* Paris to import 140,000 tonnes of wood per year from U.S.
* Says this will boost renewable energy in urban heating
* French timber industry unable to deliver sufficient wood
* Engie sees strong growth in district heating networks
By Geert De Clercq
PARIS, March 10 (Reuters) - Paris plans to import thousands of tonnes of wood per year from the United States as part of plans to use more renewable energy in its urban heating systems, city authorities said on Thursday.
Paris urban heating company CPCU - which provides heat and hot water for more than a quarter of Parisians - plans to burn 140,000 tonnes of wood pellets per year in a new 75 million euro ($84 million) plant in Saint-Ouen, north of Paris, that will start operating in a few weeks.
Environmentalists have questioned to what extent wood-fired power plants can reduce carbon emissions, especially if the wood has to be imported. But CPCU said the use of wood - as well as a switch from fuel oil to gas - will avoid 300,000 tonnes of CO2 emissions per year.
"This is a good example of how the energy transition is put in place following the United Nations climate conference," said Celia Blauel, Paris deputy mayor for the environment.
Compagnie Parisienne de Chauffage Urbain President Frederic Martin said it was cheaper to buy the pellets from the United States than in France, where the timber industry also produces pellets but mainly in small volumes for individual customers.
The plant, which will use a 50-50 mix of wood and coal, awarded a five-year contract to U.S. suppliers that runs until 2019.
"We hope that by then the French wood industry will be ready to deliver, because we prefer to buy at home," Saint-Ouen Mayor William Delannoy said.
Europe is a major market for wood pellets to replace coal in power plants, with British utility Drax one of the top importers. Drax says economies of scale justify the shipping distance, but environmentalists say burning pellets leads to deforestation.
CPCU runs a 480 km (300 miles) steam heat network that supplies many of Paris' traditional Haussmann-style apartment buildings and institutions like schools and hospitals.
Forty percent of the steam distributed by CPCU, 64.5 percent owned by gas group Engie and 33.5 percent by the city, is generated in energy-from-waste plants. The rest comes from wood, gas and coal-fired plants, including Saint-Ouen.
Engie director Henri Balzan said investment in urban heating networks in France, which is heavily dependent on electric heating from its nuclear plants, was way behind countries in northern and eastern Europe.
"We expect district heating networks in France will grow five-fold by 2030," he said. ($1 = 0.8938 euros) (Reporting by Geert De Clercq; Editing by Dan Grebler)