Carbon Commentary newsletter

1, Willingness to take action on climate. A German academic study looked at beliefs and behaviour about climate in the US. It showed that survey respondents strongly underestimated the willingness of other people to act on climate. When properly informed about this greater willingness, the study showed that individuals were themselves more willing to take climate-friendly action, such as donating to charities with environmental objectives. The researchers summarised their findings as follows: ‘We show that a relatively simple, scalable, and cost- effective intervention – namely informing respondents about the actual prevalence of climate norms in the US – reduces these misperceptions and encourages climate-friendly behavior’. Perhaps surprisingly, even climate sceptics adjust their behaviour upon understanding the wish of others to take action against global warming. (Thanks to Paul Klemperer).

2,  Better cabling on electricity transmission lines. A report argued that power grids can double the capacity of electricity transmission by using advanced materials (or ‘reconductoring’ in utility-speak) for the cables strung between pylons. This is becoming an increasingly urgent need around the world. The document refers to US transmission routes but similar advances are being widely discussed in other jurisdictions, such as India. Reconductoring will often replace the central steel cable, which provides the strength, with a material such as carbon fibre that does not stretch and sag as much when large currents cause the cable to heat up. Carbon fibre actually contracts when it gets hot, also meaning that some transmission lines can use fewer pylons per kilometre. An informative discussion on the Volts podcast about this topic here. (Thanks to Greg Yakolev).

3, Low carbon cement. Brimstone, a start-up from Caltech, uses calcium silicate not limestone as the source material to make cement. Conventional cement making drives the CO2 out of limestone whereas calcium silicate contains no carbon. Brimstone’s approach therefore avoids the otherwise inevitable loss of CO2 to the atmosphere in the production process. The US Department of Energy offered to negotiate a $189m subsidy for Brimstone to develop its first large scale plant. This is one of the most plausible of the many possible solutions to the cement decarbonisation challenge. A chapter in Possible looks at the wide range of investments by the global cement companies into alternative low carbon routes.

4, Emissions from hybrid electric cars. It doesn’t come as a surprise to read that plug-in hybrids don’t reduce emissions as much as suggested. The EU Commission reported that the typical plug-in hybrid sold in 2021 emitted over three times as much CO2 as thought, largely because drivers use petrol far more than expected and battery power much less. Fuel consumption was directly measured across a large number of cars. The typical petrol plug-in hybrid had real-world emissions only about 25% below its pure petrol equivalent. (And, also unsurprisingly, both pure petrol and diesel cars had actual emissions about 20% above the levels estimated when the cars were tested in standard examinations). The clear implication is that the current global surge in the share of plug-in hybrid sales needs to be pushed back by governments and regulators. Transport emissions are not going to be reduced rapidly if PHEVs grow at the expense of standard EVs.

5, Ammonia as a shipping fuel. MAN, the largest maritime engine supplier, is developing 2 stroke units that will burn ammonia as their fuel. It says that it will install its first ammonia engine in a vessel in 2024. However it has provided little data on its research into the emissions arising from ammonia storage and combustion. A group of 19 NGOs demanded more information on the impact of burning ammonia at sea, including missing data on the release of nitrous oxide (N2O), a virulent greenhouse gas. MAN’s research has previously suggested that ammonia made from green hydrogen is the lowest cost low-carbon fuel but shipping companies seem slow to move to this new fuel, partly because of concerns about pollution and safety on board.

6, Direct Air Capture. Avnos is another impressive competitor in the rapidly developing race to lower the cost of Direct Air Capture. Encouraged by government financing aid, there are now over thirty US ventures specialising in DAC. Avnos uses a completely new type of technology (water swing absorption) for sucking CO2 out of the air and claims substantially lower energy use than established suppliers such as Climeworks. My request for an estimate of energy use was not answered but the Avnos claims seem plausible because their approach does need to use heat to free the captured CO2 from the material that has absorbed it. This is the largest part of the energy utilisation in most other approaches. Their technology also helpfully generates multiple tonnes of fresh water for every tonne of CO2 collected, a valuable advantage in many parts of the world.

7, Lithium co-produced with geothermal power. Australian company Vulcan Energy has the rights for geothermal energy exploitation in a section of the upper Rhine in Germany. Geothermal water sometimes contains sufficiently large concentrations of lithium to make extraction worthwhile alongside the primary use for heat collection for electricity generation. Vulcan’s territory has some of the highest lithium percentages in underground water sources in the world. The company announced it had begun commercial production of lithium using relatively environmentally friendly techniques and will now process lithium chloride into lithium hydroxide in Frankfurt for use in batteries. Nevertheless, there’s still substantial scepticism about lithium extraction from geothermal waters. Vulcan’s plant is an important global test-bed. More on direct lithium extraction here.

8, Heat storage. Construction of the world’s largest heat storage ‘battery’ will start this summer. It will feed the district heating system in Vantaa, a suburb of Helsinki. The capacity is estimated at 90 GWh, or enough to cover the annual heat demand of roughly UK 8,000 homes. The size of the underground cavern used to store the hot water will be 1.1 million cubic metres in size (equivalent to a cube with sides about 100 metres long) and will pressure the liquid, enabling water storage temperatures to rise to around 140 degrees without boiling.  The full budget for the project is put at €200 million, a very large figure in the context of an estimated value for the annual heat stored of around €8m.

9, Solid state batteries. Two further steps towards the sale of cars with fully solid state batteries, which potentially offer improved power density and faster charging. A new launch from an SAIC brand in China contains ‘semi solid’ electrolytes, and provides up to 1,000 km of range (using the generous Chinese calculations). Charging rates can be as high as 400 kW, far faster than conventional chargers in Europe. GAC, another important Chinese manufacturer, indicated it would be selling cars with fully solid state batteries in 2026. Other car companies are racing towards the launch of these improved batteries but moving from R&D to general use has been slower than hoped. The signs are that Chinese firms are two to three years in front of other manufacturers.

10, Synthetic aviation fuel. DG Fuels intends to make synthetic aviation fuel (SAF) from biomass residues in Louisiana. It announced a partnership with Johnson Mathey and BP to develop its first Fischer Tropsch refinery using carbon monoxide generated from sugarcane and green hydrogen from electrolysis. The planned plant will have an output of around 13,000 barrels a day, about a quarter of one per cent of global aviation demand. It is the largest planned SAF refinery in the world. We can all be sceptical about whether waste biomass is available in sufficient quantities to meet the demand from companies making biogenic synthetic fuels, such as ethanol. But DG’s important claim is that it uses 97% of the carbon in unusable corn products compared to a typical 25% in refineries making other biofuels.

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