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T&A Survey's department of Sustainable Geothermal Energy (ODE) consists of a team of experienced geologists, engineers and project managers to whom the substrate has no secrets. T&A Survey has performed many studies for geothermal energy and in 2013 it has managed and supervised Holland's most succesful geothermal energy project Green Well Westland.

Geothermal roadmap

T&A's geothermal projects are focussed on risk minimalization and output optimalization. In order for a project to succeed, several steps have to be taken. T&A Survey can provide all necessary services. This way we guarantee consistency and a shorter lead time of your geothermal project.

With this short and cost-saving research it is possible to determine whether it makes sense to carry out further research into underground water resources, which can be used for geothermal energy or  Heat & Cold Storage (HCS).

The quick scan consists of three successive, independent components: 

  • Geological quick scan: What are the geological possibilities? Should we do further investigation? To find an answer to these question we use reports, maps and raw data to assess existing depth charts and deep exploration drillings of the research location in order to determine whether a suitable geothermal reservoir is present and, if so, where it's located.
  • P10-P50-P90 study: This general analysis provides an insight into the expected thermal capacity of the geothermal system.
  • Financial quick scan: What are the expected costs for the construction of a geothermal system?

Based on the results, T&A elaborates a concise report. By performing a quick scan, customers can be protected from unnecessary and costly follow-up studies and procedures.

In order for a geothermal project to be successful, it is crucial to know the structure and geology of the subsurface of the location. This requires an extensive geological study. In this study the figures the business case will be based on are determined, for example the optimal location in the reservoir and the potential geothermal capacity of the well.

Detail study

The detail study describes and interprets all existing local an regional underground data.In the feasibility study, the structural distribution and the depth of the groundwater reservoir are determined, in order to map the geothermal potential of the location. T&A Survey has a fully equipped seismic working station. The software we use is The KINGDOM Suite, used worldwide by the oil and gas industry.

Feasibility study

Subsequently we determine whether the heat capacity and the production of hot water are sufficient to meet the energy demand. To do so we use regional geological data and available borehole and seismic data. Potential sources of information are:

  • Publications on regional geo(hydro)logy
  • 2D and/or 3D seismic data
  • Deep drillings mainly from the oil and gas industry

When the geological, technical and financial feasibility studies are concluded with positive results, the preparations for the drilling of the geothermal doublet start. These preparations are done in  three phases:

A. Tender phase

In the tender phase the contracts  for the drilling services and equipment are selected and awarded. The purpose of the preparation and tender phase is to select a number of specialized and certified drilling (supply) companies that will perform the drillings professionally within the planning  and budget.

B. Drilling management

If all feasibility studies are concluded with positive results and service providers are contracted, the actual drilling can start. In this phase, T&A's team of experienced geologists, well engineers, drilling managers and project managers manage and supervise the drilling process for you.

C. Well optimalization

After the drilling of the first well (the production well), a pump test takes place to check if the expected production can be reached. If the pump test is positive, the drilling of the injection well can start. If the pump test for both wells is succesful, the construction of the geothermal plant will be started.


The Dutch Mining Act (Mijnbouwwet), is the leading legislation for deep geothermal energy. In the context of the Mining Act, an exploration permit is required for performing the first geothermal drilling. If the drilling proves to be sufficiently productive, the exploration permit can be converted into a extraction permit. In addition to the exploration and extraction permit, an environmental permit is required in addition to several local permits (construction permit, etc.).
Information about permits which have already been applied for or granted and the procedures can be found on the Dutch Oil and Gas Portal (Nederlands Olie- en Gasportaal). The map of the Netherlands with the overview of permits as of January 1, 2011 is also available as a pdf.


Various subsidies and guarantees apply to geothermal projects, such as RNES Aardwarmte and SDE+. These are regularly subject to change. For questions about the current state of affairs you can contact us.

Seismic data are used to map the subsurface for the extraction of both geothermal energy and oil & gas. By measuring the reflection of artificially generated vibrations on the surface, we get an impression of the structures in the deep subsurface. Seismics can be used to look into the subsurface for a few kilometers. Collecting and processing the resulting data is a costly procedure. It is also possible to enhance relatively old, already available, seismics from the 1960s to 1980s with new modern algorithms and programs. We call this reprocessing.

Affordable alternative for new seismic data

New seismic data usually give the best results, but reprocessing is a good and affordable alternative. Often, seismic data of an area is already available due to past oil or natural gas surveys. With the help of reprocessing, modern techniques can be used to improve the signal, making the addition of new seismic data unnecessary. T&A Survey has already achieved good results in geothermal energy research.

Better image of reservoir, lower risk

Reprocessing can significantly improve the seismic signal, making it easier to map underground reservoirs. In addition, nearby fractions can be better mapped and analyzed. This way drilling risks can be reduced, but more insight is also gained into the deep subsurface, so that deeper geotermal reservoirs can be better mapped. Because reprocessing significantly improves seismic data, projects can be optimized and risks reduced.

Reprocessed 3D seismic data from the West-Nederland Basin.  
Reprocessed 2D seismic data of the  Zandvoort Hoog.