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Green energy with water hyacinths

Green energy with water hyacinths, Guatemala

Lake Amatitlán (Lago de Amatitlán) is situated in south-central Guatemala, close to Guatemala City. The lake, which is 11 kilometres long and 3 kilometres wide, lies in the central highlands, almost 1,200 metres above sea level. It is used as a water source, but also for tourism and fisheries. The lake is suffering greatly from pollution and explosion of algae caused by the inflow of large quantities of untreated wastewater streams through the Villalobos River and washouts from neighbouring fields.

Martti Surakka, a Pöyry Senior Management Consultant, is heading the team carrying out a feasibility study to find sustainable solutions to improve the environmental situation at the lake and to produce biogas.

Martti, what do water hyacinths, clean water and green energy have to do with each other?

“It may sound strange at first, but it makes sense! Originally, the project’s target was to solve the problem of algae explosion in the lake. Soon the team found out that water hyacinths are able to battle efficiently against algae. So it was decided to cultivate the plant in the lake. In the second step, we utilise water hyacinths for renewable energy production as it’s also an easy-to-handle substrate. Finally, the plant’s leaves have proven to be excellent feed for dairy cows.”


Pilot biogas plant under construction

So the utilisation of water hyacinths can solve different problems at once.

“Yes, indeed. The water hyacinth is one of the fastest growing plants on the planet and for many years it has only been considered as a weed to get rid of.  But it’s also a very efficient nutrient absorber that destroys the life basis of algae. The idea is to harvest the plants from one part of the lake and put them in a biogas reactor for anaerobic digestion. The digestate is also good and affordable organic fertilizer for local small farmers.”

How is the produced energy going to be used?

It can be used for supply of the neighbouring communities where electricity is desperately needed. During the first project stage, we have designed a small biogas pilot plant to run tests. Biogas production has been successfully demonstrated on a micro scale. And our studies have shown that a full-scale biogas plant is economically feasible under the given conditions.


Algae cultivation at Galileo University

How is local population involved in the project?

We would never have progressed so far without the interest and support of local small farmers and AMSA, the local authority monitoring the lake. Our long-term local partner, EASA, has played the key role in finding the right contacts and carrying out the practical work at the plant. The farmers have really adopted the project, since they see the clear benefit for themselves in form of affordable fertilizer. The participating university, Galileo, has established a new faculty which concentrates on renewable energy. Finally, public awareness of the lake’s situation has increased significantly.


Water hyacinth seems to be excellent feed for dairy cows

And what comes next?

All project partners are working hard to secure funding for the large scale project.  We really hope that it will soon be possible to reduce pollution in the lake and at the same time produce green electricity for the surrounding communities!

Martti, we wish you and the whole team much success and hope to hear again soon from Lake Amatitlán.