EDF: hold Hinkley Point C to its cost and date

Forecast cost and completion as ranges, commit at the 80th percentile and recover each package that puts it at risk.

By OneShot · Updated October 23, 2026

Read the solution ↓

What the workflow produces

Project cost and schedule forecast

Packages: Cost to date, remaining range and dependencies per package.
Forecast: 50th and 80th-percentile cost and completion date.
Drivers: Packages and risks that move the forecast most.
Recovery: Approved actions, owners, deadlines and months recovered.

The documented problem

On January 23, 2024, EDF said the cost of completing Hinkley Point C was now estimated at between £31 billion and £34 billion in 2015 values, against an earlier estimate of between £25 and £26 billion. In May 2022 it had scheduled the start of electricity production for June 2027. EDF analysed three scenarios for Unit 1: operation in 2029 as the target, 2030 as the base case and 2031 if a further 12-month risk materialised.

EDF named the cost of civil engineering and the longer electromechanical phase as the two main reasons for the revision, and estimated that the further 12-month delay would add around £1 billion in 2015 values. These are EDF’s own estimates. The OneShot workflow below forecasts a capital project’s cost and completion date as ranges and carries the forecast into recovery actions.

EDF: Hinkley Point C update, January 2024Primary source · Checked 2026-10-23

The OneShot solution

A committed cost and date the project can hold

Commit to the cost and date the project meets at its 80th percentile, and recover every package that puts them at risk.

What it pays back

Months of delay recovered

Counted per work package, in months taken off the forecast completion date.

EstimateAbout £1bn if a further 12-month delay is avoidedBasis: EDF’s estimate of around £1 billion in 2015 values for its further 12-month delay scenario.

Work enters the queue: A monthly progress report, a package over its estimate or a new risk on the register.
Decision owner: Project director, with the project board

01
Gather the packages
Read each work package with cost to date, remaining estimate, duration and the packages it waits on, and the risk register with each risk’s chance and impact. Flag packages whose progress report is late.
- Project schedule and cost records
02
Get ranges from the owners
Ask each package owner through the goal’s private request page for a low, likely and high remaining cost and duration, and the reason for any change since last month. Record who gave each range.
- Project schedule and cost records
03
Simulate cost and completion
The OneShot agent uses its prediction tool to run thousands of outcomes for total cost and critical-path duration, with each risk occurring or not at its stated chance. It reports the 50th and 80th percentiles and the packages that move them most.
- Predict
- Project schedule and cost records
04
Get the commitment approved
Give the project director the forecast, the packages driving it and the recovery options their owners propose, each run as its own case. Record the committed cost and date and the approved recovery actions for the project board.
- Project schedule and cost records
05
Recover and re-forecast
Give each package owner its approved action and deadline on its request page, and chase it. Re-run the forecast every month on actual progress; a committed figure at risk goes to the project director before the board meets.
- Project schedule and cost records

What counts as complete

The board holds a committed cost and date at the 80th percentile, and every package driving a slip has an approved recovery action with an owner.

Decisions and exceptions

Ranges come from package owners; the agent does not set them.
Contract changes and safety decisions stay with the project director.
A forecast past the committed figure goes to the board; it does not become a new baseline on its own.

What to measure

Forecast completion against the committed date
Gap between the 50th and 80th percentiles
Packages reporting late
Months recovered by approved actions

Establish the baseline and review period before launch. Compare completed cases, unresolved work and reviewer corrections against the same scope.

The agent’s tool basket

OneShot gives its agents the tools to analyze records, communicate, research and act on authorized business data. The platform carries the workflow from the first action through to the recorded result.

Project schedule and cost records
Read work packages with cost to date, remaining estimate, duration and dependencies, and the risk register; record the committed estimate and recovery actions.