Solar paper mill

Condat is part of the Lecta Group, one of Europe’s leading manufacturers and distributors of specialty papers for labels and flexible packaging, coated and uncoated papers for publishing and promotional printing and other print media. The Condat factory in Lardin-Saint-Lazare, with about 500 employees, has an annual production capacity of 450,000 tons of coated paper, with a high energy requirement, mainly due to the direct use of steam in the production processes.

Since January 2019, a solar process heating plant with about 4,210 m² of flat plate collectors is supplying renewable heat to the factory in order to provide part of the required energy for paper production. The heat from the solar system is used to cover the high energy demand of approx. 9.75 GWh/a for preheating the make-up water for the steam boilers which is taken from the river Vézère. This river water is first demineralized and then preheated up to 90 °C by the solar plant. A 500 m³ tank is used as buffer for the demineralized water and the solar heat. On a yearly basis, a solar fraction for the degassing of make-up water at Condat of 40 % is projected.

Hydraulic scheme of solar heating plant at Condat [Source: newHeat ]

The solar process heat plant with its peak output of approx. 3.4 MW was the largest solar thermal plant in France at the time of commissioning and it is the world’s first plant with flat plate collectors that track the position of the sun uniaxially. As a result of this innovative realization of the collector field, the annual yield of the system can be increased by 15 to 20 % compared to an installation with a fixed collector slope. On the other hand, it is possible to avoid stagnation in times with a low heat demand, e.g. during maintenance of the factory. The collector field was installed on an old paper sludge dump of the factory, which was cleaned and sealed for this purpose. To connect the solar process heating plant to the factory, which is about 800 m away from the collector field, the Vézère had to be crossed, for which an old bridge could be overhauled. With a yield of approx. 3,900 MWh/a, the solar plant achieves a reduction in CO2 emissions of almost 1,080 t/a by saving natural gas. 

The system was planned, financed and realized by the French company newHeat, whereby for the collector field the expertise of the Finnish company Savosolar was used, which develops and builds solar components such as the collector and has already gained experience in the realization of large scale solar thermal systems.

At the official inauguration of the € 2.4 million plant, which won a tender for the acquisition of subsidies for large plants, ADEME, the funding agency which paid a total of € 1.4 million from the Chaleur Fund as a subsidy, was also present.