The South Pacific territory - comprising the three atolls of Atafu, Nukunonu and Fakaofo - had been dependent on diesel to generate electricity.
New Zealand, which administers Tokelau, funded a $7m (£4.3m) solar project.
Solar grids were constructed on the three atolls, with the last completed earlier this week.
"The Tokelau Renewable Energy Project is a world first. Tokelau's three main atolls now have enough solar capacity, on average, to meet electricity needs," New Zealand Foreign Affairs Minister Murray McCully said in a statement.