Carbon Commentary newsletter

1, ‘Heat batteries’. A Finnish company will supply a 100 MWh heat battery to a municipality near Helsinki. This battery contains a type of sand that is heated up by electricity when supplies are abundant and the high temperatures can be retained for weeks or months if necessary. The heat is then transferred to the water in the town’s district heating system in winter. The transfer outwards can be up to 1 MW, not a huge flow but which helps reduce the costs of running the heating system. A conventional battery would be able to deliver a much faster energy transfer but the land area taken by the heat battery - about 230 sq metres – is far less than would be needed for lithium ion.

(Thanks to Mark Ellingham, to whom I also owe much gratitude for his work structuring and editing my new book in which the prototype of this battery in mentioned).

2, Effect of trees on temperatures. A 2021 study showed that most forested areas have more cloud cover, holding temperatures down because more sunlight is reflected. Global reforestation may therefore help mitigate climate change. A 2024 article suggest a second effect: increased forest cover in the eastern United States over the 20^th century held down temperatures by increasing water evaporation through transpiration, helping to explain the anomalous lack of increase in this region. The researchers conclude that ‘Locations surrounded by reforestation were up to 1°C cooler than neighboring locations that did not undergo land cover change’. Reforestation can therefore both capture CO2 and hold down local temperatures. The research suggests that heat suppression is greatest near to younger forests composed of conifers rather than broadleaved trees.

3, Grid improvement. A striking indication of the investment requirements for the world’s electricity networks. RTE, the operator of the high voltage transmission network in France, noted that it would need about €100bn capital spending by 2040. Although large, this figure only equates to a rate of about 1% of total capital investment in the country. However five years ago RTE’s estimate was about a third of this amount. Much of this new investment budget will be spent on extending the network to offshore wind farms and other new locations but RTE also stresses the need to replace much of the existing ageing infrastructure. It says that the average age of its overhead lines is 55 years while 20% are over 70 years old. These figures are said to be better than other European countries, suggesting other networks will need even more new spending. Investment needs are also increasing because higher temperatures are tending to speed up the natural deterioration of cables.

4, Individual legal action. A Belgian farmer is suing Total, the oil and gas major. This is the first such claim under Belgian law. The farmer’s case is that the CO2 emissions resulting from Total’s fossil fuel production have damaged his ability to farm his land because of longer, more intense summer droughts and winter flooding. He claims, for example, that he can no longer grow enough feed to maintain the 160 cows he used to keep but can now only host 100 animals. Belgian law obliges an entity that causes damage to pay compensation for the costs imposed. Some claims similar to that of the Belgian farmer have already resulted in initial judgments against the fossil fuel industry around the world but most are being appealed. In this case the court is being asked both to compensate the farmer and to mandate rapid, well-quantified reductions in Total’s fossil fuel output as well as the ending of exploration for new resources. For what it is worth, my guess is that this case might well succeed in lower courts but that the appeal process will be drawn out for many years and eventual action will be slow. But legal actions like this are only going to increase in frequency and legal merit.

5, Vehicle-to-Grid. The Australian renewable energy agency published a report indicating that EV owners could earn an average of A$12,000 ($8,000) a year from supplying power back into the network, principally in the form of short term response to varying grid frequency. The agency pointed out that EV batteries will probably represent the cheapest form of short-term storage. In the UK, Octopus Energy recently launched a tariff that offers free EV charging to owners making their batteries available for vehicle to grid use for a minimum numbers of hours a year. (Thanks to Gage Williams).

6, Biochar. Biochar can be made from many organic materials by subjecting them to intense heat in the absence of air. Zurich-based Cotierra, focuses on turning residual materials from coffee bean farming into this permanent form of carbon sequestration. This newly formed startup raised $1m in early stage financing from investors specialising in carbon removal technologies. Cotierra’s distinctive approach enables small scale coffee farmers in the South to make their own biochar by using a newly designed simple furnace. The company is starting with coffee farms in Colombia. Biochar has the additional huge benefit of increasing the retention of nutrients in agricultural soils meaning that less artificial fertiliser is needed.

7, Low carbon cement. Decarbonising cement production is one of the trickiest challenges. The major global manufacturers have therefore poured money into the many different potential routes for reducing emissions, including focusing on carbon capture (Heidelberg Materials) or the use of supplementary materials to complement limestone as a cement source (Holcim). The venture capital arms of the industry are among the most active net zero investors. This week France’s Saint Gobain added to its venture capital portfolio by participating in a fundraising from Fortera, a young Californian company whose technology uses the CO2 arising from the manufacturing process to incorporate back into its cement at a late stage in the production cycle. At the same time as announcing its participation in the Fortera financing, Saint Gobain said it was ‘supporting’ Ecocem, an Irish business with a very different approach to that of Fortera which recently received full EU approval for its product for use in construction. There’s a chapter on the bewildering variety of options for cement decarbonisation in Possible, out in the UK this week.

8, Tidal barrages. Every few years, tidal barrages resurface as potential sources of UK electricity. These dams capture the energy of rising and falling tides. Although the country probably has the best resources of this type of energy in the world, the expense and difficulty of damming a large river estuary has deterred private companies and governments. Will this change? In the last few weeks, early work has (again) commenced looking at barrages on both the Severn and the smaller Mersey rivers, both pushed strongly by local government. The challenges are immense, which is probably why there are only 3 tidal barrages installed in the world. But both a Severn barrage, running from South Wales to western England, and the Mersey dam, running southwards from the Liverpool area, could generate more electricity per unit of capital expenditure than the new Hinkley Point nuclear power station, at least according to some estimates. They would be by far the largest tidal projects in the world and they would probably continue working for over a century with a low operating cost.

9, Green steel using electrolysis. Although large sums are being directed at hydrogen steel-making projects, another route for green steel is possible. Boston Metal announced it has completed its first ‘molten oxide electrolysis’ facility for recovering waste metals from mining waste in Brazil. If this plant works, it will provide an example which can then be replicated to make iron directly by passing electricity through iron ore. The potential advantages of the Boston Metal approach include an ability to use lower grades of ore than hydrogen furnaces. And, according to the company, the process will use less electricity than would be required to make the hydrogen needed for manufacturing iron.  

10, Electric charging for heavy trucks. BP said it had bought control of a large existing truck stop near the Channel Tunnel in England. The intention is to install a large number of charging stations for commercial trucks, BP’s first such plan in the UK. Some chargers will be up to 1 megawatt speed, or four times the maximum charging rate of a Tesla Model 3 and the site will have 125 chargers operating at 100 kilowatts.  This is part of BP’s plan to build very rapid charging stations for electric heavy trucks on commercial routes across Europe. It already has a substantial network in Germany.

A note about Possible from the Financial Times journalist Tim Harford in one of this latest columns:
As Chris Goodall explains in his new book Possible: Ways to Net Zero, removing fossil fuels from our energy system is technologically feasible, but it is a daunting task requiring huge upgrades to the electricity grid, our storage capacity and much else besides. We should take heart from the fact that these steps to fight climate change will also lead to large and immediate gains in our day-to-day health.