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PowerPack... for home! Why not?
- Thread starter tinm
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avg 5.5 hrs/day over the year. ie 10kW system. 55kWh/day avg over year. winter less, summer more. max output, latitude - 15 degrees tilt to max summer sun
use PV watts onlince calc PVWatts Calculator
Yep. Solar City recently got the contract from the utility on Kauai to build a large solar recharged collection of powerpacks to handle early evening demand. The bid is under their current cost of doing it with diesel generators even with diesel fuel cost down dramatically from last year. The solar component won't flow to the grid but just recharge the power packs during the day for the evening load.
That is particularly true on an island. In Calfornia at least we have the regional grid to sell excess power to. The best solution of course is grid storage. Let's hope that Tesla, LG Chem and others can ramp up production to supply that capacity. If you look at the duck curve from the California Independent System Operator we will need about 12 gigaWatts of capacity to ramp up in the three hour period from 5-6PM until 9pm. Some of that capacity exists with peaker plants, but as pointed out above, they are expensive and put more CO2/kWhr than baseline plants.
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That is what the Solar City salesperson told you, but not the way hybrid inverters can be programmed to work. Remember it is the inverter that makes those decisions, not the Powerwall. Just look at WK057's thread for a whole house system. Ten months ago I installed a microinverter solar system. Then four months ago I installed an Outback Radian Inverter and 24kWhrs of lithium batteries. It has been supplying 6kWhrs during the afternoons when my rate is $0.33/kWhr and I charge those batteries at $0.11/kWhrs at super off peak. Yes, the payback is long but I also have a battery backup system, immunity from further rate shifts and the convenience of being able to use some appliances during the peak rate period without additional cost. The inverter and batteries are behind the meter and since I don't feed the grid, no permission is required from my utility, just an ordinary building permit. I do agree that you probably can't get Solar City to do that but there are a lot more options than just Solar City.
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Actually was wondering the same thing (as thread title) and had posted the same question on the wk057 thread would comment, thinking that might hijack his project stuff so I looked and lo and behold....it has already been asked. I wonder what the 250kw inverter would cost? 2 powerpacks, the inverter, a few other goodies and some panels and you'd have a robust system. Found the dynapower specs for 60hz inverter. So, it looks to be 480v, right? That would then require X to step down?
http://44gn9v2dcuhpk71fpdc73qac.wpengine.netdna-cdn.com/wp-content/uploads/2015/07/Dynapower-Tesla-50Hz-MPS-250-.pdf
http://44gn9v2dcuhpk71fpdc73qac.wpengine.netdna-cdn.com/wp-content/uploads/2015/07/Dynapower-Tesla-50Hz-MPS-250-.pdf
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That is a huge inverter 300-600 Volts DC 300 amps. 3 phase AC. I would guess $100,000. My little Radian cost $4,000 which is $1000/kWatt. I would expect the cost per rated Watt decreases as capacity scales up.
Wow...well if that is the case it only makes sense if you are buying 5+ powerpacks, more than I need by long shot. What we need is a good inverter that can do more than the radians...opportunity for someone.
Outback did announce a high voltage DC bus inverter in the works, but I don't know if they operate on Tesla time. LOL Inverters like the Radians can be coupled so you can increase capacity in 8kW increments like WK057 did.
I don't know what features you want that don't exist in a Radian or similar hybrid inverter? The reason I bought the Radian is that it was firmware upgradeable. That isn't going to get me a high voltage DC bus but any load shifting, increased backup, rate arbitrage that I might want is available now. In the future I expect features to be added. I recently received an upgrade that allows me to run my inverter from my PC or phone.
I don't know what features you want that don't exist in a Radian or similar hybrid inverter? The reason I bought the Radian is that it was firmware upgradeable. That isn't going to get me a high voltage DC bus but any load shifting, increased backup, rate arbitrage that I might want is available now. In the future I expect features to be added. I recently received an upgrade that allows me to run my inverter from my PC or phone.
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Obviously you are living something that I'm just learning about. What I don't like about the Radians, Sunny, Schneiders, etc is the fact you have to couple/string them. Too much engineering, too much effort, etc. These companies are focused on solving a problem that existed 10 years ago (in my humble opinion)- how to sell inverter (s) to clients with a 4-20kw battery pack or something like that. They need to be ahead of the industry a little bit or Tesla will identify the inverter business as a weakness and put $100mln into overcoming that problem and away goes the off grid inverter business model.
