GE's F Class turbines use Dry Low NOx combustors.
GE F Class Operating hours.
Endesa opened the Mallorca plant in July 2006.
The new plant cost Endesa € 200m.
Two new GE F class turbines are being added to Cas Tresorer.

The recently opened 230MW Cas Tresorer CCGT plant in Palma de Mallorca, Spain, is already being expanded. The plant, which was the second of its type in the Balearic Islands, was originally opened by Endesa in July 2006 and cost €200m.

The first two GE Frame 6FA gas turbines have a net capacity of 77MW each, and these operated open cycle for the first year, generating up to 154MW. The steam turbine was added in 2007, so completing the first combined cycle. Two new gas turbines – also GE Frame 6FA types – will add about 150MW.

The plant owner and operator is Gas y Electricidad Generación, S.A., the Balearic Islands branch of Endesa. Lead contractor is Duro Felguera of Asturias, Spain. At the moment, the plant has a load factor of 47.84% when operated as a combined-cycle plant fuelled with gas oil. It will be converted to use natural gas when this becomes available on the islands.


Endesa’s investment in the CCGT plant and distribution systems comes in response to the sustained increase in electrical demand in the Balearic Islands (around 33% over the five years before the plant was built) and will enable the group to deal with similar projected increases – estimated at between 4% and 6% per year.

The original plant took the Mallorca-Menorca system’s generation assets to 1,360MW. Predicted peak demand for the summer of 2005 was 1,060MW, giving a 300MW margin (so 30% surplus capacity). The CCGT plant, along with the Son Reus plant already in operation in Mallorca, will use natural gas to diversify energy production in the region.

“The plant has a load factor of 47.84% when operated as a combined-cycle plant fuelled with gas oil.”


For the extension, GE will supply two additional Frame 6FA gas turbine-generators to the two already on site, along with additional equipment and services. The 75MW class Frame 6FA is the mid-sized member of GE’s fleet of F technology gas turbines. The turbines for the Cas Tresorer extension project will be made at GE Energy’s facilities in Belfort, France, and shipped to the site starting in the fourth quarter of 2008. The production unit uses a closed circuit water cooling system.

The new gas turbines are scheduled to enter commercial operation in the third quarter of 2009. In addition to the gas turbine-generators, GE’s contract also includes technical advisory services during installation and commissioning.


A new 220/66kW substation is located alongside the Cas Tresorer fossil fuel plant. With two 220/66kW transformers and 160MW installed capacity, the substation is one of the largest in Europe using the latest sulphur hexafluoride technology.

The substation connects the energy generated by Cas Tresorer to the high voltage network. It strengthens the interconnection between the 220 and 66kW networks in Mallorca using new transformer units for additional reliability. It also creates a new 66kW interconnection node that will strengthen the 66kW network in Palma, and increase the capacity and safety of supply.

The 220kW network at the substation will be joined to the network using two interconnection lines to the 220/66kW San Orlandis substation. It also strengthens the 66kW network using three lines to the Sant Joan substation, two lines to the future Llatzer substation, and two lines to the Son Molines substation.

“The new gas turbines are scheduled to enter commercial operation in the third quarter of 2009.”

During the project’s first stage, only the 220kW interconnection was available to take energy from the Cas Tresorer plant. The company was able to increase the power available for the following summer to meet the demands placed on the Mallorca-Menorca system.

The substation uses a reliable electrical configuration with flexible operation and maintenance for the 220 and 66kW networks. It is an interior substation, with the power transformers located outside.

The 220kW and 66kW electricity systems are made of isolated gas armoured cells in a one and a half switch configuration and are housed in a 67 × 23m building where the control and protection equipment and ancillary services are also located.