Image Credit: All photos: Paul Kuenn
Image Credit: All photos: Paul Kuenn Radiant floor tubing will carry water heated by solar collectors on the roof, with some backup help from a gas-fired water heater. The author's ultimate goal is to eliminate fossil fuels. With PEX tubing installed beneath the subfloor, the joists bays could be insulated with blown-in cellulose.
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Hot water for a radiant floor distribution system is routed through this manifold.More Guest Blogs
This is the second in a series of blogs by Paul Kuenn describing energy-efficiency improvements to his home in Appleton, Wisconsin. The first appeared here as One Man’s Quest for Energy Independence — Part 1.
In 2010, a brochure arrived from our utility, We Energies, stating it had done enough for the environment and solar credits would be drastically reduced. We Energy said it had met its 1% goal in wind and solar.
We were locked into a 10-year contract that did not permit me to either increase or decrease my solar output, with any electricity going to the grid earning 22.5 cents per kilowatt hour, the same rate we would pay for power used between 7 a.m. and 7 p.m.
My existing system could not be altered, but I decided to add another 2 kW in capacity that would not be grid-tied but connected to battery storage instead. With our original, grid-tied panels, we’d been getting checks from the utility of between $12 and $20 each month from February through October, and paying bills of between $15 and $20 in winter. I thought an extra 2 kW would put us in the black.
It was back to our engineer friend for advice and some drawings. We’d need to add five new panels to the garage roof, which already carried eight panels, and another five modules on the house roof. The 10 new 215-watt panels would produce 2.15 kW at peak. We also decided to add three additional solar thermal panels for floor heating.
I was now working as a fire apparatus consultant and had to work around that busy schedule. Most of the next year and a half would be devoted to working late into the night. Many evening building adventures would be accomplished by lamplight.
The goal is no fossil fuels
A new building permit ($35) and electrical solar permit ($35) with a two-year deadline was as easy as filling out an application. The city of Appleton was catching on. Obviously, things had changed. Our inspector had been sent for training as PV installations grew in number around the city. However, he told me up front to work with him on my new project as it would be the first battery-based system he had seen.
We were already biking to work every day, and I wanted to rid ourselves completely of fossil fuel. The 1988 furnace had to go. We had an unfinished basement with exposed floor joists, which provided the opportunity for in-floor radiant heating with PEX tubing. I would expand the hot water system to three 4-foot by 8-foot collectors with 130 gallons of storage (one 80-gallon tank plus the original domestic hot water tank of 50 gallons).
My new engineering plans included sistering new 2x8s alongside the existing rafters to handle the weight of the new PV and solar thermal panels. Hip roofs are nearly “bomb proof” but it’s hard to predict what a 1960 2×8 can handle. I added 3/4-inch plywood decking immediately under the new array where the Quikmount solar racking feet would go to hold the collector and PV array rack legs and 2×6 blocking between doubled rafters so we wouldn’t have to worry about splitting any rafters. I didn’t have the room for the collectors and a fully tilted PV array so I had to settle with a fixed tilt.
In northern latitudes we would rather have a tilt rack so the directness of sunlight is aimed 90 degrees to the panel; a 45-degree tilt at our latitude of 45 gives the best all-around performance. But a tiltable rack would have allowed me to adjust the panels and absorb more sun in the winter when it is as low as 23 degrees off the horizon.
In this case, a 43-degree tilt would keep the PV array sitting in front of the hot water solar collectors from shading the collector bottoms in the winter when the sun was at its lowest position and when you want the hottest liquid possible. To keep PV from shading the collectors and maintain the three feet of required roof access around the array (good idea if there was ever a fire) I had to be very careful in my positioning with so little south-facing roof space. Riding the bike to work over the years had not only allowed me to save for this project but also to have a clear mind to strategize my nightly building plans.
Adding radiant-floor heat
This was late in the year so I planned to start with the floor heating and end the next season with the added PV array in 2011. It took the patience of a few friends and willing spouse to get the under-floor tubing in place and insulated.
One collector came damaged so we would start the winter with three collectors and see how it would do. The fourth would eventually show up the next spring due to model size changes and a great search for a matching panel with the staff at Heliodyne.
