Solar panels reduced my electric bill in 2022 • Hacker News Board

Re: Solar panels reduced my electric bill in 2022

#421

Post by metadat » Wed, Jan 04, 2023, 1:03 AM UTC

anikom15 wrote: post #411

bjelkeman-again wrote: post #381

Earlier quoted context omitted.

I have a house from 1909, with relatively poor insulation, by modern standards. We heat the house with a heat pump and a 100 m deep borehole. The heating of the house (180 m2 and a cellar) is the main energy consumption. The total was 22 000 kWh last year (including about 3 500 kWh for an electric car). An old house with electric heating and cooling could well be what he has. When we moved in the electric consumption…

An old house in California wouldn’t have electric heating. Even new houses scarcely have electric heating.

Tell that to my old CA house.. we rely on electric space heaters a lot.

Re: Solar panels reduced my electric bill in 2022

#422

Post by [deleted] » Wed, Jan 04, 2023, 1:04 AM UTC

hbarka wrote: post #109

Assuming you are grid-tied, the reduction of electric bills is predicated on net metering, where the utility company gives you (ideally) 1-for-1 credit for the electricity you produce. In California, this was called NEM 1.0 and NEM 2.0. Every few years the California utilities lobby the Public Utilities Commission (PUC) to chip away at the NEM program. This year the PUC voted unanimously to cut net energy metering an…

[deleted]

Re: Solar panels reduced my electric bill in 2022

#423

Post by grecy » Wed, Jan 04, 2023, 1:04 AM UTC

zombielinux wrote: post #272

CTmystery wrote: post #199

Earlier quoted context omitted.

From a circuit perspective, it seems trivial to open a switch back to the grid to prevent grid-feed, while still feeding the internal circuit that is the house. Can you help me understand why this is hard?

The problem is that its not a DC connection to the grid. Not only do you have to match voltage on re-connection, but you have to match frequency AND phase. Its "doable" but to do so reliably without a stable reference can be challenging. That's why the DC requirement is there. They want some form of reliable power to well tested electronics to match phase and frequency when the grid comes back up. A heavily loaded AC…

I've read that before, and I have a further question if you could indulge me

What if, when the grid goes out the inverter keeps powering the house (and disconnects from the grid).

Then when the grid comes back on, kill the output of inverter (which results in outage to the house), reconnect to grid, then power up the inverter again, which skirts all the sync issues.

The house will see a few second outage... but it will have been "on" for the entire grid outage, which I think is much preferable.

Re: Solar panels reduced my electric bill in 2022

#424

Post by roryisok » Wed, Jan 04, 2023, 1:04 AM UTC

stronglikedan wrote: post #111

isanengineer wrote: post #77

I worked in the solar industry for years and this is a very good summary of the residential install process from the customer side. I’ll also second one of the main points of the author: do NOT get a solar lease. Either finance it through a solar loan or pay cash. A good solar company will not push you into a lease. If they try, talk to someone else.

Also should be noted to get multiple estimates, even though that's kind of common sense. I had them vary wildly, where the most expensive one was literally twice as much as the cheapest one.

I got three estimates. Huge variety in price. All three companies sent someone out to survey the house. Two were very friendly salesmen who took photos of the roof and told me how much I would save, but couldn't answer technical questions. The third company sent out an engineer, who came into the house and talked me through where the inverter would be best situated, how the batteries worked, the benefits of a diverter etc. Third company instilled the most confidence and they were also the cheapest. Went with them.

Re: Solar panels reduced my electric bill in 2022

#425

Post by dundarious » Wed, Jan 04, 2023, 1:05 AM UTC

There is an associated video where he goes through the article and answers many of the questions I see in the comments here: https://youtu.be/YWwJ-DsVT4A

Re: Solar panels reduced my electric bill in 2022

#426

Post by metadat » Wed, Jan 04, 2023, 1:05 AM UTC

manimino wrote: post #305

kibwen wrote: post #221

Earlier quoted context omitted.

