Week three of our series focused on the global race to create the next generation of both solar panels and packaging

Hundreds of you have written in asking for stories about environmental innovation and experimentation. So this week, we set Guardian journalists to work, looking at the future of both solar power and plastic packaging.

Adam Vaughan reported on the global race to create the next generation of solar panels. Solar has had a very good run for its money over the past 25 years, but there is some evidence that first-generation solar, based on cheap silicon panels, might have plateaued.

In short, the hunt is on for new materials. Could perovskite – which offers the tantalising promise of more efficient, lighter and even semi-transparent panels – be the answer? And will skittish investors scupper the next breakthrough?

“I was surprised at how many people are still working in research on the next generation of solar materials,” Vaughan said of his reporting. “A lot of those companies went to the wall over the last decade as the cost of silicon fell dramatically. So it was heartening to see there are still people working on the science and looking at clever new ways of making their research jump from the lab to a commercial product.”

Facebook Twitter Pinterest Frugalpac cup, the world’s first recyclable coffee cup. Photograph: PR

Researchers from Pennsylvania to Jakarta are also racing to improve the current state of plastic packaging, as Nicola Davis’s report revealed. While the ubiquitous material won’t be disappearing any time soon, familiar products such as bottles and clingfilm are the focus of frenzied redesigns and replacements. Efforts are under way to make these products either easier to recycle and reuse or biodegradable. In January, the Guardian revealed that Britain’s supermarkets produce more than 800,000 tonnes of plastic packaging waste every year.

Amsterdam may have pointed the way forward this week with the unveiling of the world’s first plastic-free supermarket aisle, complete with more than 700 products. The Dutch chain Ekoplaza says it will roll out similar aisles in all of its 74 branches by the end of the year. If you do pop over to Amsterdam for a quick browse, you can also take a plastic fishing tour of the canals.

What we liked

This Apolitical piece about Glasgow, once dubbed “the murder capital of Europe”, which has seen its murder rate plummet by 60% in the past decade. We also enjoyed reading about “plogging”, the Swedish fitness trend for people who want to save the world.

What we heard

To me the issue with solar is also about the development of technologies around storage. We can have high efficiency panels across the UK but what happens when the sun doesn’t come out (which is generally the case)? Efficient and lower cost panels would definitely help but I think the advancements in storage will be where the next boost in adoption comes from. Commenter MassiveKitten writing below the line.

Where was the upside?

In a small town in Germany which has never looked back after reclaiming control over its energy supplies. Aditya Chakrabortty’s piece gave us a contender for word of the month: Die Gierbremse, or “greed brake”.

Facebook Twitter Pinterest Wolfhagen stands out. It’s where the Japanese and South Koreans fly in just to take lessons. Photograph: Lukas Schulze/Getty Images

If there is a story, innovation or everyday hero you think we should report on, write to us at theupside@theguardian.com.