Technology

The rise of solar PV glass

 By Esteban Pages

Solar power is well on its way to claim an increasingly large share of global power generation

According to the International Energy Agency (IEA), renewable energy technology will represent 8 percent of total global energy generation by 2023, compared to 4 percent in 2018. Declining component and installation costs, increases in power output efficiency, favorable government policies and cost-effective generation costs compared to other generation technologies, are among the primary factors that explain this boost.
Due to solar power’s scalability capacity from utility-scale, GW generation-capable projects to residential generation, innovative solutions so houses and buildings alike can take advantage of the sun are highly sought after. One such development includes using a transparent solar cell. Research on this solution traces back as early as 2015, when a Michigan State University team of researchers developed a new type of PV concentrator that was fully transparent. The idea behind this product was to replace traditional building façades with power-generating glass.
Fast forward to 2019 and the idea materialized from a controlled-environment laboratory experiment to an actual business case, as witnessed by the multiplying companies sprouting from this idea, such as Onyx Solar (Spain), Polysolar (UK), SwissINSO (Switzerland), Brite Solar (Greece), Ubiquitous Energy (USA)and Physee (Holland), to name a few.
But keeping an electricity producing window completely transparent means that the only light that could be harvested and converted into electrical energy is only the invisible part of the spectrum: the ultraviolet and the infrared parts at the two opposite extremes of the light visible to human eyes. The problem is that the ultraviolet light that could enter the atmosphere and successfully reach the surface of our planet is (luckily for us!) practically negligible. The same happens with the infrared light, that contains also very little energy per photon.

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A transparent luminescent solar concentrator waveguide is shown with colorful traditional luminescent solar concentrators in the background. The new LSC can create solar energy but is not visible on windows or other clear surfaces (G.L. Kohuth)

For this reason, years ago Eni research had switched to transparent and colored glass windows that we have already discussed here. Those Smart Windows, based on Eni Ray Plus ™ technology, will be soon on sale for applications in residential and commercial buildings.
These companies are accumulating success stories and operational portfolios, but solar glass has yet to hit the mainstream scene of power generation in the manner as solar panels and wind power turbines. The extra cost of solar glass compared to traditional glass seems a no-brainer as the generation factor alleviates product and installation costs, so why do we not see more power-generating skyscrapers?

Efficiency first

Early efforts to counter buildings’ carbon footprint focused primarily on energy efficiency. As the United Nations Environment Program (UNEP) states, “the built environment accounts for a large share of energy (estimated to be about 40% of global energy use), energy-related greenhouse gas emissions (estimated to be approximately 30%), waste generation and use of natural resources“.
Spearheading an initiative fostering sustainable buildings, the UNEP enacted the Sustainable Buildings and Climate Initiative (SBCI) back in 2006. It promoted and supported sustainable building practices worldwide via energy efficiency and GHG emission reduction. Therefore, there is a tenured practice in building-centered energy efficiency practices that do not necessarily involve integrating renewable energy consumption.
For starters, the designs of the buildings themselves met a sizable shift toward energy efficiency. Improvements on thermal insulation and light transmission, coupled with IoT technologies and data analytics over a building’s consumption behavior, provided new insights to attain smart and efficient energy consumption. Among these improvements, some voices raised against the modern fascination with glazed skyscrapers. In an interview with CNN in January, 2018, Ken Shuttlewoth, a renowned architect responsible for London’s Gherkin, stated: “I think (glass) is a symbol for energy-guzzling buildings, and we need to move to a much more energy-conscious environment to try and save resources… That’s in a way, a manifesto for us as architects: to try and make buildings more energy-efficient”.

Mexico: a case study

Mexico underwent an ambitious and paradigm-shifting energy reform in 2014, allowing for private participation in most of the links of the energy value chain on both the oil and gas and energy fronts. As a result, energy efficiency practices also began gaining momentum. By 2016, Mexico accumulated 211 LEED-certified and 564 LEED-registered projects, totaling 15,946,290 gross square meters of sustainable-certified space.

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Mexico's President Enrique Pena Nieto (C), President of Mexico's Senate Raul Cervantes (L) and President of the Chamber of Deputies Jose Gonzalez hold up a written version of an energy reform at the National Palace in Mexico City August 11, 2014 (Reuters)

In 2018, the American Council for an Energy-Efficient Economy (ACEEE) revealed in its 2018 International Energy Efficiency Scorecard: “Mexico was the most improved country this year, with its score of 54 up 17 points from 2016″.
On the other hand, Mexico also witnessed its very own and very first fully PV glass-clad building. Coca-Cola FEMSA, the international bottling company that manufactures the bottling and packaging products for the global soda giant, inaugurated a revamped Monterrey HQ using solar PV glass in partnership with Spain-based Onyx in June of 2019.
The company claims it saves up to 35 percent of FEMSA’s energy consumption and protects users inside the building from temperature changes. Despite the infancy state of Mexico’s energy transition, the country has proven it has room for any and every renewable energy technology, whichever the scale considered. To date, however, it is the only building known to use this technology in the country.

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Coca-Cola FEMSA's Monterrey HQ (Onyx Official Website)

A report by the infrastructure specialized media Obras in January 2019 showed that Mexico’s largest cities, Mexico City, Monterrey, Guadalajara and Puebla, are on the cusp of welcoming new skyscraper developments, with close to 3 million m² of corporate offices under construction.
As Mexico’s energy transition moves forward and awareness campaigns for energy efficiency to tackle increasing energy costs and energy demand continue spreading, the window of opportunity for solar PV glass to soar in Mexico is far from closed.

Cover image by: Richard Lunt, Michigan State

READ MORE: Carribean Solar Power by Andrew Burger

about the author
Esteban Pages