The network that Porsche will reply on in the US initially is one being built by.... Porsche (VW Group) doing business as Electrify America. In Europe, VW is involved in multiple efforts to install ultra-fast charging.
I suppose it’s possible that they could install some ultra-fast chargers at Porsche-specific locations, but they certainly won’t be relying on “the existing public chademo network”. Porsche is using CCS, not CHAdeMO.
Electrify America’s schedule calls for 50+ highway charging locations in California by late 2019 with between 4 and 10 charging stalls at each locations. All stalls will be 150 kW capable and about half will also be 350 kW capable.
Outside of California, they plan to build 150 highway charging locations by mid-2019 but with no specific promises for 350 kW charging. Another 90-100 locations would be in development by mid-2019 and likely completed in the next year or so.
This is the map of the initial ~300 locations. None of these are at or near Porsche or VW dealers and they are brand neutral. It is roughly similar is overall coverage density to where Tesla was in late 2015. The highlighted yellow areas are 17 metro areas that will additionally get community 240V L2 charging and some community fast charging plaza clusters.
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