How to read this site
Each page breaks a sector of the negaWatt-BE scenario into tangible levers. This page explains what you see on a hypothesis card and how the underlying numbers are produced.
How to read a hypothesis card
Every card follows the same layout so you can compare levers at a glance:
- Now (2019) — the reference value, taken from official statistics or the scenario's baseline year.
- 2050 Target — where the scenario aims to be at the end of the transition horizon.
- Change badge — green means a reduction, orange means an increase, grey means roughly stable.
- Small chart — a simple bar comparison between the two milestone years.
- Plain-language discussion — what the lever means in everyday terms and why it matters for energy use.
- Feasibility debate — a callout summarising how realistic the assumed jump is, and what would need to happen in policy or society.
A Calculation details link at the foot of each card opens the underlying notebook section where the assumption is defined and computed.
The négaWatt method
The scenario applies levers in a deliberate order: sufficiency first (avoid waste, change behaviour), then efficiency (same service, less energy), then renewables to supply what remains.
The reference year is 2019, chosen to avoid the distortions of the COVID period. The horizon is 2050. Between milestone years, trajectories are assumed to evolve linearly unless the notebook specifies otherwise.
Keeping the site in sync with the science
The numbers on this site are not maintained separately from the models. Each
calculation notebook ends with a Website export cell that writes a
JavaScript data file to website/data/<sector>.js. Update an
assumption in the notebook, re-run the export, and this site reflects the change
automatically.
Open the flattened calculation notebooks directly:
A critical eye
The negaWatt-BE scenario is deliberately ambitious. Several assumptions are actively debated among the authors and in the wider literature — for example car occupancy rates, the magnitude of modal shift, the pace of district-heating rollout, and the depth of aviation cuts.
The Feasibility debate callouts on each card summarise these discussions. They are not disclaimers tacked on at the end; they are part of how the scenario invites a society-wide conversation about what is realistic and what is worth striving for.