In Brazil, cane sugar has long been grown as more than just food: long before E10 became available across Europe, Brazilians were already buying alcohol-fuel mixtures at the pump – even E100, that is to say, pure ethanol. To make sugar and alcohol, essentially only the sugar cane juice is used. The residue left behind after the cane has been crushed is known as bagasse. Though this fibrous plant residue can be used to produce ‘second-generation ethanol’, there has been little large-scale production to date.
RWE is now trialling a different application: from 2020, 80 percent of the fuel source for the power plant in Amer (Netherlands) will be biomass. To date, the station has used wood pellets imported from the Baltic states, but will now start testing Brazilian bagasse pellets.
Raízen, a joint venture between Brazilian conglomerate Cosan and Anglo-Dutch oil major Shell, is one of Brazil’s biggest bio-ethanol producers.
In February, representatives of Essen energy firm RWE visited Raízen’s production facilities west of São Paulo. The federal state which shares its capital city’s name is the centre of Brazil’s sugar industry. The region has been used as arable land for 150 years, so “planting sugar cane is not going to cause soil fatigue”, says RWE Executive Board member Roger Miesen. This will ensure that no forest clearance will be needed in order to farm the land.
Raízen produces both sugar and ethanol from the sugar cane it grows. Some of the bagasse which results is used to generate electricity and heat – most of it for the firm’s own production facilities. But there is always some left over, and there could be even more if some of the straw which lies unused in the fields after the harvest were used as a source of local power and heat production. Such a move would pay off for Raízen, since the bagasse could then be pressed into pellets and sold as a sustainable export.
From RWE’s perspective, using sugar waste as biomass to produce electricity would be an opportunity to move towards a circular economy, with none of the raw vegetable material going to waste, Miesen says, “The by-products are currently not being used, or if they are, not very efficiently. Making optimum use of these products is beneficial from many perspectives.”
One of bagasse’s assets is its ready availability. In Brazil alone, millions of tonnes are produced every year and thus – potentially, at least – available for export. Potentially, because it is a long way from the cane sugar fields of Brazil to the power plants of Europe. And to date, facilities able to produce bagasse pellets for export in industrial quantities have been lacking.
Yet to compete with wood pellets, bagasse pellets would need to be compressed locally, ideally before being transported to the port of Santos. Once this process is up and running, though, RWE thinks that bagasse could compete with wood on price in the longer term.
The latest from the RWE head office in Essen is that ‘project sugar power’ is now in its test phase – and it is not only the logistical issues that are under examination. At the power plant in Amer, near the Dutch town of Geertruidenberg, RWE aims to determine how the pellets perform during milling and combustion, and whether any technical adjustments are needed. To this end, 10,000 tonnes of bagasse pellets will first be burned. “Depending on how the tests go, we may well soon be using more bagasse”, Miesen says.