What's the difference between a new solar farm and new solar panels on roofs (or the ground) ?

The solar farm produces more energy per dollar spent. Rooftop solar is expensive. It produces comparatively fewer kw to amortize the fixed costs over - permitting, getting up on the roof etc.

If a country has abundant land and expensive labor, the money is probably best spent improving grid transmission capacity and otherwise getting the f- out of the way of utility-scale renewables. Places like Pakistan, which is going through a rooftop solar boom, are arguably the opposite - scarce land in the cities, but cheap labor to get up on roofs.

Happy to hear any analyses to the contrary and update my knowledge accordingly.

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PaulDavisThe1st 3 hours ago | parent [-]

OK, so rooftop solar is a higher <currency-unit>/kW solar farm. That's one argument against it.

On the other hand, it is also distributed which from some perspectives is a benefit, and is also do-able with very little planning and grid extension. So that's one argument for it.

How things come out on balance depends a bit on what you value and how you imagine the future.

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triceratops 3 hours ago | parent [-]

The generation is distributed. That only benefits the people who have panels on their rooftops. If we want them to share the excess with others during a power outage it requires further grid investment.

I think homeowners should install solar panels and batteries where it makes economic sense. If there's money left over after funding utility-scale solar then it should be used for EV incentives and/or funding electrified mass transit. The whole point is to electrify everything rapidly and reduce carbon emissions.

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margalabargala 2 hours ago | parent | next [-]

You absolutely do not want them sharing the excess with neighbors during a power outage, this is how you get dead linemen.

Solar panel grid tied inverters generally will refuse to function if there's no external power coming in.

The benefit from the distributed generation means that if your local area has large loads added you don't necessarily need to upgrade the HVDC lines from the power plant to accommodate.

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bluGill an hour ago | parent | next [-]

This is not as big a problem as it sounds - you cannot provides enough power for you neighbors and so your breakers (fuses) will cut power long before the lineman gets there.

though linemen are trained that they are working on a live line unless they have personally shorted it out. There are many other ways a seemingly dead line can be live so they don't take a chance.

	▲	PaulDavisThe1st an hour ago \| parent [-]
		> This is not as big a problem as it sounds - you cannot provides enough power for you neighbors and so your breakers (fuses) will cut power long before the lineman gets there. The load side (your neighbors) cannot pull more power than is being generated. My 7kW array can generate 7kW and no more. No breakers will trip in a hypothetical scenario where my inverter fails to shut down during an outage, and my neighbors are trying to drawing 10kW.

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triceratops 2 hours ago | parent | prev [-]

Upvoted.

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direwolf20 2 hours ago | parent | prev [-]

Solar farms don't work during power outages either. When the power isn't out, you get to use the power from your neighbor's solar panel.