As the Einstein Telescope is an international project, the Netherlands, Belgium and Germany are working together. For example, studies are under way on the differences in planning laws and regulations and their significance for the Einstein Telescope project. A mega-project like the Einstein Telescope costs a lot of money to make the candidacy possible. Preparations and construction are calculated at around €2 billion. The cooperating countries have to pledge a contribution to raise that amount. Currently, the Dutch government has earmarked about 1 billion euros for the preparation and construction through the National Growth Fund (Nationaal Groeifonds). North Rhine-Westphalia has also pledged support for construction. Belgium, Germany and the Netherlands agreed in Bonn on 13 December 2022 to work together in a task force on the bid book and the formation of a host consortium to enable the candidature.
In short, there are quite a few topics that will be further explored through research in the coming period. The answers and results will be incorporated into the bidbook, which will present the three countries as candidates to build the Einstein Telescope.