Anyhow, that is just my outside observers view on things, I'd like to be able to buy 2 power packs and 2 inverters to support them and a large set of panels I can live with the charging electronics. Simplifies installation, a little bit of redundancy if a battery pack fails or if an inverter fails. My power room would not look like wk057 (envious but I'm not doing that) and that is a good thing for me. Better yet, the powerpack should come with an inverter built in. It doesn't have to have all the bells and whistles, it could even be closed like the sunny systems (which I don't get).
But I believe you have already said basically the same thing in multiple threads and fortunately you don't have my immediate frustrations...thanks again for the insight and patience.
I am just trying to get the word out about the possibilities today. I think you are correct about existing systems. As for tomorrow, I think Tesla and SolarEdge have found a simple and elegant solution that is plug and play. That means time saving for the installer and cheaper for the consumer. We are in an exciting age.
I'm confused about your objection to the stringing of inverters. I have the same - a few years' earlier version - model of Radians that wk057 has - two of them to obtain 16kW inversion. But each of those is a doubled 4kW inverter. So how it functions is that side A of the first inverter always is on; when need jumps to more than 4000 watts then side B kicks in; when >8kW side A of #2 starts in; if I need more than 12kW side B of #2 (and wk057's then jumps to #3, and so on).
It's quite an efficient process, and it is a minuscule amount of wiring ("engineering/effort").
Which is all great but then if you want 100kw bank or maybe a 200kw bank, you have a whole wall of sub 10k inverters. No thanks.
Frankly the lack of sophistication and serious improvement in the inverter business is sort of shocking to me. Granted it is an outsiders eyes but as best I can tell really nothing new has happened in the inverter space in a few decades. They add support for new batteries, they had some communication capability (that already exists in any other industry...lets be generous and say it is a 10 year old idea), but they don't really attack the cost/structure of the inverter. It is a big clunky piece of electronic gear.
I agree with Ampster that Solaredge has an interesting solution, I only hope I can buy one by next summer.
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So do you think the hd wave could play with a powerpack?
It is hard to tell from the skimpy press release. This Youtube video explains the process but no details about DC bus connectivity or availability.
[HD] SolarEdges HD-Wave Inverter Technology - YouTube
[HD] SolarEdges HD-Wave Inverter Technology - YouTube
Yep details are scarce. They are going to show it off in England next week, Birmingham?, at a trade show. I used the comparison of CRT vs Flatscreen TVs with my son weeks ago (before I saw this announcement). Very apt comparison. Also, had not realized Google had sponsored the small inverter project.
Umm - it appears to be a transformerless inverter design or am I missing something? Nothing new here unless they are transitioning to VHF for switching frequency or something. My Power-One solar inverter is nearly five years old and transformerless. Other major solar inverter companies like SMA have been doing this for some time as well. Having a look at the Solaredge inverters on their website - it appears they are just behind the times a bit and now trying to catchup with the majors.
My Power-One unit is 3.6kW rated and weighs 8kg and is the size of a Pizza box. Their current 3500w unit weighs 20kgs and is huge. The SMA TL (tranformerless) range is very similar in weight and compactness to the Power-One unit.
My Power-One unit is 3.6kW rated and weighs 8kg and is the size of a Pizza box. Their current 3500w unit weighs 20kgs and is huge. The SMA TL (tranformerless) range is very similar in weight and compactness to the Power-One unit.
Those are all the grid tied transformerless models, right? They can't do much for me in an off grid setup, if I could use those I'd not be bitching about the transformer issue. In theory, if solaredge hd wave is going to work with a powerwall effectively, this model is going to have to have some level of transformer/capacitance built in, right?
schueppert
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You are missing something. The HD Wave is using a distributed multi-level stepped output to produce something much closer to a sine wave before filtering and smoothing. This increases efficiency and reduces the quantity of magnetics required since it is transferring most of the analog signal processing into the digital domain. It has been done before but only in inverters at much higher power ratings.
Also, your inverter weight comparisons don't look right. The smallest inverter I can find from either PowerOne or SMA weighs over 20 kg. Do you have a reference for a datasheet showing one at 8 kg?
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