Interactive calculators for comparing cost and CO₂ and CDR demand for aviation and shipping
These interactive calculators complement the three analyses published on the Substack Marginal Carbon:
Aviation cost analysis (April 2024)
Shipping cost analysis (Aug 2025)
Shipping and aviation policy analysis (Sep 2025)
There are four calculators in total. Two comparing the cost of CDR and fossil fuels with electrofuels and two looking at potential total volumes of CO₂ and CDR to reach net zero shipping and aviation.
These are simplified calculators to give a quick picture of how costs and volumes differ with assumptions change. For detailed cost assumptions, see this Google sheet.
The first is a cost calculator comparing the cost of electrokerosene made from H2 and CO₂ versus CO₂ capture and storage + conventional Jet fuel. (To the left on desktop, or below on mobile). CO₂ is needed both for the electrofuel and the CDR path. This means that the CO₂ capture capex and energy needs do not matter for the comparison. If the CDR method is DACCS, BECCS or another method does not matter for the comparison.
This second calculator (below) shows total global CO₂ and or CDR needs for aviation, depending on how much biofuel and electrofuels are used. CO₂ is needed as a feedstock in e-fuels, and CDR is needed for the share not mitigated by biofuels or e-fuels, and potentially for lifecycle emissions from the production of biofuels and e-fuels.
This shows the total volume needed for global net zero aviation, given the fuel demand; it does not show the likely actual demand, which mostly will depend on policy.
The Shipping cost calculator compares E-ammonia versus CDR + fossil fuel oil (BAU) for shipping. This differs from the aviation cost calculator as e-ammonia does not need CO₂ as a feedstock.
The CDR+BAU option is favoured at an electricity cost below 0.03kWh (€30 MWh), or CDR price above $275/t, or 75% higher fossil fuel prices (both at $0,05kWh).
Note that e-ammonia has lower energy density per unit of fuel, so more fuel is needed, the calculator takes this into account. The extra cost of shipping more fuel, retrofitting ships, and the need for larger fuel tanks for ammonia is not included
This last calculator (below) shows total global CO₂ and or CDR total needs for shipping, depending on how much biofuel and electrofuels are used. CDR is needed for the share not mitigated by biofuels or e-fuels, and potentially for lifecycle emissions from the production of biofuels and e-fuels. This shows the total volume needed for global net zero shipping given the fuel demand; it does not show the likely actual demand, which mostly will depend on policy.