Ask HN: What can I do with extra electricity?

That's going to be hard if he's literally off the grid.

This is being mounted on an RV, which is explicitly off-grid, and would only be intermittently connected at best. In my municipality they only do power buy-back from larger generators.

Also most of it isn't going through an inverter, I'm using direct DC-DC, which is much more power efficient for what I'm doing. So that means more cost for inverters, which I'd consider paying even if at the scale I'm working at it would take years for the equipment to pay for itself, but...

You can't simply tie an inverter into the grid and sell back to the power company, as that could mean that during repairs lines they thought had no power were energized by some residential customer. You need special hardware that the power company can shut down remotely, and that's only available for larger customers.

Also I'm not sure if the price I'd be getting for that power would actually offset the monthly connection fee, making connecting to the grid and selling back extra power very likely cost more than just wasting the power, which is unfortunate.

So unfortunately grid-buyback that isn't really an option for me.

Which is why I'm looking at other options. I like the wood pellet one, in an ideal world I'd be able to do some kind of carbon capture or something, but I'm not seeing any good power-to-gas tech right now.

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 and my highest demand is in the winter where lows dip to 15F or 25F. For me to save up enough energy on my own land would require more of a pond pumping scheme and it would be a massive undertaking. On the order of being able to store huge portions of energy for a quarter to a third of the year to get through winter. FYI, my system is Goldilocks's just right. I pay about $25/ year for extra power once my credits run out at the end of winter.

I've bought two different solar systems in two different states and the devil is in the details for your hypothetical situation. You need to understand average overcast days, ~90 percentile run of overcast days in your lowest intensity sun month, intensity of sun, angle of the sun, et c. Also, if you optimize for the worst days of the year, you could be reducing total energy output because your panels would be optimized for a lower sun angle.

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'd be putting back would actually pay for the basic connection fee. It would during the summer months, but during the winter it likely wouldn't, and seasonal connections aren't much cheaper.

I think that's generally the best bet if you can do it.

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.