Power plants emit a lot of heat and CO2, simply because it is waste for them. These are exactly the ‘raw materials’ that one needs in greenhouses. The heat and CO2 from the power plant is brought with flue gas ducts into the greenhouse. The aim is to save energy costs and to save the environment.
Flue gas ducts
The difference between waste heat and residual heatThe difference between waste heat and residual heat is that additional fuel is needed for the production of residual heat. Waste heat is difficult to use because it is up to 30 degrees Celsius. Residual heat is supplied at a higher temperature level and therefore can be used effectively in a greenhouse.
The function of a flue gas ductA flue gas duct ensures that the heat and CO2 is brought from the power plant to the greenhouse. First of all, a flue gas condenser cools down the flue gases to the dew point. In this way, the condensation heat in the flue gases is optimally used. This heat can be used to heat up water. Subsequently, the flue gases (which in particular consists of CO2) are cooled down far enough to be used in the greenhouse.
Saving costs with a flue gas ductBy making use of residual heat from a power plant, the boilers do not need to be turned on. This can provide significant savings as 100% of the required heat and CO2 can be supplied from the power plant through the flue gas duct. However, normally back-up boilers are installed in order to reduce risks. For example, when there is a breakdown in the power plant, the back-up boilers take the heat and CO2 production. This prevents damage to the crop.
Savings can further increase depending on local regulations on greenhouse gas emissions.