Metz: a 100% natural Lorraine network


Managed by the UEM company, the district heating network in the city of Metz (Lorraine) is one of the largest in France. Today – since the Metz-East and Metz-Cité networks were joined together in 2007 – the network is 93 km long and sold 376 GWh of energy in 2014, the equivalent of supplying more than 33 000 two bedroomed apartments. The network is powered by a biomass plant that produces energy which is 100% local, using the natural resources of the Lorraine region.


Metz in brief


The city of Metz is the prefecture of the department of Moselle and the Lorraine region and has about 120,000 inhabitants within its walls, and 390,000 including its urban area.

Located in Eastern France, Metz has a degraded oceanic climate. Winters are relatively cold (-0.5 ° C in low average, with a record -20.1 ° C), and summers around the French average (above 25.3 ° C on average in July). The topography of Metz is particular: the location of the city at the bottom of a valley softens the climate relative to surrounding plateaus. Even still, it snows around 26 days per year on average in Metz, double the national average.


Completely independent management


It took two years of work and 50 million euros of investment to construct the biomass unit of the Metz-Chambière plant in 2013. The biomass unit produces most of the heat distributed by UEM. UEM was the first local company in French independent energy distribution. Founded in 1901, the company was first awarded the title of “public electric utility” by the City of Metz, first in the form of municipal ownership in 1925 before becoming a joint venture company in 2008. UEM distributes not only heat in Metz, but also electricity and cable TV and internet. UEM, according to latest figures, presently accounts for approximately 500 employees, more than 285,000 users – including 15,000 business customers – over 142 municipalities.


Responsible and economic heat production


The Metz-Chambière plant is the UEM’s primary tool of power generation and district heating and works on the principle of cogeneration. The plant functions by recovering the heat generated by electricity production – and uses 100% natural Lorraine resources (wood chips 68%, 20% waste wood and bark and 12% sawmill residues). 100,000 tons of chips are necessary for its operation per year!


It consists of a 45 MW thermal power boiler which produces steam from wood chips, and a 9.5 MW back-pressure turbine. The operation of this plant has also enabled the creation of 40 jobs in the timber industry: the supply chain is carried out in collaboration with the National Forestry Office, the Forestry Cooperative of the Eastern Forests and woods for private forests and local forestry and environmental agencies.


Since the Metz-Chambière heating network was installed, it has replaced the consumption of nearly 20,000 tons of coal and reduced CO2 emissions by 10,000 tons annually. Consequently, the plant is now considered to be carbon neutral.



Image source: Flickr (leonhe2)

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