21 May 2015 14:22:58 IST

Why solar matters

It’s clean, easy to install and costs are going to come down

A little more about solar, before we take a break and talk about other clean tech stuff (climate change, wind, new energy and so on).

We sure get a lot of sun upon us, but the trick is to convert the light (sometimes, heat) energy into electricity. Solar panels — the crystalline silicon and thin film that we discussed in the previous section — convert only a small portion of the light energy falling on them into useful electricity.

As we speak, the industry norm is 17 per cent, that is, solar panels convert (only) 17 per cent of sunlight falling on them into electricity. The rest is lost. Obviously, the amount of sun’s energy not converted into electricity is no big loss at all, but if you are able to get your solar panels produce more electricity, you get a bigger bang for your buck, right? That is why, all over the world, solar panel manufacturing companies are spending billions of dollars into research on improving ‘efficiency’.

Scramble for efficiency

Practically, not a day passes without a solar company coming up with an announcement that it has set a new record in efficiency. The highest so far is from the Germany-based Fraunhofer Institute, which said in September that its cells could convert 46 per cent of sun’s light energy falling on them into electricity.

Of course, when the cells are made into modules, the efficiency level will come down by a couple of percentage points, but still 46 per cent is kind of a dream number.

What I would like to stress here is that ‘efficiency’ is a major area of research going on in the solar world. For sure, breakthroughs will be achieved, and costs are bound to come down. Solar power costs will come down also because research is going on in other areas, such as manufacture of polysilicon, with which the crystalline silicon cells and modules are made (thin film, of course, does not need polysilicon).

Fall in costs

All this research is expected to result in a sharp fall in solar costs in the next 4-5 years. Solar costs are already falling. In November 2014, a Saudi Arabia-based company called ACWA Power bid and won a 100 MW solar project in Dubai, quoting a tariff of $5.89 dollar cents, which translates to ₹3.74 a kWhr. Solar power at ₹3.74 a unit is like “wow”. (It might interest you to know that the President and CEO of ACWA Power is an Indian called Paddy Padmanabhan — we Indians are known all over the world for our ability to design least cost products. Some of you might know that Carlos Ghosn, the iconic CEO of Nissan and Renault, has credited India with “frugal engineering”.)

So, in sum, solar costs will come down, because of a number of factors — economies of scale (when you produce something in huge quantities, you produce it cheaper), research into cell efficiency and research into manufacturing technology, cheaper financing that will happen when financiers become more familiar and more comfortable with solar.

Rooftop panels

Now, let’s move aside to a slightly different aspect of solar — the rooftops. Up till now we have been talking about large solar plants, spread across acres of land, or “utility-scale solar plants”. But what’s equally important, if not more, are the rooftop solar plants, which you see on the roofs of some buildings, such as office complexes, hotels, shopping malls and even some residential buildings.

The rooftops are very important because they constitute what is called the ‘distributed generation’ infrastructure. Electricity is generated right where it is consumed. All over the world, particularly in Western Europe, rooftop plants are ubiquitous due to a variety of reasons, but mainly because the governments have made it attractive for people to put up solar panels on their roofs.

It would be great if that happens in India also, but we have (as always?) our own peculiar set of problems.

Indian scenario

In India, the roofs are typically flat and they are very useful space. We use our roofs to dry clothes, dry foodstuffs and pickles, even hold moonlight dinners. For commercial establishments such as hotels and shopping malls, the roofs are even more needed because they put their outdoor AC units on the roofs, or spread out an open-air cafeteria there.

Since the roofs are so actively used, people are not ready to sign off their roofs to solar plants. Further, since residential tariffs are so subsidised, people do not find solar power attractive, even with the financial support that the governments give.

But where rooftops are catching up in India are the factories. Many factories have large, high roofs and find it worthwhile to put up solar plants. The power the solar plants produce are rarely enough to support the production activity in the factories, but still whatever the solar plants produce helps in bringing down the overall energy costs.

To give an illustration for the ‘rooftop solar’ story, last year India added 1,112 MW of large solar plants, but only 60 MW of rooftops.

However, don’t write off the rooftops yet. As and when solar costs dip and the governments raise the cost of electricity, people will find rooftops attractive.

Global warming

In the last three sections, you must have got to know the basic stuff about solar and got a glimpse of what is happening in India. But why is solar so important, not just in India, but all over the world? We very urgently need energy derived from clean sources, as opposed to ‘dirty’ sources such as coal, oil and natural gas. We need clean energy not only to breathe clean air, but also to defuse the ticking time bomb called ‘global warming’.

Global warming and its consequence climate change are looming over our heads and if we don’t do something about them urgently we are in for, literally, an unmitigated disaster.

So, in the next couple of sections, we will discuss global warming and climate change.