MIRAVALLE — In Miravalle, a so-called Training and Reincorporation Territory (ETRC, in Spanish) for ex-guerillas, Ramiro (not his real name) is emotional. For the first time in all his years of involvement with the FARC, the former combatant will have Christmas with lights. Indeed, this will be the first year Miravalle, in the southwestern department of Caquetá, has electricity at all.

Two weeks earlier, a group of ex-guerillas assembled and installed an Archimedes screw hydro turbine to generate electricity from the nearby Pato river. The device produces roughly 50 kilowatts of electricity, enough to power about 50 homes.

The basic design of the Archimedes screw is ancient: As the name suggests, it was first conceived by the legendary Greek mathematician and inventor Archimedes — in the 3rd century B.C. — as a way to move water. These days, such screws are more often used to pump wastewater in treatment plants. They are rarely used as a hydroelectric device. In fact, the Miravalle screw is the first such generator in Latin America, and its installation — by members of the guerilla-army-turned-political-party FARC — coincides with the two-year anniversary of the end of Colombia's decades-long civil war.

The brains behind the project is the solar panels engineer Raphael Armando Plazas, who was just 19 when he won a grant and placement, in 2012, with the German firm Smart Hydro Power. The company operates a hydrodynamic screw project in Munich. When Plazas returned to Colombia, in January 2017, he visited the Miravalle ETRC. Three months later he decided to go live there, and that's when it occurred to him that a hydro screw might be useful.

The project is a good example of how former FARC fighters can channel their energies.

The screw complements power generated by 30 solar panels that the guerrillas set up in the Pato river and that, from a distance, resemble their late leader, Manuel Marulanda, who died a decade ago. Importing a screw from France would have cost nearly 200,000 euros, but Plazas found a construction firm in Neiva, Ged Sas, that would make it for just 120 million Colombian pesos (less than 33,000 euros). Norway, the Bishops Conference in Colombia and other donors provided money, and the structure was assembled by former guerrillas.

Bringing the five-ton screw to this remote corner was no small feat. On the last stretch of its journey, about 100 people — including former guerrillas and army personnel, working together — had to literally drag the device. That was after months of careful calculations to determine just the right spot on the river to install the screw.

"We chose this canyon for its perfect inclination," Plazas explains. "We thought of putting turbines but they would not all work because of the river's slight inclination, so we stayed with this option. The screw also moves more slowly, generates less resistance and wears down more slowly."

How does it work?

The screw rests in a small cement dike and is activated with the river's flow. Water moving into the blades on its trunk generates movement equivalent to 20 revolutions per minute (RPMs). The screw is mechanically connected to a gear box, which like an engine, converts the 20 RPMs to 1,600 or 1,800 RPMs. The gear box is also connected to a generator that turns kinetic energy into electricity.

The contraption distributes almost 50 kilowatts an hour through a grid that FARC fighters built last year. It powers the main restaurant in the ETRC, along with neighboring hamlets (home to some 300 people) and certain public venues inside the precinct. "The important thing is that it's hybridized with the solar panels," Plazas explains. In total, the mixed system produces about 10,000 kilowatts of power an hour in this area

Dark department

Caquetá has had longstanding connection problems. In 2017, the entire department was left without lights for two weeks because of breakdowns in the substations run by the local power provider, Electro Caquetá. One of the biggest headlines last year in regional dailies was the arrival of electricity to the town of Solano, where life used to wind down at around 6:30 p.m.

Other areas in Colombia face similar problems. In fact, the national electricity grid only connects about 40% of the country's total territory, meaning there are some 12,000 districts and communities without a reliable power supply, according to the Mines and Energy Ministry's own estimates.

Time alone will tell how the screw performs given changing water levels and seasonal dry spells. In the meantime, Plazas will return to Munich to learn how to maintain and operate the screw, and then share his knowhow with 20 students in the ERTC's electronics center (a brick shack in fact).

Regardless of what happens with the screw, the project is a good example of how former FARC fighters can channel their energies and improve their communities as they transition back to civilian life. And yes, when Christmas arrives in a few weeks, there will be light. It is another step toward peace.