The world’s first greenhouse installation of a microturbine combined heat and power solution began operation in Mörarp, Sweden, in September 2001. The greenhouse is 23,000 m2 and produces four million cucumbers per year.
CO2 is an indispensable ingredient for greenhouse plant production. Revenue increases by approximately 20 percent when concentrated CO2 is added to the environment. Growers have long used gas boilers or diesel engines to produce CO2, but both have disadvantages.
Gas boilers provide flue gases that can be released directly into the greenhouse. However, when the need for CO2 is highest, the need for heat is lowest. Therefore, an excess of heat must be produced to provide sufficient CO2 during warm, sunny periods. This heat must either be stored at considerable expense or simply released and wasted.
All combined heat and power solutions minimize heat storage and waste because excess energy is used to produce electricity. However, diesel engines produce high levels of NOX and CO. Besides the detrimental effects these emissions have on the environment, they are damaging to greenhouse plants. Greenhouse owners must therefore install expensive gas-cleaning equipment. The exhaust gases from Turbec microturbines can be used without cleaning.
The output of microturbines is better matched to the demands of the greenhouse than it would be with gas boilers because microturbines produce both electricity and heat. Often, if more electricity is produced than the greenhouse can use, it can be sold to the utility at a profit. Moreover, local production of heat and power is efficient and eliminates the transmission losses associated with centralized power generation.
While suitable for many applications, microturbines are in many ways ideal for use in greenhouses because heat and power, as well as the CO2 produced, can be used efficiently on site.
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Microturbine
This Turbec microturbine at the Klitte and Lund Greenhouse helps produce almost five percent of Sweden’s yearly consumption of cucumbers.
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