General GNX News, page-1106

I don't believe the engineering reasons for the 250MW decision were ever announced. However, several options were investigated during the feasibility study(ies), which settled on the 250MW/2000MWh being considered the best use for the site. There's a lot of factors to consider in these decisions, turbine size, tunnel size, construction cost, maintenance cost, transmission losses, size of transformers, cooling, etc.. As mere internet observers, even if we were qualified, we don't have the information to justify a push for larger.