This is why an ETS system works for me

[DanS26]

Thank you. Understood (I think). I suspect you did things and got costs most others would or could not do and have access to pricing most other would not. I'd also guess the 25 year life cycle also probably helps reduce the per kWh cost. Did you discount the inverter replacement costs back to present value ? Did you reduce any costs for future salvage value ?

Regards,

Actually there are credits I did not include.....such as SREC credits and tax benefits from depreciation since some of the system is farm related. And yes I did obtain good pricing on parts not generally available to the general public. But any true DIY'er knows these acquisition tricks with suppliers. In this day and age no one pays retail if you don't want to. It takes patience and willingness to research and asking for multiple quotes.

No, I did not discount the inverter replacement costs....the reason being is that I feel that costs will decrease and offset the rate of inflation thus in today's dollars the price will be equivalent. No salvage value......in 25 years I'll be dead and they will just bulldoze the ground mounts and rip the smoking inverters off the wall.

But based on my experience to date...I think the the 25 year life is doable. The Kyocera panels are very well made and the Fronius inverters run cool. But you never know.

Still, my payback is around 7.5 years and IRR is projected at 12.31%

[jflorey2]

An EV may work for commuters, but not for this retiree. Some days the Olds doesn't move, but then I might drive
across 3 or 4 states nonstop. My record is 1250 miles in 21 hours, no EV can do that.

Many could. 18 hours driving at 75mph, 4 charging stops at 45 minutes each, charge rate of 300-400mph, 250 miles per charge.

[J.P.M.]

First off I designed and constructed my grid tied solar system on my own time, thus I do not have any outside labor in the calculation. I sourced as many parts as I could locally getting the contractors discount (since they know and trust me). I over sized the system to twice my annual usage thus getting something like an economy of scale (like pallet pricing). I'm on a "net billing" plan so I could oversize (within reason up to 25 kW AC) without penalty. I added the cost of a couple of inverters in about year 12. I do my own maintenance and I took the 30% tax credit on my sunk costs. There's the numerator.


For the denominator I used PVWatts production estimate, which was adjusted to my actual system performance, over a 25 year system life derated at 0.71% per year over that life span.

The actual production cost based on the above is $0.0301086 per kWh.

Hoosier Energy that produces energy for my local REMC produces at $0.025 per kWh. They sell that production, including distribution and demand charges at $0.065 per kWh to my REMC. My REMC turns around and sells it to me at $0.105 per kWh retail. If I produce excess my REMC will buy it from me at $0.065 wholesale. I think it is a sweet deal.

When I was in the design phase of this project I knew I had to be a low cost producer. That was my driving force because I knew it would give me flexibility......do I sell my excess power or do I heat my water or heat my house? Actually I do all three but its my choice.

Thank you. Understood (I think). I suspect you did things and got costs most others would or could not do and have access to pricing most other would not. I'd also guess the 25 year life cycle also probably helps reduce the per kWh cost. Did you discount the inverter replacement costs back to present value ? Did you reduce any costs for future salvage value ?

Regards,

[bcroe]

Bruce, with a deal like that.....why would you not add to your solar plant and buy an EV? I know you're handy and could DIY.

An EV may work for commuters, but not for this retiree. Some days the Olds doesn't move, but then I might drive
across 3 or 4 states nonstop. My record is 1250 miles in 21 hours, no EV can do that. The gas engine does 19
mpg, but I put on a 28 gallon diesel tank with a gasoline pickup unit. Bruce

[DanS26]

My observation as well: most never think about energy at all, just the bills. Explaining it is useless,
because they aren't interested in thinking about it.

One thing about my size system, is the rules here give a one for one trade on KWH, no wholesale
vs retail. However, they never buy anything; its up to me to get it all back. Bruce Roe

Bruce, with a deal like that.....why would you not add to your solar plant and buy an EV? I know you're handy and could DIY.

[bcroe]

IMO only, most folks would come out ahead by spending most or all initial
time, effort and resources educating themselves about energy and how it's used.

My observation as well: most never think about energy at all, just the bills. Explaining it is useless,
because they aren't interested in thinking about it.

One thing about my size system, is the rules here give a one for one trade on KWH, no wholesale
vs retail. However, they never buy anything; its up to me to get it all back. Bruce Roe

[DanS26]

Not doubting your veracity, but I'd be interested to know the method you used to get the PV cost/MM BTU that low. That seems pretty close to or even less than what some POCOs call their avoided cost of energy.

