Counting On … – Page 41

Counting on … day 80

5th April 2024

Green Steel

Steel manufacturing produces more CO2 than any other heavy industry, comprising around 8% of total global emissions.

Traditionally steel is made in a blast furnace where the iron ore is he@ted at high temperatures together with coal. As the coal burns it produces carbon monoxide which bonds with and removes oxygen in the iron ore so purifying it to produce metallic iron. The carbon monoxide binding with oxygen becomes carbon dioxide and is one of the main sources of carbon emissions. Other sources of emissions will vary depending how the furnace is heated etc.

The industry is developing various ways of producing steel without – or with reduced – carbon dioxide emissions – known as green steel.

Replacing coal with hydrogen: Green steel can be produced by using hydrogen to remove the oxygen from the the ore – producing water (H2O). Ideally this would be green hydrogen – ie hydrogen produced using renewable energy. This method of producing steel requires heating the furnace to a higher temperature.

Reusing existing steel: steel can easily be recycled in arc furnaces powered by electricity – which ideally would be electricity from renewable energy sources with no carbon dioxide emissions.

Around 30% of the world’s steel is made from recycled steel. However steel cannot be recycled endlessly without loss of quality. Each time it is recycled the proportion of unwanted elements such as copper, nickel and tin increases. On the other hand steel has long in-use life which means that the amount of steel made available for recycling does not at present keep up with the growing demand for more steel. Our modern economies are big users of steel!

(For more detail see https://theconversation.com/green-steel-is-hailed-as-the-next-big-thing-in-australian-industry-heres-what-the-hype-is-all-about-160282)

Which ever form of green steel is produced, the availability of large amounts of renewable energy is going to be critical.

As important will be the way the transition is managed as furnaces are large and highly expensive pieces of kit – ie needing substantial investment – and can take years to install which in some instances has led to workers being laid off – as is proposed at the Tata steel works in Port Talbot. (https://www.theguardian.com/uk-news/2024/mar/25/tata-port-talbot-job-losses-labour-subsidy?CMP=Share_iOSApp_Other).

Other important issues to address are how steel is used – with product design ensuring a long life, whether other materials could be used – timber for example in building construction, and how effectively scrap steel is collected and recycled.

Further reading – https://www.bbc.co.uk/news/business-64538296

Counting on … day 79

4th April 2024

Bioenergy can also be obtained from trees – the timber is burnt to either as direct form of heat from a stove of fire, or in a power station to drive steam turbines that generate electricity. Burning timber is the most common form of bioenergy used in the UK. Whilst it can be claimed that only waste timber is used – cuts and shavings from timber plants – the reality is that power stations such as Drax import timber which already starts to add to its carbon footprint. International rules imported timber is zero carbon as the emissions are counted in the country where the trees are harvested. In fact these emissions are often not recorded at all. And whilst the timber arrives here as preformed pellets, the timber intact comes from whole trees from mono culture plantations or from virgin forests.

In reality burning timber as a bioenergy is not a zero carbon option. The carbon stored in the timber is going to be released at some point in the future but if that tree is left to grow, and in its own good time, die, that carbon is locked in longer. Even better as the tree decays in its natural environment it will take years to decay during which time it will provide a habitat for a great variety of different plants and creatures. Further a large part of the carbon will be absorbed into the soil, again storing it away. If on the other hand the tree, having been felled, is used to make doors, floor boards, paper, furniture etc so the carbon is locked away for many more years to come.

For further reading – https://www.rspb.org.uk/helping-nature/what-we-do/influence-government-and-business/nature-protection-and-restoration/bioenergy

Is burning wood for energy worse for the climate than coal?

Biomass Basics

Carbon capture and storage CCS for the ongoing burning of fossil fuels to generate energy – https://www.theguardian.com/environment/2024/mar/26/tone-deaf-fossil-gas-growth-in-europe-is-speeding-climate-crisis-say-activists?CMP=Share_iOSApp_Other

Counting on … day 78

3rd April 2024

Biofuels are fuels derived from biomass such as plant material, food waste, algae, or animal waste. There are two forms of biofuel –

“Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as maize, sugarcane, or sweet sorghum. Cellulosic biomass, derived from non-food sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form (E100), but it is usually used as a gasoline additive to increase octane ratings and improve vehicle emissions.