A very long Thanksgiving weekend was spent blowing cellulose into the floor joist bays. Not much sleep the first night as near the end of the basement job, we found that I had forgotten to tape over a few of the old registers upstairs. What a mess!
Another early snow and excellent cross-country ski season followed. We loved the feel of warm feet on the floor. Unfortunately, until I worked out the bugs of the system, we had a few cold showers. An air-source AirTap heat pump water heater was added to supply heat to the domestic hot water storage tank after I dismantled the gas-fired on-demand unit. We attempted using this one heat pump to back up the floor heating 80-gallon tank.
The AirTap worked overtime when no solar heating was available and its coils frosted up, so we reused the previously removed and unsold on-demand heater to back up the radiant floor system and planned on moving the AirTap to the domestic hot water (DHW) storage tank. I was trying not to use fossil fuel. We had to quickly redraw my plan. Luckily Rob was game, as usual. We tweaked the system enough to get us through the winter – sans cold showers.
We moved the AirTap to the DHW tank and re-installed the Rinnai between the floor heating tank and Viega floor heating manifold. If the temperature of the water in the floor tank was below 100°F, the Rinnai would kick in and heat the water circulating through the PEX tubing directly. I hated the thought of one more winter using natural gas, but at this cold late date I did not have much choice.
In my next blog installment, I’ll discuss further revisions to the hot water system.
The third installment of Paul Kuenn’s blog series is here: One Man’s Quest for Energy Independence — Part 3.
Paul Kuenn lives in Appleton, Wisconsin. He is a past owner of a climbing school and guide service who has studied environmentally sound building practices, along with plumbing and electrical. He’s a graduate of solar thermal and photovoltaic installation programs at the Midwest Renewable Energy Association. In the last eight years Paul also has worked as a third-party inspector for fire and rescue apparatus. In his spare time, he helps homeowners use the least amount of fossil fuel energy possible.
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31 Comments
Energy Independence
So how much have you spent so far? How many hours of labor?
Time is money
Over such a span of time and changing commitments, I never even thought of keeping an hour log. Suffice it to say, I couldn't afford to have anyone do the labor for me. As a one man show 98% of the time, I worked 3-5 hours every night after work from Mid March to end of November with about 2 weekends to play away each month. Now times that by 3 for the years in which I did most of the work. We did squeeze in at least 3 weeks of vacation each summer somehow.
As for the cost, keep in mind this was when PV 190w-215w modules ran $600-985 a pop on sale. Very different now. As of today, I can get US made 250w modules for $185. Balance of system components have not really changed in price.
The Grid tie system in 2007 cost $9000 with credits deducted. The larger 2011 48V, 3600w battery based system was about $10,000. On the solar thermal side, I purchased my solar panels 1 year before I needed them and before the price of copper soared. The completed DHW & floor heating system cost about $16,000. Again, I'm a thrift so I watched for sales and took my time collecting all that was needed.
So this is what we spent from 2006-2014 on solar PV and thermal. The house insulation retrofit cost about $8000. The majority of that was the closed cell foam job (blog coming soon...) and the heat recovery ventilation system.
This is all a good reason from starting from scratch, but we liked our location and loved our yard enough not to want to move. We also hate waste! Wait to see what comes in the rest of the blog. This was nothing so far...
I am enjoying the series
The series is a good read so far. It is about a man working towards the light. We need to grope our way through this labyrinth of ever changing environmental and energy information. We can not look down from a high tower of clarity and knowledge, we find ourselves sweating in a dimly lit attic with a dust mask on wondering if its worth it, only to feel triumphant and wise after the shower and a lemonade on the porch. In other words, although the story is about a specific man doing specific things, it has larger resonances. I wait with bated breath for the next installment: "what will he discover? what blunder will he have to live with? where will he succeed?"
Lots of organic lemonade!
Thanks Ven!
Mostly it was the grape juice though. I cold press grapes in October and jar the juice from my vines along the S. side of the garage. Barely visible in the top photo, I have an arbor(leafy tunnel to the back yard) with 4, 25 year old vines growing right to the bottom of the original PV array. This creates a cooling tower. Cold air from the shade of the grape arbor is sucked up from the heat rising behind the array. Not only does it create the gentle breeze grapes love, it also cools down the pv panels on the hottest days.
