That is a huge generator for a residential house. I just got a 8kw natural gas generator https://www.amazon.com/Champion-Power-Equipment-100416-Gener... for like $1300. That Generac is probably north of $17k installed. You don't need your sauna, arc welder, and bitcoin mining rigs running at the same time during the couple days a year without power.
Out of interest, why a single large unit rather than multiple smaller ones? I’m using two 5kva janky (~$1500) Honda generators that I modified to have remote start, and use a pair of victron multipluses to turn the garbage outputs into a single lovely smooth sine wave. We run one or both depending on the need - usually just one, as our OPzS batteries will do 20kW. I figured RAIG was better than going for one big genset - that and everything has to be human-luggable, as our nearest road is a few km distant. Also means that if I have a failure, I can go buy whatever junk is locally available and plug it in.
I monitor and automate the whole shebang using a venusgx, mqtt, rpi with openhab. Touch wood, two years without anything exploding.
Other nice element is that the inputs are agnostic, so hydro can run in parallel - and I can do nanogrid coupling with frequency shifting for the more remote wind inputs.
Obviously a different use case to you, but the idea of having a single and expensive point of failure doesn’t sit well with me.
Yeah, influx and Grafana are the reporting end of my stuff, which includes cistern levels, fuel levels, and all the other gumph required to run tiny water and power grids - but openhab provides the underpinnings, and hasn’t required me to do anything custom beyond defining fields and logic. In theory, anyone could pick up where I left off.
How is the sound? We have a NG generator at the school (in the basement) and you can’t hear it there buried as it is underground but ima residential setting these can be very loud, no?
I have the 22kW model which I believe is air cooled. Living under Texas’ “freedom grid”. I would say it’s kind of louder than I’d like, probably like standing right next to my Tacoma, but when the power goes out it sounds like sweet angels singing.
No. I am not. If someone has money, they can do whatever they want with it. Some rando on the internet telling someone else they shouldn't do something because they don't agree with it is the joke. There's a difference between opining on how public policy is applied, but telling a private individual what they can do is just asinine. I totally realized that this is arguing with a fence post level of conversation, as the internet is the one place to be guaranteed that logic need not apply
4000 sqft house with high humidity 90 deg summer days (so anywhere in the SE US) will need at least 8-tons of AC, so 2 units, and that's ~24kw right there if you need to cool the whole house.
But the more common practice is to run just one of your two units and then have plenty of room to run all the small wattage things in the house without needing to actively budget power.
Having lived through more than a few week+ outages in Jul/Aug/Sept heat (including 3, 6, and 8 week outages), I certainly see the value if you can afford it.
Comfortable, but not necessarily extravagant.
ETA: We also learned our lesson relying on NG and converted to dual fuel with a 2-week supply of propane.
Tesla's calculation comes out to about $200k for equivalent capacity solar plus battery.
Even deducting $25k from that for the cost of the generator and another $10k in required electrical modifications, that would more than double electricity costs (vs the grid) based on 20-yr lifespan and payback, before interest.
”It was a real pain getting the cable to push through [the conduit], so I used whatever lube I had on hand.”
FWIW, pulling can be easier. Put a cotton ball on the end of a light string and grab a vacuum cleaner onto the other end of the conduit. Very fast.
Also, the next size up of conduit doesn’t cost much more. Unless you are some sort of professional conduit sizing engineer optimizing for material cost, always get the next size up conduit from what you think you will need. Pulling is easier and you might change your requirements later.
Why would one to have a generator in your own backyard? Is there no power grid available?
As for outages, wouldn't a UPS be sufficient?
Being Dutch, this does sound a bit like overkill.
Most times I see an electric generator like this in the Netherlands is at festivals, or on the national news where a remote 100% renewable museum couldn't get hooked up to the nation power grid due to lack of capacity, and had be powered by diesel generators.
