NEW BID ON THE BLOCK
BIOMASS NOW PART OF THE ENERGY MIX

BIOMASS IS RAPIDLY CATCHING UP WITH OTHER RENEWABLE ENERGY SOURCES. NEW TECHNOLOGIES MAKE IT ATTRACTIVE EVEN TO LARGE-SCALE ENERGY SUPPLIERS.

Farmers and eco-businesses are no longer the only ones interested in slurry, straw and compost. The big players in the energy market are also taking notice. Together with wind, water and solar energy, biomass has become the fourth component in the ecological energy mix. By the year 2020 the EU expects to cover at least 20 percent of end-user energy consumption with renewable sources. Biomass is essential in that it is the only way of compensating for fluctuations in solar and wind energy supplies. The use of renewable raw materials is receiving massive support in most European countries.

BIOMASS POWER STATIONS
In the United Kingdom the conversion of fossil fuel power stations to biomass is worthwhile even if the plants will only be operating for a few years. A major power station near London is being converted to burn wood pellets instead of coal, although the plant will be taken out of service in four years at the latest. The owner is RWE, the first major energy company to develop a comprehensive biomass strategy. As part of this strategy, in May 2011 RWE acquired one of the largest timber processing plants in the United States. The pellets produced by the plant will be supplied to European power stations that are converted either wholly or partly (“co-firing”) to biomass.

Large-scale biomass power stations are also being built in the Benelux countries. In 2010, Bilfinger Berger converted a coal-fired power station in Rodenhuize near Ghent for the Belgian energy provider Electrabel. Since then, the plant has achieved a thermal output of 560 megawatts by burning wood pellets. The raw material comes from Canada.

BIOMETHANE WASH
In Germany such industrial-scale biomass power stations are not part of the long-term plan. The German Renewable Energies Act (EEG) primarily promotes small plants of up to 20 megawatts as well as the use of combined heat and power. Nevertheless, biomass now accounts for about a third of the country’s eco-power, and the proportion is steadily increasing. Most producers convert biogas into electricity in combined heat and power plants. The crucial point is that substantially more energy, around 60 percent, is converted into heat rather than electricity. A huge proportion that has to be used—again at least 60 percent—in order to qualify for subsidies.

For farms and some manufacturing industries, the numbers may add up. But not for the major energy suppliers. The latter are therefore increasingly focusing on purifying biogas and feeding it into the natural gas network. The purification process is complex. The desired methane comprises only half the biogas. The remaining components—carbon dioxide, hydrogen sulfide, ammonia—are harmful to the pipelines. BASF and Bilfinger Berger Industrial Services are using a specially-developed process to separate these from the biogas. After flushing with a type of washing solution, the remaining methane is 99 percent pure—an innovation. The gas can then be fed directly into the grid.

This new technology is already being used at two plants in central Germany, in Zörbig and Schwedt. Both are owned by Verbio, Europe’s largest manufacturer of biofuels, and provide around a fifth of Germany’s entire natural biogas supply. The gas is recovered from biofuel production residues. This is not merely extra business for Verbio, with an eye on the tightening of emissions trading rules in 2013, it also improves the company’s CO₂ balance sheet.

BIOHYDROGEN
Biomass not only lends itself to feeding the electricity and gas grids, it also can be used to produce hydrogen. Thus far it has not been possible to produce hydrogen economically from biomass on an industrial scale. Now, in cooperation with a prominent gas producer, Bilfinger Berger has found a way.

The input material primarily consists of dry plant waste that is thermochemically treated. The result is a synthetic gas from which hydrogen is produced. The gas also can be used to generate electricity or to produce other chemical materials.

Rolf Schmitt from Bilfinger Berger Industrial Services is one of the inventors of the technology and he is convinced that: “Synthetic gas not only has a wide range of applications, but that it also can be produced from various types of biomass. This means that we are playing an active role in the development of renewable energy.”

Text: Daniela Simpson
Bilfinger Berger Magazine 1/2012