The Trias Westland geothermal project is a partnership between Flora Holland, HVC, Westland Infra and the Municipality of Westland. It is the first geothermal project in the Netherlands that will drill as deep as the Trias layer, situated at a depth of 4 kilometers. For the project T&A Survey as designed a unique combined geotermal system. In 2017 the first test drilling will take place. If the results of the  test drilling are positive, the Trias Westland geothermal doublet will be completed with a second drilling, which will make the actual heat extraction possible.

Trias layer
The Trias drillings will be the deepest geothermal drillings ever performed in the Netherlands. Other geothermal projects in the surroundings went as deep as the Lower Creatceous, at a depth of 2.5-2.8 kilometers. This sand stone layer can provide for 10 to 20% of the heat demand of te Westland greenhouse area. A geological study performed by T&A Survey for the Municipality of Westland has shown that the deeper situated Trias sand stone layer, at a depth of 4 kilometers, has a heat potential able to provide for about 80% of the heat demand of the Westland area. The temperature of the water in this more than 200 million years old layer is around 130 to 150 °C.

An innovative drilling concept
The first drilling will be performed in the surroundings of the floricultural auction of Flora Holland Naaldwijk and goes hand in hand with a comprehensive research program, which will provide all  relevant information on the suitability and productivity of the Trias layer. Another interesting detail is that the drillings initially will be directed to the Lower Cretaceous layer, and only afterwards continue to the Trias reservoir. The geothermal system will be implementend depending on the success of the drillings to both layers.

February 2018: Trias Westland to become Lower Cretaceous project
The Lower Cretaceous layer, which is located at a depth of approximately 2.7 kilometers. Other Westland geothermal projects  also extract their heat from this layer. The Triassic layer, located at a depth of 4 kilometers, turned out not to be suitable for cost-effective heat recovery. The Lower Cretaceous layer instead, or more specifically the Delft sandstone layer, appears to be even better than originally thought.

The Green Well Westland geothermal project was initiated by five greenhouse growerns from Honselersdijk who wanted to switch to geothermal energy for the heating of their greenhouses. T&A was responsible for the well design, the management and the supervision of the geothermal drillings. Between december 2011 and may 2012 the drillings were performed by DrillTec from Germany.

Implementation of the project
T&A drilled a geothermal doublet consisting of a production well an an injection well, each with a length of 3.200 meters. Since the wells are slanted, the deepest point is at 2.800 meters. The distance between the extremities of the two wells is 1.500 meters. The hot water is pumped up through the production well to a heat exchangers, where the heat is transmitted and devided between the participants. The cooled off water is pumped back into the ground by the injection well.

The results
The well has a minimal potential output of 60 liters per second, approximately 180 cubic meters per hour, with a temperature of 87° at the wellhead. The doublet provides about 12MWth and is used for around 7.000 hours per year.

By using geothermal energy, Green Well Westland aims ad reducing the annual consumption of natural gas with more than 50%. If the production is higher than their demand, the remaining energy is sold to neighbouring greenhouse growers.

With its depth of 2.800 meters the Green Well Westland project is the deepest geothermal project so far in The Netherlands. In addition, it is also the well with the highest capacity and it is the project with the largest number of benefitting businesses (eight so far, with plans for further expansion).

T&A's study for the Geothermal Knowledge Agenda (Kennisagenda Aardwarmte) focuses on determining and predicting deviations in the geothermal gradient near geological fault zones in the West Netherlands Basin and Roer Valley Graben. A good prediction of the temperature is essential in geothermal energy projects. The average gradient in the Netherlands is 3.1˚C per 100 meters (depth). This can vary locally and this seems to be related to fracture systems in the subsurface. The study focuses on deviating temperature gradients near large-scale fault zones and the potential consequences (positive and negative) for geothermal projects.      

More about the Kennisagenda Aardwarmte

The Geothermal Knowledge Agenda was set up by industry and the Dutch government to finance research into geothermal energy. The ambition of the Kennisagenda is to develop geothermal energy into an efficient, affordable and reliable heat source for greenhouse horticulture, industry and the built environment by 2030, making it into a substantial contributor to the Dutch energy supply. Objectives of the Kennisagenda include reducing uncertainties and risks (with the focus on the operational phase and the design phase), improving operational and energetic efficiency and extending the lifetime of a geothermal energy source.

Project goal
KennisAgenda Aardwarmte
Geothermal potential in het West Netherlands Basin/Roer Valley Graben
Trias Westland
Development of drill concept, well engineering,  drilling program, drill management
IC Arnhem
Seismic extraction saltexploration Ganzebos
VHGMPreparations for construction geothermal plant
Well Engineering Partners
Well site geology, Kwintsheul
Propietary study Chalk potential northern Dutch offshore
Sterling Resources
Quick-scan play analysis new ventures Dutch offshore, Seismic interpretation northern Dutch offshore
Flora Holland
Feasibility study, drill design, drilling program & tender
Tracs International Consulting
Conceptual sedimentological model, Persian Gulf
Akzo Nobel
Evaluation of seismic interpretation Hengelo
Energie Partners West-Friesland
Preparation explorational drillings Andijk
AMT International
Geothermal potential Bergschenhoek, study  Carboniferous Limestone Siberië-Maasbree, Geothermal potential greenhouse area Tangmere, UK
Eneco Solar, Bio & Hydro
Reprocessing seismic data Den Haag, delivery of new doublet with reservoir map
Lans Groep
Advise for SDE-study Maasland
BAM Nelis de Ruiter
Seismic interpretation and static modelling North Sea shallow gas reservoirs
Provicie Utrecht
Seismic survey deep underground
Green Well Westland
Study of geothermal potential, preparation and management of the construction of the geothermal doublet.
Johnson Europlant
Quick scan, detection license, feasibility study
EnecoDetection license, study of geothermal protentia and geological detail study, Den Haag
Westland Infra
Reprocessing and reinterpretation of seismic data Naaldwijk
Akzo Nobel Industrial Chemicals
Quick-scan and license application, Delfzijl
MWHAnalysis and seismic survey salt exploration Isidorushoeve and Hengelo, seismic (re)interpretation
Aardwarmtekluster 1 KKP
Interpretation of wireline logs of reservoir zone  geothermal production drilling
Kwekerij VVE Oude Campspolder
Detail study for geothermal heat extraction
Gemeente Eemsmond
Quickscan and detection license for deep geothermal
Tuinbouwvestiging Deurne
Study geothermal possibilities for municipality of Deurne
Greenpeace Nederland
Mapping of the distribution and thickness of  the Booms Clay layer
Gemeente Rotterdam
Study of  geothermal potential
Provincie Drenthe
Geological study, detection license and subsidy application
Gemeente s-Hertogenbosch
Feasibility study, application detecton license
Kwekerij Het Grootslag
Quick-scan, application detection license