Comment by opportune | Hacker News Reader

Comment by opportune | Hacker News Reader

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Let’s say everybody had rooftop solar and net metering. Everybody produces an excess of energy during the day which they give to the grid, then at night they start pulling energy from the grid. They could very well have a net energy consumption of 0 and pay very little. But someone, somewhere that is connected to the grid has to be doing something to provide that energy at night, whether it’s batteries or a gas peaker plant or pumped hydro or whatever.

Who is going to pay for all that power if none of the consumers are?

At least in that thought experiment, everybody gets to pay little for electricity. But in the real world not everybody can install solar (I live in an apartment building, others in less sunny areas) and not everybody can afford it. So I don’t end up with a net 0 bill and get charged the actual per-kwh rates, which the utility company sets to recoup their costs. Sure I use energy just like the zero-metered folks, but I have to pay full price while they pay very little relative to what it actually costs to give them power when the Sun is down, so I end up subsidizing them.

> Who is going to pay for all that power if none of the consumers are?

The consumers of course, that is assuming the grid uses an hourly rate. When all those roof top solar arrays push power into the grid the price goes down, possibly even below zero - you'd have to pay to push power into the grid and "get paid" [1] to consume power - if the grid is close to capacity. During the night they draw power from the grid and pay the hourly rate which may be - but does not have to be - higher than the rates paid when the sun was up.

What if the grid gets more power in during the day than can be delivered to customers? They can use it to charge their "grid-scale" battery which they use during the peak hours in the evening when everyone comes home, turns on whatever power-hungry devices they have. That battery will save them a lot of money compared to the gas-turbine peak power plant they'd otherwise have to use.

In a hypothetical situation where everyone has enough solar capacity installed to cover their own needs it will be more efficient to have those batteries installed as close as possible to where the power is needed, i.e. in individual homes or possibly at local transformer stations. I don't think they're there yet nor will they ever be able to get there in urban environments with largely multi-storied buildings.

Here in Hawaii the electric company is installing smart meters so they can charge different rates during the day evening and night. So your solar production during the day will credit you at the day rate, then your usage in the evening charges you at the evening rates (about triple the day rate). And then late night usage is about double the day rate.

This mostly solves the retail/wholesale/base rate problem.

You can't push energy into the grid at will, there is simply an upper limit where the inverter will stop raising the voltage and leading the grid phase. So for the grid to accept your power it has to have a drain somewhere.

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