The solar switch, which took a year to complete, has both its long-term environmental and immediate practical benefits. Like many remote communities, Ta'u previously had to run on diesel generators. That burns 300 gallons of fuel per day, which is neither eco-friendly nor cheap. Solar eliminates the pollution, of course, but it also saves the cost of having to continuously buy and ship barrels of diesel. And crucially, it provides a more reliable source of electricity. Locals previously had to ration power (say, if a diesel shipment wasn't on time) or accept periodic outages. Now, they can assume they'll have power at all times.

Ta'u is clearly an ideal test case. On top of its paradise-like weather, there are less than 600 residents with relatively modest power needs. It'd require much, much more power to accommodate a full-blown city, especially in climates where cloudy days are more commonplace. However, it could still serve as a good example. Tesla's mission is to wean the world off of fossil fuels, and this shows that it's a realistic goal in at least some corners of the globe.