New Delhi: Every degree rise in heat index resulted in 187 megawatt increase in electricity demand during COVID-19 lockdown, which was six per cent higher than in 2019, according to a new analysis. The analysis by Centre for Science and Environment (CSE) was on electricity demand and its correlation with weather data during the successive stages of lockdown in Delhi.
The analysis stated that this trend was largely driven by heat stress and cooling demand in the residential sector.
It said that the overall level of electricity demand reduced during hard lockdown but with partial unlocking and even with much lower level of economic activities, heat wave combined with thermal discomfort in poorly designed buildings spiked the peak demand again - taking it quite close to the peaks of previous summers.
"Higher heat stress this summer combined with thermal discomfort in poorly designed buildings and increased dependence on air conditioning upset the energy budget. Every degree rise in heat index resulted in 187 MW increase in electricity demand during lockdown- 6 per cent higher than in 2019," says the CSE analysis.
Anumita Roychowdhury, executive director-research and advocacy, CSE, said understanding this connection is critical as climate change will increase the frequency and intensity of heatwaves in the future.
"If built environment is not designed for thermal comfort, heat stress will increase cooling demand and use of energy-intensive mechanical cooling systems, thus undoing the carbon savings from other energy efficiency measures," she said.
Roychowdhury says that according to the World Energy Outlook of the International Energy Agency, cities account for nearly 70 per cent of the global consumption of electricity.
In its study, CSE carried out a rapid analysis of real-time electricity demand during the lockdown and unlocking phases in Delhi.
It accessed real-time electricity consumption data of 5-minute granularity from the State Load Dispatch Centre in Delhi, the apex body responsible for integrated operations of Delhi's power system, the CSE said in a statement.
The analysis has considered the time slots such as Pre-lockdown from January 1 to March 21, lockdown 1.0 - March 22 to April 14, lockdown 2.0 - April 15 to May 3, lockdown 3.0 - May 4 to May 17, lockdown 4.0 - May 18 to May 31.
Also, Unlock 1.0 -June 1-30 and Unlock 2.0 - July 1-30.
As per Avikal Somvanshi, programme manager with CSE's Urban Data Analytic Lab, "Delhi is a big energy guzzler and makes an important case study".
"CSE's earlier analysis in 2018 and 2019 had found that Delhi's peak electricity demand was consistently higher than Mumbai, Kolkata and Chennai taken together.
"Delhi's appetite for electricity has almost tripled since 2000. Domestic and commercial consumers together accounted for almost 75-80 per cent of annual electricity consumption in Delhi during the period 2010 to 2017. On an average, an electrified household in Delhi consumed about 260 kWh of electricity monthly in 2016-17, that was up from 155 kWh in 2000, which is almost three times the national figure of 90 kWh," he said.
Roychowdhury said, "There is a message for the post-pandemic 'new normal'. The learning from the lockdown phases challenge the current approaches that predominantly focus on energy efficient cooling systems and do not pay adequate attention to the architectural design and material and heat management strategies to reduce the overall thermal load on buildings and the city."