There is no need to have Excel installed to use the OpenXML libraries.
https://github.com/OfficeDev/Open-Xml-Sdk
They also support being used on .NET Core.
https://github.com/OfficeDev/Open-Xml-Sdk
They also support being used on .NET Core.
Disclaimer: I'm a current ClosedXML contributor.
Is the situation different in 2017?