Note that merely having solar panels on your house doesn't automatically let you run your house off of the panels in the event that the grid goes down. Firstly, if you're connected to the grid, then a single house trying to push power into a downed grid would be like trying to refill the ocean with a super soaker. Even with lots of houses doing it, the frequency would be wildly unstable at best and cause damage to eq…

Exactly right. Typical solar installations keep you on the grid. And when the grid goes out, so do you. To become grid-independent adds substantial expense. Having your own battery adds another $10-20k, along with whatever costs are associated with switching the grid. Also, being off-grid is actually illegal in some places.

Why would it be illegal? Safety concerns? (E.g. freezing in Alaskan winter)

Re: Solar panels reduced my electric bill in 2022

#427

Post by grecy » Wed, Jan 04, 2023, 1:07 AM UTC

lawn wrote: post #100

cogman10 wrote: post #6

Earlier quoted context omitted.

> One of my biggest questions about solar is, what happens when it snows? Do you have to get up on the roof and clean them off by hand? Or do they have built-in defrosters? Nothing. In northern climates rooftops usually have more of a pitch to them so snow doesn't accumulate (because you don't want the roof to collapse). The panels, because they are black, will generally collect enough heat to melt the snow in a day…

Northern climates is relative. I live in the north of Sweden and the solar panels here will be completely covered from December to February or similar. It's true though that the snow will melt or fall off quickly when it's not that cold anymore.

In the yukon we brush them off. Still plenty of power generated at -40C.. though the days are not very long!

Re: Solar panels reduced my electric bill in 2022

#428

Post by belorn » Wed, Jan 04, 2023, 1:07 AM UTC

burnished wrote: post #397

FartyMcFarter wrote: post #373

Earlier quoted context omitted.

Net metering doesn't make sense for a simple reason: - when you use power, the grid is forced to produce it for you at that specific moment. - on the other hand, solar panels produce energy at random times, regardless of whether it's needed or not. Net metering forces symmetric pricing into a fundamentally asymmetric situation, which is not scalable. You could think of similar asymmetries in other contexts where the…

Your analogy introduces factors that aren't present in the system, I dont think you need to use one here. Solar panels arent exactly random for one, pizzas arent fungible for two, and the grid is already composed of many producers and consumers for three.

Energy as a service isn't fungible either. You can not trade energy at one point in time with energy at an other point in time and expect both to have identical value. There are many energy speculators which trade is to determining when prices are low or high, and with good weather predictions its not that difficult to make a accurate guess about the price a few days ahead in time.

Re: Solar panels reduced my electric bill in 2022

#429

Post by greedo » Wed, Jan 04, 2023, 1:19 AM UTC

prettychill wrote: post #113

kube-system wrote: post #68

Earlier quoted context omitted.

The electricity prices listed in the article are quite high, the US average is about half of that.

This is a great point. Avg cost for me last year was less than half, around 11c/kWh Though, https://www.eia.gov/electricity/state/ makes me wonder how you are getting 25c/kWh prices, as author estimates. Maybe higher price tiers due to usage.

I pay around ¢10/kWh (including all my connection fees plus the stupid surcharge from last years Texas debacle).

Re: Solar panels reduced my electric bill in 2022

#430

Post by Retric » Wed, Jan 04, 2023, 1:28 AM UTC

mcv wrote: post #419

Retric wrote: post #404

Earlier quoted context omitted.

Solar also produces power when demand is at it’s absolute peak. It varies by location but prices are still cheapest at night the vast majority of the time. There’s many ways to do net metering, but regulations are setup to maintain profitable local utilities. Utilities hate it because they make less money by selling less electricity not because it’s ever going to drive them to unprofitability.

I think the demand peak is in the evening. Whether that overlaps with daylight depends on the season. I suppose in areas where people use a lot of AC, peak demand might be earlier in the day, but I haven't seen any figures showing that. I have seen the evening peak.

It really depends on what you mean by peak demand. From the grid’s perspective a home with rooftop solar has zero demand during peak solar production.

However, that’s ignoring the home actually uses electricity during that period it’s demand simply isn’t something the utility can make money from.

Similarly, transmission losses increase as temperatures rise which requires more production to offset those losses. From the perspective of a natural gas power plant that load is just as real as actual customer demands because utilities need to pay for it.

Finally, time zone boundaries and suburbs being on the east or west of cities on the coast make a noticeable difference. https://www.dailymail.co.uk/sciencetech/article-2572317/Are-...