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Ask HN: What can I do with extra electricity?

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41–50 of 63 posts

Re: Ask HN: What can I do with extra electricity?

#41
I can highly recommend Gas diffusion. It consumes electricity like one might expect from a multistage refrigeration unit. The results will guarantee your permanent "off the grid" independence comparable to any other nation. https://en.m.wikipedia.org/wiki/Gaseous_diffusion

Re: Ask HN: What can I do with extra electricity?

#42

Earlier quoted context omitted.

Assuming the panels are connected to the grid, then the power will be consumed by neighbors - not wasted. EDIT: I see it was right there in the first line of the post that the plan is to unplug from the grid. I would reconsider this decision. If you stay connected, you can share your excess capacity - if not then you use it or lose it. Why put yourself in that position?

I personally support municipalities making it illegal to go completely off the grid.

Out of curiosity why?

Re: Ask HN: What can I do with extra electricity?

#43

I can highly recommend Gas diffusion. It consumes electricity like one might expect from a multistage refrigeration unit. The results will guarantee your permanent "off the grid" independence comparable to any other nation. https://en.m.wikipedia.org/wiki/Gaseous_diffusion

Looks like a fun weekend project

Re: Ask HN: What can I do with extra electricity?

#44

energy efficient server:old link https://www.theregister.co.uk/2010/11/11/diy_zero_energy_hom... Make hydrogen (H2)with electrolysis. Need to found a good technology for that, and be careful hydrogen is very explosive.

Running a server isn't really a predictably intermittent load, and there are plenty of servers/computer already in my power budget. Not sure what I'd do with a bunch of hydrogen. Fuel cells still aren't really a practical thing. I'd thought about maybe some kind of wood-gas biodiesel thing, but I don't know of any way to do that on a small scale with intermittent power.

Hydrogen stoves are in use in homes.

What stops fuel cells being practical?

Re: Ask HN: What can I do with extra electricity?

#45
post #44

Earlier quoted context omitted.

Running a server isn't really a predictably intermittent load, and there are plenty of servers/computer already in my power budget. Not sure what I'd do with a bunch of hydrogen. Fuel cells still aren't really a practical thing. I'd thought about maybe some kind of wood-gas biodiesel thing, but I don't know of any way to do that on a small scale with intermittent power.

Hydrogen stoves are in use in homes. What stops fuel cells being practical?

Mostly the bit where I can't actually buy them. Do you know of any good suppliers of kw-scale fuel cell systems that are cost-competitive to lithium or lead-acid batteries? Because that would be great, I just can't find them.

I think hydrogen storage is still one of the difficult parts.

Re: Ask HN: What can I do with extra electricity?

#46

Earlier quoted context omitted.

There are some intermittent things like drying my laundry that it makes sense to do only when I have extra power. I'm probably going to go tankless propane for hot water heating though. Heating water takes a lot of power, storing hot water produces a lot of waste heat, and in the winter when I could most make use of that waste heat is when I'm expecting to not have much of a power surplus. If I could get a hot water…

Similarly, you could distill water for drinking if sources are not pristine.

Probably a "water maker" for a boat, my understanding is that they use reverse-osmosis to desalinate water, so it's easier to have them take up small amounts of extra load. It's a nice self-contained unit that you can start and stop pretty much instantly.

Re: Ask HN: What can I do with extra electricity?

#47

Get an electric car?

At 190kw hours it would take me like a month to get a full charge. Also probably peek hours would be when I'm not at home, and neither is the car. I also worry that I'd end up filling it up in town and using the power at home. Still, it would certainly fix my battery situation...

Something smaller and more bicycular then?

Re: Ask HN: What can I do with extra electricity?

#48

I'm in Washington state and I'm not sure what latitude you live at, but for my house, my low, without snow on the panels, is about 8 kWh for an overcast day in December or January and my high is 107 kWh for a day in the middle of summer. For me to average out my needs I need a dam... like on the Columbia. In WA state, you don't sell the power, your extra power is future credit to your power needs. I'm on a heat pump…

I'm in Nova Scotia, Canada. So I'm expecting worse than that, but it's hard to get realistic numbers. Those numbers are a fair bit worse than the worst cases I was looking at, which assumed winter panels would be ~25% efficient on average.... So that assumes a 3kw system is producing around 4kw-hours per day. I'll need to see if that's realistic.

The middle of Nova Scotia is about same latitude as me, but you guys probably get waaaaay more snow and I am on the desert side of WA state. We get a ton of sunshine. How are you going to clear off the snow? I have 54 panels and it is a big chore to do it without scratching the panels, so I don't even try. Snow slides off like a metal roof, so you have that.

Do you guys get more overcast days? If so your panels may behave more like my place on the west side of the Cascade mountains near Portland Oregon. Looking at production on that 2.2 kW system for this January, I see a non-snow low of 0.4 kWh with an average daily production of 1.6 kWh.

Take a look at my January production, including some days with 0kWh production due to a dusting of snow:

https://i.stack.imgur.com/9qw18.jpg

That system is 6 years old.

So, IFF you get a system, your power storage needs to survive whatever is the longest run you can imagine (+50% ?) of days with overcast or snow coming down.

Re: Ask HN: What can I do with extra electricity?

#49
post #24

You can sell it to your local utility company. You will get paid for it, and another power plant somewhere (maybe a coal power plant) will need to produce 1 kW less power.

Unfortunately that won't work in my municipality, as they only do that for larger customers. The problem is that it's not a "smart" grid, and having random customers pump power back into the grid can cause lines that they thought were dead to actually be energized during repairs. They need some way to shut off the buyback during repairs, and right now they don't have that. Also I'm not sure that the amount of power I…

Most net metering arrangements require a manual power disconnect switch for your rooftop generation [1] for utility workers or first responders, and NEC requirements require inverters to shut down ("rapid shutdown") if they can't sync to the utility to prevent backfeeding power during maintenance (caveat: if you have local energy storage, the inverter will island and continue to provide power from local storage). I would encourage you to ask your municipality and their utility department what their net metering arrangements are; I would be happy to make such a phone call/inquiry on your behalf if you would prefer.

Is your utility Nova Scotia Power by chance? It appears they support net metering [2].

Everything I mention above will be cheaper than storage (which will start around $13k CAD).

[1] http://scitechconnect.elsevier.com/wp-content/uploads/2016/1... (AC disconnect in this image)

[2] https://www.nspower.ca/your-home/save-money-energy/make-own-... (Nova Scotia Power: Enhanced Net Metering)

Re: Ask HN: What can I do with extra electricity?

#50
Check out joeyh's stuff, https://joeyh.name/, esp https://joeyh.name/offgrid/

Energy storage, whether purchased batteries or built gravity storage is likely most useful.

Having consistent access to power through predictable reserves makes energy way more useful to you. You can do laundry at night, or run a heater, etc.

Storing energy allows you to adapt your power usage to your needs and preferences, instead of adapting your needs and preferences to power availability—which has daily and seasonal limitations.

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