CO2 in the horticultural greenhouse

Plants grow under the influence of light and use water and CO2 as raw materials for there photosynthesis. In the competitive horticultural market, the use of CO2 in a greenhouse is considered to be a major instrument in increasing production. In the Netherlands the CO2 requirement is primarily met by using CO2 in the form of flue gasses from the heating system (boiler). Natural gas is therefore burnt on a large scale in the Netherlands in horticultural greenhouses during the summer. This technique, however, provides limited quality with respect to CO2, because it`s limited in capacity and is not always environmentally friendly. Horticulturists can use some of the heat that is released but in many cases the heat is lost (summer heating).

Minimum costs and high quality CO2 from OCAP
Faster growth of your greenhouse crop
Higher yield per square meter
Better planning of crop production
Better crop quality
Insured against damage of none pure CO2 which is contaminated with etheen or NOx.

The mission of OCAP
OCAP,is a joint venture between gas supplier Linde Gas Benelux and VolkerWessels . OCAP supplies pure CO2 to greenhouse companies. This CO2 is produced during the production of hydrogen at Shell in the Botlek and would otherwise be expelled into the atmosphere. OCAP supplies this CO2 via an existing pipeline and a new distribution network. This enables horticulturists to save about 95 million cubic metres of natural gas per year. And it also reduces CO2 emissions by about 170,000 tons per year. It is therefore a unique form of cooperation. For both the environment and greenhouse horticulture.

The idea of supplying the CO2 that was emitted during the production of hydrogen to glasshouse horticulturists was conceived in 1994. In 2002, Syens Energy worked out this initiative of linking demand with supply and economics with the environment. Their mission was: ‘to meet the requirement for CO2 in greenhouse horticulture in an environmentally-friendly way through the distribution and delivery of the pure CO2 which is released from the refinery’.

VolkerWessels and Linde Gas Benelux have undertaken this initiative which is unique in the world. They are supplying the CO2 which is released during the production of hydrogen to greenhouse horticulturists. The CO2 supply operation has been placed with a joint company called OCAP (Organic Carbondioxide for Assimilation of Plants).

The OCAP solutions
The horticulturist has high-quality CO2 made available to him in large quantities for the maintenance of the best possible concentration of CO2 in the greenhouse. The increase in production achieved by this increases the competitive position of the horticulturist. At the same time the burden on the environment (the natural gas consumption) is lessened per unit. This saves about 95 million m3 of natural gas on an annual basis.

The CO2 which is emitted by the Shell refinery is put to good use and this lowers CO2 emissions. There is a total reduction of CO2 emission by 170,000 tons per year. These reductions can make a considerable contribution to the targets in the field of CO2 emission reduction which were set in the Kyoto protocol.

CO2 in the Botlek
At the Shell refinery in the Botlek area, (almost) pure CO2 is expelled into the atmosphere on a large scale. The CO2 is released during the production of hydrogen, a crucial process in the refinery. Many kilotons of CO2 are emitted each year. This CO2 can be used directly in greenhouse horticulture.

Delivery area
The company delivers around 160,000 kg of CO2 per hour to 500 horticultural companies which is around 1300 hectares of greenhouses between Rotterdam and The Hague.

Transport
The CO2 that is supplied to the horticulturists is purchased from Shell. The CO2 gas is pressurized using a compressor. OCAP discovered an existing old pipeline that was used to transport oil between Rotterdam and Amsterdam, but was out of service for 25 years. The use an existing 85 km transport pipeline was vital for the project to keep the cost down and make it faster profitable. The old pipeline runs alongside a number of major greenhouse horticultural areas and OCAP still had to construct a distribution grid of smaller pipes running to the individual greenhouses.

Distribution and delivery
The delivery areas are connected to the existing transport pipeline. To do this OCAP has laid an extensive new pipeline network which connects each customer to the CO2 network.

Facts and figures

Horticulture in the Netherlands
Total area: 10,000 hectares.
Total turnover: € 8.5 billion export value.

Number of hectares that qualify for CO2 from OCAP: approx. 5,000 hectares.

The distribution network
NPM pipeline (NPM): 85 kilometres.
Main pipeline (steel): 12 kilometres.
Distribution pipeline (HDPE): 130 kilometres.
Delivery stations situated at the horticulturists: 500.

The delivery
Total connected service area: approx. 1,300 hectares.
Total supply capacity: approx. 160 tons per hour.
Total delivery: approx. 300,000 tons per year.

Environmental benefit
95 million m3 natural gas saving on a yearly basis.
170,000 tons CO2 emission reduction.

Linde Gas Benelux and VolkerWessels investment
100,000,000 euros.

Project evaluation
The project is very successful, when the project started in 2004 it was estimated that in 2008 the maximum production capacity of 160 ton CO2 per hour would have been achieved. Although this was very ambitious at that time OCAP achieved in February 2007 the maximum capacity already. Biggest problems for OCAP and the growers is constant supply as there are drops in supply or Shell is not producing enough CO2 than growers in are having problem with feeding enough CO2 to there plants. As there is still more demand from the growers in the Netherlands OCAP is now looking for alternative resources to produce CO2.

CO2 acts as a “sort of fertilizer” to speed up vegetable growth

Greenhouse vegetables grows about 25% faster when the concentration of CO2 is doubled. In greenhouse farming the CO2 for CO2 fertilisation is increasingly often delivered by several sources, such as burner/boiler, CHP, OCAP and pure CO2.