I wouldn't say they're common, but I see plenty of at-home generators (Generac is popular, there are others) here in the Northeast USA. We have lots of old trees, and lots of snow, which maybe you share, but I guess it's our propensity to ignore infrastructure maintenance that leads to more, longer power outages.
In the last ~12 months, I've thrice lost power for more than four hours. Once you start losing a fridge's worth of groceries every 4 months, amongst the other challenges with power outages, the at-home generators start to look attractive.
It also helps that, at least here in Ontario (Canada), diesel is a very popular substitute to run in conventional oil-burning furnaces - having a generator is almost a no-brainer when you've already got tons of fresh fuel on hand.
On the other hand, 27kW is a LOT of generating capacity for one home. I consider that the average home (at least in my area) only has 200A service, and I don't think I've ever heard anyone complain that it's not enough (outside my dad who wanted a 16-person hot tub for two people).
Over here in the Netherlands the regulator claims >99.99% uptime (ie downtime slightly less than an hour per year), but I think they're being a bit modest since I can't remember a single outage in my area in the last 5 years. (Though perhaps they measure country wide in which case it might be "only" 4 nines.
The uptime is probably much better in cities than in rural areas. In Portugal, having run home servers both in a city and rural locations the difference is immense. I get more uptime out of a city server with no UPS than a rural server with a UPS that can power the server for ~30min. There are more long outages in rural areas than even transient outages in the city.
Grid is much more reliable in richer countries of Europe than it is in the States. This is one of the areas where US infrastructure is really lacking. Our power is cheap, but the reliability is bad.
The difference is mostly due to the fact that the grid in Europe tend to be mostly buried. A large part of the electrical grid in North America is aerial due to cost and geographical constraints (burying in solid rock is expensive, and doesn't make sense with lower population densities), which makes it much more vulnerable to damage by storms.
In South Africa we have load shedding, where the power utility switches off large parts of the grid in an attempt to retain grid stability. Aging infrastructure, incompetence and corruption means that we've been suffering like this for almost 15 years now.
During active loadshedding we can expect multiple 2-4 hour outages during the day. UPSes dont work because the batteries are destroyed after a couple of sessions. Proper battery based backup solutions are prohibitively expensive for most.
Most upper middle class households have backup generators installed, usually 4-7kW. If you can afford it, you install a full solar power system, allowing you to disconnect completely from the grid.
We don't have gas, oil furnaces or other sources of power (other than solar for the wealthy as explained above), and for most our hot water is made with electricity.
The unreliable grid has become a fact of life for all south africans, and we have adapted according to our means, all the way from a fully independent off grid solar soltion for the rich, down to candles for the poorest of poor. I keep candles in my cupboard in case my backup system fails.
Probably an area with poor electricity infrastructure or in hurricane alley.
Though 27kw is a lot. They’re on natural gas too, so I guess they’re not worried about running out of diesel (though nat gas can be another point of failure)
27kW is 225A, it’s what you want for fully backing up a 200A utility service, which is what all new construction has in my area, tho some older homes still have 100A services.
Interesting, most residential homes in The Netherlands do go beyond 40A for 1 phase and 35A for a 3 phase setup. Granted. We don’t regularly run airconditioning either and most heating is on NG, but still…
Friend of mine had a six day outage in the Scottish borders just now. Starting to look more reasonable to have some sort of backup, although 27kW could run an entire neighbourhood.
Being dutch you won't have CH4 shortages this winter (unlike what the EU might face). You'll supply your own industry, power stations and homes first and then your gas clients. You also only have one real natural disaster to optimize for, flooding. Europe has incredibly mild weather compared to the rest of the world.
Add to that that your infrastructure is newer than N. Americas - it all got rebuilt after WW2. The supply cables into my old house were 100 years old.