The last time I calc'd it, my LCOE was about $0.18/kWh for the electricity generated from my array on a 12 yr. life cycle.

First off I designed and constructed my grid tied solar system on my own time, thus I do not have any outside labor in the calculation. I sourced as many parts as I could locally getting the contractors discount (since they know and trust me). I over sized the system to twice my annual usage thus getting something like an economy of scale (like pallet pricing). I'm on a "net billing" plan so I could oversize (within reason up to 25 kW AC) without penalty. I added the cost of a couple of inverters in about year 12. I do my own maintenance and I took the 30% tax credit on my sunk costs. There's the numerator.


For the denominator I used PVWatts production estimate, which was adjusted to my actual system performance, over a 25 year system life derated at 0.71% per year over that life span.

The actual production cost based on the above is $0.0301086 per kWh.

Hoosier Energy that produces energy for my local REMC produces at $0.025 per kWh. They sell that production, including distribution and demand charges at $0.065 per kWh to my REMC. My REMC turns around and sells it to me at $0.105 per kWh retail. If I produce excess my REMC will buy it from me at $0.065 wholesale. I think it is a sweet deal.

When I was in the design phase of this project I knew I had to be a low cost producer. That was my driving force because I knew it would give me flexibility......do I sell my excess power or do I heat my water or heat my house? Actually I do all three but its my choice.

[SunEagle]

Not doubting your veracity, but I'd be interested to know the method you used to get the PV cost/MM BTU that low. That seems pretty close to or even less than what some POCOs call their avoided cost of energy.

The last time I calc'd it, my LCOE was about $0.18/kWh for the electricity generated from my array on a 12 yr. life cycle.

I would expect the labor was free or DIY and the panels were purchased at wholesale prices.

[J.P.M.]

I have four sources of heat in my house.....wood, propane, grid electricity and PV power. I can pick and choose which heat source I want to use. To make my choice I weigh in a variety of factors.....cost, convenience, efficiency and comfort.

Wood at $65 per rick delivered is least costly at ~$5.20 per MMBtu is comfortable but it is very inconvenient and messy.

Propane at $0.879 per gallon (yes that is actual price I paid for summer fill up) is ~$10.43 per MMBtu is comfortable, convenient and, at least for now, somewhat affordable.

Grid electricity at $0.105 per kWh is ~$30.76 per MMBtu is comfortable and convenient but is very expensive to use as heat.

PV power at $0.03 per kWh (yes that is my actual production cost) is ~$8.82 per MMBtu is comfortable but somewhat inconvenient since I only heat two rooms with it through my ETS systems. But in those two rooms it is very efficient and cost effective.

So there you go....I use my ETS systems and supplement with propane for heat because at my age I like comfort and convenience. Its not rocket science.

Not doubting your veracity, but I'd be interested to know the method you used to get the PV cost/MM BTU that low. That seems pretty close to or even less than what some POCOs call their avoided cost of energy.

The last time I calc'd it, my LCOE was about $0.18/kWh for the electricity generated from my array on a 12 yr. life cycle.

[SunEagle]

No, or at least not just one. Just a few observations and thoughts on how to reduce an electric bill.

But since you seem to be curious, IMO only, most folks would come out ahead by spending most or all initial time, effort and resources educating themselves about energy and how it's used. Usually, from what I've seen, after getting real information - not from those with skin in the game - the more successful methods begin with some idea of defining the problem and setting goals, and then exploring ways to achieve those goals.

What I've usually seen for the better of than half of my day/day life since getting involved in energy matters (and what I read here as well a lot of the time) is what often looks like some headlong near panic fleeing from self induced high electric bills that address the symptoms (the high bills) and not the causes of those bills - those causes most often having their origins in ignorance about the ways energy is used and ways to reduce that use.

Then, unscrupulous peddlers use that ignorance to separate the unknowing from their money and sometimes, or maybe even often, make matters worse.

Call it arrogant, condescending or whatever as you wish, NOMB or care, but my semi educated guess is that if more folks knew some of want I think I might know about the subject, their bills would be a lot less, there'd be a lot fewer residential PV systems, and those that did exist would be a lot smaller and better designed.

So, formula - no. Observation and opinion - yes : Ignorance is the lock on the door leading to the goal of reduced bills. Real education is the key to more cost effective solutions, many of which have nothing to do with solar energy which, because, in reality, PV is about the most cost INeffective way to reduce an electric bill, and therefore, for many, even most situations, ought to be one if the last measures taken, if at all.

