The next bottleneck


While work is ongoing to build up solar glass manufacturing capacity in places like China, no new projects have been announced in Europe. Indeed, while Europe’s value chain vacillates, China refuses to wait. In July 2021, Germany-based Grenzebach Group reported that it had received orders from China for more than 160 pattern glass production lines, specifically for the PV market to support the government’s annual installation targets of 80 GW to 160 GW of new solar capacity.

Ambitious targets

The targets for a “New European Solar Industry” call for an expansion of European module production capacity of up to 30 GW by 2030. Not only that, but this growth is also expected to filter throughout the entire solar value chain. This means the demand for solar glass will be eight to 10 times higher than in 2021. And yet, despite this necessity of expansion, production of this key material has thus far been largely ignored.

Today, a maximum of around 3 GW to 4 GW of modules can be produced with European solar glass. But given the necessary steps required to build out meaningful glass capacity, a lot of work still needs to be done if a full link in the value chain is to be established any time in the near future.

The construction of a solar glass factory requires an investment of up to €100 million ($107 million). In addition to consuming large amounts of energy, there is also environmental pollution in the form of CO2 and nitrogen.

The fulfillment of ever-stricter environmental requirements also demands considerable planning. Indeed, the period from planning to operation of solar glass production with 300 tons melting capacity per day is between three-and-a-half to four years. This compares to just six to 10 months for a PV module production line.

Furthermore, glass melting requires a large amount of energy and almost all of this is provided by natural gas. Production is not flexible and furnaces must be heated continuously 24/7/365. In 2020, energy accounted for around 35% of production costs, with a gas price of roughly €6/MW. On March 7, a price of €211 was quoted on the Dutch TTF Gas Futures spot market. No one currently expects prices below €50/MW to be reached.

What this means for European solar glass production can be easily calculated. If the energy share per square meter in 2020 was about €2, this would rise to €12 with a sixfold increase. The glass price would then increase from about €7.80 (2021) to €21.50 per sqm or from €14 per module to almost €39 per 1.8 sqm module.

However, this does not consider a much higher increase in the event of a supply stop or embargo. Therefore, natural gas-powered solar glass furnaces are no longer economical in central Europe and new investments have no chance of being approved. A possible alternative is so-called hybrid furnaces for glass production. With a maximum electric share of 80% and only 20% gas, up to 16% of energy could be saved and CO2 emissions reduced by 80%. However, it must be noted that these have only been developed for container glass and that no industrial plant is yet in operation.

Grid to glass

Sustainable electric energy will play an important role in the transformation of the glass industry, simply because it has the highest energy efficiency of all energy sources. For some processes, a certain amount of energy from gas is still necessary to keep the glass melting system flexible.

Hybrid furnace technology has the potential to cut the direct furnace CO2 emissions by 60%, and those of the whole installation by 50%, by replacing 80% of the natural gas with renewable electricity. The potential CO2 reduction of this innovation is even higher if it can be subsequently combined with other innovative sources of energy such as hydrogen.

This conversion of glass melting technology, optimized over decades, away from gas to electricity sounds simple, but it is highly complex. Completely different furnace construction techniques and adapted materials are necessary.

So far, the pressure for change has not been strong enough for developments from leading furnace manufacturers such as Sorg, Horn or Five to find their way into practice. Indeed, there is still no hybrid glass plant for melt volumes of 300 tons and more.

A European development project that was supposed to help this technology achieve a breakthrough was not financed by the European Union, despite the high contribution of 19 glass companies involved, and has been put on hold. That was last year and before the invasion of Ukraine. Considering that the European Union is now gripped with a new sense of urgency, perhaps the decision would be different today.

One may also be curious where the 12 million square meters of solar glass for the 3 GWp Enel module production facility in Sicily, announced in early April 2022, will come from. For its production, two large solar glass production lines with 200 tons each of melting capacity per day are needed. Enel will get €118 million from the EU Commission to expand its 200 MW cell and module plant in Sicily to 3 GW of capacity by 2024. It’s an investment along the PV value chain, but solar glass will likely again be the forgotten component.

Energy security

The Russian invasion of Ukraine has brought the issue of energy security in Europe into sharp focus. “One way in which energy independence across much of Europe can be bolstered is by accelerating solar deployment and enhancing the manufacturing base,” says SolarPower Europe.

At the recent SolarPower Summit in Brussels European Energy Commissioner Kadri Simson declared that solar manufacturing must be re-established in Europe – “whatever it takes.”

However, the current treatment of the promotion of a European solar industry is clearly too short-sighted. Without the inclusion of solar glass as the most energy-intensive and heaviest component, the dependence on China as the solar glass world market leader remains certain. In fact, the current estimated gap in solar glass of 60% will grow to 90% due to expansion plans of several gigawatts.

About the author

Erich Merkle currently leads GridParity AG and advises AGORA in Slovakia on PV module production. He was a pioneer in setting up the first production lines for PV modules in Germany and building PV power plants in the megawatt range. He was also involved in the development of the first thin double-glass solar modules. As early as the 2007-08 period, he planned the first solar glass production in Brandenburg, Germany.

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