Printed on October fifth, 2020 |
by Zachary Shahan
October fifth, 2020 by Zachary Shahan
We simply pulled down an article about vanadium stream batteries versus lithium-ion batteries for long-duration power storage as a result of Tesla CEO Elon Musk responded, “This text is wildly incorrect about lithium battery prices by an element of 5 or extra presently & 10X long-term.” Nonetheless, that raised extra questions than solutions for me, so I’ve dug in additional and have some new data to share together with much more context concerning battery costs and long-term prices.
I’ve gotten some additional particulars from Elon concerning Tesla power storage pricing, together with data that I don’t suppose was beforehand public, and I’ve reached out to StorEn Applied sciences for extra particulars on their assumptions.
To begin with, although, there are at the least just a few issues to level out right here to clear up some huge confusion and misunderstanding. To start out with, the most important factor is:
The $/kWh cost of electric vehicle batteries is under no circumstances the identical because the $/kWh value of stationary battery storage methods.
Moreover, there are literally two various kinds of $/kWh — there’s the value of the storage system primarily based on one-time power storage capability and upfront value (for instance, in case your battery has 100 kWh of power storage capability and prices $5,000, the determine is $50/kW), and there’s precise value per kWh of electrical energy saved over the lifetime of a storage system. To determine the latter, it is advisable to calculate variety of cycles and lifelong of the system (and, truly, much more than that, like effectivity, upkeep, and restore). I did this for the Tesla Powerwall versus other top options in 2015 when the Powerwall got here out — verify that out if you wish to dive extra deeply into what such calculations entail.
The pricing estimate within the article earlier as we speak that Elon was responding to was as follows: “lithium batteries sometimes value $600 to $900/kWh and final for 3,000 to 4,000 cycles. Subsequently, their value per cycle averages $0.21.”
Anybody who follows the electrical car market, particularly EV battery prices, may certainly have a look at the primary set of figures ($600–900/kWh) and have their eyes bulging out of their head. Nonetheless, this isn’t pricing for Li-ion batteries for EVs. That is pricing for stationary storage, which is far completely different. Additionally, I’m fairly assured this was “all-in” pricing — pricing for a full stationary storage system, not simply the battery cells or packs alone.
With all of that in thoughts, let’s dig in a little bit additional.
Tesla Powerpack & Megapack Pricing
One commenter identified that Tesla Powerpack pricing is now at $539/kWh. That’s after a really latest worth reduce and continues to be near $600/kWh. It’s actually not a 5× distinction, but it surely’s properly under the $750/kWh common that was used to provide you with the $0.21 per-cycle estimate. Sure, that $539/kWh worth contains inverter prices, however I imagine that StorEn was certainly targeted on whole-system prices as properly, particularly since vanadium stream batteries profit extra from that viewpoint — which is expounded to an enormous profit I’ll come again to in a second, very lengthy life.
In response to my questions on the price of a Tesla Powerpack, Elon Musk supplied some fascinating new data:
“Powerpack is an older product. Megapack is what we now ship to utility or heavy industrial customers.
“The battery pack portion of it’s lower than $200/kWh. Energy electronics and servicing over 15 to twenty years take the value as much as roughly $300/kWh. Nonetheless, it could not be correct to match a vanadium stream battery value alone to the price of lithium battery plus energy electronics and 15 to twenty years servicing.”
Once more, as I learn it, StorEn was referring to all-in, whole-system prices. One of many advantages of vanadium stream batteries is reportedly little or no want for upkeep and restore, so it’s pure StorEn can be extra involved in evaluating full-system prices. I’ve reached out for clarification and can replace this text to point whether or not that’s appropriate or not if I get a response on this matter.
Additionally, once more, it’s best to actually contemplate full lifetime value per kWh saved. As you possibly can see above, Elon famous 15–20 years of servicing. StorEn mentions a 25 12 months lifespan on a 500 kWh system with as much as 15,000 cycles. What does that imply by way of long-term value per kWh saved? Effectively, we don’t have that data since I don’t see a worth for the ST 50-500 system. Nonetheless, perhaps we do have it with a little bit math. Within the different article, StorEn famous vanadium stream batteries may have a value of $0.04/kWh per cycle, and will attain 15,000 cycles. That involves $600/kWh. (Apparently, that occurs to be the underside finish of StorEn’s estimate for Li-ion batteries.)
If I can get extra pricing particulars from StorEn, I’ll replace this text so as to add it in or I’ll write a brand new one. I may additionally then attempt to calculate a lifetime price-per-kWh vary for the Tesla Megapack.
Tesla Powerwall Specs & Pricing
StorEn presents a residential/small-scale energy storage product in addition to the utility-scale energy storage system talked about above. So, let’s additionally contemplate the Tesla Powerwall, a house power storage battery one in all our writers has. (Effectively, he has two of them.)
One 13.5 kWh Tesla Powerwall cost our writer, Kyle Field, $6,500 — not together with the Tesla Gateway or set up prices. Which means a value of $481.48/kWh. Pricing has apparently gone up a bit just lately, although, and is now $7,000, not together with the Gateway and set up (which prices $4,500, or $3,500 if included with a Tesla solar rooftop system). With a worth of $7,000, that’s $518.52/kWh. Once more, that’s properly under a low-end assumption of $600/kWh (to not point out $750/kWh or a high-end assumption of $900/kWh), however it isn’t one-fifth the price. I’m undecided whether or not it is sensible to throw in the price of the Gateway or not, particularly because it’s not clear in any respect what I ought to be evaluating these merchandise and figures to.
I don’t see pricing for the StorEn VFB battery, however have additionally requested the corporate to offer that.
There are different notable specs and guarantees to think about as properly. The StorEn battery is rated for 25 years, whereas Tesla’s Powerwall has a ten 12 months guarantee.
StorEn experiences a 15,000 cycle life. The Tesla Powerwall 1 provided a ~5,000 cycle life. The Powerwall 2 comes with “limitless cycles” for photo voltaic self-consumption/backup or “37.8 MWh of mixture throughput” for different purposes. Calculations of the previous come to a max of about 3,100 cycles over 10 years, whereas calculations of the latter come to three,200 cycles should you assume 37.8 MWh refers to each charging and discharging.
As one remaining set of specs to think about, Tesla’s Powerwall has a 90% round-trip effectivity, whereas the StorEn system has a 75–80% round-trip effectivity.
Figuring out precise value per kWh of electrical energy saved over the lifetime of the product is almost at our fingertips. If I get just a few extra particulars, I’ll replace this part and even publish an entire new article.
There are nonetheless some data gaps right here that may assist present a extra thorough comparability of those power storage methods, however listed here are some core conclusions:
- The Tesla Megapack now comes at a value of <$200/kWh, or ~$300/kWh with energy electronics and servicing included, per Elon Musk’s feedback to me as we speak.
- That’s properly under what just lately gave the impression to be a brand new low worth of $539/kWh for the Tesla Powerpack.
- A Tesla Powerwall now prices $518.52/kWh, up from $481.48/kWh earlier this 12 months, however that doesn’t embody the price of the Tesla Gateway or set up.
None of that tells us the price of electrical energy saved over the lifetime of the system. To find out that, it’s a must to add in a number of different components, a few of that are powerful assumptions to make over the course of a decade or two. They embody effectivity, depth of discharge, variety of cycles, and upkeep and restore prices.
Hopefully this clarifies — to some extent — the gentle controversy from earlier as we speak. If sufficient additional data is gathered on these matters, I’ll comply with up with one other piece.
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