ScottishPower started up a small unit on Friday to capture carbon from a British coal-fired power plant for the first time, the Iberdrola-owned company said.

The prototype -- developed by Aker Clean Carbon and part funded by ScottishPower, Germany's EON and Norway's state-owned Statkraft -- is a small portable version of a full-scale carbon capture and storage (CCS) plant and has been fitted to ScottishPower's Longannet coal fired power plant.

The test unit will capture carbon from the equivalent of only about one megawatt of the 2,300 megawatt plant but should provide data that could help the company develop a commercial scale CCS project.

The test unit uses the exact same technology that we aim to retrofit to the station for a commercial scale CCS project by 2014, and the leap from 1 MW to 330 MW is now within sight, Nick Horler, Chief Executive of ScottishPower, said.

ScottishPower -- which is owned by Spain's Iberdrola, one of the world's leading wind power generators -- has entered the British government's competition to develop a commercial scale CCS project by 2014 and plans to bury the climate-warming gas under the North Sea.

Aker Clean Carbon's mobile unit has been in operation since 2008 and has already been tested at the Risavika gas facility in Norway. It can process emissions from power stations and industrial sites for a few months before being moved to another site.

ScottishPower plans to run the test unit at Longannet for seven months, a spokesman for the company said.

As an investor in the project, Germany's EON also has the option of running the unit at one of its plants.

(Reporting by Daniel Fineren; editing by James Jukwey)