Headlines: "Grapes cool both PV and Man"
Cool. Those plant have so many uses don't they? They may be competing for the spot as "man's best friend". (Don't tell Rover) I myself use 70 large indoor plants to filter and oxgenate the air, having read NASA recommendations about the best plants to live with in a space colony!
Wow!
By my quick accounting of what you listed you've spent and the labor you've put in I calculate you've got about $94,000.00 at a minimum so far. I didn't include the insulation or the credit. How much power does your house use every month that would justify that expenditure?
Time well spent
That's not the point Rick!
When you get a near dilapidated house really cheap, rebuild it on your own time you cannot add those dollars. I don't recall saying anyone should go out and have someone do this for them. This is a DIY blog for sure. I had over a hundred visitors come and see what was happening, many were contractors who loved some of the ideas. The point was a very nice home, super warm in our long winters AND, as I retire I will never need to pay the ugly utility companies that want to pollute, actually try to kill us and rake us across the coals. There's no way I could have built something this nice from scratch in this short of time. Our 2014 total utility bill added up to $240 and it was the coldest in history. Now, minus the credit from overproducing (yes, with only a 4KW system) we only had to pay out ... $78, not too shabby! That's how I choose to live.
No way we would ever move, not when a 20 minute walk or 8 minute bike ride gets us to LU to enjoy free concerts from the world's best musicians and I can start xc skiing into the park a block away.
Cheers,
PK
How so?
How can it not be the point if your goal is energy conservation? You've used at least $94,000.00 plus interest worth of energy to build a system that will never save $94,000.00 in power. Not only that but you've no doubt taken tax credits that force your friends and neighbors to pay for a portion of your system. You've also have taken advantage of the power company through laws that force them to buy power from you at retail. How could that possibly work if everyone did it?
As for your electric bills, if you had invested the money you've spent so far you'd be making $476.00 a month in interest which I'm sure is more than your electric bill would be. I have no issue with what you're doing if that's how you choose to spend your money, some guys play golf or fish, but don't kid yourself that your electricity is or ever will be free or cheap.
Reply to Rick Parker
Oh that poor, poor power company. How could you take advantage of that poor company, Paul? They are helpless orphans generating power by walking on treadmills and the bad, bad government has forced them with laws to let you sell power to them.
And not only that. You have "forced" your neighbors to pay for your system! Did you use a gun Paul? Or did that same government rough up your neighbors for you?
Needless to say, Rick, I am being sarcastic. Your take on this is quite what?...Republican or what...no .... Libertarian. That's it, libertarian. Quite the philosophy that, but I suppose I just don't understand it.
M ath
It's math, plain and simple. Either this system creates power more cheaply then grid power or it doesn't. If it doesn't then there is nothing green about it. That you have to resort to sarcasm and name calling rather than use facts to show how I'm wrong proves that you don't have any facts at your disposal.
Math isn't everything
Rick-Don't forget to apply a value to the tremendous satisfaction Paul must justifiably feel by creating a comfortable and efficient home for his family.
Doing stuff yourself, even if it takes longer that hiring a professional, isn't a waste of time or money, nor is it necessarily inefficient. What else would Paul have been doing if he wasn't working on his house? Probably not earning money so he could hire someone to do the work.
I cook dinner, build cabinets and brush my own teeth. I guess I could hire someone for those tasks, but with the time I'd save, I probably wouldn't be doing much anyway.
Remember Thoreau's hike to Fitchburg?
Response to Stephen Sheehy
Stephen,
My guess is that Rick isn't questioning whether Paul Kuenn should perform his own repairs or remodeling at his house (or, for that matter, whether you should brush your own teeth). I think that Rick is questioning the cost of this deep-energy retrofit -- the materials cost as well as the time investment. It's a valid question.
For the purpose of this discussion, maybe we can stipulate that Paul's work wasn't cost-effective. There may be other justifications for the work -- for example, lowering one's carbon footprint, achieving greater comfort, or achieving the satisfaction of low energy bills. That said, not everyone will agree that Paul's approach makes sense, and questioning the cost-effectiveness of the work is certainly valid.
Stephen,You actually brush
Stephen,
You actually brush your own teeth? I pay someone for that. In a former life he was a veterinarian. It works well. Many of us libertarians require a good vet to stay in top form.
