By Dr Roy Moobola

Zambia’s power sector faces a fragile balancing act. While elevated electrical energy exports have earned very important overseas forex, such positive factors are juxtaposed towards the true menace of unsustainable water utilization at Kariba Dam. The El Niño-induced drought of 2024 has underscored the vulnerabilities of Zambia’s hydropower system to local weather variability, resulting in vital energy imports and financial pressure.

This article delves into the interaction between rising exports, home power demand, and hydropower water administration challenges, providing insights into how Zambia can guarantee sustainable power era within the face of mounting dangers.

Electricity Generation, Consumption and Exports

The graph under, which spans the years from 2013 to 2023, illustrates Zambia’s electrical energy era, consumption, and exports. Over this era, electrical energy era has proven comparatively regular development with dips within the drought-affected years of 2015, 2016, 2019 and 2020. Average annual development in era has been 3.8% over this ten-year interval. The sustained rise in era displays latest investments in new infrastructure, together with the commissioning of Maamba coal-fired energy station in 2016 and Kafue Gorge Lower hydropower station in 2021.

On the consumption facet, there was the same sample of development, with a median annual enhance of three.2% over the ten-year interval to 2023, pushed by rising home and industrial demand along with wider electrification efforts.

Electricity exports, in the meantime, have exhibited a much less constant sample being roughly regular as much as 2020 however have surged sharply in recent times. From 2020 onwards, electrical energy exports have grown by a median annual price of 40%, signalling Zambia’s rising function as a regional power provider.

Figure 1: Variation of Zambia’s Electricity Generation, Consumption and Exports between 2013 and 2023

Generation by Major Power Stations

The subsequent graph supplies an in depth breakdown of electrical energy era by main energy stations from 2014 to 2023. It reveals the pivotal roles performed by Zambia’s main hydropower crops – Kafue Gorge Upper, Kariba (North Bank and North Bank Extension), and Kafue Gorge Lower – in addition to the Maamba coal-fired energy station which collectively account for between 80% and 90% of whole electrical energy era every year.

Kafue Gorge Upper has been the most important and most steady contributor to the nation’s electrical energy era. Output at Kariba has proven vital variability attributable to low dam water ranges, highlighting the vulnerability of this crucial plant to climatic variability and excessive water utilization.

The commissioning of Kafue Gorge Lower in 2021 added substantial new capability, bolstering general era and offsetting a number of the declines at Kariba. Meanwhile, Maamba has supplied a constant thermal era different, making certain some diversification in Zambia’s power combine.

Exports are additionally highlighted on this graph, with their sharp rise from 2020 to 2023 ostensibly fuelled by the extra output from Kafue Gorge Lower and Maamba, permitting Zambia to satisfy rising regional demand and earn a lot wanted exhausting forex.

Figure 2: Zambia’s Electricity Generation for Major Power Stations in contrast with Exports (2014 – 2023)

Kariba Dam Water Management

The subsequent graph highlights water availability and utilization at Kariba Dam from 2014 to 2024, emphasising the influence of local weather variability. Annual Zambezi River flows fluctuated between 9 and 50 billion m³, however the excessive move in 2021 introduced a missed alternative to replenish dam reserves attributable to extreme water utilization. Lower river flows than utilization in 2022 and the El Niño occasion of 2024 have additional decreased water ranges, finally inflicting electrical energy deficits. Critical lows in dam water ranges (under 10% of dam capability) had been recorded in 2019, 2022 and 2024, underscoring the pressure extreme water utilization locations on Kariba’s sustainability.

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Figure 3: Net Zambezi River Flow, Electricity Generation Water Usage and Water Levels for Kariba Dam (2014 – 2024)

Are Exports the Problem?

One pertinent query raised by these tendencies is whether or not prioritising electrical energy exports contributed to the depletion of water ranges at Kariba Dam. While home consumption has been met by elevated era over the previous decade, it will seem that exports have been supported largely by new crops like Kafue Gorge Lower and Maamba, not solely by Kariba’s water reserves.

However, failure to replenish Kariba’s water reserves has left the sector susceptible to drought, resulting in decreased era capability and extreme load shedding in 2024. Rapid export development, outpacing era, has clearly added stress on water assets.

A calculation of the influence that elevated exports have had on water assets at Kariba is proven within the desk under.

Table 1: Excess electrical energy exports and equal Kariba Dam water in 2021 – 2023 interval in comparison with the 5-year common from 2016 – 2020

From 2021 to 2023, Zambia exported 5479 GWh of electrical energy above the typical export ranges of the earlier 5 years, utilizing an estimated equal of 29.1 billion m³ of Kariba Dam water – equal to 45% of storage capability at Kariba Dam. Conserving this water by sustaining historic export ranges might have strengthened reserves, offering larger resilience towards future water shortages just like the 2024 El Niño-induced drought.

By mid-2024, electrical energy era had dropped 15% in comparison with the identical interval in 2023, seemingly leading to a 2900 GWh electrical energy deficit for the yr. The extra energy exported in 2021-2023 would have been sufficient to cowl this deficit fully, probably stopping load shedding.

Risk Modelling

The subsequent plot illustrates the calculated chance distribution of annual water move volumes at Victoria Falls, a crucial upstream move level for Kariba Dam. The key knowledge of curiosity is the estimated river water move for 2024 of 17 billion m³, which is statistically recognized as a 1-in-14-year low-flow occasion.

Figure 4: Probability distribution curve for annual Zambezi River Water Flow at Victoria Falls (1925 – 2023)
Datapoints are whole water move for said yr (Jan-Dec). Source of information: https://observablehq.com/@westernpower/kariba

The chance distribution reveals that excessive low-flow years, just like the estimated 2024 quantity, usually are not unprecedented even in residing reminiscence, although they’re comparatively uncommon. Recent traditionally low-flow years, resembling 1996 and 1995, emphasise the potential recurrence of those occasions and the vulnerabilities of hydropower techniques to local weather variability. A 1-in-14-year occasion signifies a major threat that have to be accounted for in hydropower water administration and planning.

Conclusion

To mitigate future dangers, Zambia should undertake a multi-pronged technique to make sure power safety whereas preserving water assets.

• Investments in different power sources resembling solar energy needs to be accelerated to cut back dependency on hydropower.
• Export insurance policies ought to prioritise home power wants throughout and following low-flow years, implementing limits on exports when water reserves fall under crucial thresholds.
• Improved risk-based water useful resource administration is important in optimising hydropower water utilization.

These measures may help Zambia steadiness its function as a regional power provider, leveraging its water assets to generate overseas alternate, whereas safeguarding its personal financial stability and power safety.