From pruning waste biomass to heat the medieval castle

Surrounded by green vineyards, the castle of San Salvatore, stronghold of the Counts Collalto (Tv), has never been conquered in its almost one thousand years of history. But in the end Princess Isabella Collalto de Croÿ, who is the owner of the castle - with the Count Collalto wine cellar attached (part of the Consortium for the Protection of Conegliano Valdobbiadene Prosecco Docg) - had to fight another enemy: that of the energy inefficiency typical of a medieval manor. But it is the plants that suggest the solution. Or rather the waste from their pruning.

"The San Salvatore castle," he explains, "is a landmark not only for the municipality of Susegana, which has elected it as its emblem and coat of arms, but for the entire Veneto region, and for this reason it is bound in monumental, archaeological and landscape terms, even in its visual cone. This type of vinco+li, while preserving it, also limits its operations in terms of technology installation. One thinks of photovoltaics or other forms of energy production that are obviously prohibited in the castle'. One solution could be biomass heating, on which the property itself is doing more than four counts. But here the wood chips already used for the Conte Collalto wine cellar (two boilers for a total of 370 kW of heating power are installed here) come to the rescue. "To heat, we use waste from the vineyards, prunings from the forest and the castle garden," says Princess Collalto de Croÿ. "We are talking about the residues from the constant clearing of the approximately 40 hectares of forest on the farm: fallen tree trunks and other branches. We know that the CO2 production per kilocalorie with the use of wood and wood chips is the lowest possible among the fuels of existing boilers, so we have adopted the system of offsetting CO2 emissions anyway by networking the complex Collalto ecosystem'.

Next step, therefore, is the study to supply the castle, already equipped with underfloor heating, with a district heating system also in Energy Community mode. In fact, the Conte Collalto winery has equipped itself with a photovoltaic system of almost 400 kwh that covers the roofs (the last piece is currently being tested) and is in addition to the 90 kwh hydroelectric power plant that will come into operation in 2021.

Collalto de Croÿ points out: 'The total of these technologies can lead to an annual production of about 1 GWh (one gigawatt)' realised with a broad vision not only in self-consumption, but also in anticipation for grid production to feed the Castle.

The castle's efficiency work is completed by the latest generation of purification plants that provide hourly analyses, twenty-four hours a day, of the inputs to the sewers. As if to say: this battle is also won.