Load mismatch of grid-connected photovoltaic systems: Review of the effects and analysis in an urban context

The mismatch between generated and consumed electricity is a relevant topic of the energy and economic assessment of photovoltaic (PV) systems. Due to the load mismatch some amount of PV electricity may be exported to the grid because the electrical demand is temporarily lower than production, whereas a consumption, which is higher than production and/or that does not match the available PV generation, will require to be supplemented by the public grid electricity. The presence of the load mismatch can cause the effect of disadvantageously purchasing electricity from the grid and/or squandering the unexploited PV energy. If only a very small part of the PV generation is used to supply the household appliances, benefits may not compensate disbursements. Moreover, instead of giving a benefit to the community, an amount of surplus electricity generated by a great number of PV systems may represent a significant problem for the grid operators.