ACCURACY OF AN ABSOLUTE METHOD USED FOR RELATIVE MEASUREMENTS: STUDY OF AN ACOUSTIC TRANSIT TIME METHOD

In many parts of the world significant efforts are being made to increase the production of green CO2-neutral energy through subsidies from the government or through certificate systems. In Sweden, investments in environmentally friendly production are stimulated by a market-based electricity certificate system that is designed to assist the increase of electricity production from renewable energy sources such as hydro power. In hydro power refurbishment projects, the increase in production is regarded as new renewable energy produced. Currently, approximately 30% of the value of the production increase can be contributed to certificates, which plays a crucial role in determining the feasibility of a reinvestment. Verification of the relative improvement in the plant’s energy production is crucial to determine the correct number of certificates [3]. These two factors, especially the certificate system, make it necessary to accurately measure the actual improvement in efficiency due to the upgrade. In this case a comparison of the plant’s discharge is sufficient to determine the improvement. The goal of this study is to examine and discuss whether the before and after measurements can be used to improve the accuracy of the discharge measurement.