Carbon capture has failed. So what should we do instead?

Drax and Eggborough power stations in England. Image: Pete Richman/creative commons.

For years, optimists have talked up carbon capture and storage (CCS) as an essential part of taking emissions out of electricity generation. Yes, build wind and solar farms, they have said, but they can’t be relied on to produce enough power all the time. So we’ll still need our fleet of fossil-fuel-burning power stations; we just need to stop them pumping carbon dioxide (CO₂) into the atmosphere.

Most of their emphasis has been on post-combustion capture. This involves removing CO₂ from power station flue gases by absorbing them into an aqueous solution containing chemicals known as amines.

You then extract the CO₂, compress it into a liquid and pump it into a storage facility – the vision in the UK being to use depleted offshore oil and gas fields. One of the big attractions with such a system is it could be retrofitted to existing power stations.

The big let-down

But ten years after the UK government first announced a £1bn competition to design CCS, we’re not much further forward. The reason is summed up by the geologist Lord Oxburgh in his contribution to the government-commissioned report on CCS published last year:

There is no serious commercial incentive and it will stay that way unless the state demonstrates there is a business there.

The problem is that the process is costly and energy intensive. For a gas-fired power station, you typically have to burn 16 per cent more gas to provide the capture power. Not only this, you end up with a 16 per cent increase in emissions of other serious air pollutants like sulphur dioxide, nitrogen oxides and particulate matter. Concerns have also been expressed about the potential health effects of the amine solvent used in the carbon capture.

You then have to contend with the extra emissions from processing and transporting 16 per cent more gas. And all this before you factor in the pipeline costs of the CO₂ storage and the uncertainties around whether it might escape once you’ve got it in the ground. Around the world, the only places CCS looks viable are where there are heavy state subsidies or substantial additional revenue streams, such as from enhanced oil recovery from oilfields where the CO₂ is being pumped in.

Well, say the carbon capture advocates, maybe another technology is the answer. They point to oxy-combustion, a system which is close to reaching fruition at a plant in Texas.

First proposed many years ago by British engineer Rodney Allam, this involves separating oxygen from air, burning the oxygen with the fossil fuel, and using the combustion products – water and CO₂ – to drive a high-pressure turbine and produce electricity. The hot CO₂ is pressurised and recycled back into the burners, which improves thermal efficiency. It has the additional advantage that CO₂ is also available at pressures suitable for pipeline transportation.

It is, according to some enthusiasts, the “holy grail” of CCS. Admittedly it looks promising, but I wouldn’t go that far. It’s not suitable for retrofitting existing power stations. With many existing stations viable for several decades, this will do little for immediate emissions. And you are still obtaining and moving fossil fuels in large quantities, with the resultant emissions along the way. Finally, my experience would indicate that there is always very significant cost growth with new technology scaled up to industry.

Number crunching

One UK post-combustion CCS project that was cancelled earlier this year was the joint-venture between SSE and Shell at the Peterhead gas-fired ation in northeast Scotland. It aimed to capture 10m tonnes of CO₂ over a 10-year period and store it 2km under the North Sea.

Let’s put this saving into context. The diagram below summarises the amount of power produced and used in the UK. It shows that the country uses 108 terawatt hours (TWhrs) of domestic electricity per annum.

 

UK electricity generation/consumption. All numbers are in terawatt hours (TWhrs). Image: DECC.

Of this domestic usage, 16 per cent goes to cooking. Boiling kettles makes up 34 per cent – that’s 5.9TWhrs per annum, the equivalent of a 670MW power station. Domestic kettle use is particularly inefficient as we regularly overfill our kettles. We could save at least half the energy if we boiled only what we need to make tea and coffee.

That would negate the need for 335MW of power. Now compare that to what CCS would have saved from Peterhead – 85 per cent of a 400MW gas turbine, or 340MW. Simply by not overfilling our kettles, we could remove about the same amount of CO₂. Unlike CCS, let alone oxy-combustion, we could do this immediately, for free, and cut our electricity bills and remove various air pollutants at the same time.

Of course, being kettle smart will only deliver a fraction of the UK’s required carbon reduction goals. It’s only about 3TWhrs out of the approximately 170TWhrs produced by gas-fired power in the UK each year. But it hopefully illustrates why energy efficiency is a much smarter way of reducing carbon and other harmful air emissions than CCS.


