Ammerlaan The Green Innovator hasn’t been able to produce any geothermal heat for three months now because of a burst geothermal heat exchange pipe at a depth of 1 km. Another setback, which is going to cost the pot plant grower from Pijnacker millions of euros. In 2011 and 2012, they had to suspend their geothermal heat extraction for more than a year because they were unintentionally extracting oil and gas as well. It cost millions of euros to make the necessary adjustments to the installation at the time.
The nursery doesn’t know yet what caused the pipe to burst. But they do have some ideas. “The pipe might have been corroded or eroded, but based on how straight the burst is, we think it’s more likely that it fell out of the sleeve as this was stretched and shrunk because of temperature differences. And that would make it a construction error”, says Leon Ammerlaan.
The 6-ha nursery also supplied geothermal heat to thirteen other, nearby nurseries as well as 470 apartments, a swimming pool, school buildings, sports hall and fitness centre. Now that the geothermal heat extraction has been suspended, the required heat is supplied by gas boilers and CHP systems.
New geothermal doublet
Ammerlaan’s system could be repaired by putting a thinner pipe in the existing sleeve. But they feel that that’s going to be very expensive. Furthermore, it would reduce the capacity, which means that they will no longer be able to supply the full demand. That’s why Ammerlaan wants to have a completely new geothermal doublet installed by the beginning of next year, which will have a much larger capacity than the current system. However, Ammerlaan points out that this will require an investment of twice the amount that was spent on the current installation and they are currently discussing funding options with Rabobank, Pijnacker city council and Zuid-Holland province.
Ammerlaan thinks that a new doublet could be up and running by April 2018. “We’re now trying to figure out whether we should continue supplying heat from our gas boilers and CHP systems until that time, or whether it’s worthwhile repairing the broken pipe.”