Slashdot Mirror
Tesla Runs an Entire Island on Solar Power (engadget.com)
Jon Fingas, writing for Engadget:Now that Tesla has officially acquired SolarCity, it's not wasting any time showing what the combined entity can do. Tesla has revealed that it's running the island of Ta'u (in American Samoa) on a solar energy microgrid that, at 1.4 megawatts, can cover "nearly 100 percent" of electrical needs. It's not just the 5,328 solar panels that are key -- it's the 60 Tesla Powerpacks that offer 6 megawatt-hours of energy storage. While Ta'u is normally very sunny, the packs can keep it running for three days without sunlight. They don't have to worry about a cloudy day leading to blackouts. 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.
At $2.50 a gallon (seems to be current US price?), 300 gallons a day costs $750.
Which means that THE BATTERY for that system that runs for 3 days only without solar would cost the equivalent of 10 years of diesel.
Sure, there's a lot of losses, shipping, conversion, other equipment on the diesel side, but there's also a lot of solar etc. required on the Tesla side that's unaccounted for above. And it would take 10 years to break even just on the battery storage alone, let alone the solar + battery.
Sure, it's not linked to oil prices, but it's still only just verging on "viable" assuming nothing ever goes wrong. Same as every "green" project I've ever done the numbers for.
Diesel usually cannot be stored for longer than one or two years:
Diesel bug is a thing.
That's actually another reason for regular generator tests in backup facilities:
It frees up storage volume that can be filled with fresher fuel.
Keep in mind, also, that you need a harbor that can support a 20,000 DWT tanker.
However, overcast does not mean no power from solar. With the reduce power from the solar panels plus the batteries being fully charged to run for three days you probably have enough power to run six to seven days before the batteries are totally drained
So it is very unlikely that you will have too little sun in a tropical island to keep it running.
E.C.P.