The owners of renewable energy installations (solar panels, wind mills, biomass installations) receive 'certificates' from the Flemish government. Those certificates can be sold to electricity providers who are obliged to offer consumers a growing share of renewables in the mix. The providers are allowed to buy the certificates instead of actually producing all the renewable energy themselves. Certificates can also be sold to the distributors directly at an agreed minimum price. This is a very strong incentive for both companies and individuals to install PV panels and other power-generating alternatives. A  similar system exists for the installation of hydro-electric power stations.