Windmills are a fascinating sight! A pleasing and placid sight of churning blades against a setting sun is enough to kindle the hearts of all travellers. But seldom do we recognise that a single rotation of the wind blade can churn out power in terms of MW to accelerate the electricity-centric development of mankind. It’s time we explore the Wind Energy technology and their contribution to fight against climate change.
Just like fire and wheels, windmills have carved a niche in the development of mankind. From using windmills to grind corn into flour to groundwater pumping and to 120m tall wind turbines, they have come a long way. So what are the ABC’s of wind energy?
Solar energy has been the main driver of all forms of energy including wind. The uneven heating of air from equator to poles result in wind movement and current throughout the planet.
To state plainly, the kinetic energy of wind is converted to electrical energy. The windmills are erected perpendicular to the wind direction. The smooth shiny blades are the culmination of Mankind’s deep observation and learning from the Birds and fishes! In fact, aeroplane wings and the wind blades are just copies! The exact mechanism by which they both operate is the same – Lift Drag mechanism. There’s a pressure difference beneath and above the blade which makes the air to move towards the upper direction, lifting the blade in the process.
And now comes Michael Faraday from our high school physics with his electromagnetic induction. The slow rotation of the wind turbine is stepped up to thousand times using a gear box. This rotation is used to generate alternating current in the generator and is supplied to the grid.
India has acknowledged the significance of wind energy as it has set a target of 60 GW for wind energy within the year 2022. India has achieved 53% of it’s target as of 2017! India is indeed making good progress but still we need to up the ante to achieve the ultimate goal. We are also bestowed with excellent wind resources. Indeed, India ranks fourth in the list of countries with highest installed wind capacity.
India has had enough of offshore bank accounts. It’s time to switch concentration towards offshore wind energy. Offshore wind energy, despite high costs, paints a rosy picture for the future. The wind speed is high in the water bodies as the wind doesn’t encounter much friction or resistance. This can result in huge increase in power produced. Also, the power produced is directly proportional the the cube of wind velocity. So if wind velocity doubles, then wind power generated is eight times more. The coastlines of Rameshwaram, Kanyakumari in Tamil Nadu and the coastlines of Gujarat have a potential of more than 1 GW each. But still, technology and policy issues persist. If we could find a way past it, then the 2022 target can be achieved effortlessly.
Wind energy in Tamil Nadu
A report by The Institute for Energy Economics and Financial Analysis (IEEFA) shows that Tamil Nadu is capable of doubling its’ wind energy capacity by 2022 (7.5 GW at present) and raising its solar capacity by 6 fold. But TN’s plan of building thermal power plants of nearly double its present capacity to 22.5 GW is seen as a retrograde move. The officials cite the variable nature of wind as the reason for expanding fossil-based power plants. The solution lies in hybrids – combining all renewables. Already, the solar wind hybrid power plants are ruling roost which can produce maximum possible amount out of available land. Talks for combining wind and hydroelectricity are also doing rounds. During low demand period, the power produced from wind is used to pump water to higher level reservoirs. When demand rises, this water is released to run hydro power plants which can supply constant base load power!
Research & Development
R&D works have resulted in lighter, stronger, low cost wind turbines. There is nothing to wonder if there are 200m tall wind turbines in the future. Bladeless wind turbines are here too! They harness electricity from the vibrational motion of a cylinder due to the vortex in air.
There are also vertical axis wind turbines which can run from wind from any direction! This is unlike the usual windmills which are aligned in the most probable wind direction. These vertical axis windmills are increasingly being used in small applications along with solar panels.
Savonius and solar
Imagine a highway in which the whole length of the divider is fitted with these turbines which can produce power due to the fast moving vehicles!
And thus to conclude, Sustainability is in the air.. Wind turbines are wands which can draw power out of thin air! And we need hell a lot of these in the near future. We’ll look further in the forthcoming series…
(This article was originally published as a part of series ‘SUSTAINABLE ENERGY- FOR INDIA’S ENERGY SECURITY’ in ‘The Agraria’ e-Magazine. You can Subscribe it here)