. Also it involves huge cost and complex engineering to erect high towers and thereafter mounting hub on it. This raises the cost of wind turbine from a national average of INR 6 Crores (USD 1 mn, 1USD =INR 60) to a higher economically unfeasible.  But that doesn’t stop engineers from engineering a viable solution.

Solution:

One such possible solution emerges from the bright minds of the west, Corwin Hardham, Don Montague, and Saul Griffith formed Makani Power in USA, and their airborne turbine seems to be providing a technically and economically feasible solution. Engineered in an unorthodox manner, the turbine is actually a set of small turbines mounted over a kite, the kite which is tethered to a ground station, is capable of transferring power from the tower to the ground station through the tether itself. This technology seems quite attractive in terms of finance involved and hassles removed. Since the kite is tethered to a moveable ground station, it can be easily moved within the region, to tap the maximum potential. Not just this, but also it utilizes the wind’s kinetic energy at an altitude of 200 - 400m. The technology will help the wind energy developers to avoid hurdles like:

·         Land acquisition
·         Whimsical wind flow
·         Poor CUF
·         Reaching higher heights
·         High costs of tower erection etc.

The kite is controlled by a controller that monitors the real time data of wind velocity and other weather related parameters. Size of the turbine has been somewhat lower than tower mounted turbines, 400-500KW compared to 1-2.5 MW on a global average. But that too remains an area of development along with many others, for team at Makani Power. Just like other start ups acquired by bigger market players, Makani Power too has been acquired by Google in 2013. That would help Makani in funding its research work and continuing forward in the direction of wind turbine development. Innovation just doesn’t stop at one milestone, but it keeps modifying it forms and covers milestones. Similar airborne turbine called as The Buoyant Air Turbine (BAT) has been developed by Altaeros Energies, founded in 2010 at MIT, USA. Their concept involves a helium filled shell which has a turbine in its hollow centre; the helium filled shell easily reaches a height of more than 500m and channels the wind through the turbine. Energy generated is transferred through the tether.  The benefits of BAT remain more or less similar to that of turbines developed by Makani Power. And moreover both the technology avoids the high cost of tower erection and land acquisition.


Approach used by both the technologies involves tapping of air potential at higher altitude and providing mobility to the generator. This concept has been put to use in many parts of USA and Europe. For a country like ours, where land acquisition has remained an issue, and availability of finance to adopt new technology doesn’t exist, it remains an opportunity untouched to bring in this technology and end our power crisis. We have grown mature enough in the global world, and adopting new technologies has been one of the targets. I don’t see any hindrance or bounds that would prevent adoption of such technology in India. So it remains just a matter of time that it would take to enrich the share of wind energy in our energy mix. A cleaner and cheaper energy is all that would help us in reaching one of the Millennium Development Goals as well.


Fig 1. Turbine developed by Makani Power



Fig 2: Trajectory traced by Makani’s  turbine



Fig 3: The Buoyant Air Turbine(BAT)

    
                                   By
          InfralineEnergy Power Knowledgebase Team






Bibliography

1.     Makani Power - http://www.google.com/makani/
2.     Altaeros energies - http://www.altaerosenergies.com/index.html



Disclaimer:

The views expressed here are solely those of the author in his private capacity and do not in any way represent the views of the Infraline Technologies (India) Pvt. Ltd. (organization). The organization is not liable for any use that may be made of the information contained therein and any direct/indirect consequences resulting therefrom



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