The expectation is that in the future, CHP units and the OCAP pipeline will provide less CO2 for greenhouse horticulture. Various alternatives exist, such as CO2 from the air or biogas. However, the requirement is that crops are not harmed by these sources. Wageningen University & Research BU Greenhouse Horticulture is investigating the quality of these alternative sources and working on a standard measurement method for CO2 quality. Researcher Janneke Grit: "CO2 is an important resource for horticulture. There are alternatives, but they must, of course, be of high quality."
Many growers use Combined Heat and Power (CHP) systems to produce heat, electricity, and CO2 from natural gas. However, the use of fossil fuels must be reduced, which will likely result in less CO2 being available from CHP. Additionally, many growers receive CO2 via the OCAP pipeline, a waste stream from industry in Rotterdam. This CO2 will be stored underground in the future, which means that this source will also provide less CO2.
The greenhouse sector is therefore looking for alternative sources to support crop growth. Options include CO2 from biogas, the shipping industry, or air (via Direct Air Capture, DAC). The requirement is that neither crops nor people are harmed.
CO2 Battery
WUR is currently working on several projects related to the CO2 quality of new sources. For example, DAC devices are being tested at the IDC CO2, and a project to test CO2 from a CO2 battery will begin in early 2025. Here, CO2 released during combustion on a ship is stored in a tank, known as the CO2 battery. Onshore, the CO2 can be released to the grower using a stripper.
The overarching project, 'Quality of Alternative CO2 Sources for Greenhouse Horticulture,' aims to support suppliers of new CO2 sources as well as growers by establishing guidelines for CO2 quality. This is being achieved through a comprehensive list of requirements that new CO2 sources must meet to be safely applied in horticulture, developed through literature research, interviews, and testing experiences at IDC CO2. Grit explains: "We are looking at the effects on sensitive crops."
Unified method
Based on the findings, WUR is also developing a method that will allow CO2 source developers to measure quality in the future. "There is currently no unified method, which makes quality comparison difficult."
The project 'Quality of Alternative CO2 Sources for Greenhouse Horticulture' is funded by the Kas als Energiebron innovation program.
Source: Wageningen University & Research