Stephen
That's a valid point and I hadn't discounted it at all. I understand and even admire Paul for his commitment to his goal. I'm a GC but was a do-it-yourselfer long before that. I've done many DIY jobs at home strictly for the satisfaction of a job well done rather than for a financial payback. However, if you're spending$2.00 to create $1.00 in value there is no conservation involved.
Martin
Exactly. I'm not anti-solar at all. I truly wish a technology would come along that would make it make financial sense to me. Why wouldn't I or anyone else want to save money on my power bill? My point is that Paul could have taken a second job and with the money from that paid a commercial solar company to install his system and saved $30 to $40,000.00.
reply to Martin and Rick
I don't agree that doing work on your own house isn't cost effective. Most people have more time than money and using that time to improve one's home isn't a waste of time or money.
Not everyone has the option to take a second job. While spending $94000 might not have been the best use of Paul's money, that's not what happened. He "spent" time, not money, for the most part.
This isn't like the issue we often discuss about putting more pv on the roof instead of more foam under the slab.
Reply to Rick
Your comment had little to do with "math" pure and simple. If it had, I also would have questioned your calculation of the return on the "$94,000". However, you used the words "taking advantage of" and "force your friends and neighbors". Your tone is one of moral outrage. And is frankly some sort of political view or something. You make it sound like a scam, and are impugning the character of Paul. Get it? That is just over the top and needed to be pointed out.
Ven
I get it that it's an emotional issue for you. It's not for me, it's just math.
Everyone who has solar and is receiving a feed in rate is taking advantage of other rate payers. Like any business the power company has to make a profit or go out of business. No business can make a profit buying their product for retail and selling for retail. Receiving a tax credit for a solar installation doesn't change the price of the system at all, it just forces the difference on tax payers.
Imagine if you will a community of 100 homes. Those homes are served by a power company that only serves those 100 homes. Now 1 resident install solar. The other 99 now have a small rate increase to cover the solar houses electric bill which is now essentially free because of the feed in rate. The other 99 hardly notice the small rate increase and life goes on. But over the next year 9 other residents install solar. Now rates go up dramatically because 10 homes aren't paying for power. It looks so good that pretty soon all 100 residents have solar and aren't paying power bills. They still have to have the grid because the sun doesn't always shine and the houses still need heat and lights. Someone has to pay to keep the generators running, replace broken poles and restring snapped wires. Who do you think is going to pay for that?
the economics of solar
Rick: the net metering deal varies from state to state. But for the most part, states which have studied the issue have concluded that the grid (and users of it) get a net benefit from rooftop solar. Maine's Public Utility Commission determined that my pv generated power is "worth" a lot more than I get paid for it. One benefit is the avoided cost of peak power that can far exceed the average retail price. Another is the public benefit of each kwh produced by solar instead of by the burning of fossil fuel.
Finally, we also pay a monthly fee to the company that owns the local grid. In Maine, it's $11.51 per month, without regard to how much you put in to the grid or take out. That's about 1.5 ¢ per kwh for me.
PV owners are paying MORE than their fair share for the grid!
Very few rooftop PV systems take the house to Net Zero electricity, and even if they did, they have reduced the grid infrastructure costs for all other ratepayers on their side of the substation by freeing up grid capacity for for others during demand peaks, and deferring the peak demand to a later part of the day.
The folks who are screwing the other ratepayers on the infrastructure charges are those with 8 tons of air conditioning that they turn on when they get home from work, rather than a 2 ton system that ran during the day. The infrastructure needed to support those loads are well above the average ratepayer, but if they're only charged for the grid on a flat per kwh basis it's a significant cross-subsidy. And, since that pattern of use increase the total grid demand peak, it drives up the wholesale price of peak power, again, a cross subsidy if only paying a flat rate.
Demand charges and tiered rates are better applied to the power gulpers (even at the same total energy use) rather than the PV owners who are lowering the wholesale price of power and the total grid infrastructure requirements for the ratepayers at large. It's simply not true that the grid size and cost is the same, only with fewer kwh to spread it among when PV goes on the local grid. The cost of the grid maintenance goes down, as does the need for grid capacity upgrades. That can be costly to an investor owned utility if their profits are made primarily on the guaranteed return on capital for grid infrastructure upgrades, but for the ratepayers it's a net win.
