Power farming on the Po

Biogas production provides renewable energy alternative on Italian farms


On Farm
Saverio Acerbi used to produce milk from 500 Frisean cows but today concentrates on power production, with a one megawatt per hour biogas plant at Cascina Valentino, Pizzighettone via Codogno, Lombardy.

Saverio Acerbi used to produce milk from 500 Frisean cows but today concentrates on power production, with a one megawatt per hour biogas plant at Cascina Valentino, Pizzighettone via Codogno, Lombardy.

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A government push to meet Kyoto requirements has encouraged Italian farmers to generate electricity using crop-grown feedstock combined with agricultural waste ... but the system has a serious appetite.

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Farming the alluvial soil in northern Italy’s Po Valley is an ancient practice that intensified only in the past 40 years, after producers were convinced to follow the American model. Today some of the larger farms have included power production in their business model using biogas digesters.

A government push prior to 2009 to meet Kyoto requirements on renewable energy encouraged the construction of bio-gas power plants digesting 37 tonnes of feed stock every day to produce 1 megawatt of power every hour –  enough to supply an Italian village of 5000 people.

There are 10 of these private plants in a 10 kilometre radius of Codogno, 65km south-east of Milan, all feeding into the national grid and those that signed up when tarrifs were at their peak continue to be paid at a rate of 28 Euro cents for every kilowatt hour (kWh) delivered.

The return for those plants that were able to lock in the handsome tariff is good, although the giant rumen-like digesters are hungry animals, gobbling feedstock continuously at the rate of 37 tonnes every hour. If they were paid Australian rates, between 7-16c/kWh, they would be unviable says Saverio Acerbi, who runs his own biogas plant at Pizzighettone via Codogno, Lombardy. Only the Northern Territory, which currently offers feed-in rates of more than 26c/kWh, offers an attractive incentive to private energy producers.

The appetite for energy has already to led to conflict between food and energy producers with the price of feedstock rising as a result of the competition. However, where corn-based feed is downgraded due to fungal contamination – particularly Aspergillosis which will taint milk and cheese through the toxin aflatossina, then that feed is well suited to biogas production.

Saverio Acerbi and his wife Renata Barili, and their two daughers used to produce milk from 500 registered Friesan cows, with a smattering of Jersey to bump up their milk fat and protein count.

But with no children interested in agriculture the family has simplified and today shed-feed 70 former dairy cows who are put to a Limousin bull with the calves sold for meat. Effluent is now an income stream and goes into making biogas after passing through a pre-digester.

Half the feedstock comes off the 80ha farm –  corn in rotation with lucerne and soybeans, and ensiled for storage, the same as if it was intended for the former dairy herd  –  and the rest bought in from various sources, all of it once considered waste: tomato skins, potato peel, grape skins (after they have been used to make Grappa, of course); anything that can be consumed by methane producing microbes.

The farm, Cascina Valentino, still employs four men –  one who devotes all his time to the gas plant –  plus contract harvesters.  Of course in Saverio's grandfather's day the enterprise supported a community of 80 people but modern agriculture doesn’t work that way.

These days Saverio calls himself an energy farmer and prefers to spend his time preparing excellent fare for the guests of the family's 'agri-tourismo' business, educating all who are interested in the food culture of the Po Valley.

The story Power farming on the Po first appeared on The Land.

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