The above-discussed case is based on the recent population figures and the water demand has not
considered to be completely met. Similar estimates can be obtained for the projections on potable
water requirements in future (2021) for 26 million Delhi inhabitants – the local government utilities
and authorities have estimated this as 5.2 million m3/day (DJB, 2004). The energy required for the
production of this amount of potable water will be 0.26 106 kWh/day. Similar amount of energy
will be required for the treatment of resulting wastewater for the safe discharge in freshwater environment.
The total energy requirement of Delhi’s water supply would be 2.6 106 kWh/day, which
is still a small fraction of total energy supply. This shows that the energy requirements for water distribution,
drinking water and wastewater treatments, both in current and future scenarios, are small
as compared to the main sectors of energy demand in Delhi. The energy demands of public water sector
in other megacities may not be compared due to different geography and therefore pumpingenergy requirement. However, the energy demand of water and treatment would be similar or higher
if higher quality of treatment is sought due to local regulations or economic status. For example,
approximately 4% and 2.5% of national energy in USA is consumed by the public water supply and sewerage,
respectively, with relatively larger variation among USA cities (Raucher et al., 2008). No water
sector energy audit has been carried out for Delhi and the exact water distribution/pumping/sewerage
data is unknown, but this appears to be currently much lower than large cities of developed countries.
The possible reasons are the water consumption habits of Delhi’s population are very different as compared
to inhabitants in developed countries, and demand has not met in Delhi which has continuously
been facing the problem of water supply (Mehta et al., 2014).