Underground storage facilities are crucial to the
security of energy supply, and a key to balancing the supply
and demand in natural gas consumption between the summer and
winter months, according to Stephen Fry, director of PEB
Engineers & Constructors.
Additionally, natural gas in storage also functions as
insurance against unforeseen accidents, natural disasters or
other incidents that may affect the production or delivery of
One such underground storage project at the GHG Empelde
Underground Gas Storage facility located near the city of
Hannover, Germany, involves storing or buffering gas in four
underground salt caverns.
The end goal is to bring total natural gas storage in
all these caverns to an equivalent of four months of national
consumption to which the GHG facility will contribute,
To create a storage facility, salt beds or domes must
undergo leaching, where injected water is used to
dissolve and extract the salt, leaving a large cavern
Natural gas is transported through nearby transmission lines
and injected into the salt cavern, where it is securely stored
for future use.
These particular caverns are 500 meters under the
earths surface and run 1,500 meters deep and 200 meters
in diameter. The natural gas is stored at a pressure of 210
The installation of heavy-duty gas compressors that
pressurize the natural gas before it is fed into the caverns is
essential to the projects success.
That is why Stadwerke Hannover AG, EON Ruhrgas AG and
Wintershall AG (shareholders in the project) say
they chose PEG Rohrleitungssysteme Germany, an affiliate
of PEB Engineers & Constructors (the Netherlands), as the
PEB is an official Dresser-Rand packager and service
center for the complete range of Dresser-Rand gas
field compressors, including the HOSS heavy-duty
separable reciprocating compressor.
The Dresser-Rand HOSS compressor is especially
well-suited for gas storage projects where gas injection and
withdrawal operating pressures and gas flow volumes typically
require cylinder designs that can best accommodate changes in
pressure and flow.
For the Empelde project, the HOSS
compressor, and later two smaller units, will replace the three
30-year-old gas engine-driven integral compressors currently
installed, Fry said.
PEG/PEB will manage the service and maintenance requirements for the new
Since the official product launch of the HOSS
compressor in 2008, Dresser-Rand has sold more than 150,000
horsepower worth of HOSS compressors for various
compression applications ranging from typical natural gas
transmission to CO2 enhanced oil recovery (EOR).
One important advantage of this heavy-duty compressor is
that it has higher gas/frame loads and offers a wide range of
cylinder selections to meet specific applications.
For the Empelde project, we selected the HOSS
compressor product with its 87,000 lb (39,462.5 kg) frame rod
load rating, specialized storage cylinder designs engineered
for transmission and high pressure injection. And it met our
specific flow requirements, Fry said.
The HOSS compressor was developed to meet our
clients needs for larger, higher horsepower gas field
compressors that could still be conventionally packaged,
said Gary Tas, Dresser-Rand global sales manager for the
Separable Reciprocating Strategic Business Unit.
Furthermore, these compressors can be easily transported
and installed and, when necessary, can be easily relocated.
Its an excellent fit for large compression projects,
including gas storage.
In my experience, the HOSS compressor package
we supplied to the Empelde facility is the gas storage
blueprint for other projects of this type, Fry said.
We believe our modular compression system package
designed specifically for underground gas storage applications
has a strong value proposition for our clients in terms of
reduced lead time and lower cost for future projects.