Finally, there is heating. Most homes need some form of an electrical motor for their heat (either as a blower for the furnace or a pump for their radiators). Consider how lucky Europe is climatically: the Netherlands is 52N. By comparison, Toronto is at the same latitude as Nice - this is due to the Gulf currents. Pipes in the Netherlands will not freeze if you spend a few days without heat. The pipes in the homes in the upper half of continental US will burst after a few days without heat.
Finally, generators are not particularly bad for CO2 emissions or other pollution compared to the grid. Not when you consider their low usage. We can afford them, they address real problems, they're fairly benign, so why not?
Because in America we can have everything. There is no limit to comfort and quality of life. Our standard of living can be quite high and very affordable. This setup was only 20k installed, a pittance. While this setup is robust, it is not unusual for people to have 10 -15 kw NatGas generators as backup just in case there is an unforeseen interruption to their power (some kind of accident or calamity). It's why America is a wonderful place to live, you can have everything, what you see and hear in the media about how awful it is here is fake news.
I have a 22kw diesel and 500 gallons of fuel on site. During a disaster you can lose power for 2 weeks. It’s not overkill, it’s required in some areas.
I live in an area with an unreliable power grid — California.
My friend lives nearby and has a whole house generator. Uses it 2-5 times per year. It's funny at night when he's the only guy in the neighborhood with his lights on.
Cool to have a residential backup electric power generator. The monitoring system also looks interesting.
I wonder if the author could shed some light on the reasons for this technical choice though, because my back-of-the-envelope calculations just don't end up with this kind of tech.
The Generac is about $13000 excluding install. A Tesla Powerwall+ $11500 installed without subsidies.
The electric power consumption at our place is under 5.5 kWh per day on average, with very few peaks. Slightly less than average for Belgium, but not by a lot. I realise residential power consumption may be higher in the US, but probably not by an order of magnitude.
A popular home battery, the Tesla Powerwall does 13.5 kWh. That's 2.5 days already without any solar. Add enough solar and you've got basicly unlimited backup. In a single family home with a garage, one can also easily add vehicle to grid for extra emergency storage.
Friendlier to the environment, lower maintenance, cheaper. Unless one consumes over 7 kW continuous or 10 kW peak in an emergency situation.
I also have 17kw of solar on my roof, and overproduce. I have 1:1 net metering, so a battery will not help financially unless that ends. the only utility a battery provides is backup power
In the middle of summer I will use around 80kwh a day with lots of AC usage (Yes, I could get more insulation, better ducts, switch to minisplits. all in progress)
A lot of that is at night, because it doesn't get any cooler at night really. It still stays hot and humid. Between sun I'm using around 30kwh, so I'd need 3 x Tesla Power Walls JUST TO MAKE THE NIGHT and hope it was sunny the day before to fully charge, and sunny the next day
The cost for that is over $30,000, only makes the night, and still only outputs around the same as the generator. If it's not sunny but it's still warm, I'll be without power in a short time. If I'm spending that amount of money, I want power to stay on no matter what
I'm waiting for Enhpase or Tesla, or someone to come out with an AC Coupled grid tie battery that has full generator support. That is the dream. Then in low solar days it could pre-charge the battery with the generator for night time. I don't want to drop a ton of cash now, when that is surely on the horizon. Either that, or the ability to use a car as a battery. If I could use a Tesla as a battery, I would probably go buy a 100 model Tesla. That would be 100kwh! much better
> Either that, or the ability to use a car as a battery.
Not sure if it fits the bill for you, but the new Ford F-150 lightning can supply 9.6kw of continuous power:
> With the ability to offload 9.6 kilowatts of power, Ford Intelligent Backup Power keeps the lights on during an outage while providing security by powering home appliances, security systems and more
I think what's driving a lot of the questions is not knowing how much instantaneous power (and startup current) your AC uses when it's on. 80kWh/day is only 3.3kW avg, but assuming most of that is your AC (with 30% duty cycle) and it seems your system is at most oversized by a factor of 2. There is a 22kW model in the same product line, so presumably you had a good reason to go with the next one up.
