The horticultural sector has been known for years as a leader in innovation.

Initially, innovation was done to strengthen the competitiveness, but the knowledge and technology developed have also become an important export product. Competitiveness is no longer the only factor in innovation. Sustainability has become a must. And it is precisely here that there is still plenty to gain, says Edith Post, Senior Key Account Manager for Horticulture at Engie.

Sustainability is a theme that affects the entire business. For example, sustainability in purchasing can be achieved by switching to recycled or reusable packaging. It will also become increasingly important to use means of production with a low CO2 footprint. In the production process itself, ‘cast-offs’ can play a central role: products that may not meet ideal requirements, but for which a use can easily be found. The same applies to crop residues or pruning waste that can be used in other sectors.

In addition to purchasing and production, energy consumption is the third aspect of business operations where sustainability offers substantial opportunities.

CO2-neutral heat

To achieve the climate objectives of the Paris Agreement, we must move towards a CO2-neutral society. At present, the horticultural sector is still fully powered by natural gas and represents around 10% of Dutch gas demand. Moving away from natural gas is one of the issues that the horticultural sector must resolve to become CO2 neutral and thus future-proof. Fortunately, there are plenty of options.

Geothermal energy is a sustainable source of energy for horticulturalists to provide (part of) the base load of heat demand. Warm water is pumped up out of the earth, the heat is extracted, and the cool water is returned to the same layer of earth. Because geothermal energy provides the base load, natural gas (or an alternative) need only be used for seasonal fluctuations in demand.

Even when geothermal energy is not an option locally, there are alternatives to meet the demand for heat. For example, by upgrading heat with a heat pump, whether or not in combination with heat and cold storage. Solar heat, but also warm surface water or warmed-up cooling water can be used as a heat input.

The power of green light

In addition to heat, lighting is an important energy consumer. Traditional assimilation lighting requires a relatively large amount of energy and also produces radiant heat. LED lighting is therefore experiencing a huge increase in use. This has many advantages: higher energy efficiency, less heat dissipation, no blind current, more flexibility in the light spectrum and a longer life.

It is important to note, however, that although the usual high-pressure sodium lamps have been reasonably well developed, steps can probably still be taken in LED assimilation lighting, for example, to make the investment costs more attractive. It is therefore a good idea to always make a calculation of the payback period before switching to LED lighting.

Speaking of light: while assimilation lighting is an energy consumer at night, light is an important source of energy during the day, and not only for the crops. Solar energy is already being generated in abundance in horticulture, but the future holds many more opportunities.

A major disadvantage of solar energy is that it is only temporarily available: during the day when the sun shines. You must then either use the generated energy directly or feed it back into the energy network. Both situations are just not always financially desirable. Progressive research into battery storage therefore offers a future solution. In the ideal situation, you can then generate energy during the day and use it at night for artificial lighting! Although solar panels can currently take up a lot of (greenhouse) surface area, this need not be a problem in the future: transparent solar panels could literally turn the greenhouse into an energy source in the future.

The CO2 issue

CO2 is needed for the cultivation of many crops. The easiest way at the moment is to generate CO2 with a CHP or boiler, which usually runs on natural gas (and in some cases provides unwanted extra heat). CO2-neutral horticulture needs an alternative.

The best future scenario is that multiple external sources of CO2 are developed so that the supply is always reliable. A number of options are already under development, such as CO2 capture from flue gases of waste incineration, extraction of CO2 from outside air and the extraction of CO2 from the fermentation of biomass or production of green gas. Another very interesting source of CO2 is industry. Enough is produced there that can be captured and delivered to horticulture. And although this is already being done by OCAP in the Westland region, among others, there is plenty of room for expansion in the rest of the country.

Initiative from the sector itself

Much of the innovation in horticulture comes from the initiative of the sector itself. That must certainly continue, but is it enough? To ensure that the sector does not constantly fall back on cheaper fossil fuels, cooperation between the public and private sector is necessary. Only then can we achieve the climate-neutral horticulture of the future.