Renewable Energy

theprestige said:
TGZ is talking about Chinese solar gigafarms covering tens (and potentially thousands) of acres of desert wilderness. If rooftop solar is so awesome, why isn't China just putting solar on roofs? Rooves?
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They are. In huge quantities. At least, Google AI seems to think so.
China is experiencing an unprecedented boom in rooftop solar, installing a record 36 gigawatts (GW) in the first quarter of 2025, driven by policies promoting self-consumption to manage grid congestion. These installations, heavily featuring affordable Chinese-manufactured panels, are being deployed on residential, commercial, and industrial, and factory rooftops to meet sustainability targets.

Key Trends and Information
  • Massive Adoption: The first quarter of 2025 saw a record 36 GW of new rooftop capacity, following a strong, state-supported push for "distributed" solar.
  • Policy Drivers: New guidelines, effective May 2025, encourage "self-consumption" (using the power on-site) and restrict large-scale projects (over 6 MW) from selling excess power directly to the grid to stabilize grid congestion.
  • Factory/Industrial Focus: In regions like Guangdong, regulations require 50% of new factory rooftops to be covered by solar by 2025, reaching full coverage by 2030.
  • Technological Innovation: Beyond traditional panels, China is adopting BIPV (Building-Integrated Photovoltaics) and lightweight, flexible panels (e.g., eArc) that can be glued onto surfaces.
  • Cost and Impact: The rapid industrial expansion of Chinese companies has driven the global cost of panels down, with prices dropping from over $8 per watt to under $0.50 per watt in roughly a decade.
  • Supply Chain Concerns: While affordable, some Chinese panels have faced scrutiny regarding the use of forced labor in the Xinjiang region, resulting in import restrictions in some countries.
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Panel price hasn't really been an issue for 10 or so years. It is a minor component of the price of installing panels and storing excess energy to be used when the weather conditions prevent electricity generation.

I get around 10kWh a day from my panels during March-August, but literally 0-2kWh Dec-Feb (usually 0, since there is no point clearing snow from them with no sun). For now I am selling the excess production to the power company, but with spot prices being pretty small during summer, it doesn't really cover much. My system will have a payback time of ~30y without any additional costs. Significantly less if I can get neighbors EV cars charged during summer and have them pool into costs a bit, but that would be a taxation/bureucracy nightmare.

Most promising tech for storing power would be reservoirs/hydroelectric combo - fill reservoirs up during summer and use hydroelec during low production. Predictable and easy. Spends a lot of excess power tho, but when the panels work, they provide massive overproduction anyway.
 
until the grid is upgraded and reorganized, private EV production will and probably should take a back seat to solar farms with dedicated energy storage.
But if you have an EV and roof space, PV is a no-brainer.
 
Blank said:
Panel price hasn't really been an issue for 10 or so years. It is a minor component of the price of installing panels and storing excess energy to be used when the weather conditions prevent electricity generation.

I get around 10kWh a day from my panels during March-August, but literally 0-2kWh Dec-Feb (usually 0, since there is no point clearing snow from them with no sun). For now I am selling the excess production to the power company, but with spot prices being pretty small during summer, it doesn't really cover much. My system will have a payback time of ~30y without any additional costs. Significantly less if I can get neighbors EV cars charged during summer and have them pool into costs a bit, but that would be a taxation/bureucracy nightmare.

Most promising tech for storing power would be reservoirs/hydroelectric combo - fill reservoirs up during summer and use hydroelec during low production. Predictable and easy. Spends a lot of excess power tho, but when the panels work, they provide massive overproduction anyway.
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Wow. Where do you live? My panels generate 20-30Kwh a day or so for 9 months of the year and the payback will be about 5 years. If I knew it was 30 years I wouldn’t have installed them. Are you being truthful, or did you just make a stupid decision by installing panels in a poor location?
 
lionking said:
Wow. Where do you live? My panels generate 20-30Kwh a day or so for 9 months of the year and the payback will be about 5 years. If I knew it was 30 years I wouldn’t have installed them. Are you being truthful, or did you just make a stupid decision by installing panels in a poor location?
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That's uncalled for. What about the other 3 months, since he said Dec-Feb, which is 3 months. And neither of you said how many (or what area) of panels you have. It's not necessarily stupid if works for 9 months a year. Does it snow where you live?
 
lionking said:
Wow. Where do you live? My panels generate 20-30Kwh a day or so for 9 months of the year and the payback will be about 5 years. If I knew it was 30 years I wouldn’t have installed them. Are you being truthful, or did you just make a stupid decision by installing panels in a poor location?
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There's a significantly shorter payback period if you use your own solar to charge your EV. With the cost of fossil fuel (petrol, diesel) for cars approaching usury now, being able to charge an EV from solar means day-to-day car travel costs are reduced/eliminated too, not just household power.

In our case, we are running an EV and our solar went in six months ago. Since then, I have had to resort to grid-charging the car exactly once. Otherwise, it gets charged off the sun for free, even in winter. It has been driven nearly 10,000 kms in that time. That would have been the equivalent of 20 tanks of diesel for our old CX-5. At $120 per tank, that would have cost us $2400 in fuel alone. And that's just in six months. So we estimate solar will save us $5000 per year in vehicle fuel costs alone. That is a large percentage of the cost of the solar/battery installation.

NB. I don't have a hate thing for fuel vehicles. It's horses for courses. In a number of cases, they are a better solution.
 
Finland at the moment.. So total price for electricity is about 0,06e/kWh on a long time average. I see no point in using any other value for calculating ROI. Especially since I have to draw electricity from the grid on expensive months anyway. Economically installing those wouldn't make sense unless we have a big spike in electricity prizes. Had 1 year when it looked like they would pay themselves back faster but electricity prices went back down.

Installed it 5y ago with 8x300W panels. I mean the angle could be better, but otherwise it is running about what is expected and has produced ~2000 kWh a year (0,9ish factor)

*corrected 0,06snt -> 0,06e.. Stupid me
 
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Blank said:
Finland at the moment.. So total price for electricity is about 0,06e/kWh on a long time average. I see no point in using any other value for calculating ROI. Especially since I have to draw electricity from the grid on expensive months anyway. Economically installing those wouldn't make sense unless we have a big spike in electricity prizes. Had 1 year when it looked like they would pay themselves back faster but electricity prices went back down.

Installed it 5y ago with 8x300W panels. I mean the angle could be better, but otherwise it is running about what is expected and has produced ~2000 kWh a year (0,9ish factor)

*corrected 0,06snt -> 0,06e.. Stupid me
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So actually, the reason it takes so long is due to cheaper electricity.

Electricity costs in Australia generally range between 24c and 45c per kWh, with average residential bills approximately $125 per month or $1,500+ annually, heavily influenced by state-based regulations. South Australia (SA) and regional Queensland often face the highest rates, while South East Queensland (SEQ) has some of the lowest. Daily supply charges typically add another 70c to 120c per day.
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One Australian dollar = about .59 euros. So that's about 0.14 to 0.27 e/kWh.
 
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