The deployment of distributed photovoltaics (PV) in low-voltage networks may cause technical issues such as voltage rises, line ampacity violations, and transformer overloading for distribution system operators (DSOs). These problems may induce grid reinforcement costs, which are typically high. We establish a new methodology to price and reward flexibility within low-voltage networks, in the case DSOs are able to control distributed assets. Under such assumptions, we compare the cost of providing flexibility and the cost of grid reinforcement using the CIGRE low-voltage network as a case study. Our results highlight that using distributed flexibility is more profitable than reinforcing a low-voltage network until the PV generation covers 145% of the network's annual energy demand.& COPY; 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).