Together, they form an enterprise that is working well and constantly developing. Hence in 2014, the family decided to invest in a Combined Heat and Power (CHP) module so they could generate their own power for the greenhouse.“Simply because it’s sustainable,” is Heiko Hagdorn’s reasoning for his new acquisition. The 12V Series 4000 L64 unit from mtu Onsite Energy generates 1,523 kW of electrical power and 1,507 kW of heat. Most important for the Hagdorns is the thermal energy for heating the greenhouse. This is not needed every day, but rather in cloudy or colder weather. That is why the Hagdorns have installed a heat storage tank where they store the heat captured from the CHP module. So it is there “on tap” whenever the temperature in the greenhouse drops too far. But what happens to the electricity? “We feed it into the public power grid,” explains Heiko Hagdorn. That does not happen continuously, but only when the energy provider needs electrical power. Following the shutdown of numerous nuclear power plants in Germany and the large increase in renewable energy sources, the country’s power supply became more erratic than in the past. If there is a fresh wind along the coast and sunny weather across the country, the renewable energy sources are running at full tilt and there is a surplus of power available. However, if coastal winds are still and clouds cover the sky, energy providers have to turn to smaller, local power plants such as Heiko Hagdorn’s CHP module. The energy provider starts up the Hagdorn’s CHP module using an interface and then draws the power. “As we can be very flexible, we benefit from more favourable remuneration models. We are working on the assumption that the CHP module will have paid for itself in five to six years, even if it only runs for around 3,000 hours a year,” Heiko Hagdorn outlines. Not only is the power from the module used by the Hagdorns in their greenhouse. Even the CO2 emissions benefit plant growth. These are purified and then used later on to fertilize the crops.
“There are lots of tricks of the trade that you learn along the way,” Heiko Hagdorn relates. Along that way, he has developed from tomato lover to professional grower and is now an energy trader as well. So he is a few steps ahead of the average amateur gardener. But he still has one thing in common with that species – the delight and the sparkle in his eyes when he picks the first juicy red tomatoes of the harvest.