Buying back power

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MR. S

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When generating your own power such as with solar panels, the power Co.
will buy back unused power. Could someone in brief explain how this actually works? Thanks in advance, Mr. S.
 
In 42 states there are laws that require the POCO to install a bidirectional meter if a customer wishes to generate their own power. The utility sets standards for the frequency and voltage that the customer's inverters or other equipment must adhere to. In some states you can actually get a check because you're selling power back in the daytime at higher peak rates and buying power at night when lower rates are in effect, but this depends on the state laws. Most utilities are reluctant to participate in net metering because of the amount of the work involved just for some residential customer to end up buying less power from them, especially at this point fairly early in the game when utilities aren't too familiar with net metering.

Either way, with a net metering arrangement it saves $15-20k in battery and battery inverter costs for a residential PV or wind system.

Jeremy
 
mdshunk said:
Keep in mind that they sell it to you at retail, and buy it from you at wholesale.
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If I'm not mistaken, net metering implies that the same rate applies for power in either direction.
 
LarryFine said:
If I'm not mistaken, net metering implies that the same rate applies for power in either direction.
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That varies from place to place, or rather POCO to POCO, depending upon who has a gun to their head. Here in Calif. they pay back at the same rate (known as a "Parity Buyback Scheme), but your bill can never be a negative number (they will never owe YOU money at the end of the month). Wisconsin Energy pays back 22.5 cents / kWH; higher than what they charge (known as a High Buyback Scheme), but provide it in lieu of any installation incentives. Low Buyback schemes are out there as well where they pay back at lower rates, but they usually have very high installation incentives.

What I find interesting (but not surprising) is that you pay taxes based on the energy you buy from the POCO at night, but you then pay income tax on the value of the energy you sell back! Funny how that works out isn't it?
 
In our area,for a "solar farm" the rate is 42 cents/kw-hr.The energy is not stored,it is sent directly onto the grid.Each month the utility sends a cheque to the farm owner.
 
Jraef said:
What I find interesting (but not surprising) is that you pay taxes based on the energy you buy from the POCO at night, but you then pay income tax on the value of the energy you sell back! Funny how that works out isn't it?
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With net metering, there's no way for the utility to know how much you've produced or how much they've sold - all they get to see is the sum based on the monthly reading.

Here, the utility will "bank" any monthly credit and it can accumulate for up to one year, when it is converted into a check besed on the current wholesale Kwh cost - which of course is signifigantly less than the retail Kwh rate.
 
here it is poco based as well in our area you put it all on grid no storage and poco cuts you check monthly and your electric bill is due monthly the only real winner is the goverment taxes both ways..
 
MR. S said:
Could someone in brief explain how this actually works?
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Are you asking how the financial arrangements work? If so, there are several replies with varying schemes.

But are you asking instead how it works on a technical level? Your machine(s) are in parallel with the utility's machine(s). Power flows from all machines to all loads. If by chance the loads within your facility are lower than the amount of power your generator is providing, then the excess power will flow into the utility grid.

That's very general. Did you want something more technical? Can you clarify your question?
 
Germany does solar right. Some cities buy solar power at $.50/kWH and that rate is guarenteed for 20 years. They are trying to get to 20% solar by 2010, they are on track to be at 30% by then. Now someone has to pay for that rate, the average customer pays about $10/month more on thier bill but most people feel that they are contributing to green energy.

Because of this program Germany has the highest production of solar panels which has reduced the cost of installing systems (And many new jobs from the new manufacturing industry they have created). Solar panels can be found on about every flat roof in these cities, not to mention some huge solar farms.
 
MR. S said:
So the unused power is actually backfed into the grid, you wouldn't think anything would be backfed for safety purposes.
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The electrical protection on the generating equipment will need to meet the utility company interconnection requirements. The relaying and protection scheme becomes increasingly complex as the amount of energy generated and sent onto the grid increases. In essence, if the utility has a trip or breaker opens where your interconnected, it will cause your generating equipment to go into island mode, which may inadvertently cause a shutdown (depends on what/how you are producing the power) of your equipment. When the point of your interconnection is re-established by the utility, a signal or permissive to close will be sent to your equipment allowing it to re-synchronize. This keeps you from feeding a fault on the utility electrical system. It's nothing new although more prevalent in some areas of the country.

Is there some other safety issue you have concerns about?
 
I was looking for the technical part, All the replys were helpful, Kingpb & Charlieb pretty much helped sum it up for me, I thought it worked like that, I wasn't 100% sure. Thanks again
 
ghostbuster said:
In our area,for a "solar farm" the rate is 42 cents/kw-hr.The energy is not stored,it is sent directly onto the grid.Each month the utility sends a cheque to the farm owner.
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Did you mean 4.2 cents per KW-hr? 42 cents sounds like a bargan. At that price I think I could just buy it here, and ship it out to you to resell at a profit:grin:

Steve
 
steve66 said:
Did you mean 4.2 cents per KW-hr? 42 cents sounds like a bargan. At that price I think I could just buy it here, and ship it out to you to resell at a profit:grin:

Steve
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Steve:

The rate is 42 (forty two) cents per kw-hr.

Our local gov't is partly subsidizing that rate in addition they provide great financing rates for new solar equipment purchases.

With all that, the payback is still not that great.
 
ghostbuster said:
Steve:

The rate is 42 (forty two) cents per kw-hr.

Our local gov't is partly subsidizing that rate in addition they provide great financing rates for new solar equipment purchases.

With all that, the payback is still not that great.
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what would prevent someone from plugging an extension cord into his neighbor's outlet and feeding power bought at 10 cents/kwhr back to the utility at 42 cents/kwhr?
 
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