It is the near future. You wake in a house warmed by a heat pump that extracts energy from deep below the ground and delivers it to your home. (Your gas boiler was outlawed years ago.) You rise and make yourself a cup of tea – from water boiled on a hydrogen-burning kitchen stove. Then you head to work – in a robot-driven electric car directed by central control network to avoid traffic jams.
At midday, you pause for lunch: a sandwich made of meat grown in a laboratory. At the end of the day, you are taken home by a robot car – through countryside festooned with solar panels and turbines.
Welcome to carbon-free Britain, a nation stripped of its petrol cars, diesel trucks and trains, gas heating, methane-belching cows, and jumbo jets. The UK of tomorrow is a zero-emissions haven.
Or at least that is the dream, one that is now being pursued with passion by growing numbers of UK citizens. Indignant at the lack of political effort being made to curtail global warming, they have responded with mounting outrage which last week reached a peak during Extinction Rebellion’s protests in London.
Creating a zero-emission society in the UK has become a major cause and it will receive further serious promotion next week when the government’s climate change committee publishes its report on how, and when, Britain can achieve this status and play a proper part in the battle against global warming.
It will be hard work, as the committee will make clear. Last year 6.8 tonnes of greenhouse gases were emitted into the atmosphere per head of population in the UK. To decarbonise the nation, that figure will have to be reduced to zero.
The crucial question is: when? Just how quickly can we eliminate our carbon emissions? Extinction Rebellion protesters are clear. They want the UK to be decarbonised by 2025. That will mean massive curtailment of travel by car or plane, major changes in food production – steaks would become culinary treats of the past – and the construction of swathes of wind and solar plants. But given that we face disastrous climatic change, only massive, widespread, rapid interventions can now save us from a fiery global fate, they say.
Many experts disagree, however. They argue that such an imminent target is completely impractical. “Yes, you could decarbonise Britain by 2025 but the cost of implementing such vast changes at that speed would be massive and hugely unpopular,” says Lord Turner, former chairman of the climate change committee.
Most expect the climate change committee will plump for 2050 as Britain’s ideal decarbonisation date. “2050 is do-able and desirable and would have an insignificant overall cost to the economy,” states Turner, who is now chairman of the Energy Transitions Commission. According to this scenario, developed nations, including Britain, would aim to achieve zero-emissions status by 2050 and then use the decarbonising technologies they have developed to achieve this goal – hydrogen plants, carbon dioxide storage vaults and advanced renewable generators – to help developing nations halt their greenhouse gas emissions by 2060.
We would then have a reasonable chance of restricting global warming to less than 2C and so avoid the worst effects of climate change: unprecedented storms, melting ice caps, disappearing coral reefs, rising sea levels and drowned cities.
But just how straightforward will it be to create a zero-emissions society? How easily will we be able to kick the carbon habit? At first glance, the evidence looks encouraging. Britain has already embarked on a path of carbon emissions reduction for its power generation industry. Fossil fuel plants have been closed and wind farms have been built in their place.
And the change has already been reflected in Britain’s power statistics. In 2013, 62.5% of UK electricity was generated by oil, coal and gas stations, while renewable provided only 14.5%. In 2018, the figure for oil, coal and gas had been reduced to 44% while renewables were generating 31.7%. It is a distinct improvement – though we have yet to be given a date when engineers expect the last UK fossil-fuelled power plant to produce its final watts of electricity and to emit its last puffs of carbon dioxide.
“Decarbonising UK power production is going well,” says George Day, head of policy for the technology and innovation centre Energy Systems Catapult. “There is a clear path forward.” But as he points out, there are many other sources of carbon dioxide in the UK. “The next big challenge will be heating. Gas boilers are major carbon emitters and dealing with them is going to be very difficult.”
According to Day, about 90% of British people have gas boilers in their homes, most having been fitted relatively recently – over the past 20 to 30 years or so. “And we have really come to love them,” he states. “You get hot water and heating at a flick of a switch, after all.
And that is a problem, he argues. “Dislodging that incumbent technology in a way that is socially acceptable is going to be really hard. Indeed it is probably the toughest challenge we face in decarbonising Britain because you are talking about homes where people are used to making their own decisions.”
A solution would be to price gas out of common use, by putting increasingly heavy carbon taxes on household supplies so people can no longer afford them and are forced to change heating systems. But that would only lead to widespread protests, says Day. “Just look at the gilets jaunes,” he points out.
