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When you've confused "per kWh cost" with "energy to the house delivery costs," this sort of stuff sounds good on paper, but it doesn't fundamentally solve the p
by Syonyk 4y ago
When you've confused "per kWh cost" with "energy to the house delivery costs," this sort of stuff sounds good on paper, but it doesn't fundamentally solve the problem that in the winter, homes use a lot more energy than they can generate, and in the spring/fall, they will generate a lot more energy than they need.
I've got a large ground mount solar install I put in a few years ago (15.9kW nameplate, though mostly east-west facing panels so a bit less annual production than you'd expect, just more "sunup to sundown" production), and it's been a chilly winter, so with an air source heat pump and keeping the house fairly cool, I'm still net +4MWh from the grid in the last 4 months.
Meanwhile, when it warms up a bit more, I'm generating 10x what the house uses during spring/fall mornings (10+ kW production on a sub-1kW house draw for long periods of the day). It's not a big deal with only a few people on the grid, but if every house were doing this, it would be a very big problem for grid stability.
I've also got experience with the off-grid lifestyle, as my office is 100% off-grid/standalone, and I don't pretend that system is cheap. Just neat. And even with 5kW of solar hung for a ~100 sq ft shed, I still need propane or a generator in the winter every now and then to keep things sane in here.
- ajross 4y ago> it doesn't fundamentally solve the problem that [...] Is that the "fundamental" problem being solved, though? Or is it just an externality that needs to be addressed? It seems like the "fundamental" problem here is trying to maximize deployment of renewable generation, and that construction like this is a great step in that direction. (Not the least of which because it pushes the investment required onto consumers willing to bear the costs, and "generates jobs" in the process. Siting a new wind farm is a ton more complicated, and let's not even talk about the difficulty of installing a scratch-built reactor.) I mean, it's true, that at the end of the day home energy generation is just PV solar, and PV solar doesn't behave like gas plants and that needs to be addressed at the grid level. But that's not an argument against PV solar, it's just an engineering problem.
- Syonyk 4y ago> But that's not an argument against PV solar... It can certainly be an argument against residential rooftop solar. In general, "industrial solar" (ground mount, high voltage strings, single axis trackers) is sub-$1/W installed. Residential rooftop solar is still $2.50-$4/W depending on where you are, because it has quite a few additional requirements (per-panel rapid shutdown in NEC 2017, various other requirements on the panel and interconnects that add cost), and, often, poor siting from partial shading reasons (chimneys, vent stacks, trees, other bits of roof, etc). I don't mind making homes more suited to solar (oversize the main busbar with a "solar ready" panel, route conduit up to the roof, require all vent stacks be on the north side of the roof), but it's a rather uncontrolled solution that's of limited "actually solving the problem" use. Low levels of penetration are easy to deal with, higher levels start to get really hard, when you've got whole subdivisions shifting from "lots of production" to "lots of consumption" as clouds go over. Or, we get used to less reliable, more intermittent energy again, and a lot of the problems go away. Just, that generates other problems. The power grid is a lot more fragile than most people assume.
- ajross 4y ago> Low levels of penetration are easy to deal with, higher levels start to get really hard Well, yeah. So pick the low hanging fruit and sell it to the FAANG hippies. I still fail to see the problem here. No one is promoting rooftop solar as a one-stop-shop trip to renewable utopia, just as a effective and immediately deployable generation mechanism in a regulatory environment not well-suited to agile and rapid solutions of any kind. If we get to the point where the hippies are buying up all the panels and the grid solutions can't get them cheap enough, that's the time to start complaining. Not now.
- coffeebeqn 4y agoThat’s solvable by batteries. Of course there are tradeoffs like extra cost
- makomk 4y agoIt's the fundamental problem that needs solving in order to achieve what this announcement claims is the ultimate end goal of all this - a "net-zero carbon economy" for the country as a whole - and it has been the fundamental obstacle to achieving this for decades now. So long as this problem remains unsolved, no amount of supposedly zero energy homes will ever get the country as a whole to that goal because they're still reliant on selling excess energy to the remaining "non zero energy" parts of the country in the summer and buying energy back from fossil fuel plants in the winter.
