Nephin Renewable Gas, the company which plans to develop up to 20 large-scale anaerobic digestion (AD) plants across Ireland, has submitted plans for a second plant.

The plant, which will be developed with pig farmer James Foran, will be located beside his pig farm near Carrick-on-Suir, Waterford.

The proposed AD plant will process up to 90,000t of feedstock per year, producing biomethane gas, which will be injected directly into the gas network via a 2.5km pipe, renewable CO2 and upgraded biofertiliser made from the digestate.

The plant will involve the construction of three digestion tanks, two digestate storage tanks, a reception hall, office, laboratory, nutrient recovery building, odour treatment system and a grid injection unit on a 19ac site.

Feedstock

Each year, the plant will be supplied with approximately 9,000t of cattle slurry and manure, 26,000t of pig slurry, 12,000t of poultry manure, 9,000t of grass silage, 14,000t of wholecrop, as well as vegetable, food, drink and dairy production residues.

The manures, slurries and crop-based feedstocks will be sourced from farms in the area.

So far, 61 farmers within a 25km radius have agreed to supply feedstock to the plant and take back biofertiliser.

There are no clamps on site; instead, all feedstock will be delivered to the site via lorries or bulk tankers. When fully operational, the plant will produce 810-960 m³ of biomethane per hour.

Digestate

The digestate produced from the plant will be processed through a treatment system. Following treatment of the whole digestate, around 8,000t of digestate fibre and 17,000t of liquid digestate concentrate will be produced. The treatment process will recover around 53,000t of clean water, which will be reused on site for cleaning, with the remaining volume returned to the process as a feeding liquid, the application states.

Objections

So far the project has received a handful of objections and submissions from locals, whose concerns centre around traffic volumes, odour, biodiversity, fugitive emissions and supporting animal agriculture by managing farmers’ slurry.