America's first Combined Heat and Power (CHP) project that captures carbon dioxide to help fertilise tomatoes has been unveiled. The Houweling's Tomatoes project uses two General Electric Company (GE) 4.36-megawatt (MW), ecomagination-qualified Jenbacher J624 two-staged turbocharged natural gas engines and a carbon dioxide fertilisation system to provide heat, power and carbon dioxide to the 125-acre tomato greenhouse in Camarillo, California.

The scheme will also help California achieve its target 6,500 MW of new CHP generation by 2020.

The project is the first to use J624 two-staged turbocharged gas engines for the 60 Hz segment of the operation. The J624 was introduced five years ago and is the world's first 24-cylinder gas engine to be used for commercial power generation and other applications. It is also is the first gas engine to include double turbocharging for added efficiency.

Forward-thinking Houweling last year was presented with a 2011 Governor's Environmental and Economic Leadership Award for developing environmentally-friendly practices while contributing to the local economy by state Governor Edmund G. "Jerry" Brown.

Houweling's CHP system, which is powered by natural gas, generates 8.7 MW of electrical power and 10.6 MW of thermal power from hot water to heat the large on-site glasshouses. Its total thermal efficiency is almost 90%.

When taking into account the avoided energy needed to externally source the carbon dioxide and recover the water from the exhaust, the overall system efficiency is over 100%.

The cogeneration of the plant was planned, engineered and installed by Western Energy Systems, GE's authorized U.S. distributor of Jenbacher gas engines.

The CHP plant provides flexible energy generation and contributes electric power in peak times. It is able to start within five minutes and provide power to electric companies to augment the grid.

The thermal energy produced during power generation can be transferred to the greenhouse immediately in cooler periods kept in existing thermal storage tanks to use at other times.

The high level of efficiency is made possible by condensing out water vapour formed during combustion. Thermal energy is recovered in exhaust gas heat exchangers to be used in the ultra-efficient greenhouse, which uses extremely low water temperatures in its heating system to cool exhaust temperatures under the dew point.

Greenhouse owner Casey Houweling, says, "We felt this project was the right thing to do for both our company and our community. This CHP system will provide the necessary heat, power and CO2 for the growth of our fresh greenhouse tomatoes. However, the impact of this project on the region goes far beyond the vegetables produced in the greenhouse.

"This ultra-high-efficiency CHP plant also will provide flexible power to our local utility with a very short response time. GE's proven technology and industry-leading efficiencies allow us to have one of the lowest CO2 footprints and water usage in the region for a power plant of this size. In fact, we plan to use the water condensed out of the exhaust gas in our operations - this will save approximately 9,500 gallons per day of usage from local water sources."

Applications to connect with the electric utility and county permits have been approved.

Scott Nolen, GE Gas Engines' product line management leader, says, "GE has installed more than 800 gas engine CHP units in greenhouses globally. This represents approximately 2 gigawatts of power generation plus CO2 fertilization systems. With the installation of Houweling's engines we now have our first U.S.-based system.

Houweling's Tomatoes built the first CHP greenhouse project in the U.S. that captures CO2 for use in plant fertilization; Credit: © GE

"A key goal at GE focuses on helping our customers to reduce their impact on the environment and on their community. One Jenbacher J624 two-stage turbocharged gas engine can provide electrical power for about 4,400 average U.S. homes, saving about 10,700 tons of CO2 per year."

This amount is the equivalent of yearly carbon emissions from more than 2,000 cars in America.

Carbon dioxide from engine exhaust gases will be purified and piped into the greenhouse to fertilize tomato plants through the photosynthesis process.

The technology for the carbon dioxide fertilization system was developed by GE's Center of Excellence in Holland. The system removes unwanted carbon monoxide and nitrous oxides using special catalytic reduction equipment and provides purified carbon dioxide to greenhouses, removing the need for natural gas boilers.

Houweling uses a COdiNOx-Selective Catalytic Reduction system that minimizes levels of carbon monoxide, hydrocarbons, nitrogen oxides and toxins in the air.

The NOx emissions have been limited to a maximum concentration level of 5 ppmv. This reduces emissions from Houweling's boilers, which are currently limited to a maximum of 40 ppmv NOx.

Houweling's goal is to produce the freshest, safest and best tasting products from seed to the plate in the most environmentally conscious way possible.