The impact decades-long dependence on hydropower in El Niño impact-prone Zambia is having on carbon emissions through backup diesel generation

Abstract

Emissions associated with hydropower are often forgotten. Lifecycle assessments of greenhouse gas emissions emanating from hydropower must count embedded carbon, emissions from reservoir lakes and the loss of carbon sinks, as well as backup diesel generation emissions when dependence on hydropower fails to deliver energy. Using Zambia as a case study, we estimate using a bottom-up approach that the emissions associated with backup diesel generation from Zambia’s power utility ZESCO and three largest sectors of consumers were up to 27 000 tonnes of C O 2 in the worst months of drought in 2019. This is significantly higher than what a previous top-down approach would have estimated. We worked out ZESCO’s diesel generation attributable to drought using trend analysis. We worked out the mining sector’s emissions using copper production data, on-grid electricity consumption and calculated electricity intensity to infer off-grid electricity consumption in years of drought. From our household survey we learned average duration of generator use, average capacities of generators and acquired household income and generator use data which we ran in a Tobit regression. These together with labour force survey data helped us infer the level of diesel generation by households of different income brackets. For manufacturing firms we surveyed 123 firms. We collected rich diesel generation use data covering years of drought, input this into an OLS regression to identify predictors of diesel generation use (installed capacity of generator in kVA, in litres and whether generation was in a drought year) which we then used to extrapolate implied diesel generation for the firms for which we had less rich data. As global average temperatures and the frequency of El Niño droughts rise in hydropower dependent countries which account for a fifth of the world’s population, backup generation emissions have implications for the formulation of low carbon energy policy.

Drought impacts on the electricity system, emissions, and air quality in the western US

“…Further, we only quantify the impacts on the fossil fuel plants that are connected to the grid due to the data availability. However, drought-induced decreases in hydropower could also increase the usage of back-up generators that are not connected to the grid, as well as non-electricity energy sources especially in other parts of the world (59 ). Future research could also benefit from projections that combine our empirical estimates, while accounting for more realistic policy scenarios and energy system constraints.…”

The impact of power outages on households in Zambia

“…As global average temperatures rise, so too do the frequency and intensity of El Niño Southern Oscillation-induced droughts (Wang et al, 2017), which in turn threaten the reliability of hydropower (Ahmed et al, 2020). 1.4 billion people live 1 3 in countries where hydropower constitutes more than a quarter of the electricity production and which have experienced El Niño droughts, meaning many more power outages can be expected around the world (Ahmed, 2021a).…”