Revolutionising solar: flexible thin film flexible cells will put solar PV everywhere

A quiet revolution in solar energy is underway, driven by thin film solar technology. This cutting-edge innovation offers a flexible, lightweight, and versatile alternative to traditional silicon-based solar panels, promising to reshape how and where we harness energy from the sun.

Thin film solar cells can be integrated into unexpected surfaces, such as building facades, windows, or the growing floating solar market. Thin film’s flexibility opens doors to new applications and helps overcome some of the barriers that have long limited the adoption of solar energy.

A lot of the interest in thin film solar technologies is coming from one company, based right in the heart of the UK: Power Roll. The County Durham-based firm has spent years exploring how to make thin, flexible solar cells that can be applied almost anywhere and has recently been hitting major milestones in commercialising the technology in an effort to get it out across the world.

Solar Power Portal sat down with Power Roll CEO Neil Spann to explore how thin film solar could deliver the government’s promised “rooftop revolution” and how Power Roll’s unique manufacturing process can make solar power a cheap reality worldwide.

What is thin film solar?

In essence, Spann explains, Power Roll’s thin film solar technology rotates the solar cell setup 90 degrees from the standard layout of layers of chemicals and materials with contacts on either side. Power Roll’s cells are absolutely minuscule, with each cell being around one micrometre wide—around one-fiftieth the width of a human hair—and many cells connecting to individual contacts.

In a 100cm squared sample of the material, 55,000 individual solar cells are crammed into microgrooves, vacuum coated from either side using a process taken from methods used in food packaging manufacturing. This makes for the highest-resolution conductive surface currently available, and the thinness of the material makes it possible to manufacture it using a roll-to-roll process that is common across many industries and thus comes at a significantly lower cost than much traditional solar power manufacturing.

Perovskites and thin-film

This manufacturing process meets another material generating a major buzz in the solar industry at present—perovskites. Perovskites are arguably the most significant development that the solar industry has seen in recent years, owing to their incredibly lightweight and immense efficiency—a team of scientists from the University of Oxford was recently able to demonstrate conversion efficiency in perovskite materials of as high as 27%. The research team believes that in the future, conversion efficiency could reach well over 45%, far greater than much of the technology on the market today.

The advantages of perovskites go well beyond their efficiency and low weight—the materials used in these kinds of films don’t require any rare earth elements, unlike other solar technologies, which is hugely beneficial both in terms of financial cost and the human cost of sourcing such materials, which have been linked to human rights abuses in the past.

Spann notes: “We do not use any rare earth materials, and all the materials we use are Earth-abundant and able to be sourced globally. So we are trying to break the reliance on some of those very rare earth materials and also those which have very limited supply chains to one particular location or particular one supplier.”

Spann is keen to emphasise that perovskites are not the only or even the most significant part of Power Roll’s unique technology—it is the combination of the perovskite material and the microgroove manufacturing that makes what Power Roll is doing so effective.

He adds: “We happen to be using perovskites as the solar absorber, but we are not a perovskite company. It’s the material we’ve chosen to deploy it in. We have actually proven our microgroove technology works with various other solar absorbers.”

The thin film advantage

Spann points out that one in three buildings in the UK is unable to handle the weight of traditional solar panels on their roof, a fact that is unsurprising given the UK’s ageing building stock.

Commercial industrial rooftops, in particular, are something which Spann notes is a “very exciting” application as many industrial facilities, including Power Roll’s own, are unable to support the weight of silicon panels but have immense power usage needs—a clear use case for the tech.

Furthermore, in what Spann refers to as a “slightly left-field” application for the technology, floating solar—which we explored in a previous Solar Power Portal blog post—is a majorly beneficial use case for the tech, with the flexible nature of the film pairing extremely well with the ever-changing nature of ocean waves.

There is one more area that Spann himself is personally passionate about as a use case for the technology: off-the-grid applications. With over 600 million people across the world having no access to electricity at all, let alone green electricity, the opportunity to bring cost-effective, lightweight technology to the farthest flung regions of the world is something Spann calls “huge and exciting because you are really making a difference”.

He adds: “If there is a surface, there is potential there.”

Thin film solar: the commercial future

With any new technology, the tricky question of commercialisation will eventually come up, and this, Spann tells me, is where the company is focusing much of its efforts over the next five years and beyond. The company was recently the recipient of a £4.3 million funding injection thanks to the Northern Powerhouse Investment Fund II (NPIF II), and last month the firm partnered with packing manufacturing firm Amcor to help expand Power Roll’s processes across the UK.

Power Roll is currently developing a gigafactory to manufacture the technology at scale and plans to locate the facility in County Durham to bring the next steps in the green revolution to the area. Once complete, this factory will be the first gigawatt-scale solar factory in the UK.

Spann notes that the firm has just appointed a new COO, who joined from electronics giant Hitachi, and adds that continued capital is the final piece of the puzzle. He states: “We have got the plans, we have proven the manufacturing. We now need the capital to be able to deploy that, and we are hopeful of closing that round within the next few months.”

Beyond this first gigafactory comes world domination in the form of licensing manufacturing facilities around the world.  

“Our plan internationally is to license and partner globally, so we already have some potential early-stage commercial licensing partners engaged. So, the UK factory acts as a blueprint from which we can set up a factory in India, we can set up a factory in Japan, we can set up a factory in the US or Europe.

“So very much within a five-year horizon is to get the solar film really scaled significantly in the UK, but also to be scaling globally with international partners.”