Photovoltaic demand-side generation (PV-DSG), defined as the production of electricity by means of panels or arrays which are installed on the customer's side of the meter, has received much attention lately by academics and policy-makers all over the world. Some countries have promoted this form of generation, whereas others have lagged behind. This is the case of Spain, where PV-DSG has not taken-off. The aim of this paper is to provide a critical overview of the Spanish regulation for PV-DSG, approved in 2015, and its impact on demand-side generation in this country. The impacts of the new regulation on PV-DSG are calculated with real data from a household PV installation. It is found out that the current regulation is highly unfavourable for the adoption of PV-DSG, given the small savings for investors (consumers) for the adoption of PV-DSG compared to buying the electricity from the grid.