Building a new off grid house in wyoming need help!

Re: Building a new off grid house in wyoming need help!

myhouse07 wrote: »

...182500kw you must be joking right? " manufacturing energy costs to around 20 kWh per panel" Sharp 210 watt panel...if it took even 1 kw to make a battery I would be surprisied.

Your assumptions are way to small. This study, although old, estimates CO2 payback for stand alone home systems at 7 years when compared with a diesel generator, which is about two times less efficient than utility scale power plant. Solar radiation was assumed at 1900 KWh/m2/year or 5.21 solar hours per day average. Few excerpts:

In order to evaluate an Energy Pay-Back Time we will compare the SHS with a diesel generator which converts primary energy (fuel) into electricity at an average efficiency of 25% . (Note that grid supply in a remote area may have a comparable conversion efficiency). As the results in figure 1 show the EPBT of the assumed SHS configuration would be more than 7 years, even with the low module energy estimates for mc-Si modules. For future PV technology only a modest improvement is expected due to the large contribution of the battery (for which no improvement was assumed) to the system EPBT. One consequence of this result is that one should be careful when attributing a CO2 mitigation potential to SHS’s. Some kind of break-through in electricity storage technology will be necessary if we want to improve the CO2 mitigation potential of this application. In any case, the long-term worldwide contribution of SHS to CO2 mitigation will always be small in comparison to grid-connected systems.

As a consequence, the energy pay-back times of PV rooftops are expected to drop down to 1,7 years and 1,2 years for mc-Si and a-Si respectively. These values indicate that such future systems will definitively have a high net fossil energy substitution and CO2 mitigation potential. This is not straightforward the case for Solar Home Systems, for which energy pay-back times of more than 7 years were found. In fact, the BOS is the crucial factor determining the energy and environmental profile of these systems and limiting its actual CO2 mitigation potential. Irrespectively of PV technology improvements, some kind of breakthrough in electricity storage means will be needed if we want to improve the over-all environmental effectiveness of Solar Home systems.

Re: Building a new off grid house in wyoming need help!

myhouse07 wrote: »

I am looking at only $25,000 for my set-up and have a $10,000 grant. So $15,000 is less then a grid hook up.

I was wondering if the $10,000 grant had some requirement to be off-grid, which would throw the calculations. Also, the cost to hook up to the grid has never been stated, so it is impossible to do the financial calculations, and the political calculations are even more difficult.

I think it is a great goal to work toward. I am wishing I had enough solar to go off-grid for myself too, but as others have said, a major expense. (I still question some of the off-grid/battery based calculations, but I don't have the data to debate it yet.)

The one input I would add, as a non-expert, is to listen to Solar Guppy and the other experts (and you will figure them out quickly). I was fortunate enough to have Solar Guppy's help, and am always grateful for it. And one thing he has consistently said with the XW6048 inverters is to have a quality battery bank of sufficient capacity. The owners manual says you can operate on a 48v and 100ah bank, but it is absolutely untrue in real life, as Solar Guppy would tell you. If you are going to be using the capacity of the inverter, you must have at least a 48v and 500 ah battery bank. In my case, I'm not at the full capacity of the XW6048, and I can get by with the 357ah bank, but it is an absolute minimum. If I had it to do over again, I would really try to go with 24 2v batteries instead of 4 12v batteries, and I really would avoid the parallel banks if possible. The 2v batteries just seem so hard to find at an affordable price. I would also really be looking into the Thundersky, etc., lithium batteries, since there would be even less cells to get to 48 volts AND you can use 80% of the capacity instead of the 40% with the lead and 60% just taking up extra space AND the lithium should last twice as long. They apparently need a good battery management system, but even if they end up costing four times as much they still might be a good deal.

Re: Building a new off grid house in wyoming need help!

mike90045 wrote: »

I have my pump on a timer, from noon to 2pm When the sun is out, and batteries are still in bulk or absorb, I'm running mostly from the PV, and not the batteries. That's saves me 30% of charge/recharge losses. Come winter rains & clouds, I hope the garden wont be using nearly as much water !!

What are you growing up there Mike?

One of the reasons so many reccomended that the OP connect to the grid is he will never be able to do what you are doing in California. It will be 100 hour oil changes every month for a third or more of the year. It just does not cost out unless there is no choice or as halfcrazy said he just wanted to do it. My only problem with that kind of decision is the OP is going to have to overcome a very real chance for failure. It is not a "big" challenge for someone like halfcrazy. We logged the number of homes who made a decision like this on the Outback forum once and one in 15 came back and said it was going fine. There were about five who came back wishing they connected and nine that just never came back.

I am think good things for the OP with eyes wide open!

Re: Building a new off grid house in wyoming need help!

I understand what you are trying to do, I wish people could evolve past burning coal for electric and heat. Unfortunately, coal is so cheap that grid electric does not cost much. As such, there is not much incentive to conserve.

My Goal is to be off-grid, however only off-grid in the sense that I do not take from the grid. If everyone feed their excess capacity back to the grid than there could be a reduce in coal fired electricity.

If you going to heat with propane than maybe consider MCHP, i.e freewatt.

Re: Building a new off grid house in wyoming need help!

Nice! Ah the land of fruits and nuts...