Although there is consensus that both grid extensions and decentralized projects are necessary to approach universal electricity access, existing electrification planning models that assess the costs of decentralized solar energy systems do not include metrics of reliability or quantify the impact of reliability on costs. We focus on stand-alone household solar systems with battery storage in sub-Saharan Africa using the fraction of demand served to measure reliability, and develop a multistep optimization to compute efficiently the least-cost system with the fraction of demand served as a design constraint, and take into account the daily variation in solar resources and costs of solar and storage. We show that the cost of energy is minimized at approximately a 90% fraction of demand served, that current costs increase, on average, by US$0.11 kWh^–1 for each additional ‘9’ of reliability, and that this reliability premium could be as low as US$0.03 kWh^–1 in a plausible future price scenario.

尽管已经达成共识，电网扩展和分散项目都是实现通用电力接入所必需的，但是评估分散式太阳能系统成本的现有电气化计划模型并未包括可靠性指标或量化可靠性对成本的影响。我们专注于撒哈拉以南非洲使用电池存储的独立家用太阳能系统，使用需求量来衡量可靠性，并开发多步骤优化以有效计算成本最低的系统，其中需求量作为设计约束，并考虑到太阳能资源的每日变化以及太阳能和存储的成本。我们证明，在满足需求的90％左右的情况下，能源成本已降至最低，当前成本平均增加了0.11美元/千瓦时^-1的可靠性每增加“9”，而这种可靠性保费可以低至新台币$ 0.03千瓦时^-1在未来可能出现的价格方案。