No announcement yet.

Powering Havemore Farm

  • Filter
  • Time
  • Show
Clear All
new posts

  • Powering Havemore Farm

    We're currently hooked up to the grid...and I don't need to tell you that's an increasingly expensive way to source energy.

    We've sought advice from the suppliers of alternative energy and it appears that substituting solar-generated electricity is going to cost around $25,000...which has a payback period of more time than I've probably got left. Those quotes also assume that we need to become totally independent of the grid...and that we are going to continue to consume energy at historical levels. The first assumption ain't necessarily so and the second one is inconsistent with my emerging 'reduce, re-use and recycle' view of the world.

    One of the important underpinnings of having more for less is about saving money (where practicable) so that it can be more wisely invested elsewhere. For that reason, energy consumption at historical levels is not something that can/should continue.

    The other assumption is about total independence from the grid. Since we're already hooked up...and the power companies charge a service fee regardless of whether I use the electricity or make sense to maintain the connection - and the overall energy capacity - just for those situations that require it.

    Let me explain.

    If you look at our energy consumption, the big hitters in the house are the hot water service, oven, washer/dryer and the air conditioner. In the worshop, it's the compressor, bandsaw and a welder (should I decide to use one. A photovoltaic array, storage batteries, inverter and control electronics to provide this capacity - in all normal circumstances - costs around $25,000.

    But if we exclude these items, our peak power requirement drops substantially...and, if we model our solar power system on this figure, the installation cost also drops substantially. But it need not end there. Solar equipment suppliers apply a safety margin to their quotes that takes account of the fact that PV arrays are more efficient on some days than others. For example, power generation drops on overcast days so, to accommodate this inconvenient fact, the supplier factors in more battery storage...and that hikes the cost.

    Given that we already have a mains connection...and that we pay the service fee whether we use it or not...I regard it as a prospective back up that will allow us to install few storage batteries - thereby reducing the cost of the solar installation.

    The hot water service, which is now over 20 years old, is going to be replaced by a custom-built solar unit. The air conditioner is a luxury that is permissible for as long as the energy is available to operate it. In the event that the SHTF, it will be among the first casualties.

    To summarise...I'm thinking of a small solar system to provide for the base load...leaving the grid to provide the grunt for the appliances and machinery that require more energy...and to act as a back up in the event of extended periods of little solar power generation.

    The next step is to put some numbers together.

  • #2
    PV prices have come WAY down. Under US$0.50 per rated Watt is now commonplace - less in B-grade and/or pallet lots.
    My first 1.25 kW array - about 2001 - cost just over $6000 - not including batteries and inverter. My second 1.25 kW array - in about 2004 - cost under $3000 (both were parts only, aka 'free' labor (mine). Today those panels, mounts and charge controller would be under $1500.

    Batteries (lead-acid) have also come down in price rather dramatically. My first battery bank (1998) cost well over $3500 plus interconnects (which I made myself at 1/10th the cost). That lasted 10 years and was replaced for under $2400 which last 8 years (could have gotten more out of them).. I replaced it again last year for about $1500. All prices cited are in the then current years dollar value and we all know that fiat currency script isn't 'worth' what is once was. US$1000 in 1998 is equivalent to $1500 today.

    I'm NOT on-grid - not even close. I figured that I recouped the cost of my first array in about 2 years versus running a high-efficiency gas generator 5 to 7 hours/day (also back when gas was about $1.00/USgal). My second array paid for itself in about 3 to 4 years versus running the generator maybe 200 hours/year (in winter). For the past 10 or so years I only run the generator maybe 30 hours per year during prolonged winter storms when the batteries get low (below the recommended depth of charge for maintaining longevity).

    My hot water is LP, as too is heat, cooking and refrigeration (totals about $400/year). But I do NOT attempt to 'conserve' electrical usage. I have 2 computers and associated back-up drives on 24-hrs/day. Another 2 systems and/or Cintiq are on sometimes. My system also powers a Tier-3 Wifi distribution hub (250 Gbps) 24/7/365 on the roof which provides broadband internet to over 200 household in the valleys below. My state-of-the-art sound system is powered on about 8-12 hours/day. My guitar (and Skype) amp is on 6-8 hours/day. Several large fans and an evapo-cooler are running 24/7 for about 1/3 of the year. I have a HUGE chest freezer that is running most of the time in summer (but not in winter) ... and then there's water pumps, washing machine and lights, power tools, table saw, etc. NO effort whatsoever to 'conserve' except for maybe 5 to 7 days/year in 'deep' winter stormy periods.

