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Solar power systems don't necessarily come with batteries but a decent installation company should be able to propose and implement an integrated system. The T

Solar power systems don't necessarily come with batteries but a decent installation company should be able to propose and implement an integrated system. The Tesla battery pack is an example of some recent innovation in that area. You can sell power into the grid but PG&E only has to pay you wholesale rates, 3-4 cents per kwh, not what they are charging you to take the same amount of energy out, which is 34 cents per kwh at the top tier. It's basically a scam. You don't want to overbuild on the assumption that selling the surplus would be profitable.

jsprogrammer 11y ago
Is there no real solar power market then? If your local utility is a monopoly then you basically have to accept whatever the utility wants to pay you (even far below 'market' rate). You have no power to negotiate, only capitulate or try to get the local regulator to enforce fair trade.
- thrownaway2424 11y ago
  Local conditions may vary, of course, but if just go with the completely unimaginative system, and you live in California in PG&E territory, there is no effective market.
- _delirium 11y ago
  I suspect you'd fare pretty badly in a market, even if a better one existed. In Texas's deregulated electric marketplace, the market price for large-scale solar installations selling into the grid has fallen to around $0.05/kWh. Power from a single small-scale residential installation with less reliable delivery is probably worth less than that.
  - ZeroGravitas 11y ago
    Depends on how much "better" the market is e.g. if it priced in the greenhouse gas externalities, the avoidance of transmission losses and grid upgrades etc then solar may be worth triple the residential rate. I believe a couple of states have calculated "value of solar" to use as part of their grid regulation, though specific factors like mix of gas and coal production and projected grid expansion factor into this.
    - jsprogrammer 11y ago
      Any reasonable grid would also be wired such that the power you generate will first go to your neighbors, if they need it, instead of 'round-tripping' to the utility and back. So, the utility is taking a huge cut even though it isn't really a factor in the transaction. There are of course large-scale infrastructure costs (you get to fail-over to nuclear/coal/gas/wind/other), but it seems like all of those things should be accounted separately instead of all being lumped into two line items on a monthly bill from your local monopoly.
- marcosdumay 11y ago
  Well, you can go buy a battery.
bostonpete 11y ago
> It's basically a scam. Why is it a scam that PG&E won't pay you more for power than they can buy it wholesale?
- thrownaway2424 11y ago
  The 3-4c wholesale rate is for base power (giant infrastructure generators, hydroelectric dams and such things), but solar knocks the top off the mid-day demand curve, at which time PG&E is paying much more for "peaker" power generation. But they don't have to pay you the peaker rate, they pay you the baseline rate. Anyway, to my mind, any system in which current comes out of your PV installation at 3 cents and flows directly into your neighbor's air conditioner at 34 cents is a prima facie scam.
  - _delirium 11y ago
    Even peaker plants run ~15 cents these days, since the price of gas has fallen so low. edit: I'm more familiar with the Texas grid, but beyond the cheapish price of modern peaker plants, in that case the most expensive input sources (small peaker plants, and esp. spot-market purchases) are rarely used at all. Demand prediction and management is good enough to avoid the more expensive inputs, through a mixture of local generation management and advance wholesale purchases on the DC interconnects. On the handful of days when some issue causes a shortfall, it would be valuable to buy residential solar inputs, but this happens about 5-6 days a year. To handle those days, most utilities have a savings-rebate program, where if you agree to reduce your usage between 2-5pm on these handful of days, you get a $0.60/kwh credit. So they solve their occasional peak problem by just turning your thermostat up 2º and "buying" the unused energy at a premium price.
    - thrownaway2424 11y ago
      Yeah, but that makes PG&E's "smartrate" summer afternoon price of 75c per kWh even less justifiable. This data may not be publicly available, but I'd love to see graphs of current flowing out of PG&E substations vs. time of day. At some point the PV generation capacity is going to make them have weird upside-down diurnal cycles.

jsprogrammer 11y ago

Is there no real solar power market then? If your local utility is a monopoly then you basically have to accept whatever the utility wants to pay you (even far below 'market' rate). You have no power to negotiate, only capitulate or try to get the local regulator to enforce fair trade.

thrownaway2424 11y ago
Local conditions may vary, of course, but if just go with the completely unimaginative system, and you live in California in PG&E territory, there is no effective market.
_delirium 11y ago
I suspect you'd fare pretty badly in a market, even if a better one existed. In Texas's deregulated electric marketplace, the market price for large-scale solar installations selling into the grid has fallen to around $0.05/kWh. Power from a single small-scale residential installation with less reliable delivery is probably worth less than that.
- ZeroGravitas 11y ago
  Depends on how much "better" the market is e.g. if it priced in the greenhouse gas externalities, the avoidance of transmission losses and grid upgrades etc then solar may be worth triple the residential rate. I believe a couple of states have calculated "value of solar" to use as part of their grid regulation, though specific factors like mix of gas and coal production and projected grid expansion factor into this.
  - jsprogrammer 11y ago
    Any reasonable grid would also be wired such that the power you generate will first go to your neighbors, if they need it, instead of 'round-tripping' to the utility and back. So, the utility is taking a huge cut even though it isn't really a factor in the transaction. There are of course large-scale infrastructure costs (you get to fail-over to nuclear/coal/gas/wind/other), but it seems like all of those things should be accounted separately instead of all being lumped into two line items on a monthly bill from your local monopoly.
marcosdumay 11y ago
Well, you can go buy a battery.

bostonpete 11y ago

> It's basically a scam. Why is it a scam that PG&E won't pay you more for power than they can buy it wholesale?

thrownaway2424 11y ago
The 3-4c wholesale rate is for base power (giant infrastructure generators, hydroelectric dams and such things), but solar knocks the top off the mid-day demand curve, at which time PG&E is paying much more for "peaker" power generation. But they don't have to pay you the peaker rate, they pay you the baseline rate. Anyway, to my mind, any system in which current comes out of your PV installation at 3 cents and flows directly into your neighbor's air conditioner at 34 cents is a prima facie scam.
- _delirium 11y ago
  Even peaker plants run ~15 cents these days, since the price of gas has fallen so low. edit: I'm more familiar with the Texas grid, but beyond the cheapish price of modern peaker plants, in that case the most expensive input sources (small peaker plants, and esp. spot-market purchases) are rarely used at all. Demand prediction and management is good enough to avoid the more expensive inputs, through a mixture of local generation management and advance wholesale purchases on the DC interconnects. On the handful of days when some issue causes a shortfall, it would be valuable to buy residential solar inputs, but this happens about 5-6 days a year. To handle those days, most utilities have a savings-rebate program, where if you agree to reduce your usage between 2-5pm on these handful of days, you get a $0.60/kwh credit. So they solve their occasional peak problem by just turning your thermostat up 2º and "buying" the unused energy at a premium price.
  - thrownaway2424 11y ago
    Yeah, but that makes PG&E's "smartrate" summer afternoon price of 75c per kWh even less justifiable. This data may not be publicly available, but I'd love to see graphs of current flowing out of PG&E substations vs. time of day. At some point the PV generation capacity is going to make them have weird upside-down diurnal cycles.