Given that Texas's electricity problems involved a problem with the natural gas supply, are you not worried about that going out as well? I just got a generator, but aimed for a small one that would be more efficient so that I would need to store less fuel. Although I still need to figure out some solution for intelligent load management so that I can run (fridge,freezer,boiler,etc) sequentially rather than simultaneously.
> I'm waiting for Enhpase or Tesla, or someone to come out with an AC Coupled grid tie battery that has full generator support.
Enphase either already supports this, or is very close. Their current gateway device (smart transfer switch) for their Encharge 3 / Encharge 10 AC-coupled batteries has connections for a generator and I know the installation manuals on their site describe what kinds of generators are supported and how to wire them up. If they don't officially support that configuration yet it's only a matter of time.
Speaking of HVAC on a generator - have you heard of the Hyper Engineering SureStart devices?
They put less stress on the generator and compressor when starting up. I got them installed on both of my AC units, and they work great on the generator, and the generator doesn't bog down when they start.
Humidity is indeed the problem! You can live with dry heat but humidity just makes it hard to breathe and it’s such an oppressive, overwhelming presence. And it’s expensive to dehumidify a room via any of the conventional means.
If this is a Texas install, then the house could be running upwards of 5 tons of HVAC capacity. This is a monster load that is very unusual outside of southern US states.
Getting through a hurricane is a lot easier when you can pull humidity out of your house the whole time. Running this much cooling on 1 powerwall would take you about 4 hours before you are in the same boat as everyone else. In many cases you need to go 72+ hours non stop. Gulf coast does not cool down that much at night after a cat5 blows through. It's practically unsurvivable in some cases.
> The electric power consumption at our place is under 5.5 kWh per day on average, with very few peaks.
That's why your back-of-the-envelope doesn't necessarily add up with the author's.
In the US South (at least where people run AC) it's entirely possible to use 24 to 48 kWh per day. There are big, fancy houses people own that could double, triple or quadruple that.
> The electric power consumption at our place is under 5.5 kWh per day on average, with very few peaks. Slightly less than average for Belgium,
That's an average of about 230 watts. How do you get that low?
An idling iMac with Intel processor is around 70 watts, according to Apple. My refrigerator is suppose to average about 50 watts. That's halfway to your usage right there. In the summer, when I don't need heat, I usually have a box fan in a window to circulate air, which is another 50 watts. Add another 10 watts for my cable modem and router. There's probably another 20 watts total for various other things like TV in standby, a couple of smart speakers for voice control and music, and network switches.
So that's got me to 87% of your usage just from things that are happening all the time when I'm not even doing anything! (Oh, and there is an outdoor security light that comes on at night. I have no idea what its power use is (or even what technology it uses [1])).
Then there are the things whose power depends on what I'm doing. Microwave and toaster oven once a day to make breakfast, and sometimes to make other meals. About 40 minutes walking on my treadmill. Electric pump at my well to supply my water. Electric lights. Electric water heater for my hot water. I also actually use my computer and my TV at times, so they are often using quite a bit more than idle or standby power.
That's got me way over your usage on an ordinary day when I'm just doing my daily things. Looking at my records, the lowest I've gotten down to is about 12 kWh in a day, which I can hit in summer, although average in summer is a little higher due to things like an electric washer and dryer that I typically use a little more than once a week, and an electric dishwasher used a little less than once a week.
The internet tells me that about half the households in Belgium have natural gas. Are you doing with gas some of the things I do with electricity, like water heating and cooking?
[1] Seriously, I have no idea what the heck it is, except that it is not LED. It has been there as long as I've owned the house, running every night. It has accumulated at least 50000 on hours since I've been here, which is quite a bit longer than the expected lifetime of every kind of bulb I've found that otherwise looks like it might be the same technology.
> That's an average of about 230 watts. How do you get that low?
That's not considered low here. That's slightly below average.
> An idling iMac with Intel processor is around 70 watts, according to Apple.
