De-carbonization of global energy use during the COVID-19 pandemic

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 (~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-fuelburning 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. [245 words] Since late 2019, the ongoing coronavirus disease (COVID-19) has caused more than a million deaths worldwide . This has led to the largest disruption of human activities since World War II, with drastic changes in energy consumption and generation patterns, leading to an unprecedented drop of CO2 emissions. Moreover, the relative decrease of CO2 emissions from the electricity sector was disproportionately greater than the decreases in electricity demand and generation, pointing to a reduction in carbon intensity of the energy sector. For example, electricity use in China between January and April of 2020 was 4.7% lower than during the same months of 2019, but the corresponding decrease in electricity-related emissions was 6.0%. In particular, coal power was more negatively affected by the pandemic than other sources. The observed vulnerability of coal power to the negative demand shock of COVID-19 in many countries leads us to speculate that this sector may be close to a tipping point, beyond which substantial coal-fired generation capacity may become economically disadvantaged. This could hasten the phasing-out of coal power plants worldwide. Changes in electricity demand and supply during the pandemic may thus have important lessons for near-term reductions in energy-related CO2 emissions, but the necessary in-depth analysis is yet lacking. High spatialand temporalsource specific electricity data can help understand why de-carbonization occurred and can help interpret the short-term immediate and long term effect COVID-19 has on the electricity sector. Traditionally, this sector tend to be analyzed either in aggregated time scale (monthly or yearly, often updated with time-lag) or for refined spatial locations (national or regional) . While monthly or yearly aggregated data do provide knowledge base for evaluating the overall profiles of the electricity sector, information on day-to-day and diurnal electricity consumption and generation patterns induced by human behavior is unfortunately omitted. Regional daily electricity profiles can fill in some of this gap by providing snapshots of certain specific locations. However, it fails in providing a dynamic integral portrait of the global electricity system. A global scaled dataset on source specific electricity generation and consumption, with high time frequency and with high spatial coverage is therefore urgently needed to understand what exactly changes electricity sector has gone through during the pandemic globally, and when and how these changes happened. Here, we compiled and analyzed near-real-time, sub-hourly, sub-regionally electricity demand, electricity generation and related emissions from January of 2016 to June of 2020 (see also: http://carbonmonitor.org). Specifically, we quantify the patterns and drivers of global carbon intensity change in power generation (defined as the amount of CO2-equivalent greenhouse gases emitted per unit energy generated) since the onset of the COVID-19 pandemic. We accomplished this by providing a long-term dataset revealing the historical development and daily variations of the carbon intensity and the energy structure change (defined as the proportion of electricity generated by each energy source) in global power generation, (2) examining the drivers of the energy structure change during the pandemic by assessing the driving force: the electricity demand pattern shift in the corresponding time period, (3) evaluating how the newly formed electricity demand pattern since the COVID-19 pandemic facilitated the energy structure change by unfolding the diurnal pattern shift of each energy source, (4) assessing the reversed process by evaluating the carbon intensity and CO2 emission rebound from the electricity sector with the temporary recovery from lockdown in summer 2020. We included all major electricity generation sources in this study, covering electricity supplied by thermal power of oil, natural gas and coal, as well as, nuclear, hydro, wind, solar and other renewables (mainly bioenergy and geothermal energy). We compiled sub-hourly, hourly and daily data from 30 countries that account for ~68% of global electricity generation and global carbon emissions (See Supplementary Table S1). Accelerated decline of global carbon intensity marked by declined fossil electricity and more

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