Workers in luminescent vests are building dozens of massive, hollow concrete boulders at a shipyard on the North Sea, each the size of an apartment block.
These are to be floated out to sea and sunk to become the foundations of a giant Belgian green energy development - a world first - which is itself, however, in choppy waters amid surging costs.
Named after Belgium's Princess Elisabeth, the "energy island" was launched in 2021 to support a massive expansion in wind energy production that would drastically reduce the country's dependence on planet-warming fossil fuels. However, according to some estimates, supply chain snags have made costs triple to more than seven billion euros ($7.56 billion), sparking calls for construction to be stopped at a time of growing political pushback against ambitious green targets across Europe.
"This cost increase is a huge worry," Belgium's energy minister Tinne Van der Straeten told AFP.
The government says that just over 10 per cent of Belgium's energy supply comes from renewable sources.
According to the International Energy Agency, nuclear, gas and oil provide the bulk of its needs.
But Belgium will have to lower its dependence on fossil fuels as a European Union target requires 42.5 per cent of the bloc's energy to be renewable by 2030.
"That's why we need transformative projects, huge projects like this," said Van der Straeten, sporting a yellow construction helmet while visiting the shipyard in Vlissingen, a Dutch port near the Belgian coast.
