Building & Operating a 36,500 tons per year AD Facility in CA


To reach their state mandated 75% diversion goal by 2020, San Luis Obispo County’s Integrated Waste Management Authority (IWMA) had reviewed numerous organic waste processing options with staff visiting facilities worldwide.

Hitachi Zosen Inova ‘s Kompogas® Technology seemed like a perfect fit to handle the county’s organic food and yard waste streams.

In partnership with the local waste hauler Waste Connections, PG & E and the IWMA, Hitachi Zosen Inova developed, financed, built, owns and operates a high solids anaerobic digestion facility in San Luis Obispo County.

The facility diverts about 36,500 ton per year of food and yard waste from landfilling and produces enough renewable electricity to power about 600 homes, helping decarbonizing the PG&E electricity grid. Furthermore the system produces valuable soil amendment that is marketed to agriculture on the Central Coast.

The plant is based on the proven Kompogas®, High Solids Plug Flow Anaerobic Digestion Technology, featuring an organics receiving and pretreatment area, a continuously fed horizontal plug flow digester, along with a liquid solids separation system and a CHP biogas utilization system, producing renewable energy in form of electricity and valuable soil amendment. The facility has been in operations since October 2018.



Thomas F. Gratz
Sales Manager US
Hitachi Zosen USA, LLC

Thomas Gratz is Sales Manager for Hitachi Zosen Inova USA, LLC responsible for all sales activities of Hitachi's KOMPOGAS anaerobic digestion, BIOMETHAN biogas upgrading and P2G Power to Gas technologies.  Mr. Gratz brings over 27 years of experience in sales and sales management, providing solutions to end users in both the public as well as the private sectors.  His experience includes all aspects of sales and sales management for capital equipment and specialty technology products. He successfully managed the start-up of several European Sales Organizations in the US and has a proven track record of implementing advanced new technologies in the US.

Education: BS in Mechanical Engineering, Federal technical College of Moedling, Austria