ECB staff moves to new HQ, 3 years late

Three years overdue and almost 350 million euros ($433 million) over budget, the European Central Bank is finally moving staff into its new headquarters in Frankfurt -- but the bank has already outgrown its new premises.

Earlier this week, 722 staff members started moving into the new building – a two-tower skyscraper that overlooks the river Main near the city center in Frankfurt. Though it stands apart from the main business district, the building is the latest addition to "Mainhatten," the nickname of the city's high rise business district.

After 12 years of planning, design and construction, between 1,500 and 1,800 ECB employees -- including the bank's President Mario Draghi -- will now be housed in the high-tech 45 storey building in the city's east end.

Martin Leissl | Bloomberg | Getty Images

Initial planning stages for the building date to 1998 when the ECB was established and the search for permanent premises for the bank began. Since then it has used rented offices.

Having looked into 35 possible options across the city, the ECB chose a building of industrial heritage –the Grossmarkthalle, Frankfurt's former wholesale market hall where fruit and vegetables were sold until 2004 – as the location for its new premises back in 2002.

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Incorporating the old market place with two 185 and 165-meter tall towers, the ECB's building boasts energy-efficient technology throughout. From a rainwater harvesting system that uses rain water for watering plants and flushing toilets to a system that uses heat from the building's computer center to heat the offices, ECB chief Draghi has called it "a modern building for a modern central bank."

A conference room in the new ECB HQ
Thomas Lohnes | Getty Images News | Getty Images
A conference room in the new ECB HQ

The new building will also commemorate a darker past to the older market building, whose cellars were rented by the Nazis. Between 1941 and 1945, around 10,000 Jews were congregated in the cellars before being sent to concentration camps. Under a 8.4 million euro project funded mostly by the city of Frankfurt, with a 1 million euro contribution from the ECB - according to figures quoted in the Wall Street Journal -- the ramp and cellars will be a holocaust memorial.

The integration of old and new has not made for an easy journey from conception to completion, and the building work has been subject to delays and over-spending.

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The building was designed by Vienna-based architecture firm "Coop Himmelb(l)au" which won an international competition to design the building in 2005. Preliminary construction work started in October 2008 and the building was meant to be completed by the end of 2011.

The main construction work didn't start until spring 2010 and the building is ready for its new inhabitants in November 2014.

Defending the delays to the build, the ECB said on its website that there had been "two major challenges unforeseen in 2005."

"First, that the original tender for a general contractor did not yield a satisfactory result and the ECB had to change to a different contractor model," the ECB said. "And second, the Grossmarkthalle – a large industrial heritage building from 1928 – presented a number of challenges that were not detected in the initial examination conducted prior to the acquisition."

In 2005, the overall investment cost (including construction costs) was estimated at 850 million euros at constant prices, but the bank's cost prognosis now is estimated to be approximately 1.15 to 1.2 billion euros, a spokeswoman for the ECB, Andrea Juerges, told CNBC.

A concrete path at the former site of a train ramp in the Grossmarkthalle, from which Jews where deported, is now a memorial site.
Frank Rumpenhorst | AFP | Getty Images
A concrete path at the former site of a train ramp in the Grossmarkthalle, from which Jews where deported, is now a memorial site.

The move was meant to save the bank the bank money as it has been renting office space in four different locations around Frankfurt, most notably in the "Eurotower" building that is famous for its euro symbol outside the building.

The new building isn't large enough for all the bank's employees and around 1,000 ECB staff recruited to work on its new banking supervisory team will remain in the "Eurotower."

Juerges added that by building its own home, the bank was adhering to cost cutting measures itself. "With building a headquarters for its own needs, the ECB is following a recommendation of the European Court of Auditors to all European institutions, namely that it is more cost efficient in the long run to occupy own buildings instead of renting."

Being "cost-efficient" is a moot point for euro zone countries like Greece and Portugal that have been forced to adopt strict, cost-cutting austerity programs by the central bank in order to receive bailout packages.

- By CNBC's Holly Ellyatt, follow her on Twitter @HollyEllyatt. Follow us on Twitter: @CNBCWorld