Most of the energy required by the Gigafactory, Jaffe said, will be used to power ovens, which are used to bake chemical powders onto metal foil used in the production of cathodes and anodes -- the positive and negative points of a battery.
Tesla's choice of sites for its Gigafactory was optimal for several reasons that wouldn't necessarily benefit other types of factories. First, Reno is also one of the few areas in the world where the Earth's crust is thin enough to offer access to geothermal energy, i.e. heat from the Earth's mantle.
That geothermal heat is not variable, but constant, and can be used in the Gigafactory's ovens or to create steam to power turbines.
While Reno is an arid region, precluding manufacturing that requires a lot of water, it does get on average five peak hours of sun per day compared to other areas of the country, such as the Northeast, which get about 2 hours.
"It's the predictability that is so much better in that geography," Gaffe said.
The other top energy use in the Gigafactory will be to fully charge up batteries and then discharge them in order to condition them for use. However, in an efficient battery factory, discharging batteries can be used to charge others - to power requirements should be minimal, Jaffe said.
Lastly, the Gigafactory is producing batteries, which Tesla could then use to cheaply store power during off-peak renewable energy production.
Not really "off grid"
Lombardo doesn't believe the factory, however, will be energy independent based on its own renewable power plants. Instead, it will use "net metering", a method whereby Tesla will generate its own electricity and sell excess back to utilities. Then, during times when Tesla's own renewable energy production falls below demand, the electrical grid will intelligently route to it electricity based on energy credits.
"It's more reliable, more cost-effective, and location-independent," Lombardo said in an email reply to Computerworld. "Even Tesla isn't necessarily going off-grid. Musk said "net-zero energy," which just means that they'll generate as much energy as they use."
On average, Reno basks in five peak hours of sunlight per day.
Using an average 20% efficiency for rooftop photovoltaic (PV) panels, the Gigafactory's 10 million square foot roof would produce 850MWh of solar power daily, Lombardo said.
Additionally, using Tesla's own artist's rendition of the Gigafacotry, Lombardo estimates that the Gigafactory would have 85 wind turbines able to generate about 1,836 MWh of power daily.
"Reno is no stranger to geothermal energy - it has several plants in operation already. The newest has a 20MW capacity," Lombardo wrote in his blog. "Let's say Tesla goes small and builds one with only half of that capacity. That 10MW plant would produce 240MWh of daily geothermal electricity.
Sign up for CIO Asia eNewsletters.