We don't have desktops idling. We do have an old thinkpad with the screen switched off running as a home server. We use laptops plus two large screens.
> My refrigerator is suppose to average about 50 watts.
No idea of our consumption. I just chose one of the less energy consuming freezer/fridge combinations.
> In the summer, when I don't need heat, I usually have a box fan in a window to circulate air, which is another 50 watts.
We have heat recovery ventilation.
> Add another 10 watts for my cable modem and router.
Fritzbox dsl modem with builtin basic routing.
> There's probably another 20 watts total for various other things like TV in standby, a couple of smart speakers for voice control and music, and network switches.
No TV. One additional network switch, and a printer in deep sleep.
> Microwave and toaster oven once a day to make breakfast, and sometimes to make other meals.
Microwave, toaster, cooking hobs, oven, water cooker. All relatively simple appliances here. The cooking hobs are inductive. That saves a bit of energy.
> Electric pump at my well to supply my water.
We get our water from the city. No well pump.
> Electric lights.
All LED.
> Electric water heater for my hot water.
This is really the big one. One 24 kW flow-through natural gas heater.
> an electric washer and dryer that I typically use a little more than once a week, and an electric dishwasher used a little less than once a week.
We use an electric dishwasher very often, at least every other day. It's a fairly energy efficient one. Clothes we usually dry on a rack, though we sometimes use a dryer. Fairly energy efficient one, heat pump based.
I also run around 6kWh/day. Natural gas for heating, hot water, stove (but electric microwave and oven). I run a mini-itx Intel i5 server 24/7, a PS4 constantly I standby, a bunch of ESP8266 smart plugs and sensors, a projector in place of a TV (I think it uses 500W when it's on). No dryer, no particular effort to reduce electricity usage beyond what I was taught as a child. Three people (one of which working from home) and a bunch of pets in a 110m2 house.
Must not read the news much, but there are all sorts of things that cause people to be without power especially weather related. However, since you're claiming that the Dutch never loose power for more than minutes at a time, perhaps we all should consider relocating.
I'm in Florida. We get storms, tropical or otherwise, that will take out the power anywhere from hours to days during the summer. Our (my neighborhood) lines our buried, but the feed is still above ground. A lot of people here have generators for running essentials.
Same, except I use an STM32 and an esp8266 piggy-backed to it. But I would definitely prefer hard-wired over wifi for anything with an uptime requirement.
Does anyone know if this violates your warranty? I literally had an 18kw Generac installed this week and their software is a joke. I'd much rather run Genmon but I'm wondering what my electrician will say when he can no longer monitor my system.
i have a 5kw https://www.phocos.com/product/psw-h-hybrid-inverter-charger...
phocos solar inverter but their only "interface" currently is a bluetooth "app" that requires me to stay near the inverter and there is no logging or use some sort of rs232 interface with a windows app. uh.
they do have a "cloud" option but that requires additional device purchase and a subscription service. shit.
i would love to integrate it with a home-assistant network at home but till now nothing.
good thing this generator had a linux app otherwise it would've been like my case
I suspect its reliability. having stuff hardwired means its much less likley to be a network problem when something goes wrong.
In my house I had a tesla powerwall installed (yes I know, rich prick alert) the gatway has some shitty wifi that cant be disabled, and kneecaps the range of my house wifi, because it insists on using the same channel.
The back of the house can pick up the AP in the garden, the top front not so much. So a bunch of things are sporadic now.
tldr:
Wifi is fine until its not. Hardwiring for critical path stuff reduces a hard to diagnose mode of failure.
I agree that wifi sucks and I would take a 100mbps Ethernet connection over wifi any day. That said, a wifi ap on the same band that isn’t in use shouldn’t add too much interference; it’s just going to be the ssid broadcast packets. Unless you are using it? Can’t you change your house wifi to another channel to avoid the interference?
