Solar glass – the forgotten component – ​​the next bottleneck is inevitable

When discussing the entire PV value chain, the component that is heaviest by weight after the solar cells is consistently neglected: the solar glass. I am unaware of any publication to date that has described the problems involved in procuring large quantities of solar glass for the gigawatt-scale production of PV modules to realize the energy transition.

The EU is entering into a dangerous dependence on China because it is ignoring this component

European module production is still insignificant on a global scale, and dependence on China is dangerous. Germany and the EU want to drastically change this and ramp up European production capacities. The fact that this also includes the procurement of solar glass is consistently overlooked. Yet the industry is already struggling with problems.

In Slovakia, for example, Agora Solar is preparing to commission a production line for 150 MWp modules. However, it is proving difficult to obtain the heaviest component, the solar glass. Offers from European and Indian solar glass manufacturers were either not submitted or even withdrawn due to the current gas shortage.

The Chinese are taking a holistic approach, because module production is impossible without solar glass, and consequently, gigantic quantities of glass are needed for their ambitious PV expansion targets. This is why the German company Grenzebach received orders from China as early as 2020 for more than 160 glass drawing lines specifically for the photovoltaic market (Solarserver, May 21, 2021). These have since been delivered. In Europe, there are only a handful of such lines, and there are no known plans to close this ever-widening gap. Germany offers the world's best melting technology, with global market leaders like Sorg and Horn. France and England also have excellent suppliers. Lisec in Austria provides the best systems for coating and hardening. These solar systems are being delivered to China, not to Europe.

That this will not remain the case is shown by patent statistics. Over 1,000 Chinese patents stand in stark contrast to the mere few from Europe. Here, China is the technological leader and aims to dominate the manufacturing of production facilities in the future.

Building a solar glass factory is a huge investment of up to €100 million for an optimally sized production line with a melting capacity of 300 tons per 24 hours. The energy consumption (80% gas) and the significant environmental impact in the form of CO2 and nitrogen oxides result in considerable planning effort and lengthy permitting processes. The period from planning to operation of a solar glass production facility is therefore 3-4 years. This is a long time compared to six to ten months for a PV module production line.

A 100% reliable gas supply 24/365 is also essential, as current technology for manufacturing solar glass requires the use of 80% gas for the melting processes.

One could argue that we should buy solar glass from China. However, this undermines the argument of securing a European supply chain and saving on logistics costs through European production. This would further increase our already highly critical dependence on China. Finally, the serious criticism that production in China takes place under poor political and environmental conditions is also significant. Several glass factories are located in the Xinjiang province, the repressed Uyghur region. With glass accounting for up to 80% of the weight of a standard PV module, transporting the glass is almost as costly and time-consuming as transporting the finished modules.

The expansion targets for a “New European Solar Industry” are gigantic and have recently been significantly revised upwards in light of the war in Ukraine. In most cases, the expansion of production capacities is intended to occur along the entire value chain, i.e., from silicon to wafers and cells to module production. Strangely, one crucial component is consistently missing from this list and from the plans for gigawatt factories: the solar glass required for 99% of all modules. This indispensable component is not sufficiently available in Europe. The following arguments demonstrate this:

1. Ultra-white solar glass is primarily manufactured as textured glass using a rolling process. Special forming rollers create a microstructure on both sides of the glass, matching its thickness. This structure largely retains reflection within the glass, resulting in high transmittance. Conventional flat glass production methods are less suitable for solar glass.
2. Currently, a maximum module production of approximately 3-4 gigawatts can be achieved using solar glass produced in Europe. Until 2021, a nominal portion of the glass was imported from India and a few other countries. However, India will need the glass produced there for its own gigantic PV production plans. It is therefore noteworthy that the largest European solar glass supplier, Interfloat, along with its GMB Glasmanufaktur Brandenburg manufacturing plant in Tschernitz, was sold to the Indian market leader Borosil in April 2022 (PV Magazine, April 25, 2022). Given that the production facility there is entirely dependent on uninterrupted gas supplies, industry experts were surprised by this. Apart from the risk of an interruption in Russian gas supplies, cost-covering production is only possible at today's gas prices with almost unrealistically high selling prices for the solar glass produced. Borosil was probably more interested in market access, especially since costs of approximately €30 million will have to be incurred in about three years for a likely "cold repair" of the melting furnace. Borosil intends to increase its production capacity to a total of 2,600 tons per day by 2025. Whether the claimed 450 tons of this will actually be produced in Brandenburg is questionable. But even this quantity would only be sufficient for approximately 2.5 GW of module production.
3. The expansion targets published by the EU assume an increase in European module production capacity of up to 30 GW by 2030. These targets were further increased following the Russian invasion of Ukraine. Even if module efficiencies improve, this would lead to an almost tenfold increase in demand for solar glass in 2030 compared to 2021. The question arises as to how this demand will be met, given that no new production capacities for solar glass are currently in sight.
4. Glass production requires a high energy input, 80% of which must be covered by natural gas. Production is inflexible, and the melting furnaces must be heated around the clock, 365 days a year. With a gas price of approximately €6 per MW, energy accounted for roughly 35% of production costs in 2020. On March 7th, a price of €211 was recorded on the TTF Dutch Future spot market. Even though this peak price has since fallen to €87 (on May 27, 2022), no one currently expects prices below €50 per MW to be reached in the coming years.
5. The implications for European solar glass production are easy to calculate. While the energy cost per square meter was around €2 in 2020, a sixfold increase would raise it to €12. The glass price would then rise from approximately €7.80 (2021) to €21.50 per square meter, or from €14 per module to almost €39 per 1.8-square-meter module. However, this calculation does not account for a significantly higher increase in the event of a supply disruption or embargo. Therefore, natural gas-fired solar glass furnaces in Central Europe are no longer economically viable, and new investments have no chance of being approved.
6. As a possible alternative, so-called hybrid furnaces are being considered. Hybrid technology for glass production is compelling: with a maximum electrical input of 80% and only 20% gas, energy savings of up to 16% and CO2 emissions reductions of 80% are possible (according to publications by the company Sorg – www.sorg.de). However, it should be noted that these technologies were developed primarily for container glass, and no industrial-scale production facility using this technology is currently operational.

