6 April 2017
The Energy Chair of Orkestra-Basque Institute of Competitiveness of Deusto University has undertaken a study of the economic viability of photovoltaic installations for domestic use.
The work analyses two types of photovoltaic installations for converting solar energy into electricity: off-grid and on-grid. The analysis considered different possible cases of electricity supply in installations located in Bilbao and Seville, locations with different levels of sunlight, and contemplating different levels of production and energy consumption.
The report analyses the supply costs for domesrtic consumers connected to the grid, comparing them with the cost of supply from off-grid or on-grid photovoltaic installations. This work considers different hypotheses of a technical nature adapted to annual demands of 3.000 kWh and 5.000 kWh, typical of an average domestic consumer.
In the case of off-grid photovoltaic installations, the cases considered generate costs far higher than those produced by the power grid. This kind of installation demands a sizeable initial investment of between 17,000 and 34,000 Euros and requires a surface area to install the solar field estimated at 44-58 m2 in Bilbao and 29-44 m2 in Seville. The characteristics and constraints of these kinds of installations mean a period of recovery of the investment of over 26 years. Therefore, the study concludes that, based on the cases analysed, off-grid photovoltaic installations do not make economic sense when there exists the possibility of access to the grid.
For photovoltaic installations connected to the grid, Orkestra’s study considers the same cases, and annual supply rates of 30% and 100%. The conclusions of the report reflect that the average supply cost with photovoltaic installations connected to the grid, with a supply rate of 100%, is between 16.6% and 60.8% higher than when obtained from the grid, so is an option that does not interest the consumer from an economic point of view.
In the case considering a supply rate of 30%, the average supply cost with photovoltaic installations connected to the grid would be approximately 8% lower in Seville and 2% inferior in Bilbao. This would represent an annual saving of between 11 and 53 Euros which, though modest, might be of interest to consumers who are prepared to make an initial investment of 1,100-2,000€, have at their disposal a surface area of between 6 and 14 m2 in order to install the panels and would anticipate recovering their investment over a period of between 10 and 16 years.
The conclusions of the study highlight the value of power grids and their support systems, indispensable in the case of on-grid photovoltaic installations, in ensuring continuity of supply and facilitating other services such as energy exchange.