You could also tape some antistatic bags together around the power wall box to act as a faraday cage, and throw in a Pi acting as a wifi-to-Ethernet bridge into the box or inside the f cage to get a wired signal out, if the interference is really that bad.
I think metal housing is still part that is designed to block EM radiation from generator. Which will also block wifi. Then there is all EM that is inside and agree would be nice if it outputs decent waveform.
we see lots of houses here in the pacific northwest in the US have generators like this. For me as a european it was a foreign concept because the reliability of the network seems to be higher in europe.
I think much of the difference is the above ground electricity cabling, forested areas, and just the economics of providing service to a large geographic area.
if you live in the suburbs of a city like seattle which I wouldnt call having super bad weather its pretty common to lose power for a few days every year due to power cuts - it gets annoying and if you can afford it, why not install a genny.
If you are shopping around for gensets with this much power look at high end welding generators. Depending on where you live you may be positively surprised by the pricetag.
Do these generators auto-start when the power goes out? Do they auto-stop when it comes back on? Do they do automatic weekly self-tests/diagnostics? How clean ('true sin') is the AC output? For the portable ones, are they multi-fuel?
They typically are the same heads with another winding on it, everything else can be wired in like regular. I've had one of these for years and it suited me quite well.
Oh, and don't pay 'list', go for a 2nd hand one otherwise you'll end up negating all your gains, in the industrial world nobody pays list except suckers.
I'm a little confused why he replaced direct burial CAT6 with fiber because of fear regarding lightning strikes versus the easier and more cost effective solution of installing Ethernet surge protectors at each end.
"surge protectors" arent that reliable, and are sacrificial parts.
Any length of wire between two electrical ground points might, if there's a lightning strike in the vicinity, be subjected to huge "ground surge" currents. I buried 25 pair copper in a conduit and saw it vaporized; both ends of the conduit run belched flame and smoke and molten bits from a lightning strike that wasn't that close (half mile or less), and certainly not direct.
I'm sure it would have to help; but i would not make any bets in the close presence of lightning and long wires. weird shit happens.
My experience says that a free length of wire grounded at a midpoint (like when you disconnect the far end) will still be a potential resonator for enough volts to cross a respectable gap; so unplug it and insulate the unplugged end. Been there, seen the sparks.
I maintained various configurations of wire and fiber across a 1/4 mile run through heavy woods on a ridge that gets direct lightning strikes a dozen times a year. nothing involving a conductor that length is simple in that circumstance: see the things the power companies have to do.
Thanks. I do have the other end up bundled up, but I guess I might as well make a note to disconnect and bundle up the remaining side, too.
> I maintained various configurations of wire and fiber
Separately or at the same time? What was the wire for in your case if you had it parallel to the fiber, and what did you do to protect it against the lightning strikes? We have it between two directly adjacent buildings that are maybe only 150ft apart (mostly underneath an asphalt access road) but there are no lighting strike rods/redirector on either structure.
I had this link between two buildings (no line of sight and radio was too expensive and slow then anyway), it began as redneck engineered "leased line" with modems on either end, with multi pair copper and replacing the modems periodically. The battery that floated that line was kept outside because it would occasionally "vent vigorously" with storms. USR modems had good isolation hardware those so they were pretty robust.
Upgraded that to coax Ethernet as soon as I could, 3c509 cards in cheap linux routers at either end of the link, with "modem failover" until the incident that blew away the 25pair. Those cards would lose one or both with every other storm it seemed; but were ~$2/ea off ebay at that point so not so bad. I've got at least one of those motherboards still, somewhere, with multiple bodge wires where i repaired traces blown off by lightning strikes.
When we got the fiber we buried the first run, with coax beside it, in conduit again. That lasted a few years before a "landscaping accident" tore out enough that there was no fix. Then we went to suspended coax, and then another fiber tied to that, for a few years, before the business folded.