It will be interesting to see where the 12 million square meters of solar glass for Enel's 3 GWp module production plant in Sicily, announced in early April 2022, will come from. The plant will require two solar glass production lines, each with a melting capacity of 200 tons per day. Enel will receive €118 million in subsidies from the European Commission to expand its existing 200 MW cell and module factory in Sicily to a production capacity of 3 MW by 2024. This represents an investment in the entire PV value chain. Solar glass will once again be the forgotten component.

Even more surprising is another press release (Photon Newsletter, April 21, 2022): The start-up Carbon SAS, based in Roche-la-Molière, France, has announced a partnership with the French ACI Group. ACI will support Carbon in realizing its plans for a fully integrated solar factory in France. Module production is scheduled to begin in 2024 with a capacity of 500 megawatts. This capacity is then to be increased to five gigawatts by 2025 and to 15 to 20 gigawatts by 2030. The company states that it intends to cover the entire value chain, from the production of ingots to wafers and cells – IBC and TOPCon.

Russia's invasion of Ukraine has brought the issue of energy security in Europe into sharp focus. "One way to strengthen energy independence across large parts of Europe is to accelerate the deployment of solar power and improve the production base," according to SolarPower Europe.

An official from the European Commission pointed out at the recent solar power summit in Brussels in April 2022 that solar production in Europe needed to be rebuilt – “whatever it takes”.

However, the current approach to promoting a European solar industry is clearly too short-sighted: Without including solar glass, the most energy-intensive and heaviest component, dependence on China as the world market leader in solar glass will persist. The current estimated gap in solar glass production of 60% will increase to 90% due to expansion plans to several gigawatts.

No one would dream of excluding the necessary steel from the automotive production chain. Yet this is precisely what is done when examining the value chain for PV module production!

Due to the high anti-dumping duties on solar glass from China (customs and anti-dumping charges of up to 100%), imports from China currently play a less significant role. This will change, however, because due to a lack of alternative sources, only China will be able to supply the required quantities. The anti-dumping surcharge will have to be paid, resulting in a cost disadvantage for PV modules produced in Europe compared to Chinese PV modules imported without surcharges. This is because the anti-dumping duty is only levied on imported solar glass, not on the PV modules themselves (which, of course, also contain the glass).

“Similar to the situation with Russia, the asymmetry and one-sidedness of Germany’s dependence on China is a key problem,” said DIW President Marcel Fratzscher. China is increasingly using this as leverage against Germany and Europe. The dependence on Chinese components (including BOS components and inverters) is around 90%. This will increase further with the expansion of module production in Europe.

Simon Hage writes in his editorial in Der Spiegel on May 28, 2022: “The exploding prices for gas and oil as a result of the Russian invasion of Ukraine illustrate what a policy of turning a blind eye can lead to – a dependency that can only be corrected at high economic cost. And the dependency on China is already greater than that on Russia.” This applies especially to the photovoltaic (PV) sector. … “The EU needs an industrial policy that consistently supports the development of key strategic industries.” Certainly not a policy that ignores the future dependency of more than 90% on the indispensable component of solar glass.

Erich Merkle has been working in the PV industry for over 20 years.

He was one of the pioneers in both the establishment of the first production lines for modules in Germany and the construction of PV power plants in the megawatt range.

He played a key role in the development and market launch of Almaden's first thin double-glass modules.

As early as 2007/8, he planned the first German solar glass production facility in Brandenburg. The project was not realized due to the collapse of the PV industry in Europe and the financial crisis.

Dr. Merkle heads GridParity AG and advises AGORA sro in Slovakia on the construction of a PV module production facility with up to 150 MW in 2023 (450 MW from 2024).