Self-sufficiency in Bengaluru, the solar way

Bengaluru has a massive untapped potential to generate 3.2 GigaWatts of solar power from rooftop installations

Summer, with all its associated extremes, is just round the corner, and the prospect of more intense power cuts looms. But should Bengaluru, a city that gets more than 55% of its power from renewable sources – solar, wind and hydel put together - worry? Is the city’s solar potential rich enough to underline self-sufficiency in the near future?

Sustainability on the energy front has the Bangalore Electricity Supply Company Limited (Bescom) focus on expanding the city’s solar rooftop installations. Under the Soura Gruha Yojane, Bescom has targeted 300 MW of grid-connected solar rooftop plants for individual residential consumers and group housing societies / residents’ welfare associations, exclusively for Bengaluru city.

Bescom Managing Director Rajendra Cholan informs that the process is already on with the commissioning of 705 solar roof top photovoltaic (SRTPV) installations of 16.56 MWp capacity during 2020-21 and 741 SRTPVs in the current year with a capacity of 23.65 MWp.

Targets to achieve

Currently, more than half the power supplied by Bescom for Bengaluru comes from renewable energy, he reiterates. “The 300 MW target for rooftop solar plants will be achieved this financial year. These include both residential and government buildings, plants with 5KW, 10KW capacity. We will identify the vendors. The Centre is giving 40% subsidy. Consumers can directly get in touch with the vendors and install the rooftop plants.”

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The city’s peak power load - residential, industrial and commercial combined – is about 2,500 MW. “This average peak is between 7 and 10 in the morning and from 6 pm to 9 pm. During summer, the peak load could go up to 2,800-3,000MW. More than half of this is now met through renewable sources. We have also struck long-term agreements with wind and solar generators.”

Once the SRTPV installation project is completed, Rajendra says, the city’s LT2 (Low Tension, domestic) and LT3 (commercial) load could almost entirely be covered with solar.

Eco, economic benefits

The advantages of putting up rooftop solar systems have been well established. The benefits are both economic and environmental. On an average, apartments that have installed a rooftop system saves about Rs 1,000 every month for every KiloWatt peak (KWp, electricity generated during peak performance). Experts have estimated that a 5 KWp system equals planting 2,500 trees.

Sustainability is written all over it since solar energy is infinite and freely accessible. Most solar panels currently installed in the city are easy to maintain without any safety hazards.

Awareness gaps

But despite the optimism, Bescom’s attempt to generate 300 MW from rooftop solar projects, as mandated by the Ministry of New Renewable Energy (MNRE) has not been easy going. The public response is still muted, and Bescom has proposed to increase its awareness campaigns.

The Center for Study of Science, Technology and Policy (CSTEP), a leading thinktank, had launched its Rooftop Evaluation of Solar Tool (CREST) in September 2020. This virtual tool enables consumers to gauge the potential of their rooftop to generate solar energy both for their own use, and to supply the excess power to the Bescom grid.

Huge growth potential

CSTEP, informs research scientist Saptak Ghosh, had calculated that Bengaluru city has a potential to generate about 3.2 Giga Watts (GW) of solar power from an estimated 8 lakh rooftops.

“Of this, 6.5 lakh are in the 0 to 10 KWp range, which works out to around 2 GW. The remainder, about 1.2 GW, is in the 10 to 2,000 KWp range, which includes apartment complexes, industries and commercial complexes.”

So, as Saptak points out, the number of rooftop installations that can be put up is huge even if the system size is only about 3 to 10 KWp. But to scale up, a massive publicity campaign is required. Besides, consumers who install it should be convinced that this is financially viable.

Innovative financing

To make it workable, suggests Saptak, some decent financial schemes should be available for the residential consumers on top of the capital subsidy offered by the Centre. “Unless you have some bank or some scheme on, say, 10% interest for 15 years, it becomes a bit arduous in terms of the payback and return on investment for the residential consumers. We are trying to see if there can be any innovation in financing.” Despite the high costs, the medium to big apartments have done reasonably well in installing rooftop systems, notes Vishnu Gattupalli from the Bangalore Apartments Federation (BAF). “About a hundred complexes with 30-40 apartments and even those with the 400-500 apartments have gone for these systems. The savings have also been substantial. For instance, in a complex with 84 apartments, the savings have been in the range of Rs 84,000 to 90,000 on the monthly power bill.”