Oct 27 (Reuters) - Wärtsilä booked more orders in the third quarter than analysts had expected, driven by strong data centre demand, but the Finnish engineering group's shares fell 8% on Tuesday as its new financial targets failed to impress.

Wärtsilä's energy business, which builds modular power plants and cooling systems for data centres, has been benefiting from the AI-led construction boom. However, analysts said the mid-term goals appeared less ambitious than some investors had expected.

The supplier of power generation equipment and marine engines is aiming for yearly organic sales growth in a low double-digit percentage and a 16% operating margin in the medium term, which covers a timeframe of 3 to 5 years.

Analyst Jussi Mikkonen from Finland-based OP Markets said the targets may have disappointed investors because they imply an 18% margin for the energy division. "If the data centre cycle continues, many have expected margins above 20% (for the unit)," he said.

Wärtsilä shares were at the bottom of Europe's benchmark STOXX 600 index as of 0955 GMT.

The group reported new orders worth €2.37 billion ($2.65 billion) for the third quarter, while analysts polled by Vara were expecting €2.06 billion on average. Its comparable operating profit grew 19% to €212 million, also slightly above consensus.

"We continue to see strong momentum in balancing and data centres for the years to come," CEO Håkan Agnevall said in the earnings statement.

Demand from data centre customers remains strong, with visibility extending beyond 2030, while rising US power costs and water constraints could accelerate demand for Wärtsilä's off-grid power solutions, Agnevall told Reuters.

He added data centres were only one of several long-term growth drivers for the group, naming electrification, air conditioning and broader power demand as other examples.

($1 = 0.8946 euros)

(Reporting by Marta Frąckowiak in Gdansk, editing by Milla Nissi-Prussak)

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