Wärtsilä kept Madrid Barajas Airport running during the blackout.

The SAMPOL power plant is a key element of the infrastructure at Madrid’s Barajas Airport, designed to keep everything running smoothly even during major outages of the Spanish power grid. In April, Spain and Portugal experienced a 10-hour blackout. The airport, however, continued operating flawlessly thanks to the reliability of the power plant and the ingenuity of the Wärtsilä and SAMPOL teams, who implemented an innovative solution.

Have you ever wondered how huge airports like Madrid Barajas continue running without disruption even during power failures? Let’s take a look at the SAMPOL power plant, which supplies terminals T4 and T4S. Designed, built, and operated by SAMPOL, the facility is equipped with six Wärtsilä 18V32DF engines. These engines not only provide backup power but also produce hot and chilled water for heating and cooling by recovering waste heat from their operation.

What exactly happened?

Under normal conditions, the power plant generates electricity as well as hot and cold water, operating in parallel with the grid. The operator sells excess electricity to the market, reducing costs. In the event of a blackout, the system automatically disconnects from the grid and switches to island mode, continuing to supply electricity, heating, and cooling without interruption. At that point, the control algorithm switches fuel from natural gas to backup liquid fuel (LFO), stored in two onsite tanks.

This reserve is sufficient for 24 hours of full-load operation, assuming the grid is restored or additional LFO is delivered by truck. This time, however, gas in the pipeline was still available. Thanks to the reciprocating engine technology, which operates at low gas pressure, it was possible to continue running on gas—even though this was not originally foreseen in emergency mode. SAMPOL consulted with a Wärtsilä advisor to see whether the program could be modified. Together, they decided to deviate from protocol and test gas operation in island mode.

One of the six engines was disconnected from liquid fuel, the necessary adjustments were made, and it was switched to gas. The process was closely monitored to avoid errors. The test was successful, and since delivery of additional LFO was confirmed later that afternoon, there was no need to switch the other engines. However, the team confirmed that if necessary, all six engines could have run on gas—even without liquid fuel available.

“During the recent outage, our team demonstrated extraordinary flexibility and innovation. By quickly adapting to the situation, we helped SAMPOL ensure that Barajas Airport remained fully operational. This event confirms the reliability of our solutions and our commitment to energy security, even under critical conditions,” said Kenneth Engblom, Vice President of Wärtsilä Energy for Africa and Europe.

“This incident shows how resilient SAMPOL’s CHP concept is and how effectively it supports uninterrupted airport power supply. All critical systems remained continuously powered, allowing the airport to operate normally,” added David Gabiola, Director of the Barajas power plant at SAMPOL.

Throughout the entire blackout, the airport experienced no power issues whatsoever and continued to operate as if nothing had happened.