There is nothing holy about the utility business models of the past century. They served well for getting power to everyone cost-effectively when there was substantial economies of scale. The economy of scale of PV just isn't there in the same way that it is for gigawatt coal plants, heavy hydro, or nukes. Distributed PV makes the grid more reliable, not less, and the utility business models need to change, rather than simply competing (unfairly, as a protected regulated monopoly) against behind the meter generation or storage assets.
Nope
Once again, it's math. The cost of any system, PV, wind, gas turbine, you name it is a reflection of the energy required to build it. Just because your PV panels were built in China doesn't mean there was no energy coats involved. The aluminum had to be mined and smelted, the glass made, the cells material mined and grown, the workers ride buses to work, all those things go into the cost of the panel. A PV system in Wisconsin with a capacity factor of what, maybe %12 to 15%, that cost $94,000.00 will never, ever create $94,000.00 worth of electricity.
Lets do the math. Paul has 10 KW on his roof. There are 8760 hours in a year which means his panels have the potential of producing 87,600 kw per year. But since they only produce power 15% of the time they really only produce 13,140 kw. At a rate of 22.5 cents per kilowatt that comes to $2,956.00 annually. Principle and interest on $94,000.00 comes to $5,712.00 annually, or a difference of $2,746.00 annually that Paul has to earn. At the average American wage of $20.00 that means 137 hours of work devoted to paying his real electric bill. How is that energy conversation or green?
I live in sunny south Florida where solar at least has the potential to work but the solar companies and the government still have to pay people to install solar and not many bite even at that. How many successful products do you know of that have to be subsidized? If solar PV was as great as you all claim every government office, every shopping center, every home would be covered with PV panels, but they aren't because you can't overcome the math.
Rick
"How many successful products do you know of that have to be subsidized?"
Off the top of my head: The automobile, any house in the suburbs, much of North American agriculture...
Really?
But still no answers to the math huh?
math
Just because you concluded that he spent $ 94000 doesn't make it so. In addition, you conclude that whatever he spent in time and money went entirely to pv, which isn't the case. He did a bunch of other stuff.
My real world 2015 example: 6.6kw system cost $22000. Expected production is 8000 kwh per year. At .15 per kwh that's $1200 per year or better than 5%. At your .225, that 8000 kwh yields $1800 per year, or better than 8%. These are unsubsidized numbers.
In sunny Florida, your production would be better than mine in Maine.
If you are paying .225, and don't install pv, you need to work on your math skills.
Oh, come on.
Rick, you need to face facts. The reason all of us are on the opposing side of your argument, and yet still are not going into the mathematical minutia that you have brought up, is for one reason and one reason only. All of your arguments about our subsidizing PV can be applied to virtually all products used in a capitalist society, not just PV. It can be applied to roads and all the infrastructure within any country for manufacture and assembly and transportation of goods and services. All those things have a worth that society assumes have a balance of cost and benefit. Most of them balance out between the two has having a net of zero. There is nothing leftover after balancing the cost and benefit.
After everything is balanced out according to your theory about PV installation - that would mean the money from the green jobs created, the material and assembly costs, and the transportation and installation costs that value is assessed at zero. This is using the same standard you are applying to everything else produced in the world. There is no difference.
Oh, wait, there is a difference. With PV that is not true. After all the plusses and minuses are balanced out after the final product is installed on roofs around the country there actually is something left over. That is the power being pumped out of the PV panels day in and day out for probably a minimum of 30 years. No manual labor or material cost is required for those 30 years. No transportation costs are involved in transporting materials or goods for those thirty years. Yet power is still being pumped out and can actually be used to build and support and enhance the lives of everyone.
Rick, who are you kidding? Personally I think its yourself. You sure haven't convinced many here.
Stephen
It's not my 22.5 cents, that s from Paul's blog as he states that what he pays. I pay 14 cents.
Eric- Look, I have n o problem with you kidding yourself, it's your money, spend it where you like. Just don't pretend it involves energy conversation or green energy. You, Stephen, Paul, everyone with a PV array is just as dependent on the grid as I am. You're not using any of the power that comes off your roof. It all feeds into the grid and your house uses the grid power just like everyone else. The difference is that you have a very expensive, very inefficient generator on your roof that pays you back some of what you spend on power. If you had to sell your power to the power company at wholesale like all other generators do at 4 cents a kw the pretext that solar works would be gone in a day. Do a Google search on what happened in Germany or Spain when they cut the feed in tariff in half.