Take what you want of the above. Scrap the rest.

+1. Good observations.

[J.P.M.]

"I'd respectfully suggest better sizing methods during design,"

Got a formula? Or is this like pornography, "I know it when I see it"?

No, or at least not just one. Just a few observations and thoughts on how to reduce an electric bill.

But since you seem to be curious, IMO only, most folks would come out ahead by spending most or all initial time, effort and resources educating themselves about energy and how it's used. Usually, from what I've seen, after getting real information - not from those with skin in the game - the more successful methods begin with some idea of defining the problem and setting goals, and then exploring ways to achieve those goals.

What I've usually seen for the better of than half of my day/day life since getting involved in energy matters (and what I read here as well a lot of the time) is what often looks like some headlong near panic fleeing from self induced high electric bills that address the symptoms (the high bills) and not the causes of those bills - those causes most often having their origins in ignorance about the ways energy is used and ways to reduce that use.

Then, unscrupulous peddlers use that ignorance to separate the unknowing from their money and sometimes, or maybe even often, make matters worse.

Call it arrogant, condescending or whatever as you wish, NOMB or care, but my semi educated guess is that if more folks knew some of want I think I might know about the subject, their bills would be a lot less, there'd be a lot fewer residential PV systems, and those that did exist would be a lot smaller and better designed.

So, formula - no. Observation and opinion - yes : Ignorance is the lock on the door leading to the goal of reduced bills. Real education is the key to more cost effective solutions, many of which have nothing to do with solar energy which, because, in reality, PV is about the most cost INeffective way to reduce an electric bill, and therefore, for many, even most situations, ought to be one if the last measures taken, if at all.

Take what you want of the above. Scrap the rest.

[bcroe]

All true. The handyman store pipe insulation is warm to the touch, and I don't have any on
the 5/16" return line. I note the foam I put on garage doors doesn't feel cold to the touch at
all; maybe some of this could be grooved to fit over both the main pipe and the circulation
return line together? The length is nearly equal to the length of this noodle shaped ranch;
don't think increasing diameter is to my advantage. The day the circulator pump stopped,
I heard about it immediately. The temp is set low enough that a minimum of cold water
mixing is needed. Restricted shower heads are for people who waste too much time in
the shower, instead of getting on to other matters. Seems pretty silly when there might
be a pool on the property.

Most months temp control here is achieved by a fairly efficient heat pump; relatively
few days rely entirely on resistance heat. Of course a clean sheet approach suggests
insulate to the max; use a very efficient heating and cooling plant, and build the minimum
size solar plant. In reality the heat pump is relatively competitive with propane here, and
I have seen times when even resistance heat was only half the (manipulated) cost of
propane. And the smaller class PV system rules weren't the ones I wanted to be under.

Time wise, it doesn't take long to throw up a very capable PV solar system. It takes
longer to get a really good set of state-of-the-art heat pumps in place, and the full
insulation upgrade can run into many years and in some cases pretty big bucks. While
annual energy collection has been pretty consistent here, usage has varied hugely with
the weather; so much for "just right sizing".

Each will chose their own priorities, I have mine. Creature comforts will come first
without compromise. The idea of of supplying all home energy without burning any
kind of fuel on or off premises appeals to me. And minimize the number of utilities
I must connect to, each adds their overhead cost (recently observed to be growing
exponentially). The circulator will continue to run.

The PV system cost isn't a problem, and is giving lots better ROI than so many of
the things I see being bought everywhere. I own a lot of chain saws. Bruce Roe

[DanS26]

I have four sources of heat in my house.....wood, propane, grid electricity and PV power. I can pick and choose which heat source I want to use. To make my choice I weigh in a variety of factors.....cost, convenience, efficiency and comfort.

Wood at $65 per rick delivered is least costly at ~$5.20 per MMBtu is comfortable but it is very inconvenient and messy.

Propane at $0.879 per gallon (yes that is actual price I paid for summer fill up) is ~$10.43 per MMBtu is comfortable, convenient and, at least for now, somewhat affordable.

Grid electricity at $0.105 per kWh is ~$30.76 per MMBtu is comfortable and convenient but is very expensive to use as heat.

PV power at $0.03 per kWh (yes that is my actual production cost) is ~$8.82 per MMBtu is comfortable but somewhat inconvenient since I only heat two rooms with it through my ETS systems. But in those two rooms it is very efficient and cost effective.

So there you go....I use my ETS systems and supplement with propane for heat because at my age I like comfort and convenience. Its not rocket science.

