19 June 2015 14:33:42 IST

Living in solar’s shadow

It is now all ‘solar, solar’; but wind is still a major part of India, and the world’s, renewable energy

Along comes a newer technology, and the first is banished to a corner.

For the Indian clean energy business, ‘solar’ is the younger, dashing tech … and flavour of the day. Solar gets all the attention, adulation and money. So, what’s gotten lost in the hullabaloo about solar?

Wind energy. Been around for long, sheet-anchored the renewable energy movement in India, helped many make money, but in the clean energy discourses in the recent years, ‘wind’ is, at best, a footnote. It is now all ‘solar, solar’.

Not fair? Windmills have been spinning themselves crazy to give us electricity since the early 1990s. India’s renewable energy capacity today stands at 35,800 MW - of which 23,500 MW is wind.

Old, it may be, but no less significant. ‘Wind’ is a major part of India’s, as well as the global, renewable energy scene. In 2014, the world added 128,000 MW of renewable power capacity, of which 37 per cent - the highest - was ‘wind’. Solar came second, at 32 per cent. (By the way, the 128,000 MW itself was 45 per cent of all power capacity that came up in 2014 - an example of the growing importance of renewable energy.)

Wind power is today in solar’s shadow, but don’t discount its value. To get to know wind well might be useful, because there is a lot of scope for activity in ‘wind’.

Wind is highly technology-intensive. It embraces various branches of engineering - mechanical, electrical, electronic, material and aerodynamics. Some of you who might have seen wind mills from a distance might be surprised to know that the ‘box’ that sits on the top of the tower is as big as a bus. You could even plan a small holiday up there, but be warned that the box - called a ‘nacelle’ - is very cramped, as it is full of machines. Mainly, there is the big turbine-generator that produces power by converting the kinetic energy of the wind to (first mechanical, and then) electrical energy. Then there are also machines to make the windmill turn around so that the blades catch as much wind as possible, machines that turn the blades so as to make them spin faster, slower or stop, and machines that re-set the electrical energy to the kind that our home appliances need.

All these machines make the nacelle heavy. For example, the nacelle of a 2 MW windmill made by the Spanish company, Gamesa, weighs 70 tonnes, or as much as 95 Maruti Alto cars. Imagine 95 Maruti Altos compressed into one single block and made to sit on a tubular tower - that’s just one example of the technological intensity of windmills. The German company, Siemens, makes a monster machine - a 6MW turbine. The nacelle weighs 360 tonnes, (486 Maruti Altos!). Each of its three blades is one-and-half times longer than the 100-metre sprint track. When these blades spin, the area they sweep is so big that you can fit three football fields into it.

Wind power is also very R&D-heavy. Research is going on all over the world on how to make these machines produce more electricity at even less windy sites. Basically, the higher you go, the longer the blades can be and more wind the blades can catch — so the aim is to make bigger turbines and put them on higher towers. Since land is scarce, and since moving very long objects such as blades by road is very costly and since there is more wind blowing on the seas, more and more windmills are now being put up in the seas. Some of them stand on the sea bed, while others can be towed to wherever there is more wind.

Today, a large windmill stands 100-120 metres high, and they are getting even taller because ‘the higher you go, the stronger are the winds’. There are even attempts to lift a nacelle twice or thrice, or even six times that size, using helium-filled balloons, to generate electricity up there and cable it down.

Wind is also more productive than solar. One MW of on-land wind can produce typically 2.4 million units a year, though some outliers can do even up to 3 million units. In contrast, you’d be lucky to get 1.7 million units out of 1 MW of solar capacity. Today, it costs roughly ₹7 crore to set up 1 MW of solar; wind is marginally lesser. Solar needs at least 5 acres of land per MW of capacity, wind needs about a fifth of that.

The wind energy sector is also terribly important because the government has thrown its weight behind it. India has been adding between 1,500 MW and 3,000 MW a year, but Power Minister Piyush Goyal has told industry he wants it to ramp up capacity additions, so as to reach 10,000 MW a year from 2019.

Now, that is not easy. There are problems: Land, finance, manpower, manufacturing capacity, logistics, building transmission lines to move the electricity to consuming centres….But then, where there are problems, there are challenges… and opportunities too.

Wind has its own typical problems. Wind projects cannot be put up just anywhere; it requires careful ‘siting’ based on wind flows. The machines are generally noisy, going rrrrrrr-ing all the time! But more importantly, wind power is fickle. It comes on when the wind blows, and goes off when wind stops. Now, how can you run an electricity distribution company with such an ‘infirm’ power?

But like we noted earlier, wind has its merits … and we need to find ways to get around the problems. Like we said, wind power still comes first in renewable power generation … and solar is still catching up.