Approximating bauxite as pure aluminum oxide [1], 40 million tons of bauxite contains about 21 million tons of aluminum. A ton of aluminum takes about 14 megawatt hours of electricity to produce [2]. That would be about 294,000,000 megawatt hours (294,000 gigawatt hours, or 294 terawatt hours) to turn Australia's bauxite exports into aluminum. Australia could easily double its electricity production/consumption to refine bauxite into aluminum metal instead of exporting the bauxite.

[1] https://en.wikipedia.org/wiki/Aluminium_oxide#Production

[2] https://www.mining.com/web/aluminum-price-hits-13-year-high-...