Energy storage. 2-3M watt/hrs. grid tie, Hydrogen, etc for large building

fastline

We are looking to build our small machine shop outside of town. We can probably have 3ph brought to us but at a substantial cost plus the monthly bill. Due to that, we are looking to be power independent. We are in KS and have a very good wind supply BUT energy storage is our problem right now.

We are an aerospace engineering/mfg company but small. I have already heard "build where you have power, pay for the service, forget about it, etc". We want to be independent and I think we have the skills to do it but still cannot get the storage problem resolved. We would not only need a way to store the energy, but be able to use it mostly as electric power later with an easy to use system. I have already explored steam and it seems too complex and finicky for our load delta.

We have the ability to build our own wind generator from scratch, build our inverters, etc but still governed by technology right now. We have looked at hydrogen generation with wind, compressed air, hot water, Ethanol production, batteries, you name it.

A quick estimate for lead/acid bats was around 100 grand! That is with us buying the bulk lead and machining the plates and building the bats in house. Not ideal! Hydrogen seems easy enough at surface level. When the wind blows, Hydrogen is made along with running the shop. However, storage of H and O is scary as well as how to convert it back to electric. My understanding is the use of a fuel cell that will harness the reaction of combining H and O.

Very open to ideas and thoughts here. I think we can make the power but storage is a whole other issue.



OH, I have also looked at solar but at a ballpark price point of 1 dollar/watt, and the amount of power we need, the price would be steep. Couple that with our high wind and hail storms in KS and I am not too excited to look at solar unless things get real cheap real fast. We have the room but I think wind is a better resource here in KS

BB.

Re: Energy storage. 2-3M watt/hrs. grid tie, Hydrogen, etc for large building

Hydrogen gas has its major issues too... Generally, it is around 50% +/- to generate via electrolysis. If you have to compress it for storage (very high pressure for vehicles ~3,000-6,000 psi for reasonable range). And hydrogen embrittlement--The small hydrogen atoms diffuse into many metals and make it brittle... Need to use stainless steels for fittings/lines, etc.

Battery wise--Some of the new Lithium batteries may be interesting:

Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

And there are now Liquid Metals (sodium-sulfur?) batteries that are being used in a few utility scale installations.

Molten salt battery - Wikipedia

If you have single phase power, going with a grid tied inverter system is going to be the most cost effective solution.

I assume you have experience with rotary (i.e., on the cheap) 3 phase inverters and using VFD as phase converters?

For most folks, they are looking at $1-$2+ per kWH for the cost of electricity from a fully off-grid solar PV system. Just battery losses and replacement costs probably account for 1/2 of those costs.

Doing a bunch of back of the envelope calculations will probably help narrow down the possible.

For you, much of your power use is during the day. Looking towards industrial (forklift/traction batteries) which basically buffer the power between the solar panels and the equipment and provide enough standby power (short AC mains outages, time to start a genset, etc.) will help keep the costs a bit lower (but the battery efficiency goes down too--so you need more solar panels to make up for the losses).

We do have one poster here that built a metal fabrication business off-grid in Hawaii using used forklift batteries and old MSW inverters (for the most part). And has been very happy with the results. Of course--he has lots of sun, access to a reasonable supply of used batteries, and every expensive grid power.

Search for threads started by "adas".

-Bill

fastline

Re: Energy storage. 2-3M watt/hrs. grid tie, Hydrogen, etc for large building

Thanks.. Regarding Hydrogen, it was my understanding there was some new nano technology that was going to enable low pressure storage? I think my biggest question with Hydrogen is not storage or production as much it is "how do I get electric power back from it"?

I am not sure if I am all that concerned about eff losses since I plan to over build my wind systems substantially and will likely have more than i could use.

I am not real sure about the grid tie solutions for 1ph. I was looking into just connecting to 1ph anyway for another source of power if needed. I am betting they still will want a few grand for that! I did not have much interest in a grid tie for return power unless I was going to connect a large 3ph system in which I still was only calculating that at most I would make about 2-3 grand/year figuring on a 30kw/hr wind system and I would be using 50% of it. I guess I might rather install another machine or two and use that power rather than give it to the PC BUT I do understand the issues of balancing my frequency, speed, etc. I think I would have to invert the power for clean, reliable 60hz power with regulated voltage.

The problem here that I did not mention is th PC will NOT allow any more than 10HP load on a 1ph service so it is not like I can just request a 600A, 240V, 1ph service and run digital conversion.... Certainly would not be THAT easy...lol

let me clarify that. the service would be 200A but across the line loads (motors) over 10hp are not allowed due to V sag. As you know, that 40A motor will pull 200-400A on start up.

mike95490

Re: Energy storage. 2-3M watt/hrs. grid tie, Hydrogen, etc for large building

I think the easiest solution is to bite the bullet, order 3 phases installed, and then install your own 3ph Solar & Wind grid-tie to offset your cost, and if you add batteries, that will greatly increase your cost, but could also keep you running while the sun shines. But it's expensive!

BB.

Re: Energy storage. 2-3M watt/hrs. grid tie, Hydrogen, etc for large building

Vfd controller with soft start can be very nice.

Although, I have a friend who is a machinist and he thought that motors on vfd converters had higher failure rates.

-Bill

solar_dave

Re: Energy storage. 2-3M watt/hrs. grid tie, Hydrogen, etc for large building

How much to get 480V grid installed? has to be less than the $100,000 battery deal.

fastline

Re: Energy storage. 2-3M watt/hrs. grid tie, Hydrogen, etc for large building

BB. wrote: »

Vfd controller with soft start can be very nice.

Although, I have a friend who is a machinist and he thought that motors on vfd converters had higher failure rates.

-Bill

There are some theories regarding VFDs but it has been time proven that motors still last with VFDs. We have one that is 21 years old on the same drive and motor. The problems really are the high frequency harmonics that VFDs produce. The creat havoc in the bearings and winding insulation thus the "inverter rated" motors. However, in our experience, a standard 3ph will survive just fine.