Great Island Power Station

Case Study

Scottish and Southern Energy are currently constructing Great Island natural gas Combined Cycle Gas Turbine plant which will deliver an economic power boost to the South East.

The €331m project will be operational in late 2014 and will significantly decarbonise electricity generation in Ireland. The modern and efficient 460MW gas-fired power plant will be Ireland’s cleanest and most efficient power station and will replace the existing 240MW fuel oil unit at the site, significantly decarbonising electricity generation in the all-island Single Electricity Market.

Banagher Precast Concrete Ltd were engaged by John Sisk and Son to work with the design Team of Dragodas and Initec to develop a bridge deck design to span the cooling outflow channel. The channel had a span of 16m and was over 90m long. The design favoured by the contractor and the clients design team was a beam and slab deck comprising of TY9 beams. The deck slab was formed using Banagher Precast fibre reinforced permanent shutter spanning between beams to allow John Sisk and Son to pour deck slab on site.

The project had a number of unique design features. It was essential that the channel remain functioning while the construction of the deck was ongoing to enable the existing power plant to remain operational. This involved detailed planning with John Sisk and Son to establish a safe working methodology which could allow work to continue on a watercourse which could turn from a benign stream to a raging torrent in a matter of seconds.

Due to the length of the deck the structure was split into 4 sections with expansion joints and edge beams at the end of each section. This allowed Banagher to introduce intergrated safety features into the bridge beams with fixings for handrails castin to the units the work area was effectively safe as soon as the units were placed.

Banagher also developed a unique installation system for placement of permanent shutter which eliminated operatives working to a leading edge and halved the installation time required on site.

Upon successful completion of the bridge deck the design team requested a precast alternative to transformer Blast walls which were a critical item on the construction programme. Banagher Precast Concrete had completed similar projects with John Sisk and Son on power plants in the UK and were able to offer a precast alternative to the cantilever Blast walls which were over 16m high. The units were installed in less than 2 weeks saving the client months off the original programme. The units were arranged in a complex geometrical formation with large designed openings in the wall. These complications were all overcome by our design team and by using our unique foundation connection the units were installed in rapid sequence without the need for temporary propping.

Banagher Precast Concrete use BIM and 3D modelling to ensure complex structures such as these blast walls are designed and installed without encountering problems.

The Great Island CCGT is one of the largest infrastructural projects currently under construction on the island of Ireland and is the single largest capital project in power generation that SSE is currently developing in either the UK or Ireland. Upon completion next year, the project will generate enough electricity to power around half a million homes.