Combined Heat and Power with Thermal Storage for Modern Greenhouses
Combined heat and power engine-generator with thermal energy storage for modern greenhouses.
Southern California Gas Company (SoCalGas)
Recipient
Monterey Park, CA
Recipient Location
25th
Senate District
49th
Assembly District
$1,488,459
Amount Spent
Completed
Project Status
Project Result
Following the successful demonstration of this CHP technology in a modern California greenhouse, other CHP greenhouse projects have applied for incentives through the California CHP Feed-In Tariff program.
The Issue
Modern greenhouses, because they need temperature control and enriched carbon dioxide (CO2) levels, can represent a good application for combined heat and power technology. In this concept, a natural gas-fueled engine-generator produces hot water to warm the greenhouse and electricity to power grow lights, plus capture the CO2 from the engine exhaust to accelerate photosynthesis.
Project Innovation
This project demonstrates the economical operation of a combined heat and power (CHP) system with thermal energy storage (TES) for modern greenhouses. TES allows the engine's heat to be stored as hot water, allowing the greenhouse operator more flexibility to run the engine when electricity or carbon dioxide is needed. On the other hand, when the greenhouse grow lights are off but the engine is running to supply heat or CO2, the operator can sell power to the electric utility. The greenhouse operating strategy depends strongly on the value of this surplus power. For combined heat and power projects, a special feed-in tariff applies to exported power. The rate paid by utilities varies by the time of day (peak, mid-peak, off-peak, or super-off-peak) and the season of the year (summer or winter months). Also, the various utility charges that can be avoided by powering the grow lights onsite can greatly improve the economics of CHP.
Project Benefits
The market potential for CHP and TES technology in California greenhouses could exceed 2.2 gigawatts for four major crops: cucumbers, lettuce, bell peppers, and tomatoes.

Affordability
CHP and TES allows for significant cost savings for four necessary energy streams needed to run a greenhouse: power, heat, hot water, and carbon dioxide.

Economic Development
Proliferation of CHP systems for greenhouses not only creates jobs for those installing and operating the CHP systems, but also makes greenhouse as a whole more economically viable, spurring growth in both industries.

Environmental Sustainability
In addition to the typical CHP benefits of higher overall efficiency, greenhouse application allows for near 100% carbon capture and sequestration from the waste stream of the engine-generator system.
Key Project Members

Michael Lee
Subrecipients

DE Solutions, Inc.

Penn Power Group, LLC d/b/a Western Energy Systems

Diener's Electric, Inc.

Houweling's Tomatoes

Match Partners

Southern California Gas Company (SoCalGas)