I tried various grounding strategies over the years. The power companies and "best practice" suggest regular connections throughout the span of the line, and at both ends. I found that seemed to invite strikes by being a very good RF ground in the air.
Grounding at both ends is bad because of ground surge, pick one or the other end and have the best ground point there you can get, but let the other float, and hope. Also, any actual power system imbalances between two ends of a grounded line will seek to use that nice conductor rather than the cold earth.
150ft isn't that far. Also you haven't got trees to complicate things, they draw lighting and ground it deep. Hickory trees were my bane; they got deep roots that found our high iron sandstone layer and combed the sky for electrons. I'd say consider the switches at either end of that link to be sacrificial buffer parts, and not really worry about it. If its worth considering running fiber under a street, it might be worth considering a free space laser link or something.
Thanks for taking the time to share that. It sounds like you made pragmatic decisions which are much harder to discover online since no one with the actual expertise/experience wants to ever officially/publicly recommend anything less than "this is the textbook-correct way of doing it," which never takes $finances into account.
I do understand why you would want to leave an end floating but I'm not sure to what extent that is possible since ground surge voltage is probably enough to jump from the cable shielding to the inner twisted pairs, and so you're always going to have some grounding on both sides (via the switch fabric through to the mains), but I guess all you can do is make the alternative grounding path lucrative enough; if it's a short run and you have a nice, fat ground on one end, hopefully that should direct the surge away from the skimpy 20awg cables grounding it on the other end.
Surge protectors are absolutely enough for most lightning related surges which are absolutely not the full current of a lightning bolt going through your equipment, but a little bit finding the path through to ground though your stuff.
Back in the dialup days we used to lose a few modems a year to lightning, our computer didn't explode into a ball of fiery doom. (and the ancient phone would ring for a fraction of a second and you'd think "shit, I forgot to unplug the modem, there goes another one".
You’re not going to see the 300MV unless you had the lightning strike a pole with your cables connected to it, though. I wonder if optically isolated Ethernet couplers (do they even exist??) could work instead of the much more expensive fiber hardware on either end.
Completely optically isolated Ethernet couplers requires a power source on each side, but it can be done; the most accessible one is a set of media converters with a very short optical patch cable. In this particular case to protect both the garage and generator side keeping the CAT6 cable underground you need one optical double conversion on each side and an independent, sacrificial power supply for the copper part converters. Doable, but too complicated.
Right, that's the obvious option. I was thinking of a barebones "on the wire" approach but I'm not sure that's possible. The fastest integrated optoisolators I can find seem to all max out at 50MBd/s which simply isn't going to be enough to switch 100BASE-TX (which has a ~125MBd/s rate) without needing some sort of ethernet-aware logic (e.g. a primitive MAC controller) on either end to handle buffer overruns. 10BASE-T should be plenty possible though: it only needs a 16MHz channel and even sampling that 2x at the Nyquist rate of 32MHz is still within the capabilities of the $1 optoisolators. 10Mbps is plenty for an application like this one (and probably most industrial control purposes) but it's not exactly something anyone will publicly confess to wanting or using even if it's in order to pay two orders of magnitude less.
I don't know how the small optoisolators do when the current from a lightning strike can easily arch over several inches or a few feet. The ugly solution with a fiber patch cord on each side gives several feet of electrical insulation.
Fiber itself is cheaper than CAT6 and SFPs are indeed affordable (mainly thanks to the likes of FS.com where I can get for $30 an SMF transceiver that HP sells for over $250 and uses DRM to enforce in even their switches that cost less than the cost of a single transceiver), but switches with more than two (and extremely recently, four) 10G SFP+ ports are still too expensive for my liking (and haven't really yet hit the second-hand market).
Mikrotik has that famous CRS305-1G-4S+IN switch with 4 SFP+ for just $135. If you need more ports, CRS309-1G-8S+IN gives you 8 ports for $300. Double the ports again, you have CRS317-1G-16S+RM for $400, at $25/port it is the best price for many ports.
