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Title: Forbes: Why Tesla's Powerwall Is Just Another Toy For Rich Green People
Source:
Forbes.com
URL Source: http://www.forbes.com/sites/christo ... her-toy-for-rich-green-people/
Published: May 1, 2015
Author: Christopher Helman
Post Date: 2015-05-03 14:46:55 by Operation 40
Keywords: Tesla, Battery, Energy
Views: 2788
Comments: 7
All the breathless coverage of Elon Musk’s Powerwall battery brouhaha last night is missing the most important thing: a sober discussion of real-world costs. So let’s take a look at the costs and see if this world-shaking, game-changing innovation really makes any sense. Musk said Tesla’s 7 kwh capacity battery would cost $3,000, while the 10 kwh capacity one would be $3,500. (That doesn’t include the cost of a DC-AC inverter – about $4,000 $2,000– plus professional installation.) The implication is that a 10 kwh system could supply 1,000 watts of current to your home for 10 hours. That’s a good amount of energy. The average American home draws an average of 1,200 watts of power around-the-clock, according to the U.S. Department of Energy. For a sense of scale, a desktop computer draws about 100 watts, a big TV 200 watts. Refrigerators cycle on and off, but average about 100 watts. So how much is that battery power going to cost? Setting aside for a moment the cost of making that electricity in the first place, let’s look at just the cost of using the battery to store it and get it out again. Researcher Winfried Hoffman, the former CTO of Applied Materials , has done some interesting work on the falling costs of battery power. He figures that for a lithium-ion system with an initial installation cost of $400 per kwh capacity, 80% efficiency and ability to run 5,000 cycles, the average cost of stored electricity will be 15 cents per kwh. This might be conservative. Solar installer Sungevity is working with a German battery company called Sonnenbattery, which claims it can do 10,000 cycles. But this calculation might also not be conservative enough. It’s unclear how many cycles you could expect to get out of Powerwall. Tesla says its 7 kwh Powerwall can cycle daily, while the 10 kwh system would cycle weekly. The cost of the battery is amortized over the total amount of electricity cycled through it over its lifetime. The less you use it, the higher your average unit cost. Either way, 15 cents per kwh for battery storage seems ball-park reasonable. To get your real electricity cost, you have to add to that 15 cent battery charge whatever you’re paying for that electricity in the first place. Since the idea is that batteries will work in tandem with solar, we’ll look at what Tesla’s sister company SolarCity charges its customers. According to SolarCity, a customer pays no upfront costs for a system, but then gets dinged for 15 cents per kwh of power generated. In the contract, SolarCity has the ability to increase that rate 2.9% a year, which doesn’t seem like much, but would end up raising your cost per kwh above 20 cents by the end of the 20 year term. So adding together your 15 cents per kwh for solar power plus the 15 cents to cycle a kwh in and out of the battery, and you’re looking at 30 cents per kwh for electricity. I think 30 cents per kwh is bonkers. At my home in Texas I pay 10 cents per kwh to Reliant Energy for electricity that is mostly generated by natural gas burning power plants. Nationwide , the average retail electricity price is 12.5 cents per kWh, according to the Dept. of Energy. Now I understand that power prices are considerably higher in California and Hawaii and other parts of the world with shoddy power grids, but in the vast majority of the United States no one pays anything close to 30 cents per kWh for electricity. But it gets worse. Let’s think some more about the real utility of this Powerwall system. According to the Dept. of Energy, the average home uses 10,900 kWh per year, which equates to about 900 kWh per month or an average round-the-clock power demand of 1,200 watts. Now with some attention to efficiency, the average home could probably get itself down to 1,000 watts of power demand on average, which would probably be low enough that Tesla’s 10 kwh Powerwall battery could handle the loads for about half the day...SNIP ...And here’s where the economics of the Powerwall break down. If you do not have a big enough solar system to get your home entirely off the grid, then there is simply no point whatsoever in paying 30 cents per kwh to get electricity via the Powerwall. At night, when you’re not generating solar power, you could simply get your electricity from the grid. For an average 12.5 cents a kwh...SNIP Complete article: http://www.forbes.com/sites/christopherhelman/2015/05/01/why-teslas-powerwall-is-just-another-toy-for-rich-green-people/
Elon "Enron" Musk introduces his latest tax credit scam
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#1. To: Too Conservative, Operation 40 (#0)
Check out another thread based on "Tesla's Inventive Spirit."
I know someone who installed a natural gas back up generator and the cost was more than that. So, if this can serve as a power back up - it's on par - I presume when you count the cost of the solar panel. So I don't think this is a rich person's toy at all. At least upper middle class.
#4. To: Pericles (#2)
The problem is that a battery source is a DC charge. In the case of "Tesla's miracle marvel" it is relying on relatively inexpensive or cheap rates by the grid energy companies to store charge for day use. Who is to say the energy companies don't flatten their rates 24/7/365? It is expensive fixed plant home equipment to install and maintain. It requires a AC to DC charging circuit to store electrical energy into the battery and then convert the DC to AC energy for consumable household use. More than that, there are switching circuits required. So, the method offered by Tesla doesn't do anything new or revolutionary other than waste energy through the conversion process. It is NOT a new energy source; it IS a converter. It is a high dollar conversation piece for the freaks in San Francisco.
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#2. To: buckeroo, Too Conservative, Operation 40 (#1)
(Edited)
Replies to Comment # 2. I know someone who installed a natural gas back up generator and the cost was more than that. So, if this can serve as a power back up - it's on par - I presume when you count the cost of the solar panel. So I don't think this is a rich person's toy at all. At least upper middle class.
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