Erwin Schiefer

Austrian farmer Erwin Schiefer faced unsustainable electricity costs that made conventional grid supply impractical for his agricultural operations. Wood gasification — a technology with roots going back 200 years — offered a path to energy independence, but the process had defeated many operators before him. Producing combustible gas from wood is relatively straightforward; maintaining system stability is not. The reactor requires continuous monitoring across four distinct zones (drying, pyrolysis, oxidation, and reduction), with the control system needing to detect and counterbalance process deviations in real time. Without proven high-availability performance, the plant could not achieve commercial viability or serve as a replicable model for other energy producers.

Schiefer partnered with Rockwell Automation to build an integrated automation platform centered on an Allen-Bradley CompactLogix 1768-L43 controller, which manages the complete material and energy workflow — from silo feed through reactor, particle filtering, gas cleaning, and grid-connected output. PowerFlex 40 and 70 AC drives regulate pumps, compressors, and conveyors throughout the facility, while 1734 Point I/O modules supply the fine-grained process data the controller uses for continuous tuning. A custom Walking Floor drying system developed by Schiefer integrates directly with the CompactLogix logic, automatically adjusting feed speed based on wood moisture content to stabilize combustion. Operators monitor the plant via FactoryTalk View Studio on PanelView 600 terminals and access remote diagnostics over a secure VPN connection using EtherNet/IP — enabling proactive maintenance without requiring permanent on-site staffing.

The plant achieved 95% availability in its first full year of operation (February 2010 to February 2011), logging 8,300 productive hours out of a possible 8,760 — well above the industry baseline target of 7,800 hours annually. Key outcomes include:

• 440kW electrical output and 1,570kW thermal output at current operating scale, with a second-phase expansion planned to reach 900kW electrical
• Remote diagnostics capability reduced unplanned interventions, keeping the plant operational with minimal manual oversight
• Demonstrated performance earned Schiefer international recognition and enabled him to commercialize the technology under the Xylogas® brand, with installations subsequently deployed in Germany, Italy, and Slovakia

• Precise ventilation control in the reactor's oxidation zone is the single largest determinant of availability in wood gasification — CompactLogix-based zone management makes this tractable at farm scale
• Integrating moisture-adaptive drying logic directly into the PLC eliminates a major source of feedstock variability and improves combustion stability
• Remote diagnostics over secure VPN is essential for economically viable operation of unmanned renewable energy installations in rural or agricultural settings
• Proving technology at small scale before commercializing creates a replicable blueprint that reduces adoption risk for subsequent buyers
• A single-vendor automation platform spanning controllers, drives, and HMI simplifies integration and long-term support across a complex multi-zone process