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Response to kristopher (Reply #10)

Tue Feb 28, 2012, 11:20 AM

13. It does legally create that option, Kristopher

And it is intended to create that option. It's not as if those of us who might do this are going to pick up a phone directory and call homeowners in upper GA one by one. If the law creates an individual right, then it also creates an aggregate right. You have to understand that big hunks of GA are quite rural with low population densities, and farmers naturally think in terms of co-ops.

Our local grid is remarkably stable now - one can go years, including years with hurricanes and 60-70 mile hour winds, without a power outage, but it is rural so there isn't the line capacity to handle the type of power generation that would be set up. A bunch of us are interested in this.

Now I would think this law would work much better for the more metro counties. First, installations would tend to be smaller, and since metro counties have higher population densities most of the households are much closer to higher capacity lines, so there is the ability to move the generated excess. Nonetheless, there would be problems - go to the end of this post to see why.

An appropriate law would recognize the differences and create categories to allow this to be done where it can happen without undue cost.

Solar inverters may stabilize line voltages locally or they may destabilize them. It all depends on the circumstances.

My objection to the bill is that it diverts most of the benefits to those with significant ability to invest and spreads the real costs to those who have no money. This will wind up shorting the real required investments, jacking up the bills of those in trailer parks, and creating a destabilized grid across much of the land area of GA.

Because the bill ignores realistic limitations it is a bad bill.

I realize that you are not that technical, but everyone has known for quite some time that there is a capacity issue with maintaining line voltage in the presence of significant solar penetration (either small solar thermal or PV). Even in Germany they have already run into issues in the more rural areas, and that's remarkable because Germany doesn't really get that much sun so installing X capacity in Germany compared to Georgia generates amost an X-2 or X - 3 load in Germany in some of the areas now seeing grid problems.

Here are two papers that have nothing to do with power companies in GA. The first is non-technical. The second is quite technical:
http://www.nrel.gov/csp/pdfs/45653.pdf

http://itee.uq.edu.au/~aupec/aupec04/papers/PaperID75.pdf
Note that for the purposes of this analysis they are grouping the generating sources into feeders. They are not looking at individual fluxes.

To give you some idea of just how important the local flux issues are, please read this thread:
http://forums.energymatters.com.au/solar-wind-gear/topic942.html

For solar installations to feed power back into the lines, the solar inverter output needs to be a touch higher than the line voltage. But solar inverters have to be set to cut out (stop feeding power) when line voltages rise too high.

Thus there is a paradox in some areas already - those who have installed these systems in some areas actually get more revenue on shady days than on sunny days, because on sunny days the net output of the local installations rises quite rapidly with a high degree of correlation and pushes grid voltages to the max point. So in effect, when the PV installations should be putting out the most, they get to feed in the least.
The not so good news is that the inverter with the monoxs must be of Mediterranean extraction and likes a siesta on sunny days between 10 and 4, occasionally popping its head out to see if there is any cloud about. If there is cloud, it may stay on for a while until the sun shows itself again. When it is on between 10 and 4 it runs ok when it shows grid voltage of under 256V but drops out when it hits 258V.I note that when this inverter is running at 254-257V, the above inverter is showing 2 - 4v less.The Pv array voltage is around 250 - 280V when its running whereas the thins run at around 200V. Today it is raining and I haven't noticed any drop outs and the Grid is showing 252 - 5V. Does sunlight increase grid voltage :?: It managed 4.5Kw on Sunday and 2Kw on Saturday.


If you don't have these systems cut out then you get line faults. If you do set them to cut out, you have to vary cut out voltages because otherwise the synchronized cut outs cause hugely fluctuating line voltages locally. So then you get a situation where those with the higher cutouts routinely drop out on sunny days, causing them to get little revenue while those with the lower cutouts generate more revenue.

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