And “Biodiesel is produced from oils or fats using transesterification. It can be used as a fuel for vehicles in its pure form (B100), but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles.” (https://en.wikipedia.org/wiki/Biofuel)

Brazil is the largest producer of bioethanol and the EU is the largest producer of biodiesel.

Both forms of biofuel differ from fossil fuels in that they are produced from organic materials being grown now as opposed to using organic materials that were decomposing millions of years ago.

Both produce greenhouse gas emissions but less than do fossil fuels. Biofuels may be made using only waste materials, but often are made from crops that have been specifically grown for this purpose. This may have the affect of diverting land that would otherwise be used for growing food, or may involve deforestation to create new crop lands.

Drax power station which burns timber as a biofuel to generate electricity uses wood pellets. Although wood pellets can be made from waste wood, most of the pellets that are burnt at Drax are made from whole trees that were once growing in virgin forests in South Carolina and British Columbia. These are then imported to the UK. For more information- https://www.bbc.co.uk/news/science-environment-68381160

Counting on … day 77

2nd April 2024

Land management is key in reducing damaging emissions and improving biodiversity. This is acknowledged by the Government but not always pursued.

“Globally, around a quarter of GHGs come from land management activities, including deforestation and agriculture. However, terrestrial and marine ecosystems take up carbon dioxide equivalent to over half of the emissions caused by people. The challenge is to reduce anthropogenic emissions and increase uptake by ecosystems, storing carbon in soils, sediments and vegetation….

“In the UK our land, coast and seas have been managed for millennia to provide food and other resources for people. Some patterns of management were sustainable over the centuries, supporting biodiversity and storing carbon as well as providing for the needs of people. However, there has also been habitat destruction and degradation, leading to declining biodiversity and substantial emissions of carbon to the atmosphere.

“Repairing this damage to stop emissions and capture more carbon is an essential element of achieving net zero, alongside deep cuts in emissions from other sectors such as energy and transport. The Climate Change Committee estimates that 20% of agricultural land will need to be released before 2050 to deliver actions that reduce emissions and sequester carbon. Such a shift in land use change will require us to prioritise opportunities that also deliver wider co-benefits for climate change adaptation, biodiversity, water management, air quality and soil health.”

Natural England publishes major new report on carbon storage and sequestration by habitat

Counting on … day 76

28th March 2024

Biodiversity is “the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic, species and ecosystem levels. Biodiversity is not distributed evenly on Earth; it is usually greater in the tropics as a result of the warm climate and high primary productivity in the region near the equator. Tropical forest ecosystems cover less than 10% of Earth’s terrestrial surface and contain about 50% of the world’s species.” (https://en.wikipedia.org/wiki/Biodiversity)

Biodiversity is linked to climate change. When the climate is changing, ecosystems change and with them species must also adapt and change. If the climate change is rapid, some species may not be able to change at a sufficient pace and their numbers will decline rapidly. Conversely biodiversity is often boosted by practices designed to reduce climate change – eg planting more natural woodland, restoring natural habitats such as peat bogs and wet lands, etc benefits and therefore boosts biodiversity.

Counting on … day 75

27th March 2024

Agroforestry offers another approach to farming that enables the long term increased sequestration of carbon dioxide. Agroforestry has two main forms:

“Silvo-pastoral agroforestry: which means the grazing of animals under trees. The animals enrich the soil while the trees provide shelter and fodder for the animals.