Instead, ways will have to be found to entice householders – not compel them – to move away from gas heating to alternatives such as electric heating, heat pumps and hydrogen-burning radiators. “They will have to see it as a better alternative to gas heating,” says Day. “It will be a big task but I believe it can be done.”
Time will be a key consideration. At present around 20,000 homes a year are being converted into low-carbon housing units. “However if we are serious about reaching zero emissions by 2050 then we are going to move with a lot more urgency,” adds Day. “By 2025, we will have to be converting around a million houses a year.”
Nor is household heating the only headache facing the decarbonisation of the UK. Steel-making, cement manufacture, shipping, aviation and trucking also pose problems.
Consider cement. It is the basic ingredient of concrete, the second most consumed substance in the world – behind water. Around 10 million tonnes of cement are used every year in a host of construction projects across the UK, from homes to new underground lines. (Hundreds of thousand of tonnes are being used to build the access shafts, underground stations, and tunnels for Crossrail, for example.)
Cement manufacture requires heat which could be supplied using electricity generated by renewables. But a major problem remains: making cement involves breaking down limestone to obtain calcium oxide and that process releases carbon dioxide in significant amounts. It is estimated that cement manufacture is responsible for about 8% of current global emissions. Nor is it obvious how to find ways to eradicate them completely.
Then there are farms and planes. “In the case of aviation, you might use batteries and hydrogen to power relatively small aircraft for short distances: a 100-seater for a flight of an hour or so,” says Turner. “But for a jumbo across the Atlantic you will still need fuels with the energy density of heavy liquid hydrocarbons.”
As for agriculture, it is estimated that around 6 billion tonnes of greenhouse gases (carbon dioxide, methane and nitrous oxide) are emitted from farms around the world. Major reductions could be achieved through improved management practices, say researchers. Nevertheless eating the meat of belching cows, no matter how tasty is the resulting steak, undoubtedly has a major impact on emission levels. Changes in the British diet will be needed.
In the end, it will simply not be possible to reduce Britain’s fossil-fuel emissions to zero, say scientists. To compensate, we will have to take carbon dioxide back out of the atmosphere. “That is the logical, inevitable consequence of trying to achieve zero net emissions in this country,” argues Corinne Le Quéré, of the University of East Anglia. “If you are looking for any net zero target then you have to remove carbon dioxide from the atmosphere.”
This can be done in three ways: naturally, by planting trees and shrubs that absorb carbon dioxide. Or artificially – on a larger scale – the gas can be removed as it is produced at a factory or power station that burns trees for energy.
Or it can be removed by huge numbers of man-made air filters, known as direct air capture. The carbon dioxide can be liquefied and stored underground in underground caverns, or old, depleted gas fields under the North Sea. This is known as carbon capture utilisation and underground storage (CCUS).
“In the end, your choice of replanting or of building underground storage facilities depends on how much carbon you will need to remove,” says Le Quéré. “Most calculations suggest Britain will need to take quite a lot of carbon dioxide out of the atmosphere to keep its net emissions at zero.”
That arithmetic clearly implies that Britain will need to build a number of CCUS plants, a point backed by Charlotte Morgan, who chaired a recent task force that urged the construction of several carbon storage facilities in the UK. Each of these would be able to hold millions of tonnes of carbon dioxide.
“These could create an enormous industry for Britain,” says Morgan, who envisages the creation of five industrial clusters – in Humberside, Merseyside, South Wales, central Scotland and Teeside – where CCUS facilities could be built and attract industries from around the world. “However, if we want to these up and running by the end of the next decade, we need to act quickly.”
This need for speed is shared by many other parts of the zero-emissions programme, as we have seen. It may seem odd given it is unlikely it will reach its conclusion for another three decades. Nevertheless, scientists are adamant that even if choose 2050 for our decarbonisation date, we need to act now.
This urgency of the task is emphasized by Joeri Rogelj at Imperial College London. “If the world limits emissions of carbon dioxide to no more than 420 billion tonnes this century, we will have a two in three chance of keeping global warming down to around 1.5C.
“However, if we go above to 580 billion tonnes then our chances will be reduced to 50-50. The problem is that in 2017 alone, a total of 42 billion tonnes of carbon dioxide was emitted in a single year. By that calculation, we clearly do not have a lot of time to waste.”