111–120 of 262 posts
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tibbydudeza didn't post about a fast payback period. Maybe neebz is his wife?
Broadly speaking, payback period in South Africa is very fast due to similar grid economics to Pakistan.
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That's a 7% yearly ROI, which is a pretty decent number, better than you'd do on average in the stock market and more predictable. If he had a little storage so he didn't have to sell any, it would improve further. But also 6000W of panels in the low-cost category now costs €300: https://www.solarserver.de/photovoltaik-preis-pv-modul-preis...
You need more information to calculate the ROI. I gave you the peak efficiency, Which comes from clean panels and no clouds. The average efficiency is closer to 70%. While the canaries are pretty sunny, the panels get dirty very quickly (fine dust from Sahara), Actually, if you count cleaning costs, the ROI goes down even more. And also consumptions is at its peak in the evening when there is no sun. He was thinking…
Anyway, you said they paid €7000 and get back €500 per year, which is enough to calculate the ROI at 7.1% per year.
Powerwalls are indeed extremely overpriced. But battery prices are down to below US$70/kWh (US$19/MJ, €17/MJ); if we assume the maximum production in a day is about 25%, that's 36 kWh (130MJ), so it would be about US$2500 for that amount of battery. But probably even €500 of battery (7.2kWh) would make a big dent. That would be 1800 watts for four hours in the evening.
Depending on the type of evening consumption, it might be possible to ameliorate it dramatically with various kinds of thermal storage, or even plugging the washing machine into a timer. Those are much cheaper than batteries.
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Don't they charge a minimum just for keeping the wires connected?
When they start charging that way, the rich will buy batteries and disconnect from the grid entirely.
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In a random German apartment usage tends to be on the order of 30-ish EUR per person, and the connection fee is typically around 10 EUR per month.
Is the €30 usage fee going directly to the producer of electricity, or is part of it a variable transmission fee that goes to the network operator? My monthly electricity bill in Sweden, averaged over a year to 1600KWh/month, is approximately €90 production, €50 transmission fee, €25 fixed connection-size fee (25A, 400V), €70 national electricity tax and €50 VAT for a total of €285/month. We'll be moved to yearly-pea…
It basically pays off the grid stability provision bids for fast-response power, and the transmission itself.
It'd likely be helpful if the peak part could be regulated in a way that's more condusive to match the actual impact you create on transformer sizing, not the worst-case impact you might have. Because there's a difference between a mostly-uncorrelated peak of shower+cooking vs. the car+cold day, because your neighbours don't shower the same time, but the several hours of charging do often overlap and the cold is the same across a neighbourhood that shares a local substation.
But yeah, for the most part, transformer size isn't that large of a contributor to overall electricity provision expenses, so I don't expect that to be a significant problem by that 2027 law.
Imagine being the CCP and you’ve managed to turn your industrial capacity into the world‘s single largest renewable energy source. PV‘s Saudi-Arabia.
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Grids in Germany if you're not a "typical household/office" with therefore atypical grid usage bill for peak power and energy separately; the billing related peak power is measured by averaging power over 15 minute chunks, and taking the worst one of a year. Alternatively it's also practical for such solar situations to bill for market rate price of the energy in each 15 minute chunk separately; this doesn't correctl…
> averaging power over 15 minute chunks, and taking the worst one of a year. What an interesting metric. Wouldn't even a very cheap and small battery (definitely small enough to keep inside an appartment) provide enough smoothing to, like, halve this peak number? You could rig it to not even output energy until you are beyond the current year's peak usage... How much money would you save this way? I just feel this nu…
The 15 minute chunks are due to the German and much of the European grid market being in that chunk size.
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> averaging power over 15 minute chunks, and taking the worst one of a year. What an interesting metric. Wouldn't even a very cheap and small battery (definitely small enough to keep inside an appartment) provide enough smoothing to, like, halve this peak number? You could rig it to not even output energy until you are beyond the current year's peak usage... How much money would you save this way? I just feel this nu…
> relationship between users' reward/punishment and the grid's health seems wildly disproportionate. It's still much closer to the real costs for the grid operator than $/kWh. The fundamental problem that rooftop solar has revealed is that people think they are paying for the electricity, but they are not. Electricity is dirt cheap. Most of what they are paying for is the maintenance of the grid, and simple usage bas…
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> averaging power over 15 minute chunks, and taking the worst one of a year. What an interesting metric. Wouldn't even a very cheap and small battery (definitely small enough to keep inside an appartment) provide enough smoothing to, like, halve this peak number? You could rig it to not even output energy until you are beyond the current year's peak usage... How much money would you save this way? I just feel this nu…
> Wouldn't even a very cheap and small battery (definitely small enough to keep inside an appartment) Like namibj mentioned, this does not apply for residential contracts.
We switched to solar in 2021 expecting a 3.5-year payback. Electricity prices rose so fast that we recovered the investment in under two years. Also the national grid is notorious for it's frequent blackouts (load-shedding) since the early ’90s. Solar allowed us to have uninterrupted supply in the mornings and longer backups during night.
We got roof top solar 1.5 years ago in Canada. Payoff will be 6-7 years, but we got an interest free loan to cover it. So we’ll just pay what we would have for power for those years ~$1000 a year, then we’ll have free power for 20 more, saving something like $20,000 for $0 investment.