Power supply options for a large-scale greenhouse

As part of the project “Electricity procurement options for a large-scale greenhouse”, FfE analyzed the economic efficiency as well as regulatory framework conditions and trends of various electricity procurement options for a planned large-scale greenhouse of BayWa Greenhouse Development GmbH, a subsidiary of BayWa Global Produce GmbH (baywa-gp.com). The project aimed to support selecting the most cost-effective green electricity supply option for a planned greenhouse in central Germany. By operating the greenhouse with climate-neutral electricity, local food production in Germany will be increased, thereby reducing imports and the associated transport emissions, known as Scope 3 emissions.

Methodology

At the beginning of the project, the following six options were identified for the possible purchase of electricity for the greenhouse:

1. Grid electricity with green electricity certificates
2. Construction of a local wind turbine with direct line
3. Construction of a local PV system with direct line
4. Conclusion of a PPA contract (local or virtual)
5. Use of surplus electricity from a nearby paper mill via a direct line
6. Construction and operation of a CHP plant using biogas from a nearby biogas plant and construction of a direct gas pipeline

In the first step, these six electricity supply options were analyzed in detail. The focus was on estimating the specific costs of the options for a time horizon of 2025 to 2045. In addition, trends and developments, regulatory framework conditions, funding opportunities, and risks and opportunities for BayWa were examined.

The initial classification of the electricity procurement options was followed by a more detailed analysis. The in-depth analysis included an examination of the generation profiles. The plant sizes of the wind and PV systems were designed based on the availability of space, capacity utilization and the degree of coverage of the total electricity demand.

The cost estimate in the first step showed that the use of PV and wind power are the most cost-effective alternatives. The purchase of electricity from the grid and via the paper mill, for which the same electricity price as on the stock exchange was assumed, was the most cost-effective alternative.

The cost comparison between the backup power supply options was carried out by comparing the costs for the amortization of a direct line between the greenhouse and the paper mill over a period of 20 years as well as the costs for grid fees and other levies and charges incurred. In the final step, the total costs of the electricity supply combinations were calculated and recommendations were derived from the previous analyses.

Results

In the short term, it makes the most sense for BayWa to build a wind turbine as the primary electricity supply option. At the same time, a small PV system can also be built on the roof of the greenhouse. The paper mill should be selected as a backup power supply option, as the construction of a direct line over a relatively short distance is much cheaper than paying levies, surcharges and grid fees. Figure 2 shows an overview of the electricity supply combinations and their costs.