Energy for Plants

The diffuse white light of the greenhouse makes the color of the plants, which are waiting for their delivery to retail, appear even more intense. The new greenhouses of the Hartmann GmbH & Co. KG in Schwarzach am Main cover almost 2.9 hectares. Heat and electricity for the greenhouse, which runs almost fully automatically, come from the CHP plant next door. The plant was built by the planning office PRO>>OPT GmbH and is also serviced by them. The electricity from the combined heat and power plant, which was connected to the grid in November 2018, is marketed in accordance with the 2017 Act on Combined Heat and Power Generation, short KWKG-2017. Robert Hackl, planner at PRO>>OPT, explains: "When we started planning the plant, the KWKG-2017 had not yet been finally adopted. Of course, for such an endeavor, you need a little bit of courage and trust in the legislature. But in our case, it has paid off and the plant is one of the first plants operating according to KWKG-2017."

Today, the plant consists of a CHP plant with 530 kW output. A further CHP plant with the same capacity is already in the works and will be installed next to it. "At the moment, our plant delivers about 650 kW thermal energy per hour. But overall, we need about 3000 kW of thermal energy in peak times. We have got this gap well covered with our thermal storage system.” The storage system of the CHP, which is already designed for both CHP units, comprises one million liters. “This gives us a lot of flexibility,” explains Robert Hackl. “I can pause power generation for a few days if the electricity prices are unappealing or if I already made use of very good prices at the energy exchange in the beginning of the week. This leads to roughly EUR 3,000 more revenues each month as compared to just running it heat-controlled,” Hackl states further.

A particularly important tool for Hackl and the Hartmann GmbH & Co. KG is the scheduling tool of the Next Kraftwerke user portal “My Power Plant”, which allows users to transmit plant operation schedules online. A traffic light symbol shows the hours in which Next Kraftwerke’s analysts predict profitable prices, and in which hours the operation of the plant is not as lucrative. Schedules can be either transmitted daily or weekly.

"The customer portal makes our work much easier. For example, while I was on holiday with my son, I scheduled the plant’s operation from the caravan. Every morning, when we came home from sheatfish fishing, he used his mobile phone to connect my laptop to the internet via tethering and while we had breakfast, I set the plant’s operation schedule based on the electricity price forecasts displayed in the portal. That was extremely convenient,” says Hackl.

Even though the plant currently makes its revenues solely at the spot market of the energy exchange, it could theoretically also provide balancing reserves to the national grid. “Of course, the plant is also prequalified for balancing reserve. Unfortunately, however, prices at the balancing reserve market were unappealing in recent years. And because the revenues from the peak-load optimized operation were so profitable, we did not see a reason to change anything about it. If the prices at the balancing reserve market increase again and we have completed our second CHP unit, this option is also somewhat more attractive again,” explains Robert Hackl.

The CHP plant of the Hartmann GmbH is not the only plant marketed through PRO>>OPT GmbH by Next Kraftwerke. "I have been in contact with Next Kraftwerke for a long time and appreciate the individual expert advice very much. The cooperation works smoothly and I get answers to my questions quickly. That is what you really want from a business partner," says Hackl in summary.