Electrical mini-grids can provide electrification to rural communities far from the national network. However the benefits of such schemes are disputed. We observed changes in two matched trading-centres in Makueni County, Kenya, neither of which were initially electrified. During the study a solar photovoltaic mini-grid scheme (13.5 kWp) was constructed in one of the trading-centres. After electrification there were relative increases in the number of businesses and business income. Comparing the households in the areas around the trading centres, perceived wealth increased more around the electrified trading centre. Qualitative interviews indicated improvements in service provision by the local school and health centre. The co-operative set up to run the mini-grid was free to set its own kWh tariff and chose to reduce it to a level that covers operating costs and would recover 70% of the initial investment interest-free. However, the tariff finally agreed is higher than the national grid tariff, which would be difficult to achieve if the mini-grid was not owned by and run for the benefit of the local community. Overall, we found that the mini-grid had a positive effect over background development, recovered some of its cost and charged a higher tariff than the national rate.