Comment by adamcharnock | Hacker News Reader

Comment by adamcharnock | Hacker News Reader

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I just spent 6 years living off-grid, running 5kw of solar, and 14kWh of storage. I setup a fixed array that I welded together myself. I could certainly see that tracking wasn't worth it even then.

However, in the off grid-setting I did discover some nuance. Sometimes you could really do with some power around sunset or sunrise. In the winter, being able to more reliably run my air-source heat pump at sun-up would have been very handy. Or likewise, some extra power to run the AC (which is the same device) in the early evening in the summer would have also been handy.

There were plenty of cold mornings when I was keeping an eye on the solar grafana dashboard, waiting for that hockey-stick moment when the sun swung into the right place!

I did consider the possibility of setting up an additional east or wast facing array to capture sun at the extremes of the day. Unfortunately that would have required its own MPTT charge controller, and would have just been more complexity in general.

Tom Murphy shows in his excellent book on energy that over-tilting your solar panels by 15 degrees is a good idea (Table 13.2):

https://escholarship.org/uc/item/9js5291m#section.13.4

Basically take your latitude and add 15 degrees and that'll get you good annual coverage.

Some of that you can solve with dual side vertical panels mixed in. Obviously murders their output but you get it when it matters - on the shoulders of the day

Wouldn't it more reliable, day to day, to oversize the production during the sunniest parts of the day and then dump that into storage to use whenever you wanted, not only during twilight but whenever it was cloudy, freak weather conditions, etc.?

I honestly don't think I would be comfortable off grid without 4x+ that size. Of course, environments vary so significantly that these numbers don't translate well when discussing them without geographic context.

My primary concerns would be consecutive cloudy days, and winters with very short days. While my actual heating/cooling needs are more mild than global averages, I think the combination of short daylight hours and increased heating needs makes off-grid solar unviable for climates closer to the poles, especially those not near sea level. I do think relaying on propane or wood for heating might make off grid viable for these locations, but that introduces questions of scalability and increased carbon footprint.

There is some argument that burning wood should be considered carbon neutral if the trees are replanted and used as a renewable resource (Carbon is released to the air, and then captured by the next tree in a cycle), but the land intensive approach wouldn't scale to meet the heating needs of a significant portion of the population. Additionally it ignores the carbon required to grow, harvest, process, and transport the trees or the alternative uses the wood might find elsewhere.

My point is for others to take their local climate into consideration before thinking that 5kw/14kWh would be enough for them to go off grid.

I think it entirely depends if you want a 'just works' solution or you're willing to adjust your lifestyle day by day based on availability of sunlight.

Merely a 10 watt panel in the Netherlands has been fine whilst camping for weeks, but obviously I have to severely compromise on modern life - 10 watts powers a lamp for a few hours in the evening and a phone charge each day.

In these sorts of rare situations it is of course possible to run a generator to charge everything up. Off-grid doesn’t mean on an island.

The insane energy density of fossil fuels means this is an excellent “emergency” back-up plan should the sun not shine often enough.

I'm not sure it's rare to live about 45°N, where we start to see >9 hours of sunlight in the winter. The intersection of places that are both above 45°N and very cloudy (Portland, Seattle, London, Detroit, Copenhagen, Dublin, Vancouver) or in high altitude probably includes a good chunk of HN readers. Northern Europe gets down to about 6 hours of daylight in the winter. If you're in one of these regions, and you plan to use a generator to augment your energy needs, I don't think that's considered an emergency as much as a secondary power source. If one of your goals is decreasing carbon emissions then a diesel generator is going to set that back.

Other regions will have their own considerations, but the primary concern is balancing harvesting sunlight with heating/cooling requirements. I'm just encouraging people to do their own homework for their own situation when considering off grid. I've seen a lot of people under build and end up spending way too much to heat their homes in winter.

What is the appeal of living off-grid?

Sometimes the appeal is not in the "off-grid" itself, but in living in a remote location where having access to the grid is impossible or inconvenient (it does not have to be too remote either to not have easy access to the grid).

This is what I observe as a Realtor and living in a somewhat rural area - there are some people who like the idea of living the self-sufficient lifestyle, there are others who are convinced Armageddon is upon us and they are going to be ready, but mostly its because they found a beautiful location that speaks to their soul and the only way they can make it work is to use off-grid resources.

You don’t have to be around other people, and all the hassles that human society and population density entail.

Some people are really into that. I’m really into same-day Amazon delivery and 30 minute latency on fresh pizza that I didn’t have to cook.

I just wanted to say thank you for the phrase “30 minute latency on fresh pizza”

I’d never considered it latency but you’re right and it’s hilarious.

Taking time to cook elaborate meals is enjoyable if it isn't getting in the way of some other demand on your time. Living off grid you're probably going to have a lot less of those.

Living off grid means off the electrical and water/sewer/gas utility grid.

In almost no case does it mean off the internet now given Starlink; thus I think it’s silly to assume that a) being connected to the internet and b) having to admin all of your own utilities and associated equipment means you’re going to have fewer demands on your time. :D

Separately I love cooking as recreation, but don’t have much recreation time these days given my project-load (most of my projects being a form of recreation notwithstanding).

One of the reasons I am building a (mostly) off-grid place is because I like adminning infrastructure recreationally. I can’t wait to hook up my solar system to Home Assistant and Prometheus/Grafana.

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