The goal of Austria is to become climate-neutral by 2040, which poses significant challenges for the industry. Ensuring energy supply security, investing in renewable energy, and finding ways to increase efficiency in production processes are just a few of the many issues that are currently prevalent. This scientific work addresses this situation and focuses on three related topics. The first topic concerns flue gas condensation, which represents an opportunity to increase efficiency by utilizing the often unused potential of the condensation enthalpy of the carried water vapor in the flue gas. An EXCEL program was developed to calculate the degree of condensation of water vapor based on the combustion air ratio used, exhaust gas temperature, prevailing humidity, and air pressure. The second topic involves the proposed installation of a photovoltaic system on the roof surfaces of the Hofstetten brewery in Upper Austria. The available roof surfaces facing south, east, and west were first determined using the satellite view available in Google Maps. This made it possible to derive the potentially installable system capacity. Using the freely accessible photovoltaic calculation tool PV-GIS (Photovoltaic Geographical Information System), the expected annual photovoltaic yield could be calculated. In addition, the data generated in hourly resolution could be used for further investigations of the time-of-day and seasonal variation of photovoltaic output. The third and final topic determined the waste heat potential of the most energy-intensive companies in Gmunden. Common methods for calculating this were first collected and applied through literature research. Ultimately, a top-down approach emerged as the most promising approach. This first determines the total energy demand of the companies assigned exactly by ÖNACE-CODE using industry-specific key figures/benchmarks. Using suitable waste heat factors, a theoretical waste heat potential could be derived from this.