ORNL installs biomass gasification system to save money, energy
A woody biomass-based gasification steam plant has phased out four fossil fuel boilers at Oak Ridge National Laboratory in an effort to save money and energy efficiencies. The biomass steam project, which brought together Nexterra Systems Corp., the U.S. DOE and Johnson Controls Inc., was one of ORNL’s energy conservation measures in the national lab’s broader Energy Savings Performance Contract aimed at lower energy costs and higher energy efficiency at the facility in Oak Ridge, Tenn. Through the contract, the lab spent a total of $90 million, with $65 million going towards the biomass steam plant. According to ORNL, the estimated annual savings from the biomass plant is roughly $4 million which results in a pay-back period of just over 15 years.
“The project demolished four fossil fuel boilers that had reached the end of their useful life,” according to Mike Parkison, complex facility manager for mechanical utilities at ORNL. The new biomass system was integrated with the remaining boilers and will now supply steam for the entire campus.
The biomass plant underwent a rigorous 30-day testing period, endurance trial and third party emissions evaluation, according to Nexterra. For Nexterra, the ORNL biomass steam project marks the sixth biomass project led by the company to go commercial. The system converts woody biomass into syngas to produce 60,000 lbs/hr of saturated steam at 180 psi, a process that reduces fossil fuel consumption by 80 percent. The syngas is combusted in an oxidizer and the resulting hot exhaust gas steam is used in a heat recovery boiler.
The new gasification facility will also be used for future research and ORNL has already dedicated space and syngas sample ports for such future work, according to Parkison. Although the plant has only been in official operation for a few weeks, Parkison said he has learned a lot about the plant and the process of commissioning. “Our operator training program has been very successful and in a short period of time our operators have become proficient in controlling and operating the plant,” he said. For other project developers looking to install a similar system, Parkison said fuel procurement and ash disposal should be structured to provide flexibility for increased or decreased demands and, he added, automation should be addressed early in the project to allow for the consideration of systems testing, configuration control, remote access, data acquisition and systems trends.
Mike Scott, president and CEO of Nexterra, said his company is proud to have been such a large part of the project, noting that with this installation, Nexterra systems now have over 100,000 hours of operation in a range of institutional and industrial settings.