If we took the same approach to lighting, computer monitors, TVs on stand-by, running water and everything else, it becomes a very different proposition. If we could achieve the aim of a carbon-neutral house, we could shut down half the UK’s existing gas-fired power stations. And if industry and other non-domestic consumers made energy savings of the order of 20 per cent, that would bring down the gas-fired power requirement by a corresponding percentage.

Is 20 per cent realistic? As a chemical engineer with a 40-year industrial career, I am confident it is. Key areas to be considered would be pump and compressor efficiency, energy use in separation processes, combined heat and power, furnace fuel management, green concrete and energy integration.

Together with the government giving greater priority to renewable energy like offshore wind and solar, you have a viable plan for delivering the UK’s carbon goals. CCS may still have its place, but as a means of removing carbon emissions from burning things like wood and rubbish as opposed to fossil fuels. Suffice to say it looks more promising on that front.

The ConversationBut in short, it is time for governments to stop wasting time and money on technologies like CCS that aren’t working. They need to finally get serious about leading a major drive for energy efficiency instead.

Tom Baxter is senior lecturer in chemical engineering at the University of Aberdeen.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

A growing number of voters will never own their own home. Why is the government ignoring them?

A lettings agent window. Image: Getty.

The dream of a property-owning democracy continues to define British housing policy. From Right-to-Buy to Help-to-Buy, policies are framed around the model of the ‘first-time buyer’ and her quest for property acquisition. The goal of Philip Hammond’s upcoming budget is hailed as a major “intervention” in the “broken” housing market – is to ensure that “the next generation will have the same opportunities as their parents to own a home.”

These policies are designed for an alternative reality. Over the last two decades, the dream of the property-owning democracy has come completely undone. While government schemes used to churn out more home owners, today it moves in reverse.

Generation Rent’s new report, “Life in the Rental Sector”, suggests that more Britons are living longer in the private rental sector. We predict the number of ‘silver renters’ – pensioners in the private rental sector – will rise to one million by 2035, a three-fold increase from today.

These renters have drifted way beyond the dream of home ownership: only 11 per cent of renters over 65 expect to own a home. Our survey results show that these renters are twice as likely than renters in their 20s to prefer affordable rental tenure over homeownership.

Lowering stamp duty or providing mortgage relief completely miss the point. These are renters – life-long renters – and they want rental relief: guaranteed tenancies, protection from eviction, rent inflation regulation.

The assumption of a British ‘obsession’ with homeownership – which has informed so much housing policy over the years – stands on flimsy ground. Most of the time, it is based on a single survey question: Would you like to rent a home or own a home? It’s a preposterous question, of course, because, well, who wouldn’t like to own a home at a time when the chief economist of the Bank of England has made the case for homes as a ‘better bet’ for retirement than pensions?


Here we arrive at the real toxicity of the property-owning dream. It promotes a vicious cycle: support for first-time buyers increases demand for home ownership, fresh demand raises house prices, house price inflation turns housing into a profitable investment, and investment incentives stoke preferences for home ownership all over again.

The cycle is now, finally, breaking. Not without pain, Britons are waking up to the madness of a housing policy organised around home ownership. And they are demanding reforms that respect renting as a life-time tenure.

At the 1946 Conservative Party conference, Anthony Eden extolled the virtues of a property-owning democracy as a defence against socialist appeal. “The ownership of property is not a crime or a sin,” he said, “but a reward, a right and responsibility that must be shared as equitable as possible among all our citizens.”

The Tories are now sleeping in the bed they have made. Left out to dry, renters are beginning to turn against the Conservative vision. The election numbers tell the story of this left-ward drift of the rental sector: 29 per cent of private renters voted Labour in 2010, 39 in 2015, and 54 in June.

Philip Hammond’s budget – which, despite its radicalism, continues to ignore the welfare of this rental population – is unlikely to reverse this trend. Generation Rent is no longer simply a class in itself — it is becoming a class for itself, as well.

We appear, then, on the verge of a paradigm shift in housing policy. As the demographics of the housing market change, so must its politics. Wednesday’s budget signals that even the Conservatives – the “party of homeownership” – recognise the need for change. But it only goes halfway.

The gains for any political party willing to truly seize the day – to ditch the property-owning dream once and for all, to champion a property-renting one instead – are there for the taking. 

David Adler is a research association at the campaign group Generation Rent.

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