The meteoric rise of renewable energy has consequences for our electricity supply. While coal and gas fired power stations can generate electricity whenever you need it, renewables are intermittent by nature. So we need a backup plan for when the wind stops or the sun goes down.
All over the world, engineers and scientists are racing to solve one key problem; how to safely and efficiently store electricity at a huge scale but at a low cost. The quest is producing some truly remarkable ideas and this episode details three of them.

As summer spreads across our planet, honey bees toil, snow geese breed, tadpoles awaken and lions stalk wildebeest in search of lush grass.
Our planet is solar-powered. But due to the Earth's tilt, it doesn't strike its surface evenly. This solar energy arrives in varying amounts at different times of the year. The huge increase that comes with summer also triggers countless migrations.

In the captivating second part of “Our Universe”, chapters 4 to 6 are presented together in an unmissable journey through the cosmos and life on Earth. These episodes delve deep into the elements that formed our world, the essential role of water, and the unseen forces that shape our lives. They offer an enthralling exploration of our place in the Universe. Dive in to experience this profound story of existence, from stardust to soulmates.
In the fourth chapter, we uncover how the elements essential to life were forged in the hearts of stars. Following a green sea turtle’s quest across the ocean for these elements, this episode reminds us that life is built from the remnants of ancient stars. The fifth chapter takes us back to the miraculous arrival of water on Earth, exploring how this vital substance transformed a barren landscape into a thriving blue planet. In the final chapter we witness gravity’s grand influence on life, following two king penguins as their journey of attraction and survival unfolds against the cosmic force that binds us all.