Is it genuinely true that reports on renewable energy have led to doubts on the efficiency of our current renewable energy sources?

True

Some reports on renewable energy sources, such as wind turbine, have shown that current systems are not sufficient to replace traditional energy sources. Reports are often giving mixed results and more research need to be done to 1) Access the efficiency of current renewable energies 2) Develop these to make them more efficient 3) Continue to develop and create more renewable energy sources