GE turbocharges CHP facility
31 Oct 2012
Camarillo, California – GE has unveiled an innovative combined heat and power (CHP) greenhouse project in the US that captures carbon dioxide (CO2) for use in plant fertilisation.
Using two of GE’s 4.36MW, ecomagination-qualified Jenbacher J624 two-staged turbocharged natural gas engines and a GE-designed CO2 fertilisation system, the plant provides heat, power and CO2 to grower Houweling’s Tomato’s 125-acre greenhouse in Camarillo, California
The project represents the launch of GE’s J624 two-staged turbocharged gas engines for the 60 Hz segment and the first of these engines sold in the US.
Introduced by GE in 2007, the J624 is the world’s first 24-cylinder gas engine for commercial power generation and can be used in various applications. It also is the first gas engine featuring double turbocharging, which makes it even more efficient.
Fuelled by natural gas, Houweling’s CHP system provides 8.7 MW of electrical power and 10.6 MW of thermal power (hot water) for heating the large-scale glass greenhouses on-site. The system offers a total thermal efficiency of nearly 90%.
Including the avoided energy that would be required to externally source the CO2 and the recovery of the water from the exhaust, the overall system efficiency exceeds 100%, said GE.
The CHP plant will enable flexible generation and contribute electric power during peak daytime demand periods. With a five-minute start-up capability, this high-efficiency plant also provides power to the electric utility for augment of the power grid.
The thermal energy produced from the engine during power generation can also be transferred to the greenhouse immediately during cooler periods or retained in existing thermal storage tanks for use at other times of the day.
The concept of a power plant being able to generate heat and power at nearly 100 percent overall efficiency is made possible by condensing out water vapour created in the combustion process.
Thermal energy is recovered in exhaust gas heat exchangers for use in this ultra-efficient greenhouse, which utilises very low water temperatures in its heating system to cool down exhaust temperatures below the dew point.
“This CHP system will provide the necessary heat, power and CO2 for the growth of our fresh greenhouse tomatoes,” says Casey Houweling, the owner of the greenhouse facility.
The CHP plant will also provide flexible power to the local utility with a very short response time, he added.
Houweling plans to use the water condensed out of the exhaust gas in its operations, which will save around 9,500 gallons per day of usage from local water sources.
CO2, which is present in engine exhaust gases, will be purified and piped into the greenhouse to fertilise the plants during the daylight photosynthesis process.
GE’s ‘centre of excellence’ in the Netherlands for greenhouse applications developed the technology for the CO2 fertilisation system that removes unwanted carbon monoxide and nitrous oxides with special catalytic reduction equipment and provides purified CO2 to greenhouses like Houweling’s.
Houweling’s has invested in a COdiNOx-Selective Catalytic Reduction system to minimise the amounts of carbon monoxide, hydrocarbons, oxides of nitrogen and toxic air contaminants. The final emitted levels of pollutants will meet the levels required by the local regulatory agency as identified in the air permit.
The local air pollution control district in Ventura County has required the installation of best available control technology for the CHP plant.
The NOx emissions have been limited to a maximum concentration level of 5 ppmv. This represents a reduction from Houweling’s current boilers, which are limited to a maximum of 40 ppmv NOx.
Developed with specialists from ABB Turbo Systems Ltd., GE’s J624 50-Hz version achieves approximately 10 percent higher output (4 MW to 4.4 MW) and offers an electrical efficiency of 46.5%, an increase of about 1 percentage point.
Improved efficiency is vital for the competitive cost of electricity and for the reduction of CO2 emissions in a carbon-constrained environment.
Western Energy Systems provides application, sales engineering, systems integration and parts and service capabilities for GE’s Jenbacher natural gas and special gas power generation projects.
As part of the Penn DDA/Penn Power Systems organisation, Western Energy Systems and its sister company, Northeast Energy Systems, bring more than 50 years of experience in reciprocating engine power applications.
