In Aragon, farms are starting to do something with their slurry ponds: cover them with solar panels

only in Aragon there is more than 4,000 farms of pigs, farms from which every year thousands and thousands of tons of meat that later is marketed in the rest of the world. In the pigsties where the cattle are raised, however, something else is generated: an enormous amount of slurry that represents a real challenge environmental. At the end of the day, these wastes end up stored in ponds that emit harmful gasessuch as methane, ammonia or nitrous oxide.

In Aragon they have had an idea: cover them with solar panels.

From farms and slurry. Spain is one of the big producers of pork in the European Union, something that is possible thanks to a vast network made up of thousands of farms. The problem is that not only cattle come out of them. The industry generates millions of tons of slurry, a manure that can be used as fertilizerbut whose management poses some challenges.

Although the composition varies depending on its source, farm manure generally generates greenhouse gases and pollutants, including methane and ammonia. It is not a minor issue if we take into account that some calculations They estimate that the Spanish pig sector produces just over 60 million tons of slurry each year.

A challenge, an opportunity. Manure management takes time under the magnifying glass of the environmentalists and is regulated in the lawwhich includes measures such as cover at least part of the ponds or the use of systems that reduce their emissions.

With this backdrop, a few years ago a consortium formed by the Aragonese firm Intergia Energía Sostenible and two other entities became a question: What if necessity were made a virtue and the space occupied by the slurry ponds was used to generate energy? What if, at the same time that manure deposits are covered to reduce their emissions, photovoltaics could be expanded?

A “win-win”. The result was a project developed between 2020 and 2023 which, with the support of the European EAFRD fund and the Government of Aragon, dedicated itself to investigating this path. His idea was very simple: cover the slurry ponds with floating solar panels to achieve a win-win manual.

Polluting emissions remain at the levels established by regulations and, at the same time, the farms improve the performance of their ponds, converting them into sources of solar energy production. Instead of covering rooftops or acres of fields with solar panels, they are deployed directly over manure deposits.

Rethinking floating systems. From Intergia they explain that the project developed between 2020 and 2023 let some interesting lessons. For example, the ammonia in slurry ends up oxidizing and degrading some elements of photovoltaic installations. Specifically, certain parts of the module fastening system and wiring. Now the company wanted to go one step further and open the way.

“While floating photovoltaics are already widely used in bodies of water, such as irrigation ponds or lakes, their use in other liquid bodies is in the study phase,” claims. Hence, the firm (along with other allies, such as the University of Zaragoza) is promoted Fotopura project that wants to help the pork sector reduce its emissions while generating energy.

One project, two bets. To move in this direction, the company has set up two facilities pilot with which he hopes to learn more about the potential of photovoltaic panels to cover slurry ponds.

In fact, both are designed to “maximize” reducing polluting emissions and resisting ammonia corrosion, although they differ in a key aspect: one of them uses standard commercial parts, designed for floating photovoltaics; the other has been designed specifically for ponds in which livestock manure is stored.

A Zamora farm. That is the place where Fotopur has assembled its first prototype. In November They installed their photovoltaic cover on an 880 m2 slurry pond located on a breeding farm in Calzada de Tera, Zamora. To be more precise, Intergia deployed a 13.5 x 25 m floating platform with 56 panels and a peak power of 33.04 kWp. In total, the entire installation covers 90% of the pond and those responsible hope that it will help cover up to 22% of the farm’s electricity bill.

The interesting thing is its components. The company used a commercial floating photovoltaic system used in water ponds. That is, it was not created specifically for slurry ponds. What Intergia and the rest of Fotopur’s partners have done is apply small changes. For example, to avoid corrosion, they replaced the steel parts that came from the factory with aluminum and stainless steel parts. To reduce friction they also incorporated a plastic sheet.

…And a Zaragoza farm. He another prototype It was assembled weeks later at a bait farm in Tauste, in Zaragoza, and unlike the Castilla y León version, it was designed specifically for use in slurry ponds.

For example, its creators devised a system that “minimizes the air-slurry contact surface between the floating elements and that will facilitate the support of the photovoltaic panels.” Another of the tasks they have had to face is “design a specific structure”formed by a matrix of anodized aluminum beams anchored to the platform and with brackets that allow the panels to have an inclination of 15º. In total they house 16 panels with a power of 9.44 kWp. The screws are made of aluminum and stainless steel to prevent corrosion.

If its authors’ plans are fulfilled, the floating platform will “effectively” cover 10% of the pond’s surface and its photovoltaic production will reach 15.2 Mwh/year, enough to cover up to 53% of the farm’s electrical demand. That plus, claims Intergiawill allow the Aragonese exploitation to reduce its fuel consumption, “expensive and polluting.”

And now what? With its prototypes Fotopur aims to continue advancing on the path that was already opened in 2020, solve the problems that were identified then and demonstrate the advantages of covering the slurry ponds with solar panels.

Now, once the Zamora and Zaragoza facilities have been set up, the experts will dedicate themselves to controlling two parameters: emissions of polluting gases and the energy generated. “The analysis of the measurements will allow us to identify which of the two systems is more effective” and which is more profitable with a view to bringing it to the market.

Images | Intergia 1 and 2

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