How does the configuration of an energy community impact its key performance metrics (prosumer profitability, self-sufficiency rate of the community, and grid impact)? Through a deterministic techno-economic analysis based on high-resolution real-world demand data from 3,594 households, this project analyses how the configuration of a solar energy community (EC) impacts its economic and technical performance. EC planners, policymakers and grid operators can build on these results as rules of thumb to incentivize EC formation while maximizing welfare for all stakeholders.