Microsoft is gearing up to finish its first West Des Moines data center, a project that spearheaded the tech giant’s plans to eventually invest more than $3 billion in the suburb.

The $680 million data center, located on Grand Avenue west of Interstate 35, originally broke ground in 2009.

The Iowa Economic Development Authority announced this week that Microsoft has pledged to complete the fourth and final phase of the project by May 31, 2018. 

Since developing the Grand Avenue data center, Microsoft has started building its second West Des Moines data center, a $1.1 billion project near Willow Creek Golf Course, and announced plans to build an even bigger data center (the company’s largest to-date) near Dale Maffit Reservoir. The latest project could cost as much as $2 billion, according to the city of West Des Moines. 

The Iowa Economic Development Authority on Friday approved changes to Microsoft’s original tax break deal for the Grand Avenue project. Microsoft plans to spend about $65 million more than originally planned for the fourth phase, and as a result the state will increase the tax subsidy by $366,000, according to the IEDA. Microsoft will also add 13 more jobs that previously expected.

In all, the project is set to receive $20 million in tax breaks and other subsidies, according to IEDA.