Eight19 is a technology-based start-up company based on Cambridge Science Park. The company is developing a new (and very low cost) solar-panel technology aimed primarily at domestic use in developing countries. The case describes the issues faced by eight19 as it develops a business model for the new technology – in particular balancing competing needs: to generate sufficient revenue to fund operations (and not run out of cash), to generate a sufficient return for investors, to ensure widespread adoption of the system by users by users who cannot afford the up-front costs, to incentivise distributors, to guard against opportunistic behaviour by users, to create loyal users and to build and maintain a positive brand. The case illustrates the importance of the business model (rather than the product per se) and the imperative to build and maintain the ‘social legitimacy’ of a venture in order to assure profitability in the long term.