India's first solar housing complex
Gargi Gupta in New Delhi
August 02, 2008
Rajarhat, the new township coming up on the outskirts of Kolkata,
is a series of gated residential colonies, each more high-profile
than the next.
All the big local builders have flagged their presence here, and so
have a number of reputed national ones. But there's one recently
completed development that's truly revolutionary.
This is Rabi Rashmi Abasan, India's first "solar housing complex".
Piloted by the West Bengal Renewable Energy Development Authority
(WBREDA), the 26 villas in this complex are a showcase for the
exciting possibilities that BIPV - building integrated photovoltaic
- technology offers for residential projects of a similar
nature.
BIPV refers to solar panels integrated into the architecture -
mostly into the roof, the facade or the glazing - that convert the
sunlight to which they are exposed through the day into
electricity.
According to Lyn Toh, spokesperson for SunTechnics India, the firm
that supplied the hardware at Rabi Rashmi: "BIPV makes a building
highly energy-efficient and reduces carbon emissions, while
ensuring basic functions of standard building elements, such as
water tightness, light transmittance and thermal insulation."
BIPV is all the rage in the West. Indeed, it makes a lot of sense
in a world that's fast running out of oil and coal - the two,
extremely polluting sources of energy that have powered
industrialisation.
According to S P Gon Choudhuri, director, WBREDA, BIPV constitutes
around 15 per cent of the around 5,000 mega watts of installed
capacity of solar power, and is growing at 50 per cent
annually.
So each house in Rabi Rashmi will generate 2.2 kwh - which will
account for 40 per cent of the power needed to run the standard
household electrical appliances. Whenever these are not being used,
the power generated will be fed into the grid.
In addition, each house has a solar water heating system which is
good enough to supply 100 litres of hot water every day. The design
of the houses uses elements of "solar passive architecture" to keep
the house cool in summer.
Essentially, this means ensuring cross ventilation so that the cool
breeze from the water bodies to the south can circulate through the
house, and making the most of natural light. "The houses are carbon
neutral," says Gon Choudhuri.
BIPV sounds great, but like all good things it has downsides too -
primarily the high cost of installation. As Toh says, "The cost of
an installed BIPV system can vary from $12-20 per watt peak, or
even higher, depending upon the complexities of installation or
type of solar modules. The payback will significantly depend upon
the local utility's willingness to buy the green energy at a
preferential feed-in tariff [the rate at which the power utility
buys the power from the producer]. This is what drives the urban PV
market the world over, and we envisage that it is going to happen
in India as well in the years ahead."
At Rabi Rashmi, the cost of each house - around Rs 45 lakh - was
quite a notch higher than similar developments in the vicinity.
Says Debabrata Dutta who's bought one of the houses, "We were given
an estimate that we were paying about Rs 6 lakh more for all the
BIPV paraphernalia, which was okay because we would be paying far
less for our electricity and recovering the cost in a few
years."
As for maintenance, WBREDA has contracted SunTechnics India and
Mackintosh Burn, the civil contractor for the project, to help the
residents' association for five years.
Given the costs, the maintenance and all that, it takes some amount
of push by government to make people turn to such technologies.
That's been the experience in the West where a number of European
countries, the US and Japan offer financial incentives to encourage
the adoption of BIPV, whether as subsidies on the cost of
installation or as a generous "feed in" tariff.
The West Bengal government's contribution in this regard has been
two-fold. It put in around Rs 50 lakh, which went into the street
lighting, the landscaping and so on. Of the rest of the total
project cost of around Rs 12 crore (Rs 120 million), Rs 11.5 crore
(Rs 115 million) came from the sale of the houses. "In that sense,"
says Gon Chaudhuri, "Rabi Rashmi was a completely commercial
project."
But the government has also stepped in with a feed-in tariff of Rs
5.60 per kilowatt hour, which is the peak slab for domestic power
in the state.
"There is a benefit of Rs 7 per kilowatt hour to the residents,"
the WBREDA director calculates. Incidentally, West Bengal, he adds,
is the only state in the country which allows domestically
generated solar power to be fed into the grid. "No other state
allows this."
But as Lyn Toh of Suntechnics says, "We must realise that switching
to solar is not just about payback. It is also about taking that
all-important first step towards securing your own energy source
and about making a 'green' choice."
Already Gon Choudhuri says DLF and a few local builders have signed
MoUs with WBREDA to build similar houses in the state, and
officials from the Centre and other states are trooping down to
Rajarhat to check out Rabi Rashmi.
http://www.rediff.com/money/2008/aug/02solar.htm