Solving The Energy Crisis
11 March 2010
As the UK's North Sea gas reserves dwindle and the
country increasingly relies on supplies from overseas, the need for
reserves to cope with peaks in demand and other contingencies
becomes ever greater.
To improve this situation Costain is helping to create huge gas
storage facilities deep under the Cheshire countryside.
Cheshire has one of the UK's main rock salt deposits and two
projects involve pumping water down wellheads to the salt beds
around 600 metres below the surface. The water dissolves the salt
and the resulting brine is then extracted, creating vast
underground caverns.
The first of these, the Stublach Gas Storage Project, will
create 28 caverns capable of holding 400 million m³ of gas by
2018.
It will accept natural gas from the UK's national transmission
system, storing it until needed to cope with spikes in demand.
Costain's involvement in the £400 million project initially
involved front-end engineering design (FEED) of the brine and water
facilities for INEOS, which subsequently 'sold' the project to
Storengy, a subsidiary of the giant French-based GDF SUEZ energy
company.
Storengy subsequently awarded Costain the contract for
engineering, procurement and construction management (EPCm) of the
brine and water facilities, which have been recently completed
safely, on time and on budget.
The brine and water infrastructure contract included the
creation of 10 wellheads, 26km of buried pipelines, a pumping
station capable of delivering 45,000m3 per day, an electrical
substation and control systems.
Costain has also successfully completed another Storengy
contract for the FEED of the associated Stublach gas plant.
Some 2km away, Costain is also involved in a gas storage project
at Holford for Holford Gas Storage, part of German energy utility
E.ON. Under this contract, eight caverns will be created,
capable of retaining up to 156 million m³ of gas. This is
equivalent to supplying 3.5 million homes for 10 days.
Each cavern will be 100 metres in diameter and 100 metres deep -
tall enough to hold Big Ben.
Costain's responsibilities include the engineering, procurement
and construction management contract to complete the gas plant
infrastructure and wellhead modifications.
As always, the projects have had their own particular hurdles to
overcome, explains Charles Sweeney, Managing Director of Costain
Energy and Process. One of these has been their locations, close to
several working farms and residential villages.
Stublach "is being installed in the heart of the Cheshire
countryside, so developing the design so that it would be
acceptable and get through the planning process was a challenge.
Then we had to execute it within the strict rules and regulations
that were set against the plant's construction."
Other environmental aspects of the sites included the relocation
of great crested newts, bats and birds and drainage issues.
"Site drainage was a significant issue because the local area is
highly susceptible to flooding, so early drainage work was
necessary," says John Meakin, Project Manager at Holford.
With only one brook available to dispose of excess water from
the site, Costain installed an underground 'storm cell', to gather
excess water and dispose of it into the brook gradually.
At Stublach, meanwhile, the rural nature of the site meant
constraints on deliveries of materials, says Project Manager David
Richardson: "We could only bring in 30 HGVs a day." Close liaison
with the Environment Agency was also required to build crossings
over several drainage ditches and streams, as well as laying
pipework under them.
Both sites picked up several plaudits for safety including RoSPA
Gold Awards and, in Stublach's case, a safety award from the
Society of British Gas Industries.
Costain's work will bring security of supply to UK energy users
for years into the future and is a further example of the Group
helping improve the nation's infrastructure.