CertiQ certifies renewable energy and energy generated from fossil sources. It issues certificates for both types of energy. When certificates are issued, CertiQ credits them to the account of a trader. If you want to buy and sell certificates, either in the Netherlands of internationally, you need to open a trader's account with CertiQ. This also allows you to cancel the certificates for sustainable energy production from your account, or for turning grey power into green.
A trader is an organization that trades in certificates. Anyone can register with CertiQ as a trader, providing they meet the requirements. In practice, most traders are energy suppliers. When a supplier delivers renewable energy to an end user, the supplier must cancel Guarantees of Origin from its CertiQ account. If the supplier delivers energy from fossil fuels to an end user, it must cancel Disclosure Certificates from the CertiQ account.