So, I built a big model to optimize the renewable energy system in a planned community. It calculates building loads based on local weather data, models how those loads would be satisfied by a slew of different technologies, estimates the capital and operation costs of those systems, and outputs a simple payback for the community energy system. I've made a central control sheet where you can choose which configuration of technologies are currently being modeled and the operating parameters of the respective technology. Each decision is made by selecting an option in a cell with data-validation accepting some list, usually, strings containing the name of each technology but sometimes they're numerical operating temperatures or capacity factors. Based on the options selected, the back end of the model considers different spec sheets and gives a different performance output. I'd like to minimize the payback period. As it stands, I could run through all the options manually, but given the number of options, I'd be doing this for a while. I was hoping there's some way that Excel can monitor the payback cell while running through the valid options for these decision cells. Ideally, I'd like to find the lowest 10 configurations, but I'd settle for not having to run through every option manually. I'm really just hoping I won't have to completely retool the model.