It requires weaning humanity off the coal and oil that powered the 20th century and still dominates global energy supply. But with oil prices crashing below zero, multinational oil and gas companies reimagining themselves as clean energy leaders and the world’s largest nuclear fusion project under construction, we might begin to imagine a different path.

An electric revolution

The Intergovernmental Panel on Climate Change is clear: to limit global warming to 1.5°C, renewables will have to supply 70-85 per cent of electricity by 2050. Coal will have to drop to close to 0 per cent. In the UK, we might reach 100 per cent renewables, and sooner: the national grid is preparing Britain’s electricity system to be able to run on purely zero-carbon electricity by 2025.

So where will it come from? Solar and wind are likely to lead the way. Hydropower, while currently a significant source of energy, has little opportunity for growth. New nuclear, at least in the absence of small modular reactors, has currently priced itself out of the competition. The guaranteed electricity “strike” price for Hinkley Point C is more than twice the bid price for North Sea wind in 2019. Translation: wind has grown up. It’s as clean as ever, and it’s cheap and getting cheaper.

The tipping point for subsidy-free renewable electricity is generally regarded to be a dollar per watt, or $1 billion per terawatt, and that is expected to come by 2023. In many markets, new construction of wind or solar power is already cheaper per unit of power than gas, coal or nuclear. The offshore wind farms auctioned in the UK last September are likely to be the world’s first “negative subsidy” wind farms. Meanwhile, a recent study by UC Berkeley and GridLab found that a 90 per cent clean grid in the US by 2035 is not only feasible but cheaper than the typical 2050 goal. (The caveat? This would mean retiring all coal plants by 2035. Even if renewable energy is cheap, retiring operating equipment before its natural end of life is a significant economic disincentive.)

Nevertheless, the outlook needn’t be bleak. Far from it. We’re facing the possibility of “unrestricted availability of low-cost carbon-free power, based on technologies that we already have to hand and which can be expected to improve over the decades,” says Peter Littlewood, physics professor at the University of Chicago and former Director of the Argonne National Lab. It’s not crazy to envision a world where cars, light aeroplanes, buildings and vast IT networks are all fuelled by clean electricity. According to the IPCC, these “rapid and far-reaching transitions are unprecedented in terms of scale, but not necessarily in terms of speed”.

Can the grid cope?

Increased electrification will put pressure on the grid – but so will increased demand. “There is a strong link between human progress and energy consumption,” according to BP’s 2019 Energy Outlook. “The global energy system faces a dual challenge: the need for ‘more energy and less carbon’.”

BP has since dropped its ‘dual challenge’ language, but the reality remains: growing populations and prosperity will drive increased demand for energy even if it’s used more efficiently – as it must be. Today, 80 per cent of the world’s population lives in a region where the average energy consumption is below 100 gigajoules per head. If that fell to a third of the world’s population by 2040, it would require around 25 per cent more energy – roughly equivalent to China’s energy consumption in 2017.

Can the grid cope? The short answer is probably, with investment in residential grids to cope with all the electric vehicle charging. But theoretical capacity is only one consideration; the grid also needs to deal with daily and seasonal fluctuations in demand. It needs to be flexible.

“Historically most flexibility has come from the supply side of the electricity system; by varying the amount of gas produced or imported, or by turning up or down electricity generation, such as gas turbines,” writes Archie Corliss of National Grid ESO. But the variability of renewable sources, dependent on whether the wind blows or the sun shines, removes that supply-side flexibility.

Instead, it’s likely that a clean grid will rely on energy storage, either in batteries or by converting energy to a liquid or gas fuel. Again, money talks: research from the Trancik Lab at the Massachusetts Institute of Technology puts the price of “cheap enough” storage for the US to maintain a 95 per cent renewables grid at $150 per kilowatt hour. Lithium-ion batteries aren’t there yet but they could be by 2030, as could sodium-ion batteries. Another option might be solid-state batteries (SSBs), which lack the liquid electrolyte found in your typical AA batteries. SSBs are considered to be safer, have higher energy density, charge faster and live longer.

Meanwhile, for the millions living in weak and off-grid areas, often in developing countries, replacing diesel generators with battery generators and localised renewable grid systems could make a world of difference.

Where do our greenhouse gas emissions come from?

What we talk about when we talk about hydrogen

The other prime candidate for energy storage? Green hydrogen. Unlike brown or grey hydrogen, which are produced from coal and natural gas respectively, green hydrogen is produced by electrolysis of water using electricity from renewable sources.

It can be burned for heating or power in times of high demand. It can be reacted with atmospheric carbon dioxide to produce carbon-neutral natural gas. It can be the starting material in carbon-neutral synthetic fuels as an alternative to biofuels, or pumped into specialised hydrogen fuel cells to power heavy good vehicles and trucks. Or more simply, it can replace the 55 million tonnes of dirty hydrogen in industry.

“A big challenge is finding an emissions-free substitute for combustion,” says George Crabtree, Director of the Joint Center for Energy Storage Research in the US. “Many energy needs are best served by combustion [for example], when a great deal of high temperature heat is needed for cement, steel and petrochemical processing, or high power-high energy transportation as in aviation or maritime shipping.”

Green hydrogen is currently not cost-competitive against brown and grey. But costs for renewable hydrogen are going down quickly. Electrolyser costs, the major factor in the cost of green hydrogen, have fallen by 60 per cent in the last ten years. In regions where renewable energy is cheap, green hydrogen is expected to be able to compete with fossil-based hydrogen by 2030.

So we might begin to imagine, as Crabtree puts it, “a decarbonized economy centered on three interacting pillars: electricity plus storage plus hydrogen.” This is the “energy system of the future” for which the EU set out plans last month: a system that is “planned and operated as a whole, linking different energy carriers, infrastructures, and consumption sectors”.

By 2030, the EU expects to deliver 10 million tonnes of renewable hydrogen. Meanwhile CrossWind, a consortium of oil major Shell and Dutch utility Eneco, plans to have a 759-megawatt offshore wind farm integrated with solar, storage and hydrogen up and running in 2023.

In the UK, Labour’s Green New Deal outlines a similarly integrated plan for net zero by 2030: mass electrification with solar and a thousand new wind turbines, and batteries to stabilise supply; plus buildings and industry decarbonised through electric heat pumps and green hydrogen.

The UK’s Energy Networks Association wants to see Britain create the world’s first carbon-free gas network. In the States, the House Democrats’ climate plan achieves net zero in the power sector by 2040. Under a Biden presidency, American electricity would – Biden says – be “carbon pollution-free” by 2035, with accelerated investment in grid-scale battery storage and green hydrogen.

These are all promises that would be hard to keep even without back-peddling by climate deniers. They’re ambitious, they won’t be cheap, and they rely on significant investment in research and development. But as Stephane Hallegatte, Lead Economist in the Climate Change Group at the World Bank, puts it: “The challenge is not to start by doing a little, and then gradually do more over time until you have zero emissions. It is to start by doing a lot, to change the patterns of growth, so that further change becomes increasingly easy over time.”

With the right people and enough political will, we might just say anything’s possible.

Illustrations by Lizzie Lomax