Rabi Rashmi Abasan in
Rajarhat showcases how ordinary householders can harness the energy of
the sun. Gargi Gupta gives a low-down of the project.
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 11.5 crore 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.
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