Combined heat and power (CHP) for greenhouses

Beginning in 2001, greenhouse growers in the Netherlands have been able to generate electricity and sell what is not used to the electrical grid at a reasonable price.  Since then, the amount of power generated by the greenhouse industry has rapidly increased and today, greenhouse growers produce around 10% to 15% of the electricity consumed in the Netherlands.  Amazing.  How is that done?

Combined heat and power (CHP) engines burn natural gas and generate heat, electricity, carbon dioxide, and water.  Yesterday, we visited GE Jenbacker and learned more about the technology.  Their gas engines can produce from 250 kilowats to 4.4 megawatts of energy.  Although most of them burn natural gas, they can be adjusted to burn methane, landfill gas, and other alternative gas fuels.  Efficiencies can be 90% or higher.

CHP engines provide heat, electricity, and CO2 to tomato

grower Red Star

The CHP engine creates electricity that is used to power artificial lighting and other electrical devices, or can be sold to the electrical grid at a reasonably good price (the price depends on the season, time of day, market conditions, etc.).  Heat that is generated is used to heat greenhouses immediately or heat water that is stored in insulated tanks for later use.  Carbon dioxide is used to increase photosynthesis, which is especially useful in the production of vegetables and cut flowers because it increases yield.  The water that is released by burning natural gas goes down the drain, but in the future, Jenbacker plans to add filters so that it can be used to irrigate plants.

Unfortunately, some of the benefits of the CHP engines are difficult (and sometimes impossible) to realize in the U.S. greenhouse industry.  Connecting generated electricity to the power grid is difficult, permitting is usually excessive and can be extremely expensive, regulations very widely from state to state, and prices received for electricity sold to the power companies are often not reasonable.  What a shame.  This green technology could be widely implemented in the U.S. with very favorable outcomes to the grower and society in general.