Drax Power Limited - 75 day outage challenge

Drax Power Limited - 75 day outage challenge

Fast track control system upgrade / 75 day outage challenge

Drax power station plays a central role in energy production for the UK, with the site providing 12% of the country’s renewable power and 6% of the electricity

The site has evolved considerably since construction in 1973, and is now home to the largest decarbonisation project in Europe.

With a portfolio of flexible, low carbon and renewable power solutions, the site has a capacity of 3906 megawatts (MW) and produces around 15 terawatthours (TWh) of power a year, with 94% using compressed wood pellets, a form of sustainably sourced biomass. The use of biomass pellets reduces our carbon emissions by 80% compared to coal.

The Need

Playing a significant role in the UK power system, Drax
is committed to maximising uptime of its assets and
reducing its operating costs whilst decarbonising the
power market.

Having completed control system upgrades on Units 1
and 2, Drax needed to replicate the same approach on
its third unit. Although the control system at Unit 3 had
a strong operational track record, the technology was
becoming obsolete, increasingly difficult to support,
and less flexible to respond to changing performance
or regulatory drivers.

Drax power station min


  • Delivering a comprehensive upgrade pathway to deliver modern, powerful and flexible control platforms
  • Upgrading an obsolete control system in an accelerated timeline with a focus on maintaining uptime
  • Assuring “return to service” of the unit and early income from the revenue stream
  • New power plant control system gives the UK’s largest biomass plant the capacity and flexibility for continued process performance improvements
  • Extensive re-engineering of complex software applications to a new control platform, minimising operational risk

Why Capula?

Delivering the upgrade to an accelerated timeline, and despite having to work in a backdrop of the global Covid-19 pandemic, Capula successfully delivered the project ahead of the major commissioning and mechanical testing and in accordance with the time, cost and quality standards demanded. The scope of work included the disconnection and removal of the legacy control system, installation of new cubicles, installation of new cabling and the reconnection and test of all plant signals.

Capula solution

As a trusted partner, having worked with Drax since 1997, Capula had completed 80% of the control system upgrades at Drax as part of an ongoing comprehensive upgrade pathway to deliver modern, powerful and flexible control platforms.

Having successfully delivered the control system upgrade programme for the first two units to time sensitive outage challenges of 53 and 60 days respectively, Capula was selected to upgrade the control system at Unit 3.

The work required to upgrade the unit was extensive and based around the most advanced technology available. It included the replacement of obsolete legacy controllers with modern Schneider Electric M580 dual redundant processors and X80 I/O with more than 5000 channels. The new systems underwent extensive factory-acceptance testing and simulation to verify its control performance and integration with 3rd party systems.

Through the experience gained on previous projects, and noting the critical path for control systems, a scheduled window of time was allocated to ensure that all follow-on commissioning could remain on schedule. In line with the other upgrade projects, the installation and test scope of this project was to be delivered in an accelerated outage timeline of 75 days from start to completion to allow installation of control panels, cabling and testing of all plant signals.

The time allocated on this occasion was slightly increased to accommodate the impact of the global Covid-19 pandemic compared to the timings given for the other two Units.

Future developments

In continuing to deliver a programme that ensures more modern, powerful and flexible control platforms, Capula continue to support Drax to deliver further operational improvements. Drax has already identified further equipment upgrades, including the installation of a more efficient Siemens HP Barrel Turbine on Unit 1, this follows successful conversions with supporting control system modifications on both Units 2 and 3 which were delivered by Capula.