Becker, a Danish national and former deputy permanent secretary at the Danish Ministry of Climate and Energy, came to the association with a strong background in government and policy.
He had three ambitions at the outset: to promote the view that wind can survive without subsidies; to push for an ambitious renewables target for 2030; and to convince European politicians of the need for a European-wide grid.
In October, the EU agreed a target of at least 27% at EU level for renewable energy by 2030, to the disappointment of many including Becker. He continued to focus on the COP21 global climate talks and in promoting an improved European Energy Union.
Becker leaves the association ahead of the COP21 summit in Paris in November, having pushed through a number of internal changes in the organisation including a new board structure.
EWEA Chairman Dr Markus Tacke said: "We thank Thomas Becker for his dedicated service over these past two years. Mr Becker came to EWEA following a long and distinguished career in high-level international energy and climate negotiations and he has served the Secretariat with great pride."