Head of Energy & Sustainability
Mustab AHMED

Footprints – February 2023 | Glass Solar, Smart Materials and Rooftop Gardens

Welcome to your February edition of Footprints, the place where we report on some of the most interesting stories happening in the global energy and sustainability market!

In this issue, we’ll take a look at some of the latest technology working hard to aid the energy transition, including new transparent glass solar panels and a new smart material that conducts like a metal, but is built like a plastic. We’ll also see how CO2 repurposed from building ventilation systems could reap plentiful harvests for rooftop gardens.

Sound interesting? Read more about the articles below!

Want to hear more from us on the hottest energy & sustainability topics? Check out our energy & sustainability videos here.

Transparent Solar Panels to Replace Windows in the Future

Think about it, in modern society, glass is practically everywhere.

From the screen of your smartphone to towering skyscrapers. The car you drive to work in and the windows of the home you fall asleep in. It doesn’t take a lot of imagination to conjure up the sheer amounts of electricity that could be generated if we could tap into a power that took advantage of that.

Solar energy, as we know, is and will be one of our strongest allies in the fight towards a low-carbon future… but how viable is a technology like transparent solar in the long-term and could we really generate electricity from the windows in our offices, homes or even cars? We’re here to discuss.

With the potential to be a game-changer for the energy transition, transparent solar is tech that gathers light energy through any glass surface, regardless of the angle. Solar engineers and researchers have already created several means of this technology, the most common of which function as a concentrator, meaning they are made to absorb specific UV and infrared light waves and transform them into energy capable of powering electronics.

This technology is also called Photovoltaic (PV) Glass, and is already manufactured, with a ranging level of transparency.  In 2020, the worlds leading researchers, scientists and engineers achieved an 100% transparency rate for solar glass, bringing us one step closer to the goal of a sustainable future that does not rely on the grid backed by the fossil fuel industry.

We’re already seeing transparent solar tech appear around the world, especially in urban and metropolitan areas where building glass rate is high.

One such example is the Copenhagen International School design, of which utilises over 12,000 hued, clear, solar panels across the building, all of which produce 200 MWh of energy annually – which is apparently over half of the energy the building consumes itself!

With all that said and done however, there are some hurdles standing in the way for PV glass and other such transparent solar tech. Before this sort of tech can be up-scaled to the scenario we envision, scientists will need to up its efficiency, as currently there is an trade-off between transparency and efficiency. The simple fact of the matter being – the more transparent the panel is, the less efficient it is.

This is the primary reason why see-through panels are currently not expected to exceed, or indeed replace the traditional solar panels we’ve become familiar with.

Either way however, with a slight adjustment and the dedication of solar technicians, researchers and engineers across the globe, transparent solar technology certainly has the potential to help humanity reach a truly sustainable future much faster.

Picture – Courtesy of Michigan State University

New Plastic-Like Smart Material That Conducts Electricity Like Metal

Scientists at the University of Chicago have made a recent breakthrough and developed a material that can be made like a plastic, but conducts electricity like a metal!

The material in question contains molecular fragments that are jumbled and disordered, but which, can still conduct electricity extremely well and has led scientists to reconsider a whole new world of possibilities for an extremely important technological group of materials and conductivity.

“In principle, a material like this opens up the design of a whole new class of materials that A) conduct electricity B) are incredibly easy to shape, and C) are very robust in everyday conditions.” says Associate Professor of Chemistry, John Anderson.

Conductive materials are absolutely essential in the creation of any electronics, and by far the largest, oldest and most well known group of conductors are ‘the metals’, the likes of copper, gold, aluminium etc. However, around fifty years ago scientists created a chemical treatment known as ‘doping’ which allows conductors to be made out of organic materials.

Obviously, this was, and still is, extremely advantageous for many reasons, especially due to the fact that other materials are a lot more flexible and easier to process than your traditional metals. The downside to that is that they are typically very unstable and can lose their conductivity if exposed to elements such as moisture or high temperatures. However, on an atomic scale both of these organic materials and traditional metallic conductors are made up of closely packed rows of straight molecules, meaning that electrons can very easily flow through the material.

Whilst developing this new material, the researchers at the University of Chicago strung nickel atoms alongside the likes of carbon and sulphur resulting in a surprisingly stable material with strong conductive properties.

“We heated it, chilled it, exposed it to air and humidity, and even dripped acid and base on it, and nothing happened,” said Jiaze Xie, PHD, one of the lead scientists on this project.

After multiple tests, simulations, and theory work, the leading researchers believe that their discovery suggests a fundamentally new design principle for electronics technology. One of the material’s most attractive characteristics are the new options for processing it creates. For example, whilst metals usually have to be melted in order to be made into the right shape for a chip or device, which limits what you can make with them, this new material has no such restriction as it can be made at common room temperatures.

It’s simply mind-blowing to think of how revolutionary a breakthrough like this could be with the University of Chicago research team currently exploring different forms and functions the material could take!

Picture – Courtesy of E&T

Repurposed CO2 From Buildings Could Accelerate Rooftop Garden Growth

A study from the University of Cambridge has found that rooftops on buildings could be utilised as incredibly efficient vegetable patches that repurpose waste carbon dioxide from their ventilation systems as a fertiliser.

In a world with an ever-expanding urban population, researchers are constantly on the look out for ways to make cities more sustainable.

Rooftop farms and gardens that take advantage of under-utilised roof space have become a popular option, as not only do they provide a new food resource but they simultaneously cool the surrounding area, improve air quality and increase a buildings insulation.

However, a major flaw with rooftops, is that they face a greater exposure to the elements, which typically means that crops face more wind exposure, solar radiation and less soil moisture than those on the ground. This often results in plants that are often less healthy and much smaller in size.

The University of Cambridge team leading this study has theorised that by repurposing the CO2 from building ventilation, some of these challenges could be countered.

To explore this in more detail, the team from the University conducted a study in which they grew the crops spinach and corn, common edible plants that use different pathways to photosynthesise, one of which (C3, used by spinach) is increasingly sensitive to elevated CO2 levels.

“We wanted to test whether there is an untapped resource inside buildings that could be used to make plants grow larger in rooftop farms,” said Dr. Sarabeth Buckley, who led the team of researchers in this study. “Creating more favourable conditions that increase growth could help make rooftop farms more successful and therefore more viable options for installation on buildings.”

The two crops were monitored throughout the study for growth, size, number of leaves, and then, after harvesting, for wet and dry biomass. The research showed that spinach grown next to the exhaust vents had four times the biomass of spinach grown next to a control fan. Even when inclement weather decreased the size advantage, the plants were still twice as large as the controlled crop of corn.

“There are still many aspects of this system that must be determined before it can be implemented, such as the optimal air application design and the possible extent of the enhanced growth effect,” cautioned Buckley.

This study offers important possibilities for reusing CO2 that would otherwise be considered waste to increase the yield of urban farms and shield them from harsh conditions.

“We are hoping this could lead to the further development of this system and eventual implementation in rooftop gardens and farms,” Buckley said.

“If that happens, then hopefully more rooftop farms will be installed and could provide a multitude of environmental and social benefits, such as energy savings for the building; carbon drawdown; climate mitigation; urban heat reduction; local food production; community building opportunities, and aesthetic and mental health benefits.”