    This time of year (near the equinoxes), even on overcast days, both charge controllers are in 'idle' (float mode) by about noon. On sunny days, the batteries are 'maxed' by 10AM. During 3/4 of the year, the vast majority of my loads are direct solar (no battery loads/usage/wear) except freezer and fans at night in summer.

    Bottomline - I couldn't be more pleased with PV solar unless it had been totally free - which it now is !!! (except about $12/month or so for battery replacement) Can't say the same for wind turbines, BTW - TOTAL waste of money despite being in a Class-5 (best possible) wind zone. In maybe 100 years, they might pay back the price of the wiring but never the cost of the 'turdines' or masts, etc. There is more energy in a standard Bic lighter than I get from both 500W turbines over an entire year. Seriously,

    Anyway - PV 'makes cents', is 'a-piece-of-cake' and a 'no brainer' - even if one is on the grid IMO. NTM, the piece-of mind that comes in the knowledge that when (not if) TSHTF, then I'll be 'rocking out' and 'jamming' - and with hot showers and cool breezes - as the 'civilized' world goes crazy(-ier) and tears itself asunder.

    IOW, just do it! ... whilst ye yet may
    Last edited by Mark McMurtry; 05-15-2017, 03:56 PM.
    "There are in fact two things, science and opinion: the former begets knowledge, the latter ignorance." ~ Hippocrates, "Law", 400 BCE


    • #3
      I have to agree Mark. I was recently tasked with developing a viable business plan for a Bitcoin mining operation (if such was possible). Bitcoin mining is an energy intensive operation, in fact energy cost is 97% of OpEx and the price they pay for it is the constraining factor that determines when miners are driven out of operation. So naturally I turned my attention to alternate energy sources to see if a competitive advantage could be gained that way.

      The overwhelming conclusion I reached was that solar is the most economical capex for a given energy output when done on a small scale. I even looked at using wood gasification to produce biochar (a profitable and very low capex exercise in itself) and various methods to convert the hundreds of KW of waste heat to electricity. Steam turbines, stirling engines etc. All of those technologies and a few others have potential, but they are not economically ready yet. One day when stirlings or home scale steam generators are mass produced they may outcompete solar but right now the economies of scale in the solar industry win hands down. It also has a big advantage in that it is a direct conversion from light to electrical energy. Almost all other energy sources require a conversion to mechanical energy in between which not only cost efficiency but complicates builds substantially.

      Having said that, if you've got a decent workshop (preferably with a small metal lathe) and some time on your hands there's an awful lot of fun to be had scavenging old parts and jamming them together in ways god didn't intend. As a proof of concept I once took an old whipper snipper engine (freely acquired from the dump) modified it ever so slightly with a valve then made a fitting that let me attach an air compressor to the spark plug port. The air compressor was to simulate steam pressure. Hey presto, when I hooked the drive shaft up an alternator (also rescued from the dump) and I had power. I can't recall how much, I think in the hundreds of watts though which isn't bad for a 40cc two stroke engine block I got for free... I'm quite sure I could have scavenged other parts to build some sort of steam boiler. I just would have needed a way to hook them up. That's where a metal lathe comes in handy. They're great for making that missing piece to get two system attached to each other. Anyway the point is if buying off the shelf gear then solar is almost the only way to go. But if you're that way inclined and willing to risk blowing yourself up there's lot of other options. If I had a natural source of energy on my block like a flowing creek or an endless source of biofuel (another type of battery for storing solar energy) I'd definitely be going down the DIY route.
      Last edited by Shadders; 05-15-2017, 05:50 PM.


      • #4
        Micro-hydro presses my buttons but, like you, I have no flowing creek...and I love small-scale steam and Stirling engines, but I lack the engineering facilities to make it cost solar for electricity and hot water is probably where we'll this stage.