TWh/year makes sense if you want to talk about the entire energy consumption over a year. 1.7GW lacks a time frame, 15TWh/year is more useful in that context,

TWh/year makes sense if you want to talk about the entire energy consumption over a year. 1.7GW lacks a time frame, 15TWh/year is more useful in that context, even if you can just short it down to 1.7GW.