[PNPmacnab]

"I'd respectfully suggest better sizing methods during design,"

Got a formula? Or is this like pornography, "I know it when I see it"?

[J.P.M.]

Almost intuitively obvious, isn't it? I saw the time constant change when the hot water circulator system (with
home brew control) was fully insulated. Also discovered that common pipe insulation might keep pipes from
sweating, but in fact performed very poorly as insulation. Haven't developed an improved insulation scheme yet.

One thing I never hear mentioned, is that the better a house is insulated (increasing the thermal time constant),
the less benefit there is from an automatic timer setback thermostat.

However my problem is getting good storage efficiency over 12 months, which directly drives my use of PV solar
collection/grid tie. Collection efficiency is low, but convenient, low maintenance, with 100% storage efficiency!

As for a microprocessor based commode, the theme here is the most simple and rugged system will fail least and
be easiest to fix. With all the plumbing repairs that come up, here there will be no micros involved. As it is, a lot of
extra shutoffs and unions are added to make it easier to isolate an area without whole house shutdown. Bruce Roe

You would think so, wouldn't you ? Unfortunately or otherwise, my experience in dealing with folks in such matters such matters is that common sense sometimes isn't so common.

On pipe insulation: In general, pipe insulation will seem less efficient than expected for several reasons. For 1 thing, pipe insulation is often relatively thin (~ 1/2") w/R values of about 2 or so, and often poorly applied. The air over bare pipe will have an R value of about one. Also, and of a bigger influence most of the time, is the fact that the ratio of surface area to contained volume of a pipe is, depending on length and dia. of pipe involved, something like 6 or 7 times larger than that of a right circular cylinder with the dia. equal to the height., meaning a lot more surface area to lose (or gain) heat through. Example: 100 ft. of 1" dia. tubing has the same approx. volume as a 10 5/8" dia. cylinder, 10 5/8" high ~ = 942 in.^3., but a surface area about 7 times as great ( ~ 3,770 in.^2 vs. ~ 532 in.^2) from which to transfer heat ~ 7 times faster to or from the contents. Partial solution: Get fatter pipe and 1" Armaflex insulation. Before that, if you're interested in hot (enough) water without too much $$cost, turn down the temp. settings, and/or get mixing valves at the tank, scrap any recirculation, get low flow faucets/heads and 1500 W spot heaters for boost at points of use.

True about set back thermostats, the higher the time constant, the less the interior temp. will change as f(time), but better insulation, and usually equally or more important in terms of economic return, better sealing, will always result in lower heat transfer with lower bills to show for it. The lower the building time constant, the more the bills will be lowered by a set back thermostat, those savings being governed by the RATE of change of temp. (2d derivative) as well the inside/outside temp. diff., but that's a bit of false economics - you might save 20% of a $200 HVAC bill with a set back thermostat and poor insulation, but only 5 % of a $100 HVAC bill in a well insulated building. I don't know if I'd insulate the building and then compare the cost of the setback thermostat against the 5 % savings, or do the setback thermostat before insulating because the payback on the thermostat is probably quicker and it costs less, and then insulate until the cost equaled the life cycle savings over however long a time period I chose. I'd probably do both, with the setback thermostat first.

For that matter, high insulation levels mean less savings per degree of setback, but no one is saying lowering thermostats in the winter or raising them in the summer is still not a good idea. That cost (changing thermostat settings) is still zero with an immediate payback - just that more insulation is less cost effective as a result of lower (higher) thermostat settings.

Effectively using or considering the grid as a storage medium via net metering is certainly one of the considerations and ways to look at net metering. But in doing so, the costs may need to take some account of the way seasonal storage system costs are accounted for. I'm not quite sure how the accounting would work for that, especially when assigning a value to the convenience and maintenance, but I'm quite sure it's possible.

Still, and one aspect I'm pretty sure of, is that using electricity to supply most or all of the heat to a residence via resistance heating elements when other means of heating are available is almost always more costly whether or not thermal storage is involved. In such cases, with the possible exception of some spot temp. boosting, using electricity to heat things is still like cutting butter with a chain saw. Use fossil fuels. To those who say it's better to use the excess PV electricity than the paultry sum the POCOs pay for excess generation, I'd respectfully suggest better sizing methods during design, and less oversizing up front is a lot better in the cost effectiveness dept.

I'm with you on KISS for commodes. Life is complicated enough. Somehow, high tech crappers seem like an invasion of my privacy, but opinions vary.