Smarter cultivation with seasonal storage and heat storage

In our previous article, we explained the basics of Medium Temperature Storage (MT-ATES) and highlighted the difference with a geothermal (LT-ATES) system. In this article, we dive deeper into Medium Temperature Storage (MT-ATES) and how growers can optimally use a seasonal buffer. The result: lower energy costs, more stable cultivation conditions, and greater flexibility. MT-ATES offers many advantages and has the potential to become increasingly important for climate-resilient and energy-independent cultivation.

Optimal use of heat sources
Every situation is unique, but in practice, the following solutions are often used to efficiently charge a seasonal buffer:

• Geothermal or residual heat connections: in summer, there can be too much heat, while in winter there is not enough. Purchasing additional heat in summer can also be a solution, ensuring a stable heat supply in winter and lower energy costs.

• Solar panels for direct energy savings: with the phase-out of net metering in the Netherlands, feed-in may be limited. By storing heat generated by heat pumps during sunny hours, this stored heat can be used later in the season, saving on direct winter heating.

• Aquathermy: heat can be extracted from nearby waterways, which warm up significantly in summer, reducing the need for additional heating.

• Solar thermal energy: panels on office spaces or processing locations can provide heat for storage without taking up extra greenhouse space.

• Combined Heat and Power (CHP): exhaust gases can be further cooled, and the released heat stored in the MT-ATES system, maximizing efficiency from existing CHP installations.

Tip for growers: The above heat sources are often cheaper in summer than in winter, when energy is needed to heat the greenhouse. By storing excess heat in an MT-ATES source during these times, you can reduce annual energy costs.

Using heat: directly or via heat pump
When stored heat is extracted from the MT-ATES source, there are two options:

• Direct use in the greenhouse
• Upgrading with a heat pump

Which option is most suitable depends on the crop and the business. The temperature in the MT-ATES source plays a crucial role. In the pilot, temperatures can be charged up to 55°C. Over the season, however, about 5°C is lost in the soil, resulting in an average extraction temperature of around 50°C.

Practical tip: Lower charging temperatures result in lower extraction temperatures. This is ideal when many low-grade heat networks are available in the greenhouse.

Practical example
Let’s look at a potted plant company with a concrete floor and underfloor heating. The underfloor heating runs from October to April and has a maximum supply temperature of 35°C. Because the underfloor heating has a constant demand, the MT-ATES can deliver the lower temperature directly.

Important: Keep the return temperature low so the source can cool efficiently and be recharged. This maximizes the return from the seasonal buffer.

Conclusion
MT-ATES is a strategic seasonal buffer that can already benefit growers today and will become essential for climate-resilient, energy-efficient, and independent cultivation. By making smart use of available heat sources and the right temperature strategies, you can reduce energy costs and optimize cultivation results.