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How the model works

Viable Pathway turns an inventory into projections on three pathways: business-as-usual (BAU), plus external trends, and plus internal actions. A scenario is a stress test of those pathways. The pages below explain the next layer of the model.

Model pages

Each page uses short sentences and the same terms. Diagrams and examples are illustrative. They are not a calculation from your data.

Marginal abatement cost (MAC)

The MAC curve ranks internal actions. The method changes attribution, not the combined pathway.

NPV and equivalent annual cost (EAC)

Discount cash flows in real terms. EAC compares projects that have different lives.

Pathway Solver

Size the plus-internal-actions pathway to a target. The solver does not invent actions.

Location-based vs market-based Scope 2

Grid average versus contractual electricity. Residual mix can raise reported emissions.

REC, LGC, and PPA

Inventory in the projection start year. Later purchases are an internal action.

Balancing activities

When one activity decreases, a linked activity can increase. This models electrification.

FERA / well-to-tank

Scope 3.3 companion rows sit under fuel and electricity. MAC can include this effect.

Packs, timing, and targets

External trends, action ramps, intensity, shadow carbon price, and SBTi sit on the same three pathways.

External trends packs

Pin a pack so a new publication does not change the plus-trends pathway unless you upgrade.

Action timing

Start ramp and after-end behaviour. Annual opex always stops after the end year.

Intensity vs absolute targets

Intensity times output Q. Growth can raise tonnes while intensity falls.

Shadow carbon price

Planning dollars per tonne on MAC cash flows. Constant, step, linear, or custom.

SBTi and Forward Looking Ambition

4.2% or 2.5% per year. FLA applies to Scope 1 and 2 when the base year is not the latest year.

Related About pages