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Grid connected Solar PV in H-Town - any experience?


Leon

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Does anyone have experience with grid connected Solar PV in Houston? My house could be a pretty good place for PV panels: low slope south roof; fairly high power bill (in the summer). I looked at Southwest Photovoltaic website and the cost is pretty high: a 3 kW (peak power) system costs $20K (and probably more due to certain excluded items). What is difficult is to estimate annual production from the system: they say minimum is 390 kW/mo, but I would hope it should make more: 3 kW * 6 hrs per day * 30 = 540 kWh. If the system makes 500 kWh/mo and costs $20K, then payback is about 266 months assuming 15 cents / kWh power. Pretty long but could be better if power prices keep climbing.

Questions:

- Has anyone had any experience with Solar PV?

- Any reputable contractors (on spec, on budget, on schedule)?

Thanks!

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... they say minimum is 390 kW/mo, but I would hope it should make more: 3 kW * 6 hrs per day * 30 = 540 kWh.

I'm not PV expert, but I think you're ignoring clouds. I'm going to guess that 3 kW figure is in direct sunlight.

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Does anyone have experience with grid connected Solar PV in Houston? My house could be a pretty good place for PV panels: low slope south roof; fairly high power bill (in the summer). I looked at Southwest Photovoltaic website and the cost is pretty high: a 3 kW (peak power) system costs $20K (and probably more due to certain excluded items). What is difficult is to estimate annual production from the system: they say minimum is 390 kW/mo, but I would hope it should make more: 3 kW * 6 hrs per day * 30 = 540 kWh. If the system makes 500 kWh/mo and costs $20K, then payback is about 266 months assuming 15 cents / kWh power. Pretty long but could be better if power prices keep climbing.

Questions:

- Has anyone had any experience with Solar PV?

- Any reputable contractors (on spec, on budget, on schedule)?

Thanks!

Like meme said, on days that are cloudy or raining, the array produces much less electricity. Also, it is less efficient the hotter it is (kinda weird for something that works off of sunlight, but true), so this affects power output as well.

The owner of Southwest PV is a friend of mine, and an Aggie, but I've never given him $20k for a solar array, either. Give them a call. They'll explain all of this stuff to you. Or google it...lots of sites explain why you never get the peak power.

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  • 1 month later...
Like meme said, on days that are cloudy or raining, the array produces much less electricity. Also, it is less efficient the hotter it is (kinda weird for something that works off of sunlight, but true), so this affects power output as well.

The owner of Southwest PV is a friend of mine, and an Aggie, but I've never given him $20k for a solar array, either. Give them a call. They'll explain all of this stuff to you. Or google it...lots of sites explain why you never get the peak power.

I am not convinced that there is a good upside. First of all, 6 hrs/day already takes clouds into account. Secondly, power prices are going up - current peak ERCOT rates are way north of 20 cents / kwh (note that Natural gas is already above $13/MMbtu and climbing). Key issue is whether centerpoint would allow net metering (i.e. meter rotating backwards when solar panel is at max rates). Also solar would make the most sense if power companies implement time of use pricing (see http://mospublic.ercot.com/ercot/jsp/balan...ervices_mcp.jsp for actual real time power price in Texas; note how high prices get during afternoon - this would be the peak power production by a solar panel. Should electric provider allow you to take advantage of this pricing, payback will be pretty good.

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http://www.dsireusa.org/library/includes/i...CurrentPageID=1

Looks like the free market only applies to middlemen. This link suggests that the Texas Lege outlawed net metering in those areas where electricity competition has been introduced....basically, all of us. I suppose that as long as you do not get too big a system, so that you never net meter, you are all right. I would also suppose that the only penalty is that your meter may reach zero, but not run backward. However, I have yet to see a single electric deregulation rule benefit the consumer, so I may be completely wrong on this as well.

Could some free marketeer explain to the board why we can't do this?

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The only reason why I would even suggest this is for the very reason that people have been complaining about and that is the increasing power prices.

Right now you can get a 16-16.5 per hour KW, but that is more than in the past 5 years and THAT will go up again in the next few years as fuel prices go up.

I wasn't aware that you couldn't sell power back to grid, so that's a new one on me.

If you CAN NOT sell back to the grid on days you're on vacation, then I guess batteries? I'm not sure, ever dealt with anyone who had a system such as that.

One more factor you need to do is look at the price trends for the past 5-10 years. Every penny increase in power lowers your 26 year payback a tad.

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  • 1 year later...

Have we had any change in this? I know there is now a 30% tax credit and the price of PV panels has dropped slightly BUT do we have net-metering in Houston? I can see this payback period really jumping but not sure and cannot find any information. Thoughts?

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the new meters do calculate what is generated.

Yeah but does Centerpoint give credits? Is it required? Its one thing if we track whats being generated but if we were to get paid retail price it would be something else.

Edited by SaintCyr
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