Driving energy savings in the automotive sector

From pre-processing to final inspection, there is huge potential in every step when it comes to optimising energy consumption in automotive glass production, writes Jukka Immonen from Glaston, which supplies machines and services to this sector in addition to serving the architectural, solar and display glass industries. The full version of this article appears in the Nov/Dec 2023 issue that has been mailed globally and is also now available free of charge in the digital archive*.

Driving energy savings in the automotive sector

The recent energy crisis has made conservation and efficiency top priority. New regulations and carbon-neutrality commitments are pushing organisations to transform their use of energy in all areas of operations. Along with everyone else, automotive manufacturers have been forced to accelerate the move toward carbon neutrality. Below are some top tips for saving energy in each of the process steps.


Although pre-processing consumes far less energy than other steps in automotive glass production, every saving counts. So, if there is a way to optimise energy efficiency during pre-processing, we should know about it.

Since glass pre-processing typically consists of lots of movements, when the tools are decelerated by electric motors, it’s a good time to capture energy and feed it back into the grid. Using equipment that has been designed with lighter moving parts and offers energy capture options can save up to one-third of the energy required by more traditional pre-processing machines.
For further energy savings, it’s important to reduce the material waste in this step of the process. Here, modern glass positioning applications can help to achieve consistent quality and less scrap during production.

Bending and tempering

By far the most energy-intensive processes in automotive glass production, bending and tempering also have the biggest potential for a factory-wide cost-reduction impact. One of the easiest ways to optimise energy consumption in glass tempering is to load the furnace up to its maximum. Unfortunately, this is often too challenging to achieve.

Convection heating technology offers a solution to this. Convection follows the glass through the heating cycle, only releasing as much heat as is needed for any specific load. This means that even with low bed utilisation rates, savings are high. On top of that, convection ensures better heating control and higher performance.

Glass bending

There are many things to consider when it comes to improving energy efficiency in automotive glass bending. Firstly, heating technology is key. Again, it is good to remember that convection heating has a better heat transfer rate than radiation heating. In turn, targeted and efficient heat transfer means that less energy is lost during the process.

Furthermore, convection provides uniform heating of both clear and printed surfaces. When windscreens and sunroofs are produced, convection makes it possible to minimise the number of old-fashioned reflection plates, resulting in further energy savings per unit produced.

Secondly, convection heating cuts back on the need for extra assets in tooling, such as suction plates or radiation shields that are traditionally needed to compensate for black print overheating. Therefore, tooling weight and energy consumption decreases.

Thirdly, size matters. It makes sense to have just the right chamber size for the market you serve. An oversized chamber means more energy than necessary is used.

Next up: insulation rules. It’s good to make sure that the wagon frame is well insulated. This way, less steel mass will be needlessly heated in each cycle.

A nice design is not just for show. Any design needs to be backed by solid strategic thinking. For instance, new-generation heaters fitted in grooves in the furnace chamber form an ideal reflecting surface for radiation, making the heating process much more efficient. In principle, they enhance the focus of the heat and minimise radiation scatter.

Plus, if the design of your line supports natural cooling, this gives you several additional ways to save energy. For example, it takes less time to reheat the wagon for the next cycle if the line allows for side unloading. The glass can be unloaded at higher temperatures, and the wagon doesn’t need to go through complete cooling.

Lastly, lightweight but robust moulds make a difference. The lighter the moulds, the less energy is required for the process. Because of this, mould-making training shouldn’t be neglected.


In windscreen and sunroof lamination, de-airing lines with vacuum rings are of help. In these systems, the mass of tooling – and consequently, the energy consumption – is very low compared to vacuum bag systems.

Maintaining best practice

As you can see, just a bit of training on best practices may do the trick in decreasing your ever-rising energy bills. But for even more measurable results, upgrading the existing machines with more advanced technology is the way to go. After all, investments like these not only lead to immediate cost reductions, but in the long run, they also contribute toward sustainable business practices targeting climate change mitigation.


This article originally appeared as a Glastory blog post (www.glastory.net)

About the Author: 

Jukka Immonen is Product Manager for Automotive Heat Treatment Products at Glaston Finland

Further Information: 

Glaston Finland, Tampere, Finland
tel: +358 10 500 500
email: info@glaston.net
web: www.glaston.net

* The full version of this article appears in the Nov/Dec issue that has been mailed globally. The digital version of this issue can also currently be read free of charge in its entirety in the Digital Archive (sponsored by FIC) of over 65 issues of Glass Worldwide at https://www.glassworldwide.co.uk/Digital-Issues.