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Title: Geothermal carbon dioxide for use in greenhouses

Abstract

Geothermal fluids often contain carbon dioxide, which is a very effective growth stimulant for plants in greenhouses. Studies have shown that as CO{sub 2} concentration is increased from a normal level of 300 ppm (mmol/kmol) to levels of approximately 1000 ppm crop yields may increase by up to 15% (Ullmann`s Encyclopedia of Industrial Chemistry, 1989). It is suggested that geothermal greenhouse heating offers a further opportunity for utilization of the carbon dioxide present in the fluid. The main difficulty is that plants react adversely to hydrogen sulphide which is invariably mixed, at some concentration, with the CO{sub 2} from geothermal fluids. Even very low H{sub 2}S concentrations of 0.03 mg/kg can have negative effects on the growth of plants (National Research Council, 1979). Therefore, an appropriate purification process for the CO{sub 2} must be used to avoid elevated H{sub 2}S levels in the greenhouses. The use of adsorption and absorption processes is proposed. Two purification processes have been modelled using the ASOEN PLUS software package, using the Geothermal Greenhouses Ltd. Operation Kawerau New Zealand and an example. A greenhouse area of 8,000 m{sup 2}, which would create a demand for approximately 20 kg CO{sub 2} per hour, was chosen basedmore » on a proposed expansion at Kawerau. The Kawerau operation currently takes geothermal steam (and gas) from a high temperature 2-phase well to heat an area of 1650 m{sup 2}. Bottled carbon dioxide is utilized at a rate of about 50 kg per day, to provide CO{sub 2} levels of 800 mg/kg when the greenhouse is closed and 300 to 350 mg/kg whilst venting. In England and the Netherlands, CO{sub 2} levels of 1000 mg/kg are often used (Ullmann`s Encyclopedia of Industrial Chemistry, 1989) and similar concentrations are desired at Kawerau, but current costs of 0.60 NZ$/kg for bottled CO{sub 2} are too high (Foster, 1995).« less

Authors:
 [1];  [2]
  1. Univ. of Auckland (New Zealand)
  2. Univ. of Stuttgart (Germany)
Publication Date:
OSTI Identifier:
543084
Resource Type:
Journal Article
Journal Name:
Geo-Heat Center Quarterly Bulletin
Additional Journal Information:
Journal Volume: 18; Journal Issue: 1; Other Information: PBD: Jan 1997
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; GREENHOUSES; HEATING SYSTEMS; CARBON DIOXIDE; PLANTS; GROWTH; STIMULATION; GEOTHERMAL FLUIDS; A CODES

Citation Formats

Dunstall, M G, and Graeber, G. Geothermal carbon dioxide for use in greenhouses. United States: N. p., 1997. Web.
Dunstall, M G, & Graeber, G. Geothermal carbon dioxide for use in greenhouses. United States.
Dunstall, M G, and Graeber, G. Wed . "Geothermal carbon dioxide for use in greenhouses". United States.
@article{osti_543084,
title = {Geothermal carbon dioxide for use in greenhouses},
author = {Dunstall, M G and Graeber, G},
abstractNote = {Geothermal fluids often contain carbon dioxide, which is a very effective growth stimulant for plants in greenhouses. Studies have shown that as CO{sub 2} concentration is increased from a normal level of 300 ppm (mmol/kmol) to levels of approximately 1000 ppm crop yields may increase by up to 15% (Ullmann`s Encyclopedia of Industrial Chemistry, 1989). It is suggested that geothermal greenhouse heating offers a further opportunity for utilization of the carbon dioxide present in the fluid. The main difficulty is that plants react adversely to hydrogen sulphide which is invariably mixed, at some concentration, with the CO{sub 2} from geothermal fluids. Even very low H{sub 2}S concentrations of 0.03 mg/kg can have negative effects on the growth of plants (National Research Council, 1979). Therefore, an appropriate purification process for the CO{sub 2} must be used to avoid elevated H{sub 2}S levels in the greenhouses. The use of adsorption and absorption processes is proposed. Two purification processes have been modelled using the ASOEN PLUS software package, using the Geothermal Greenhouses Ltd. Operation Kawerau New Zealand and an example. A greenhouse area of 8,000 m{sup 2}, which would create a demand for approximately 20 kg CO{sub 2} per hour, was chosen based on a proposed expansion at Kawerau. The Kawerau operation currently takes geothermal steam (and gas) from a high temperature 2-phase well to heat an area of 1650 m{sup 2}. Bottled carbon dioxide is utilized at a rate of about 50 kg per day, to provide CO{sub 2} levels of 800 mg/kg when the greenhouse is closed and 300 to 350 mg/kg whilst venting. In England and the Netherlands, CO{sub 2} levels of 1000 mg/kg are often used (Ullmann`s Encyclopedia of Industrial Chemistry, 1989) and similar concentrations are desired at Kawerau, but current costs of 0.60 NZ$/kg for bottled CO{sub 2} are too high (Foster, 1995).},
doi = {},
url = {https://www.osti.gov/biblio/543084}, journal = {Geo-Heat Center Quarterly Bulletin},
number = 1,
volume = 18,
place = {United States},
year = {1997},
month = {1}
}