Food growing: electricity instead of land and waterJordan has approximately 61 cubic meters of renewable freshwater available per capita per year. This is far below the international threshold of 500 cubic meters per person per year, which defines absolute water scarcity. To grow food, you need water. This limits Jordan's food production. It is possible to reduce water usage drastically by using much electricity. 
How could the greenhouse in Vienna be improved? Maybe a winter break? How long should the winter break be? Advanced greenhouse: Very low air exchange. The air exchange is controlled by holding the oxygen level at 25%. At the air exchange, humidity recovery is used. CO2 is blown into the greenhouse to achieve the 800 ppm CO2 optimal level for growing tomatoes. The CO2 can be provided by DAC - Direct Air Capture or from cement factories heating the clinker electrically, only providing pure CO2 from the chemical reaction. Water for cooling is cooled down during the coldest hours of the day to improve the COP of the heat pumps. A GEMINI 60 house has 40 m³ water as low-temperature heat storage, which can be used for this optimization. In aeroponic/hydroponic setups, the recirculating solution concentrates salts over time as plants transpire pure water. To prevent toxicity (maintaining EC <2.5–3 dS/m for tomatoes), a fraction must be periodically discharged and replaced with fresh water. For a further reduction of water usage, this water is also recycled as well as economically feasible. LED usage: Amman has enough light all year to grow tomatoes. In Vienna is the decision is to supplement natural light in winter with LED light for optimal plant growth. The outcome in kWh/kg tomatoes is nearly the same, but using much more electricity in winter would further decrease the 24×365 conversion ratio. |