- ajross 4y agoSo.. you're saying this specific technology can only get us 60-70%[1] of the way to the "ultimate end goal". Ergo... it shouldn't be deployed and we should whine about it on HN? No, that's silly. Build the panels. Build the solar. Fix the externalities, but absolutely pick the low hanging fruit. Every panel on a hippie's home means less total joules needed elsewhere. To be blunt: the kind of argumentation you engage in is absolutely toxic, and HN is awash in it. Engineers love to scream about perfect solutions, but real engineering is about tradeoffs. And folks here are absolutely terrible, just really, genuinely shit-tier, at discussing them rationally. [1] Depending on locale, obviously. In e.g. Arizona it's probably much closer to 80-90%
- antisthenes 4y agoOnce use cases like yours become more common (e.g. 4MWh surplus), industries will adjust and buy surplus power from homeowners like you, and the nation as a whole will spend less time and effort on maintaining the grid and power plants that generate electricity. We will be able to run power-hungry industries (e.g. steel-aluminum/smelting) for very little cost. > And even with 5kW of solar hung for a ~100 sq ft shed, I still need propane or a generator in the winter every now and then to keep things sane in here. What about a large thermal mass wood/pellet stove? There's plenty of wood waste floating around that could heat a small house/shed in the couple of winter months when the solar panels don't do the job.
- Syonyk 4y agoWrong way. The house has pulled an extra 4MWh from the grid during the winter months (and pushes more than that back during the rest of the year). I'm past net zero on an annual basis, but that doesn't mean that even a large array is able to cover my energy needs in the winter few months. I'm grandfathered into an arrangement where I pay my $5/mo and get unlimited net metering, but it's not remotely reasonable to pretend that I'm not heavily using the grid overnight, in the winter, etc.
- eppp 4y agoYou still have to maintain the grid for others to buy it and to balance it. The maintenance costs of the grid are going no where but up. More usage, more right of way, more towers, more wire, more labor.
- jonfw 4y agoIf we expect industry to take up the excess, than either 1. that industry will only operate according to the weather or 2. We'll still need some variable power generation that can be switched on when wind or solar isn't producing enough
- Symbiote 4y agoA few industrial users can weather changes in supply, with notice of the expected price in advance. The aluminium smelter can heat to x+250°, let things cool to x° while people cook their evening meal, then heat up again afterwards. A large supermarket chain can set their refrigerators to 5°, but by allowing the range to move between 3° and 7° can save significant power. (One of the big British supermarkets already does this.)
- eppp 4y agoI have been toying with the idea of buying used panels in bulk and doing the same, but the payoff just isnt there at the current battery price. What kind of frame did you install to mount the panels? I have tons of room for ground mount and would love to do it diy as soon as the costs line up.
- Syonyk 4y agoMy system is grid tie, because the local plans review process and I didn't see eye-to-eye on batteries. I have a solar power trailer for backup power. https://www.sevarg.net/tag/solar2020/ https://www.sevarg.net/tag/solar2020/ documents the build. My frames are timber, though a neighbor built a very similar system with metal frames and 72 cell panels, and got his costs down quite a bit further - he's around $1/W installed, mine was somewhat higher at about $1.50/W (more expensive panels and a good bit more expensive frame setup). If you can weld, and find used pipe to build your frames with, you should be able to do sub-$1/W for a DIY install.
- AdrianB1 4y agoNo welding is needed, you can use metal clamps to hold the pipes together. I have my panels on metal structure with no welding, I used bolts for joins.
- Syonyk 4y agoYes, but the clamps I've found designed for that sort of use are quite expensive, and add a substantial margin to the project cost - and they're not needed if you can weld it up, or have someone else weld it up. As I understand NEC from talking to various people and reading quite a bit of it myself, someone else can do the frames for a homeowner installed solar project, but "rails and up" has to either be the homeowner or a licensed electrician, because the rails are typically considered part of the grounding system and therefore electrical work. In any case, costs doing it yourself are far, far lower than paying someone else to do it. And ground mount is an awful lot nicer to work with than roof mount.
- anonuser123456 4y agoSounds like you need a geothermal ground loop.
- Syonyk 4y agoI live on what can be reasonably approximated as a "pile of rocks." It's fairly thin dirt on top of a lot of basalt. I've considered it, but the cost to install such a unit is quite staggering, before I buy a backhoe to install it. I'll consider one of those if I have to replace my unit at some point, but I'm far more interested in adding simple solar thermal collectors to directly add energy from the sun on the partly cloudy or clear days we have, vs ripping up half an acre of rock to put the loops in, or figuring out where I can punch another well for heat exchange.
