The chemical industry is one of the most energy-intensive sectors. WACKER is constantly improving the energy efficiency of its processes. This enables us to remain globally competitive while at the same time contributing to climate protection. Charleston (TN, USA) – alongside our German plants in Burghausen (Bavaria) and Nünchritz (Saxony) – is our third major integrated production site. In addition to the production site in Holla, Norway, these sites account for roughly 90 percent of the energy consumed throughout the Group.
Our primary source of energy is natural gas. At Burghausen, our largest site, we produce steam and electricity in a CHP plant. Combining this plant with the output of Burghausen’s hydroelectric plant and that of smaller generation facilities, we produced 1,236 GWh of electricity in 2020 (2019: 1,075 GWh). This covered some 21 percent of our overall electricity demand for 2020.
We installed a new gas turbine to modernize the Burghausen site’s CHP plant for electricity and steam generation. The new turbine has an output of over 137 MW, which makes the CHP plant more efficient than the previous, almost 20-year-old plant, and produces fewer emissions.
Energy from Renewables
The Burghausen site has been supplied with electricity from Wacker Chemie AG’s Alzwerke GmbH hydroelectric facility for more than a century. In 2020, the Alzwerke plant generated 248 GWh of electricity (2019: 273 GWh). It has generally increased its energy yield and annual availability in recent decades. Water is used for supplying electricity, as cooling and process water, and as an emergency power supply at the Burghausen site. In 2020, we generated 0.4 GWh of electricity from solar power.
WACKER’s aim is to reduce the Group’s specific energy consumption (the amount of energy per unit of net production output) to one-half of the 2007 level by 2030. During the period under review, we reduced specific energy consumption by another 3.1 percent.
Many chemical reactions generate heat that can be put to use in other production processes. In addition to recovering heat from these reactions, we also operate integrated heat-recovery systems, which we are continually developing and improving. In this way, we reduce the amount of primary energy (natural gas) consumed by our power plants. We are also continually optimizing our electricity consumption.
Between 2016 and 2020, we optimized the integrated energy production system at our Nünchritz site, achieving a substantial increase in the heat recovery ratio. Thanks to our Steam Roadmap project there, we now recover 70 percent of the energy used in the form of heating steam (from a base value of 62 percent in 2016). Doing so has allowed us to reduce our use of primary energy (natural gas) at the Nünchritz cogeneration plant and lower the site’s annual CO2 emissions by over 30,000 metric tons.
We document our energy efficiency projects in the WACKER Operating System (WOS). During this reporting period, we recorded 150 actions that saved some 205,000 MWh or 36,420 metric tons of CO2e in 2020 (2019: 192,000 MWh or 37,240 metric tons of CO2e). The following are a few sample projects:
- We reduced steam consumption at WACKER SILICONES’ Distillation North plant (Burghausen) by roughly 9 percent relative to the previous year; we also implemented an automatic process control (APC). We improved product yields by reducing product side streams and reflux in the distillation column.
- We improved processes in WACKER POLYSILICON’s distillation columns at the Burghausen and Nünchritz sites, likewise implementing an APC.
- By improving deposition processes, we reduced specific electricity consumption at the polysilicon deposition facility in Burghausen.
- Modifications to the CHP plant in Burghausen improved steam generation by reducing the minimum amount of what is known as D2 steam from the steam turbine.