Abstract Photovoltaic (PV) systems transform solar irradiation into electricity, thereby substituting for traditional energy sources and reducing environmental pollution. The present work evaluates a developed market (Italy) in which subsidies have been re-introduced for PV plants with a nominal capacity above 20 kW through the FER1 (renewable energy sources) Decree. The discounted cash flow (DCF) methodology is applied to several cases of PV plants in public buildings, in order to determine the value of several critical variables (i.e. level of insolation, plant size, share of self-consumption, investment cost, electricity purchase price). In particular, differences in net present value (NPV) and discounted payback time (DPBT) between subsidy and no-subsidy scenarios are quantified. Break-even point (BEP) analysis is used to define the share of self-consumed energy for which NPV is positive. This share is found to range from 9 to 28% in 105 kW plants and from 10 to 35% in 25 kW plants. In addition, the results verify profitability in almost all of the baseline case studies and only half of the alternative scenarios (involving no subsidies). The estimated profits are consistent with investments aimed at increasing the share of self-consumed energy.

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公共建筑光伏系统的经济可行性：来自意大利的证据

摘要 光伏（PV）系统将太阳辐射转化为电能，从而替代传统能源，减少环境污染。目前的工作评估了一个发达市场（意大利），其中通过 FER1（可再生能源）法令对标称容量超过 20 千瓦的光伏电站重新引入补贴。贴现现金流（DCF）方法应用于公共建筑光伏电站的几个案例，以确定几个关键变量的值（即日照水平、电站规模、自耗份额、投资成本、电力采购）价格）。特别是，量化了补贴和无补贴情景之间的净现值 (NPV) 和贴现投资回收期 (DPBT) 的差异。盈亏平衡点 (BEP) 分析用于定义 NPV 为正的自消耗能源份额。发现该份额在 105 kW 电厂中为 9% 至 28%，在 25 kW 电厂中为 10% 至 35%。此外，结果验证了几乎所有基线案例研究的盈利能力，只有一半的替代方案（不涉及补贴）。估计利润与旨在增加自用能源份额的投资一致。