  The COVID-19 pandemic has disrupted human activities, leading to
unprecedented decreases in both global energy demand and GHG emissions. Yet a
little known that there is also a low carbon shift of the global energy system
in 2020. Here, using the near-real-time data on energy-related GHG emissions
from 30 countries (about 70% of global power generation), we show that the
pandemic caused an unprecedented de-carbonization of global power system,
representing by a dramatic decrease in the carbon intensity of power sector
that reached a historical low of 414.9 tCO2eq/GWh in 2020. Moreover, the share
of energy derived from renewable and low-carbon sources (nuclear, hydro-energy,
wind, solar, geothermal, and biomass) exceeded that from coal and oil for the
first time in history in May of 2020. The decrease in global net energy demand
(-1.3% in the first half of 2020 relative to the average of the period in
2016-2019) masks a large down-regulation of fossil-fuel-burning power plants
supply (-6.1%) coincident with a surge of low-carbon sources (+6.2%).
Concomitant changes in the diurnal cycle of electricity demand also favored
low-carbon generators, including a flattening of the morning ramp, a lower
midday peak, and delays in both the morning and midday load peaks in most
countries. However, emission intensities in the power sector have since
rebounded in many countries, and a key question for climate mitigation is thus
to what extent countries can achieve and maintain lower, pandemic-level carbon
intensities of electricity as part of a green recovery.
