Why the Extra Cost?
If it catches on, your house could soon run on battery power whether you buy a Powerwall or not. Tesla’s cars use NCA batteries with cathodes made of lithium, nickel, cobalt and aluminum oxide. Lithium ion, or Li-ion, batteries come in a variety of flavors. But must household users wait for market forces to work their magic, or can the gurus of green make a case for Tesla Powerwalls today? In short, the prognoses for the utility and business side looks good, and that could make the consumer side look increasingly better.
On the positive side, Tesla has already forged partnerships with corporate heavy hitters, and its price point looks attractive to utilities. Moving away from Panasonic and Samsung batteries and manufacturing its own is a key fixture in Tesla’s plans. That said, in absolute terms the Powerwall remains pricey. The greenies and the gadget junkies of the world will join in no matter what and, in terms of bang per buck, no other residential cell is fit to hold Tesla’s battery box. The real story of Tesla Energy is arguably the gigafactory currently under construction in northern Nevada. After that, only time will tell whether Tesla’s batteries jolt the grid or fizzle out.
Downing, Louise and Ehren Goossens. Helman, Christopher. “OK, So Maybe Tesla’s Powerwall Isn’t ‘Only’ For Rich, Green People.” Forbes. Fehrenbacher, Katie. “Why Tesla’s Grid Batteries Will Use Two Different Chemistries.” Fortune. Galbraith, Kate. “With Tesla Entering Market, Hopes for Home Batteries Grow.” The New York Times. Groom, Nichola. “Tesla Faces Competition for Customers, Subsidies.” Reuters. Gies, Erica. “Lithium Producer Chases Tesla’s Bold Battery Plan.” The New York Times. Geuss, Megan. “Tesla Already has 38,000 Reservations for the Powerwall, but Use Case is Narrow.” Ars Technica. Gangemi, Jeffrey. “Selling Power Back to the Grid.” Bloomberg Business.
That means until we start parking solar panels in space and beaming power back to Earth, solar users must spend their nights hooking to the grid, consuming generator power or re-enacting pioneer days. To put that in perspective, the average American household uses around 30 kwh per day. Ideally, they could store the day’s solar energy to “self-consume” at night, but the batteries currently on the market leave something to be desired. Mainly, they’re too expensive. Costs can reach as high as $600 per kwh of storage, with $100 per kwh marking a kind of industry sound barrier.
The units deliver 2 kW continuously (3.3 kW peak) at 350-450 volts and 5.8 amps (8.6 amp peak). Bear in mind, though, that appliances only draw power while running, so even energy-heavy appliances like microwaves can work if properly managed. Thus, a 1.0 kW air conditioner will take up half of your power pipeline and drain your 7 kwh energy tank in less than 7 hours. If you think of energy as water, then kilowatts describe the size of the pipe and kwhs define how much the tank will hold – or how many “gallons” you use over time.