Silvo-arable agroforestry: where crops are grown beneath trees, often in rows which are large enough for a tractor to tend to the crops without damaging the trees. This is farming in 3D, the trees and the crops occupy different levels above ground, and also below ground where the tree roots will reach down deeper than the crops.”(1)

The additions of trees in the farm enhances the amount of carbon dioxide that is being . At the same time the practice also benefits the condition of the soil. “Tree roots reach deep into the ground, releasing much-needed carbon into the soil. They cycle nutrients and bind the soil together, preventing it from being eroded by the wind or the rain.”(1)

(1) https://www.soilassociation.org/causes-campaigns/agroforestry/what-is-agroforestry/

Counting on … day 74

26th March 2024

Regenerative farming is one way in which carbon dioxide levels can be reduced. Regenerative farming aims both to increase the amount of carbon stored in the soil and the plants it sustains, and by lowering livestock numbers, reducing emissions. Livestock account for about 14% of greenhouse gas emissions.

For further reading – https://greentau.org/2023/12/15/windows-of-opportunity-16/

Counting on … day 73

25th March 2024

Carbon offsetting is akin to an accounting exercise where the carbon emissions released by one activity are offset – rebalanced – by another activity that sequesters – takes in – carbon dioxide. Typically this might be offsetting the carbon emissions from an air flight by as many planting trees as would absorb that quantity of carbon dioxide. The catch there is one of timing. The air flight produces emissions now but the tree will only absorb the equivalent amount of carbon dioxide over a number – tens of not hundreds – of years and a young sapling may in fact release more carbon dioxide than it absorbs. Another option it to offset the carbon emissions by not felling trees so allowing them to continue to absorb carbon dioxide – but that questions why the trees might have been felled in the first place.

Further reading – https://www.theguardian.com/environment/2021/may/04/what-is-carbon-offsetting-and-how-does-it-work?CMP=Share_iOSApp_Other

– https://www.theguardian.com/environment/2023/mar/30/quality-standards-hold-carbon-offsetting-industry-account?CMP=Share_iOSApp_Other

Counting on … day 72

22nd March 2024

Carbon sequestration is a formal name given to the processes by which carbon is captured from the atmosphere and stored on a long-term basis. Such long-term storage might include peat bogs, forests, kelp beds etc and may be referred to as ‘carbon sinks’.

Carbon sequestration can be used as a means of mitigating the effects of climate change. This can be biologically by, for example, planting more forests, restoring peat bogs and wetlands, and re-establishing kelp meadows. This natural sequestration can be enhanced, in the case of forests, by using felled timber to make items such as buildings, furniture etc and keeping those items for hundreds of years. However growing trees for timber needs to be carefully managed to a) maximise the carbon captured by the growing tree, and b) to maximise the flourishing of biodiversity.

Carbon can also be sequestered geologically if the CO2 can be captured eg from a cement factory. Then the CO2 “can be compressed to ≈100 bar into a supercritical fluid. In this form, the CO2 could be transported via pipeline … and injected deep underground, typically around 1 km, where it would be stable for hundreds to millions of years.” (https://en.wikipedia.org/wiki/Carbon_sequestration)

Counting on … day 71

21st March 2024

The carbon cycle

The earth’s systems have various ways of absorbing and using carbon dioxide in such a way as to enable life to flourish. Plants absorb carbon dioxide as part of the process of photosynthesis storing the carbon as cellular material in their leaves, branches etc. Plants release carbon dioxide back into the atmosphere as they respire – breathe. A living growing plant absorbs more carbon dioxide than it releases. When the plant dies, the carbon that has been stored as leaves and branches etc slowly decays – breaks down – and the carbon returns to the atmosphere as carbon dioxide. This is as true of water and marine plants as it is true of land plants.

(For a short video describing how trees absorb and use carbon – https://www.woodlandtrust.org.uk/climate-change/carbon-trees/)

Soil in part is made up of dead plant and animal material which decays slowly overtime. Soil is therefore a storer of carbon.

The seas and oceans also contain carbon dioxide that is dissolved in the water. This carbon dioxide cycles through the water as marine plants take in, store and release the carbon as they grow. Marine waters and the layers of sediment at the bottom of the seas and oceans store carbon in the same way as does soil.

This brings us back to an earlier post about how much carbon dioxide there is in the atmosphere (measured in part per million) and the rate at which that concentration is increasing due to human activities – https://greentau.org/2024/02/19/counting-on-day/