Loose monetary policy can get people to use idle resources. But this new economic activity will likely be in the service of bubble industries that don't create real wealth. Moreover, these bubbles create many idle resources of their own when the bust comes.
When governments devalue the currency to push more exports, the country is getting rich in terms of foreign currency, but it is getting poor in terms of real wealth.
The ECB, always happy to repeat the mistakes of Japan, is likely to start new programs of debt monetization for green projects and claim it is a different, radical and new measure.