Recorded Sunday 29th March. Two very different stories highlight the complexity of the energy transition - from industrial decarbonisation in steel and cement to the increasingly political battle over offshore wind in the US and UK.

Key topics:

• Why steel slag matters for low-carbon cement
• How electric arc furnaces (EAFs) are reshaping industrial waste
• How Cocoon Carbon could decarbonise both steel and concrete
• Trump refunding offshore wind leases in favour of oil and gas
• The UK rejecting Chinese turbine manufacturing investment
• What this means for costs, jobs, and industrial strategy

Connecting two hard-to-abate sectors: steel (7%) and cement (8%) together account for ~15% of global GHG emissions, yet both remain under-discussed due to their reliance on hard-to-abate process emissions.

Cocoon Carbon is a UK based company developing technology to convert EAF steel slag into supplementary cementitious material (SCM) that can replace up to 30% of ordinary Portland cement.

Historically, ~70% of steel came from blast furnaces, producing slag that could be reused as SCM in cement. However, as steel production shifts from blast furnaces and basic oxygen furnaces to direct reduced iron and EAFs - cutting emissions by 40–70% - the slag chemistry changes, making it unusable in cement in its raw form.

Cocoon's technology can process this EAF steel slag while molten (~1,500°C), directly at the steel plant, into a form usable as SCM, restoring its value. With ~100–150 kg of slag produced per tonne of steel, this creates a major new source of low-carbon cement input.

The economics are compelling: raw slag sells for ~$15–25 per tonne, while processed SCM reaches ~$80–120 per tonne (~5× uplift). This improves steel plant economics, reduces waste, and supports the shift to EAFs.

The US is the first target market, where ~70% of steel is already EAF-based and regulations are performance-driven.

Cocoon has raised $15m in a Series A round; its modular units can be installed in 6–9 months.

In wind, the US story centres on Trump refunding ~$1bn in offshore wind lease payments to TotalEnergies to cancel a 4 GW project and redirect capital into oil and gas. The leases were part of a ~$5bn auction round, with the refund representing ~3% of project cost. This reflects a broader anti-wind stance and may increase costs in regions where offshore wind is cheaper than gas.

Offshore wind also raises a structural question: could it replicate fossil fuel royalties? US oil and gas generated ~$6bn in royalties in 2024 (ongoing payments), whereas wind leases are typically upfront rather than recurring.

In the UK, a £1.5bn Mingyang turbine factory (≈1,500 jobs) was rejected on security grounds. A smaller £200m investment from Vestas (~500 jobs) may proceed, depending on auction demand.

The UK’s decision prioritises energy security but highlights a trade-off: without stronger negotiation, the country risks missing out on manufacturing, jobs, and long-term industrial leverage while remaining dependent on foreign developers.