À steam generation system at a biomass fueled power plant uses an electrostatic precipitator (ESP) to clean its gaseous effluents. The power plant has consistently made use of the same

type of ESP over the past several years. The installed cost of a new ESP has been relatively constant at $85,000. Records of operation and maintenance expenses indicate the following average expenses per year as a function of the age of the ESP. The MVs of the ESP are also reasonably well known as a function of age. Determine the best time to replace the ESP if the MARR is 8% per year.