Reduce and replace: will renewables solve the energy equation?

People walk next to wind turbines at sunset in Taichung, Taiwan, 15 September 2020. According to news reports, Taiwan will produce twenty percent of its electricity through renewable energy by 2025. EPA/RITCHIE B. TONGO

Next week, on the fifth anniversary of the Paris agreement, the UN Secretary-General Antonio Guterres, Boris Johnson and Emmanuel Macron will host the Climate Ambition Summit, during which governments are expected to affirm plans to reduce greenhouse gas emissions drastically in the next decade.

The increasing number of countries pledging for net zero emissions by mid-century provides good reason for hope as it would allow to stabilise the climate at 2.1 C if all new pledges are fully implemented, according to Carbon Action Tracker. The roadmap to “well below 2 C” is getting closer.

There are however still very serious reasons to be worried. Success indeed depends on the following assumptions: replacing all fossil fuels by decarbonated energy; reducing the demand for energy itself; turning agriculture into a carbon sink rather than an emitter. All that in less than 25 years, as the world did not take scientists seriously enough when they made their first warning to humanity back in 1992.

But can renewables really deliver on expectations, substitute for dirty energy over such a short timeframe and solve the equation? Only one part of it, alongside a dramatic reduction of 40 to 50 per cent in energy demand and use before 2050, insist specialists at the Exponential Roadmap Initiative or Negawatt in France. To avoid dangerous illusions, the sooner this is understood the better.

What the debate is about. Our societies are addicted to energy and growth - the two being largely interconnected- and must now contemplate a very different world to remain within the safe operating space of planetary boundaries. From there, a debate runs between two main lines of thought. Believers in “green growth” consider the climate challenge to be mainly technological, a new “industrial revolution,” substituting one source of energy by another and innovating to use less energy. On the other side, some thinkers question the possibility to sustain the full expansion of renewables, to satisfy the demand and envisage economic stagnation and de-growth as the only possible horizon. Both agree on the need to reign in the energy demand through radical sufficiency and efficiency measures.

Why it matters. In the battle for a stable climate, the excitement about renewables and double-digit growth in dedicated investments often covers up what needs to be done simultaneously: reduce energy use to a level that renewables and other decarbonated sources can actually meet in reality.

This race to reduction is as important and may represent the difference between make or break. We are now at a crossroads for humanity, and yesterday Antonio Guterres issued a remarkably strong statement:

“Humanity is waging war on nature. This is suicidal. Nature always strikes back – and it is already doing so with growing force and fury. (…) Human activities are at the root of our descent toward chaos. But that means human action can help to solve it.”

Sunny perspectives. Renewable power is increasingly cheaper than any new electricity capacity based on fossil fuels, and is set to progressively phase out coal through pricing. Headlines are full of announcements on multi-billion investments in renewables and the “costs revolution” confidently taking place. Indeed, in the last decade, the installed capacity for solar and wind power generation has picked up and renewables, including hydropower, represent already 27 per cent of the world’s power generation. A capacity expansion by 50 per cent more is expected in the next five years, and if growth rates continue at their initial pace, the expectation is to see renewables replace fossils fuels within just one generation.

IRENA on Twitter: "#Renewableenergy capacity additions in 2019 took # renewables share of all global power capacity to 34.7%, up from 33.3% at  the end of 2018. Learn more from @IRENA's latest data:

The hard reality of today’s energy mix. Unfortunately, power generation is just one part of the energy consumption, and in 2019, only 11 per cent of global primary energy came from renewable technologies, with more than half from hydropower. The rest is not electricity, but primary energy directly consumed for transport, buildings and industry mainly. The graph below represents the different sources of energy and their evolution. While the growth rate of renewables has overtaken that of fossil fuels, in volume the rise in energy is still essentially driven by fossil fuels.


The extra gas and oil per year exceeds by far the extra capacities in wind and solar. In fact, the historic course of events shows for the moment no influence of the political commitments taken to tackle the climate crisis. Apart from a recent slump in coal consumption, the impact of the Paris agreement has yet to translate into tangible facts.


And while the rise of renewables in the electricity mix is good news, over this same period, the share from nuclear production decreased by almost exactly the same amount. This means that the total share of low-carbon electricity production is almost exactly the same as a decade ago.

Progress on electricity decarbonisation has therefore until today been cancelled as a result of a growing aversion to nuclear energy. And the real story of replacement of fossil fuels by renewables only begins from now on, at a very late stage already.


The production gap. Last but not least, as UNEP informs us in their latest report issued this week, projections and plans for fossil fuels continue to lead towards an increase by two per cent a year instead of the decrease by six per cent that would be consistent with a 1.5 C scenario for global heating. Post-Covid recovery plans have unfortunately confirmed this direction with the majority of subsidies going to the fossil fuel linked sectors. Unless a radical change of course happens in 2021, these investments will lock in part of the energy mix for the future.

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Physical resource limits. Renewables have a much better record than fossil fuels on carbon emissions, but as other sources they also consume a lot of non renewable mineral resources and need energy to transform them into industrial materials. Some climate think tanks question whether the full replacement of fossil fuels by renewables is feasible and desirable given the competition for physical resources that are getting increasingly scarce at the rhythm they are unsustainably consumed. Recycling and circular economy are a big part of the answer but this perspective also reminds us that the best energy is the one you don’t use.

The bottomline. At the end of the day, if the demand for energy use does not decline sharply over the two next decades (by almost half) instead of continuously growing, there is virtually no chance that renewables will be able to catch up and replace fossil fuels. Together with greater electrification of transport, industry and buildings and efficiency gains supported by innovation, absolute reduction is a perspective with which societies must come to terms to avoid the worst climate scenarios. Net zero pledges will not be sufficient, and the dilemma between mitigating the crisis and cooling the economic engine or promising continuous growth has come to such a point it needs proper explanation by political leaders.