By Nick Fone

THE KYOTO agreement has meant that the government has a commitment to producing more energy from renewable resources.

Coal-fired power stations receive tax incentives to run on just a small percentage of woodchip and there are substantial grants available for new environmentally-friendly power-generation projects.

Combined with the Landfill Directive – which diverts biodegradable waste away from landfill – this has prompted massive growth in the green-waste processing industry. That trend is set to continue if the government is to reach its target of 10% of energy produced from renewable resources by 2010.

Once material is composted it must be screened to make a fine usable product. The by-product of this screening process is mainly woodchip that has not broken down in the composting process.

Often this is returned to the heap, although it can be sold on to woodchip burning power-stations or an emerging market of schools, factories and communal buildings which are being encouraged to invest in wood-fired heating systems as an alternative to conventional non-renewable fuel sources.

Fuelled by both woodchip market growth and the Landfill Directive, the green-waste processing market seems to have a limitless appetite for horsepower and several shredder manufacturers now build machines that are nearing 1000hp.

German firm Jenz has introduced a new shredder range that tops out at 600hp.

The three models in the AZ660-series can be equipped with a choice of power plants – a 200kW or 315kW electric motor or 445hp to 600hp diesel engines.

A redesigned intake system has reduced maintenance costs by as much as 15%, according to importer Westcon. This has been achieved by swapping to a roller rather than an overhead conveyor to help propel material to the cutting head.

Combine this with the 600hp variant”s claimed throughput of 100t/hour and it stacks up to be an impressive performer on paper.

Extra long discharge conveyors mean that material can be stacked up to 5m high and, if the unit is supplied on a tracked chassis, shredded green-waste forms a windrow as the shredder moves, avoiding the need for double-handling.

A cleaner conveyor runs along the underside of the shredder, avoiding the build-up of trash, easing the time-consuming clean-up operation.

fwmachinery@rbi.co.uk