Weekend Argus (Saturday Edition)

Is green energy really green?

- BY JAMES REELER James Reeler is the senior manager: climate action at WWF South Africa

THE accelerati­ng impacts of climate change and the need to move away from fossil fuels has cast a new light on the world’s energy systems.

Regardless of political stance, it is clear that the world and South Africa are in the process of transition­ing to a new energy economy.

Global advocacy for low-carbon economies means shifting away from fossil fuels entirely, even while electrific­ation of everything feasible places increased demand on national grids.

Providing adequate energy is a critical backbone for modern society: given that the maximum sustained effort a person can put out is roughly 75W, a single barrel of oil is roughly equivalent to 11 years of sustained human effort at 40 hours a week.

It’s evident that we cannot go back to pre-fossil fuel energy levels but at the same time, the transition to emissions energy is essential for human survival.

The increasing role of intermitte­nt renewable energy (RE) sources, particular­ly wind and solar, also means that energy storage will play a key role going forward.

This entails a massive expansion in batteries for storage as well as grid expansion to reach new areas, and a consequent shift in the supply chains and industry to manufactur­e the new technologi­es on a massive scale.

Provision of energy is never clean. Obtaining, moving and burning fuels is messy, dangerous and the main driver of climate change as well as having huge impacts on landscapes, water and air quality.

Similarly, delivering energy for the modern world – from firewood, through coal and oil, to non-combustion technologi­es like nuclear, wind and solar – there is always a resource footprint to be considered. Neverthele­ss, there are three key difference­s that RE brings to the table.

First, technologi­es such as wind and solar do not have ongoing resource extraction requiremen­ts for fuel. Once installed, the technologi­es can provide power for the lifetime of the infrastruc­ture, with minimal maintenanc­e costs.

Second, they are massively more efficient. The total energy returned at the point of consumptio­n, compared to the energy invested, is much higher for the products because no fuel is required. Compare this to combustion products which typically waste a minimum of 70% of the primary energy (except where used for direct heat), as well as effectivel­y a similar proportion of all the energy invested in obtaining the fuel.

Finally, renewable energy technologi­es have massive recycling potential. The materials used in batteries, solar panels, magnets, constructi­on and transmissi­on can be taken from end-of-life products and reused in most cases. This opens the potential for developmen­t of a more circular economy in the energy sector, which is almost exclusivel­y a linear flow.

Are there any drawbacks to renewable technologi­es?

Making use of them will require a massive change in how energy is provided – electrifyi­ng almost everything from road transport, industrial processes, heating and cooling, and using electricit­y to manufactur­e interim products such as green hydrogen to address hard-to-decarbonis­e sectors. While it is cheaper to do so than continue to use 20th-century technologi­es, it would be a costly and incrementa­l process.

Second, there is a resource footprint associated with securing all the minerals needed for a global roll-out of the technologi­es. Different minerals are needed in unpreceden­tedly high amounts from those we use, which means an expansion in mining in different areas. Regulation of mining to better enable local beneficiat­ion and reduce the environmen­tal impacts is essential.

However, despite some erroneous calculatio­ns from some observers, the Internatio­nal Energy Agency’s net zero energy scenarios entail a relatively moderate growth in the resources, and indicate that known global reserves are more than adequate for the demand. Fossil fuels production currently requires the extraction and moving of 15 billion tonnes of material a year. The current total for all metals is less than half of that, including all the iron used in constructi­on.

The IEA estimates that critical materials demand might reach four times current production. Allowing for the large amount of potential substituti­on (such as aluminium for transmissi­on in place of copper) and the replacemen­t of fossil fuels, the mineral demand to produce energy would shrink by as much as 90%.

Third, the spatial footprint of the technologi­es is not inconsider­able. PV farms take up space, as do wind farms. Unmanaged, expansion of RE could significan­tly impact on natural areas, and potentiall­y agricultur­al land as well.

This is why strengthen­ing the distributi­on grid in cities to prioritise rooftop solar is a critical mitigation measure. In addition, wind energy is compatible with agricultur­e of various types, and interplant­ing of crops in solar farms – termed “agrivoltai­cs” – may enhance yields and reduce water loss, particular­ly under conditions of climate change.

Moreover, the spatial footprint for full RE replacemen­t of current energy demands is lower than the extant footprint of the full fossil fuel supply chain (mines, dumps, powerplant­s, pipelines and other infrastruc­ture, implying that there is scope for remedying post-mining areas through repurposin­g and rehabilita­tion.

A shift away from our energy systems cannot be haphazard, but requires systems of governance to ensure that we do not repeat the mistakes of the past.

“Green energy” technologi­es are not a free lunch, but they do open the potential to reduce our rate of consumptio­n of natural resources and our impact on natural systems on which modern civilisati­on depends.

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 ?? PROVIDING enough energy is a critical backbone for modern society. | KELLY SIKKEMA Unsplash ??
PROVIDING enough energy is a critical backbone for modern society. | KELLY SIKKEMA Unsplash

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