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Using waste to produce high-quality ethanol

St1 is committed to reducing the impact imposed on the environment by motor fuels and energy generation, and to developing and commercialising technology to make this possible. The group’s St1 Biofuels subsidiary was founded in 2006 and focuses on producing ethanol from waste.
St1 Biofuels Oy

St1 launched its decentralised ethanol production concept in September 2007, when it commissioned its first small-scale Etanolix® plant. This runs on bakery waste, reject, and by-products, and is the first anywhere to produce ethanol from waste for commercial use in motor fuel.

St1’s technology separates the production of bioethanol from dehydration of the end-product, enabling small, modular units to be located as close as possible to waste sources, making waste a commercial commodity and reducing transport costs. Plant capacity can be downsized significantly and still remain competitive in terms of production costs and energy efficiency when only producing between 1,500 and 2,000 cubic metres of absolute ethanol a year. Production costs compare very favourably with conventional first-generation bioethanol plants, which can be 20 to 200 times larger.

Decide where you want to dewater

The Etanolix® process is based on continuous fermentation and associated evaporation, and generates an 85% ethanol/water mixture. Depending on the raw material used, by-products are suitable for use as animal feed, fertiliser, or feedstock for anaerobic digestion.

St1 Biofuels’ second Etanolix® plant, at Närpiö in western Finland, processes sludge from the local potato industry. Modular design means that it could be assembled rapidly from standard parts and can be operated from a remote control room.

An on-site dewatering unit can be installed to further refine the ethanol produced to 99.8% purity, or this can be done separately at a higher-capacity facility, such as the new energy-efficient ethanol rectification plant that St1 completed at Hamina in June 2008. The resulting pure ethanol can be blended with petrol at an oil terminal for onward distribution to service stations.

The Hamina plant will play a central role in making decentralised ethanol production a reality. Capacity at Hamina is in the order of 44 million litres a year, and the plan is to duplicate this later and build a similar plant in Sweden.

Extending waste potential

Etanolix® has made it possible to use a completely new and cost-effective source of raw material – waste – to produce a commercially viable fuel in small volumes at costs comparable to those of large-scale production plants. While St1’s current technology enables waste containing starch, sugars, or low concentrations of ethanol to be processed, product development is being pushed ahead to extend the range of feedstocks to include household biowaste, waste paper, municipal waste, and other manufacturing waste.

St1 Biofuels completed the first of a new type of energy-efficient ethanol rectification plant at Hamina in June 2008. This processes the 85% ethanol produced by the first Etanolix® plants into pure ethanol ready for blending with petrol and onward distribution.

The next dedicated technology to be launched will be Bionolix™, which will be able to utilise mixed waste and will launch a completely new way of making use of biowaste collected from households and commercial kitchens. The first plant of this type is expected to be opened in 2009. Bionolix™ technology will also enable thermal sludge processing units to be developed capable of generating bioelectricity instead of ethanol.

Next in line will be cellulose-based raw materials. Cellunolix™ technology, now under development, will be targeted at making use of packaging waste from sorted municipal waste streams from homes, retailing, and industry. St1 plans to open its first Cellunolix™ plant at the end of 2009.

This will be followed by Fiberix™ technology, aimed at producing ethanol from agricultural by-products, such as straw. This type of input will benefit even more from decentralised production and small production units.

St1’s target is to produce 300 million litres of ethanol by 2014, equivalent to around 10% of the energy content of petrol then on sale in Finland from a mixture of industrial, municipal, and agricultural waste.

St1 was founded in 1997 and, following the acquisition of ExxonMobil’s Finnish subsidiary in 2007, now has an estimated turnover of some ​ €1 billion (2008).

St1 operates more than 400 service stations in Finland, over 40 in Sweden, as well as eight distribution units in Poland. The company also sells electricity to consumers and smaller companies, and is a large vendor of heating oil across Finland. Aviation fuel is distributed at Helsinki-Vantaa, Tampere, and Vaasa airports.

Renewable energy sources are a growth area of the company’s portfolio, and cover not only waste-based ethanol but also wind power and fuel pellets.

> Risto Savolainen
(Published in HighTech Finland 2009)