The road map for a sustainable and economic viable greenhouse horticulture depends on the local conditions and climate.
Netherlands and Northern Europe
As fossile free electricity is coming more and more available in the (near) future, electrification of greenhouses is an ongoing trend. Geothermal or waste heat, possibly combined with a heat pump, will be a part of the solution, where these renewable sources will cover the majority of the base demand of heat. If necessary, crops will be illuminated with high efficient LED’s. A serious problem with electrification is the current net congestion from which it is expected to become far worse. For existing growers of illuminated crops this should be no bottleneck because of their usually large existing contract capacities.
It is expected that the consequences of increasing taxes on natural gas will be huge, in particular for small growers. The need to reduce natural gas consumption will be enormous and therefore the traditional natural gas boilers will disappear. For the time being, CHPs will be tolerated because of their net balancing and peak shaving function, but not for the base load. They will be used as long as they are economical viable, thus with a positive spark spread.
In far future hydrogen might be an option and developments in this field have already started. Because of the conversion loss, for now hydrogen will be only useful when there is an electricity surplus. Large-scale application will take at least 10 years and because of the 'merit order' the mobility sector will be the logical first consumer.
Mediterranean
The rapid growth of the greenhouse industry in southern Europe followed the introduction of plastic-houses. The industry's remarkable success, coupled with limited economic alternatives for the local population, has highlighted the importance of preserving intensive horticulture for the future. Simultaneously, there's been a growing recognition of the ecological diversity at regions which are most suitable for greenhouses, namely the coastal regions .
Mediterranean plastic greenhouses are generally used in areas with high radiation and favourable temperatures, allowing almost year-round production of tomato, sweet pepper or cucumber. The use of fossil energy for heating is negligible. However it is expected that there will be a gradual increase in the application of artificial heating in greenhouses. This even can add to sustainability, since it will allow the optimisation of other product factors like fungal diseases due to humidity. Currently the heated greenhouses are usually high tech greenhouses heated with natural gas, but there are clear commitments to limit the use of fossil energy and seriously search for alternative sources, such as biofuel or new applications of solar energy.
Middle east
The full text of this FAO-analysis can be found here.
East Asia
In the context of greenhouse gases and sustainability there have seen various shifts and developments in recent years. Many East Asian countries, including China, Japan, and South Korea, have been increasingly investing in renewable energy sources like solar, wind, and hydroelectric power. Despite the push for renewables, coal remains a significant energy source in East Asia, particularly in countries like China and India. However, there's a growing emphasis on reducing reliance on coal due to its significant contribution to greenhouse gas emissions and air pollution. Many countries are investing in cleaner coal technologies or gradually shifting towards cleaner energy sources.
In general, the total greenhouse area is increasing, also high tech greenhouses, driven by the demand for year-round production of fruits, vegetables, and flowers, especially in regions with extreme climates or limited arable land. The Asian greenhouse sector has increasingly incorporated advanced technologies such as climate control systems, hydroponics, and automation. This integration aims to optimize growing conditions, improve yields, and reduce resource usage and in general the focus has shifted towards growing high-value crops, such as tomatoes, cucumbers, peppers, and various leafy greens. Efforts are being made to enhance sustainability, including the adoption of energy-efficient technologies, recycling water and nutrients, and implementing eco-friendly pest and disease management practices. This is partially driven by government support through subsidies and, technology incentives. Current challenges are excessive water usage, pesticide residue and energy consumption.
However, there is discussion on whether it is profitable to operate high-end glass greenhouses and whether more high-tech greenhouses are needed. High energy consumption because of heating in cold regions and coolling in warm regions leads to high energy cost and limits the sustainability of greenhouse production.
In recent years, photovoltaics have gradually become a reality from a long-term perspective and has been put into operation in more and more regions of China. This can contribute to the electrification which is to be excpected.