South-east of Cდrdoba, two traditional grain producers decided to add value to the company. They set up a pig farm and a factory to get energy from animal manure. Today they supply electricity to two nearby cities.

Cecilia and Gabriela Debenetetti own 1,000 hectares of farm “El Triunvirato”, located southeast of Cordoba, near Monte Maiz. These are agricultural lands with Class I and II soils and an average rainfall of 900 millimeters per year.

Historically, it has been used exclusively for grain production, with one-third of the area turning early in corn, one-third in first-class soy, and one-third in wheat / soy.

The industrial and economic results of the industry were satisfactory, but in 2015 the owners decided to add the company to the business. To do this, they set up a pig farm with 150 full-cycle mothers, 100% bounded by a collective pregnancy.

In this modern system, pigs are not kept in separate boxes, but in open enclosed spaces called “lives” where pregnancy takes place to meet the latest European animal welfare requirements. In these areas animals can walk, feed, socialize, and so on.

“Breastfeeding is fully automated,” explains Cecilia Debenedet. Each animal has a chip in its ear, which is “read” by a computer, which provides it with the appropriate diet for the reproductive stage, in the required dose in the trunk.

The computer “orders” a mixture of ingredients for each week of gestation. Cecilia says this system improves the yield and condition that pigs go to when sowing and is a trend in new farms that have been installed.

The animal sediment went through several processes and poured into waterproof lagoons for cleaning, but they found that this system was polluting the environment and required an increasing number of lagoons.

In 2017, they attended a report on gas production from pig wastewater and left enthusiastically. It was immediately decided to set up a methane production plant to generate electricity from the hatch discharge, along with corn silage and other feed, as the final product to be sold in the national interconnected system. They did this with the support of the Renvar 2 program, which was available at the time to promote renewable energy.

A new partnership was formed with two owners, Cecilia’s wife and a fourth person. They submitted a tender for the program in November 2017 under the project to generate electricity at 2 MW / h, a significant generation that currently supplies electricity to two nearby cities (Guatimosine and Kawana).

After several cases, the project was approved, after which they requested funding, which was set by BICE in 2019, when the construction of biodigesters had already begun, a condition imposed by the program.

Subsequent construction progress continued, albeit with some delays due to the supply of materials during the pandemic period. Finally, the plant was opened in August 2020 and on November 20, after complicated procedures, it was approved to enter the wholesale electricity market and gain commercial authorization.

Installations

The power plant consists of three biodigesters operating (27 m in diameter and 8 in height) and one in processing. Biodigesters are reinforced concrete tanks, covered with thermal insulation and plates, covered with gauges. Each tank is based on a pile of 48 reinforced concrete at a depth of 13 meters and a diameter of 80 cm.

Digestion and extraction is carried out through stainless steel pipes controlled from the pump chamber, which is the heart of the biogas plant.

The electricity produced by biodigesters is “green”. It is formed as a result of fermentation of corn silage and cut winter crops (vetch and rye) combined with hatch fertilizer to produce methane. This fuel is included in two engines that produce electricity. The energy produced goes to the transformer and is then directed to a nearby cooperative, which incorporates it into a national interconnected system.

Methane is produced in biodigesters by the decomposition of the substrate by mesophilic anaerobic bacteria (operating at 35-45 ° C). To maintain this temperature, each biodigester is equipped with a coil in which hot water circulates.

Biodigesters also have agitators: one reaches the bottom and there are two more superficial ones that work intermittently every 20 minutes. Its function is to ensure the uniformity of the mixture.

Methane is produced in biodigesters, which are fed 90 tons of feed per day – mainly corn silage and cover crops, represented by vetch and rye – plus 20 cubic meters of sludge per day. The inclusion of feed is justified by its great potential for gas production.

The waste of a biodigester is called digestion. It is an organic fertilizer that is divided into liquid and solid phases. The solid digester enters the field through a 38 cubic meter spreader that operates on a mechanism that gives a working width of eight meters. Liquid digest is distributed by a 22,000-liter “duck tail” tanker with a working width of 15 meters. Both devices have three axes and a high flotation deck. By returning the waste from the process to the field, the circle of environmental protection and circular economy is completed.

Intensive meals

At Debenedet’s farm Eight balanced diets are used to feed pigs, piglets and pig caps.

At home, piglets begin to eat solid food 7-10 days after birth with expensive but very tasty commercial food to encourage early consumption. From 22 days of life, already in foster care, four categories of food are consumed, for 49 days. They differ in the protein and energy content of the ration.

Puppies that become expectant mothers primarily consume food for development. Then, when they reach over 145 kg and are fertilized, they take another category to meet the requirements of the pregnancy stage; Finally, after childbirth, the category changes to the lactation phase. The main component in all rations is corn (60%), plus soy extract or grains and vitamin and mineral kernels. Almost all diets are produced in our own food factory.

Antibiotics are not provided in the diet as they inhibit the growth of methanogenic bacteria in the biodigester.

Energy production as a business

ᲨPerformance

The energy produced by the company reaches 2 MW / h. This equates to the consumption of two nearby towns with a total population of 4,000 – Guatimosine and Kawana – and includes several industries (flour mill and balanced feed mill).

Investment

It is important to invest in the construction of a “green” energy production plant. For example, generating 1 MWh requires $ 5 million, which equates to 330 hectares of main area.

ᲮEfficiency of costs

In the El Triumvirato area, a pig farm association and electricity generation have increased billing by more than 100% compared to the conventional agricultural scheme with corn, soybeans and wheat.

Alternatives

If official support for a program such as Renovar is not available, smaller biogas plants may be built than El Triumvirato. For example, there are some refrigerators that are self-sufficient in energy with plants that produce 500 kW / h.

State policy

Cecilia Debenadetti says that “promoting the production of non-polluted electricity should be a state policy”, as seen in Germany, a country with more than 9,000 biogas plants. In this way, a lot of electricity can be generated by systems that are not derived from fossil fuels.