Greenhouse Geothermal plant

Greenhouse Geothermal plant

Agriport A7 is a business park and a location for large-scale greenhouse horticulture. ECW’s objective is to contribute optimally to the most sustainable energy supply in the area. Most of Agriport is intended for Greenhouse Horticulture, approximately 750 hectares. In May 2006 the first construction work for the glasshouse horticultural companies started. Kwekerij De Wieringermeer and Royal Pride Holland were the first growers to build their greenhouses here. The number of nurseries has now increased to 9 and the total surface area of the greenhouses has grown to 300 hectares. Of this, 200 hectares are tomato cultivation and 100 hectares are peppers. Tomato cultivation on Agriport covers approximately 20% of the total market. Geothermal energy, also called geothermal heat, is the extraction of heat from the earth. This is a form of sustainable energy in which warm groundwater is extracted by means of a production tube and cooled (after recovery of the heat) injected again by an injection tube. The wells are usually 2000 – 2500 meters deep and are 1000 – 1500 meters apart underground. ECW is a so-called geothermal operator and is responsible for the safe, reliable and sustainable realization, operation and closure of such installations.

 

ECW has realized 3 geothermal production plants in Agriport area, for heat recovery. ECW also manages these production plants on behalf of the operators Agriport Warmte BV and Geothermie Wieringermeer BV.

Each production plants consists of 2 sources (wells). One well for pumping hot water and one well for injecting the cooled water. All this water comes from the ECW geocentric plant, where it gives off its heat to the water from the heat network, which goes to the customers.

The wells at Agriport are approximately 2,250 meters deep. From that depth, water of about 92 ° C is pumped up. This water is very salty and also contains a little gas. When the water comes up it first goes through a gas / water separation tank. In this tank, the salt water is split from the gas. The gas is usefully used to generate electricity and heat in a CHP or goes to the gas boiler for the production of heat. The water is pumped through filters through a heat exchanger. In the heat exchanger, the salt warm water transfers its energy (heat) to the fresh water circuit. This freshwater circuit is the heat network and runs towards the customers. After the heat exchanger, the salt water is about 34 degrees and is pumped back into the earth. Between the heat sink and injection well there is a floor between 0.7 – 2, 0 kilometers depending on the production wells. It has been calculated that it takes up to 30 years for the cold water to flow underground to the heat sink, so enough time to heat up again!

Wells 1 – 6 are connected to the power station at Oostlanderweg (A). Together with gas company Vermilion, ECW is investigating whether the old gas wells (no. 7 and 8) can be used for geothermal energy from a power plant to be built on Alkmaarseweg (B). ECW’s ambition is to expand its geothermal activities at Agriport with additional wells in the region.

In the pumping room there are 4 pumps feeding the eating exchangers and 2 pumps re-injecting the water in the wells. Due to the chemical composition of the water all the pumps parts are made of Duplex stainless Steel.

The Marly re-injecting pumps performance and main features are as follow:

  • Pump model HPR 125.6/8R-Duplex-710kw
  • All wet pump parts are made of Duplex stainless steel
  • type EN (X2CrNiMoN2253) ASTM (S31803)
  • Flow= 350m3/h
  • Delivered Pressure= 550m
  • Rotation speed=2400rpm
  • Pump Absorbed Power=655kw
  • Pump bearing oil lubricated
  • Balanced Mechanical Seal type SIC/SIC/Viton
  • Thrust bearing housing of the pump is equipped with air-cooling system for high thrust applications
  • Pump-Motor coupling with 250mm spacer
  • ABB brand Motor:
  1. a) Nominal power 800Kw-2950rpm
  2. b) Middle Voltage 6.000V-50Hz
  3. c) Execution B3
  4. d) Bearings Oil lubricated
  5. e) Driven by 1000Kw ABB inverter
  6. f) Bearings oil lubricated

Hydraulic Performance Curves of the Pump model HPR 125.6/8R-Duplex-710kw

Some process plant “inside” pictures:

 

 

 

 

The complete Agriport A7 compound energy consumption from the heat used to warming-up the greenhouses, is today estimated in about 70MW saving the equivalent CO2 and electricity from other hydrocarbon energy resources.