Recently IIT Bombay along with 5 other organizations released a rooftop solar potential report for Mumbai saying that it could generate 1720 MW of solar power which is 50% of its peak consumption of 3200 MW. I think this is a huge underestimation. The methodologies used by IIT Bombay are too hackneyed in my view and miss the larger picture of the potential. They focus too much on rooftop structures, shading etc. without considering the effect of new technologies and improvements in existing solar equipment. They have not considered the huge impact that solar energy storage will have on the energy landscape where solar plus storage becomes cheaper than retail electricity prices and completely do away with the cumbersome distribution utility related paperwork and approvals required for net metering. They also do not consider the effect of cheap lightweight modules and improving solar cell efficiency which could make almost any structure support solar equipment. They also do not consider the effect of very cheap solar power (INR 2-3 /kWh) which could itself expand the total amount of electricity requirements of Mumbai.
Read about Various Components of Rooftop Solar
As solar energy becomes much cheaper than every other energy source, it will increase the total energy requirements of the citizens and industries as demand elasticity kicks in. There will also be a shift from the use of other energy sources to electricity generated by solar power which becomes much cheaper than traditional fuels like biomass and natural gas.
While some of the recommendations of the report are good from the immediate sense, the long-term potential of Mumbai in my view is much higher than what is being predicted in the report. Use of government building rooftops to push solar energy is indeed a good recommendation as the government will not face red tape and lethargy from other government departments. Getting finance and rooftop rights is also much easier for government buildings. On top of it all, its also makes economic sense for the government to reduce its power bill by going solarGoogle+