There are more and more companies specializing in the PV business but I cannot find a documented tag for those nor a topic here in the forum dealing with this issue. I am not talking about companies manufacturing photovoltaic panels nor about shops selling photovoltaic miniplants for your balcony.
My issue are small to midsize companies selling, installing and servicing PV plants to private or business customers. Sometimes this goes together with other crafts like electrical works or heating installation but here I am looking at companies offering this as their core business.
and a couple of craft=solar_*
I would understand this business more as a craft than a shop and I would definitely prefer photovoltaic instead of solar because the latter does not specify if the subject is solar generated electric power or solar generated hot water.
That is why my own choice would be craft=photovoltaic if there are no objections or better proposals.