- londons_explore 4y agoThis isn't a problem as long as your grid does dynamic minute by minute pricing. When the price of power drops to zero in the spring/fall, you can be sure there will be plenty of people lapping it up to smelt aluminium, make glass, make steel, make cement, liquify air, make hydrogen, etc. When the price of power is high in the winter, companies will swoop in with gas turbines, power cables from other places, and extra insulation to keep houses warm with lower energy costs. Entrepreneurs will see this coming, and will be there ready to provide power or power-saving measures to those who did not prepare. As long as the market can set a price, the market will solve each problem. The people to lose out will be customers who don't adapt to keep their costs down - for example those who heat their 1960's uninsulated home with electric baseboard heaters. There are already plenty of seasonal industries - like tourism. Power hungry industries will become seasonal or migratory too.
- dahfizz 4y ago> Power hungry industries will become seasonal or migratory too. Electricity will have to become orders of magnitude more expensive for this to be true. After you've bought the building, the smelter, and the guy to operate it, the cost of electricity to smelt aluminum is negligible. Its never going to make sense to leave all that idle if the cost of electricity bumps up a few cents.
- bluGill 4y agoI work for a.company that melts steel. Cost of electric is a very large issue. We pay workers extra to work overnight shifts when electric is cheaper and shut down during the day. We also shutdown for annual maintenance in December when Christmas lights raise electric costs.. not one that melts metal, but I know one plant runs 5 months and does maintenance the other 7. Note, the above is as of 10 years ago. Now wind provides most electric so hours may be different to account for that.
- erikerikson 4y agoWe have Nucor in West Seattle and rumor has it running 24/7/365+ because the cost of shutdown/startup is too high. I've seen steel coming out is there everything I've driven by regardless of hour.
- turtlebits 4y agoEnergy efficiency is always good, and I'm glad the government is incentivizing it. A passive house can have 10% the energy cost/use of a regular "code" house. Even off grid, this can immensely help in the size of your battery required.
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- PaulDavisThe1st 4y agoAs someone with a smaller scale version of the "problem" you describe (3x overproduction from our ground-mount 6.7kW array in summer, 1/3x production in winter given air source heat pumps), I'd say this is where, even with this amazing contemporary technology, we need to get back to ... insulation. As others have noted, passivhaus standards would help fix the "in the winter, homes use a lot more energy than they can generate" part of this. I've read of homes in Scandanavia that are heated by their inhabitants plus the output equivalent of a few candles. Not totally convinced by these stories, but they point the way: once you've got the carbon-reduced/free energy supply in place, work on massively (if possible) reducing how much of it you need. We have an old adobe in the high desert, and it is so far from passivhaus as to be a joke. I'm fairly sure that if this was built to passivhaus standards, even our currently undersized array could handle the heating needs.
- twarge 4y agoI live on the east coast, paid for excellent insulation and thick windows with good seals, installed solar, and don't pay a dime more for energy. That includes heating, cooling, hot water, and our two EVs. This is possible almost entirely because of the insulation. We were generating a surplus, so we installed an electric clothes dryer, which seems to have balanced everything nicely.
- G_z9 4y agoIf you had a modern well insulated house you could heat your house with a hair drier in the dead of winter in climate zone 5. If your stacking up to 4mwh then your house is not really a good example.
- hcurtiss 4y agoI have a modern well-insulated house (built three years ago) in Zone 4. There is no universe I heat it with a hair drier.
- Syonyk 4y agoI mean... that's all our energy inputs, including pumping water from a fairly deep well, almost all our transportation miles (300-400kWh/mo), heat, hot water, etc. It's a ~7 year old manufactured, 2k sq ft, 2x6 exterior walls, pretty tight (blower door and ducting tests have concluded "Nothing to fix here"), though I'm still running down a few weatherstripping issues on one of our doors. A 1800W hair dryer running constantly is 1.3MWh/mo, and this isn't 4MWh/mo, it's since about Nov, on a colder than usual winter. I'm right on the north end of Zone 5. In any case, I've yet to figure out how to get our heat pump outdoor unit from freezing up in icing fog, but neither is it worth $20k to put a ground source unit in right now.
- SamBam 4y ago> It's not a big deal with only a few people on the grid, but if every house were doing this, "Renewable is great, but if we're already generating all our power by renewables then..." This argument is silly because we are nowhere close to having this problem yet. And as we start to approach that golden age (I mean, "problem") we'll have other alternatives.
- bluGill 4y agoIowa is actually close to having the problem of more renewable power than demand. We are a small state yet ranked number two in wind production: your state should aim to overtake us.
- Gigachad 4y agoThis is not really a problem. You just send out a signal to shut solar off. Then people and businesses buy batteries to take advantage of the free power and sell it back at night.