“Certificates can be used to disclose the source of energy, and thus the environmental impact of energy production, to consumers. They might also be used to demonstrate to government the achievement of national targets. They can also be used to enable many types of support schemes, whether voluntary (green energy and green label schemes); or obligatory (such as supply obligations, portfolio standards and feed-in systems). They do so by enabling the source of the energy to be guaranteed, and can in some cases be traded internationally.
EECS certificates are currently exclusively for dislcosure to consumers, and are internationally transferrable throughout Europe.” Source: https://www.aib-net.org/faq/market