UNDERGROUND STORAGE

GAS ON TAP IS BECOMING INCREASINGLY IMPORTANT. IN UPPER AUSTRIA BILFINGER BERGER IS HELPING TO BUILD ONE OF EUROPE’S LARGEST NATURAL GAS STORAGE FACILITIES.

For Europe, the start of last year was marked by a heated dispute. The Ukraine defaulted on its gas payments and Russia suspended supplies to its neighbor. At that point, the Ukrainians threatened to prohibit the transport of Russian gas through its territory and demanded higher transit fees. The state gas company in Russia, Gazprom, accused the Ukraine of helping itself to millions of cubic meters of gas in the pipelines destined for Central Europe, and turned off the tap. Supplies to Central Europe were held up for two weeks. Consumers began to wonder whether they would find themselves huddled indoors wearing every sweater they owned. In poorer countries such as Serbia, heating systems failed.

In Austria, however, Markus Mitteregger, Director of Natural Gas Storage at energy exploration and supply company RAG, had soothing words for his countrymen: “We are the leaders. No other country in Europe has more storage capacity.” Austria is twice blessed in that it has extensive deposits of natural gas, and when these are exhausted the fields can be used to store gas from Russia. Back in 1997 in Haidach on the border between Salzburg and Upper Austria, RAG tapped into a huge deposit at a depth of 1,600 meters. Sealed by an upper layer of clay, a total of 4.3 billion cubic meters of methane were locked in the pores of a 100-meter thick bed of sandstone covering an area of 17.5 square kilometers. RAG drilled down, and the gas obligingly flowed to the surface like carbon dioxide in a bottle of mineral water when the cap is unscrewed. However, the process also works in reverse. Once the gas has been extracted, with some technical effort, fresh gas can be forced back into the sandstone pores, creating a vast reservoir of a kind that could never be built above ground. And that is what happened in Haidach.

DOUBLE THE CAPACITY
In 2007 RAG and its partners WIN GAS and Gazprom initiated the first stage of the Haidach gas storage facility. Since then 1.2 billion cubic meters of gas have been bunkered there ready to be drawn off at times of peak demand — or during a gas dispute in Eastern Europe. The second stage of the project is now underway to double the capacity, making Haidach the second-largest gas storage in Central Europe. As in the first stage, BIS VAM Anlagentechnik, a subsidiary of Bilfinger Berger Industrial Services, is responsible for erecting the complex technical plant:

Huge compressors are required to pump Russian gas into Austrian sandstone. The pipes must withstand pressures of up to 250 bar. Bilfinger Berger is erecting two compressor stations each comprising 850 tonnes of pipe and 1,700 tonnes of other equipment: filters, adsorbers, dryers. The installation work began in September 2009 and is due to be finished by September 2010.

IMPORTANCE OF NATURAL GAS INCREASING
At the same time, Bilfinger Berger is also working on another major project for RAG not far from Haidach: “Seven Fields.” This project involves linking seven smaller former gas fields on the border between Upper Austria and Salzburg with pipelines for use as another reservoir. Seven Fields and Haidach will between them be able to store enough gas to meet the needs of 2.2 million homes for a year. “At any given time we have 100 to 150 of our specialists working on site,” says Peter Lorenz, the manager responsible. “The trick is to coordinate our crews not just with one another but also with the trades that come before and after them in order to complete the project in the short time available.” Thus far natural gas accounts for a quarter of primary energy needs in the EU. According to forecasts from Brussels, over the next ten years demand will increase by 25 percent. By 2050 the International Energy Agency (IEA) expects natural gas to become the world’s most important energy source. Those who invest in storage capacity now will secure a strategic advantage for themselves with the ability to make money as an intermediary via the Central European gas networks. The trend toward renewable energy supports this position.

Many experts regard natural gas as a bridge between fossil fuels and the age of green energy. In comparison with coal and oil, burning natural gas produces less carbon dioxide. And for now, wind and solar power can only function in combination with other forms of energy that can be made quickly and reliably available when the wind ceases to blow or clouds block out the sun. “The combination of renewables with natural gas is ideal,” says RAG Director Markus Mitteregger: “Gas-fired power stations can be rapidly run up and shut down as required and they are very efficient.” Stations equipped with the latest gas turbines achieve an incredible 90 percent efficiency. By comparison, the average coal-fired stations are only 30 percent efficient, with newly built plants reaching 45 percent.

Text: Bernd Hauser
Bilfinger Berger Magazine 1/2010