Tidal power has massive potential, but also comes with massive costs and logistical issues. A new wave of tidal generator designs could solve these issues.
Humans have put a lot of obstacles in the way of fish wishing to migrate and spawn. A new 'Fitbit for Fish' will test just how stressful their journeys are.
A new approach to storing renewable energy looks to recreate the process of hydroelectric dams under the ocean.