Bio–Based Energy/Cogeneration Clever Energy Production on the Side: Power Cogeneration From Sugar Cane

Author / Editor: Jürgen Ponweiser / Matthias Back

Tres Valles produces not just sugar in the sugar cane factory of the Piasa group, but also power on the side. WEG has delivered the integrated energy production solution for the first power-heat coupling plant of Mexico.

WEG provided two process control room units to monitor and control the lower and medium voltage motors
WEG provided two process control room units to monitor and control the lower and medium voltage motors
(Picture: WEG)

belongs to the Piasa Group and can process more than twelve tonnes of sugar cane daily. As the first cogeneration (power-heat coupling) project in this country, the power station uses sugar cane bagasse as renewable energy source for the production of nearly 155 GWh electrical energy per year. This is sufficient to suppy power to approx. 28,000 households for twelve months.

Bagasse (also: Ampas) means the fibrous remains of the sugar production from sugar cane and sorghum. It is therefore an auxiliary or coupling product, which accrues during the pressing of sugar juice from the plant.

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The plant in Tres Vallas has been using bagasse as a renewable energy source since 2010 and also produces electrical and thermal energy (vapour) simultaneously. This energy is then used to produce 1,500 tonnes of sugar per day on an average. With the electrical plant developed and delivered by WEG, the plant can not only generate sufficient energy to meet its own demand, but also deliver the surplus energy to other group companies and feed it potentially to the grid.

Control Centres for Medium and Low Voltage Motors

The original plant had been in operation for more than 35 years. As a substitute, WEG delivered a generator SPW1250 (50,000 kVA, 13.8 kV, 4-pin, 60 Hz), control cabinets, protection and measurement systems for the generator, a medium voltage soft starter, control centres for medium- and low voltage motors, transformation and maximum voltage transformers as well as medium voltage frequency converters. In addition, WEG also provided the complete commissioning of the plant.

The electrical plant of WEG offers numerous advantages to the plant in Tres Vallas. With the use of bagasse as bio-fuel for the production of electrical energy instead of fossil energy sources, production costs could be reduced substantially and the negative effects on the environment too, could be reduced significantly. The sugar cane factory avoids carbon dioxide emissions amounting to more than 3.6 million tonnes per annum. This corresponds approximately to the exhaust gases of 70,000 vehicles. Simultaneously, it increases the throughput during grinding and in sugar manufacture.

Recognition for Mexico’s First Cogeneration Plant

“Thanks to the support of WEG, we were recognised by the government as the first cogeneration project in a Mexican factory and received an award for special technological innovations by the National Council for Science and Technology Conacyt”, explains Guillermo Mendoza. “The solution implemented in Tres Valles has become the role model for the entire company. And the not required energy can be forwarded to other group companies”, adds the coordinator for power-heat coupling projects of the Piasa Group.

“On the whole, we estimate that the plant will be amortized within six years.” The Piasa Group will now continue the successful collaboration with WEG and in the next step, install a steam generator with a capacity of 250 tonnes of live steam production/h, 87 bar, live steam temperature 525 °C and a steam turbine coupled to a 50 MW generator in its plant in Adolfo Lopez Mateos. It should go live in November 2017.

* *Jürgen Ponweiser is Marketing Manager at WEG