You all seem to hate the power company for some reason so step up and disconnect your house from the grid. Get down where the rubber hits the road and show the world that solar can compete with the power company. But of course none of you will.
Distributed power has more value than remote central power.
Every independent analysis on the valuation of distributed PV demonstrates that it has more value than wholesale centralized power, since it lowers the cost of the grid infrastructure and frees up peak capacity. As more & more distributed PV goes onto the grid, the marginal value of the next kw of PV goes down, and eventually (at a saturation rate more than 10x the current US implemenation) it goes beyond break-even, and begins to impart a (relatively small) cost.
According to NREL estimates only about 25% of US residential roofops are suitable for solar, and if ALL of those roofs were covered in panels there would be a net cost to non-solar ratepayers in SOME neighborhoods. But by the time those levels are reached it's likely that there will be sufficient electric cars on the grid to stabilize the output of distributed PV. At the moment the only part of the US where PV may be approaching the problem point is some neighborhoods in Oahu. In these heavily saturated neighborhoods there is backfeeding onto the grid (the PV output on the neighborhood feeder line exceeds the total neighborhood load on some sunny days), but while grid perturbations were initially blamed on excess solar, the second-by-second data being uploaded by one inverter manufacturer's equipment in those areas analyzed by a third party showed that the PV was stablizing rather than causing the problems, and that with a remote software update to the inverters to give it a longer ride-through capability that they could stabilize those feeders even better.
One consequence to the other ratepayers was that the utility did not have to add more equipment to fix the problem. So, maybe when the mid-day production is 250% of the mid-day load there may have to be equipment changes on the grid to deal with it, but it may be cheaper for the non-solar ratepayers to just subsidize electric vehicles or residential scale batteries in those neighborhoods to deal with it.
haha!
Electric cars ! How's that working out so far? The only successful electric car in America is a hot rod rich mans play toy that has to be subsidized to the buyer to the tune of nearly $20,000.00. Elon Musk isn't in the car business, he's in the subsidy business. Other than Tesla nobody is buying electric cars. Do you drive one?
Do you have solar on your house? If you do what did it cost? Not what did you pay, what it cost. If you don't why not?
Please scroll up and address my scenario of the 100 homes community.
Response to Rick Parker
Rick,
Q. "Do you have solar on your house?"
A. Yes.
Q. "If you do what did it cost? Not what did you pay, what it cost."
A. No subsidies except for my last purchase ($1,000 of used modules that were eligible for a 30% tax credit). The other modules probably cost between $3,800 and $4,800. Not connected to the grid.
The same PV modules would be much cheaper if purchased today.
Ven, Dana and Rick and Eric, great discussion
Sometimes I feel like I am learning master degree level education credits here at GBA.
I am almost always able to see all sides of a discussion. And this one has IMO truth in all directions and in all points.
On a side note... think about this... we are observing life... and the creation forces of the universe... as we observe.... nature... then man... then man and fire... for light and energy... wood burned then whales burned... then dinosaurs... and now sun burned fusion from a distant source... the youth of the grid... the teenage years... the adult years... the senior citizen years soon coming for "the evil grid" which, come on now... we do love switching on power... I do!! Gonna jump in my F350 turbo diesel and blow some soot out now... as I burn some rubber... I so want a Tesla... they stopped in our area for a drive... try one... you'll want to buy one so bad... you'll ask your kid to fund his own college years so dad can go like hell on the roads... in a "green, electric, machine!"
Elon Musk is my ultimate hero and genius extraordinaire. Jobs too... Bill Gates... hate the guy... worst code writer ever to write a line of code.
Merry Christmas you crazy Christians...
aj
Happy Solstice!
Thanks for jumping in AJ!
I hope all can just let this go now, too many pages. Anyone who asks the question of why I did what I did would never understand the answer. All the unpaid voluntary rescue/EMS I did. Hmmm...Should have just let them all die knowing they were just riding the shirt tail of the system. Sorry I must go now and prep. Have to get ready to dance naked around the fire next Monday. Guinness for Strength!
Let's all just enjoy a sunnier tomorrow,
PK
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