German economic growth will accelerate this quarter as Europe's largest economy recovers faster than expected, even if deep structural challenges continue to hold it back, Bundesbank President Joachim Nagel said on Wednesday. Germany, the world's third-biggest economy, has stagnated for most of the past three years as its vast industrial sector lost some of its competitive edge. A recovery has started to take hold this year, and a surge in government spending on defence and infrastructure has given it an additional boost.