Quite a few places. Your location is Orihuela City so I'm assuming you have the same type supermarkets.
Consum do a red and a white non-alcoholic which they don't call wine and is in the fruit juice section as grape juice. But it is in a wine bottle. Mercadona and Lidl and Mas y Mas do a low alcohol fizzy wine at 5% if you want to go up a bit.
Not sure if you have an Iceland near year but they do Schloer, Elderflower and Elderflower and Apple but are a bit more expensive than the stuff in Consum and the others (€1.04 for the Consum, €1.89 for the others but Iceland is €2.80 or €3)
Fair few places, like Consum and Carrefour, also do alcohol free Gin and alcohol free gin and mixers.
I drink the Consum red and mix it with soda for a very nice spritzer.
Just don't look for the alcohol free wine in the wine section.