Time to admit my mistake.

I had thought that rooftop solar electricity was a much worse option than rooftop solar hot water because:

• Vulnerability to cricket-ball sized hail
• Rooftop hot water is about five times more efficient than rooftop solar electricity
• Storage of hot water is easier and less expensive than storage of electricity
• No control over when solar electricity is generated, and is not available at all in peak usage periods
• Batteries for rooftop solar use rare non-renewable materials
• Fairly rapid decay of solar cells over time
• Solar cells stop working when they get hot.
• Batteries for rooftop solar are are so expensive as to gobble up half the money generated by feeding power into the grid.
• Bad inverters could stuff up the quality of grid power for all users.
• Lose all economies of scale possible with centralised power plants
• Can choose between single crystal which is super-expensive, or polycrystalline which is super-inefficient
• In older systems, a drop in the amount of sunlight on one panel will make it shut off entirely
• etc.

I was wrong.

mollwollfumble said:

Time to admit my mistake.

I had thought that rooftop solar electricity was a much worse option than rooftop solar hot water because:

• Vulnerability to cricket-ball sized hail
• Rooftop hot water is about five times more efficient than rooftop solar electricity
• Storage of hot water is easier and less expensive than storage of electricity
• No control over when solar electricity is generated, and is not available at all in peak usage periods
• Batteries for rooftop solar use rare non-renewable materials
• Fairly rapid decay of solar cells over time
• Solar cells stop working when they get hot.
• Batteries for rooftop solar are are so expensive as to gobble up half the money generated by feeding power into the grid.
• Bad inverters could stuff up the quality of grid power for all users.
• Lose all economies of scale possible with centralised power plants
• Can choose between single crystal which is super-expensive, or polycrystalline which is super-inefficient
• In older systems, a drop in the amount of sunlight on one panel will make it shut off entirely
• etc.

I was wrong.

Do we get to find out where you went wrong?

The Rev Dodgson said:

mollwollfumble said:

Time to admit my mistake.

I had thought that rooftop solar electricity was a much worse option than rooftop solar hot water because:

• Vulnerability to cricket-ball sized hail
• Rooftop hot water is about five times more efficient than rooftop solar electricity
• Storage of hot water is easier and less expensive than storage of electricity
• No control over when solar electricity is generated, and is not available at all in peak usage periods
• Batteries for rooftop solar use rare non-renewable materials
• Fairly rapid decay of solar cells over time
• Solar cells stop working when they get hot.
• Batteries for rooftop solar are are so expensive as to gobble up half the money generated by feeding power into the grid.
• Bad inverters could stuff up the quality of grid power for all users.
• Lose all economies of scale possible with centralised power plants
• Can choose between single crystal which is super-expensive, or polycrystalline which is super-inefficient
• In older systems, a drop in the amount of sunlight on one panel will make it shut off entirely
• etc.

I was wrong.

Do we get to find out where you went wrong?

FWIW, a combination of solar electric and solar hot water seems to make sense to me, especially in areas where you need heating in winter.

The Rev Dodgson said:

mollwollfumble said:

Time to admit my mistake.

I had thought that rooftop solar electricity was a much worse option than rooftop solar hot water because:

• Vulnerability to cricket-ball sized hail
• Rooftop hot water is about five times more efficient than rooftop solar electricity
• Storage of hot water is easier and less expensive than storage of electricity
• No control over when solar electricity is generated, and is not available at all in peak usage periods
• Batteries for rooftop solar use rare non-renewable materials
• Fairly rapid decay of solar cells over time
• Solar cells stop working when they get hot.
• Batteries for rooftop solar are are so expensive as to gobble up half the money generated by feeding power into the grid.
• Bad inverters could stuff up the quality of grid power for all users.
• Lose all economies of scale possible with centralised power plants
• Can choose between single crystal which is super-expensive, or polycrystalline which is super-inefficient
• In older systems, a drop in the amount of sunlight on one panel will make it shut off entirely
• etc.

I was wrong.

Do we get to find out where you went wrong?

FWIW, a combination of solar electric and solar hot water seems to make sense to me, especially in areas where you need heating in winter.

Cogeneration – electric power plus hot water – is quite popular overseas, but not in Australia for some reason.

I’m wrong because:

• It’s popular – if it didn’t work then it wouldn’t be popular.
• Fingers crossed a properly designed solar roof panel is no more vulnerable to hail than roof tiles. So it you’re replacing the roof anyway …
• Electricity usage during sunlight hours per person has increased enormously, as we’ve all become far more lazy about not wasting money. It’s not just refrigerators any more. It’s NBN and air conditioning and TV and indoor lighting and sensor lights and home security and chargers.
• Battery is an option not a necessity. Non-renewable materials aren’t a problem in the next hundred years, and by that time battery recycling will have approached nearly 100%.
• Inverters sold seem to be high quality, at least I haven’t heard of any complaints yet.
• Economies of scale can apply to mass production as well as centralisation. Let’s hope that’s true in this case.
• Costs have been coming down and efficiency is going up. Efficiency is 15 to 20%, it used to be 5 to 10%. Polycrystalline tends to be 13% or so.
• I’ve heard that less sunlight doesn’t make solar panels shut off in newer systems.