Question to Residential Solar Power Experts - ...

[CRH]

I am presently considering installing a 4-6 panel solar array to offset the future cost of grid electricity. The plan is for a two way meter and grid tied system.

The current price I pay per kwh at a usage rate near 200 kwh/month is about 22 cents. I anticipate, as I get older and might need in house care, a duplex situation and increased usage could occur.

The initial cost of an array, converter, two way panel and meter, and installation will be significant, but not overwhelming. But I fear it will be 'high risk'.

Electrical storms here have been getting more intense, with more ground strikes every year occurring. Three or four times a year, often for a hour or more, we are peppered with lightening, many strikes are flash/bangers very close indeed. You can actually feel the static electricity resulting, sometimes the hair on your arm will stand and tingle.

I have been reading about lightening and grounding electrical systems, components, and appliances; including articles specific to solar arrays and collection systems. They all say about the same thing, in areas with high electrical storm activity, thorough grounding is necessary to give you the 'best chance' of diffusing the electrical charge from a near strike by diverting the energy away from the components of the system. It is obvious with a direct hit the game ends, but what about a near miss?

Most of the articles I am reading are from the solar industry itself. None of the articles are giving any indications how likely it is, even with grounding, the whole investment could be rendered worthless in a single flash bang event.

If a professional in a high activity electrical storm location installs a hundred systems, and severe damage to ten systems is realized before the fifteen year payoff, that would seem pretty high odds. If on the other hand, one in a thousand systems didn't make it to payoff, that would be different. There is a point when accepting a high electric bill and allowing the electricity company to shoulder the risk, might be more prudent than a cost offsetting self generation system.

Nowhere can I find articles or information from sources independent from vested interest, that gives an indication of the risk to investment from lightening in high activity areas. Does anyone know from experience or have sources that could help me evaluate this risk scenario, or is buying solar in this situation, equal to visiting a casino? Do you feel lucky?

Thank you.

[kristopher]

1. Call your homeowners insurance agent

[CRH]

4. I'm checking, but I'm not sure homeowners insurance, ...

even covers that here in Costa Rica. Roof top solar is in its infancy here, and grid tied systems are still in a pilot program. Time and need might change this in the near future, as CR's hopes of 100% clean renewable power by 2021, might be at risk with accelerated changing rainfall patterns. Much of the 80% clean renewable produced now, is hydro, and the mountains are getting drier, and geo thermal is an expensive alternative by comparison.

I expect roof top solar to evolve more quickly, soon.

Thanks for your reply.

[northoftheborder]

2. These are very enlightening questions....

I have no knowledge in order to answer your questions about the statistics of risk with individual solar panel owners, but the question comes to mind, that don't the utility companies assume risks' and losses from the same weather caused outages, lightning, or other, and that we, as consumer would absorb those losses in our bills, anyway? I'm presently debating whether to put solar panels on my house.

[CRH]

5. Those are the same questions,

I am trying to answer now. At this time where I live I'm not sure there is an insurance solution, and I am sure the electric company will not be assuming any risk my side of the meter. So then it becomes a matter of measuring risk.

Thanks for your thoughts.

[Yo_Mama]

3. No expert, but this will give you some tips

http://www.solarinsure.com/protect-your-solar-power-system-from-lightning

When you hire a contractor ask what the contractor recommends). If the recommendations seem "off" then maybe you need to find another contractor.

There are some very specific instructions in that article. The grounding will be your most important line of defense, but a standard ground isn't good enough based on what you are saying.

You would definitely want lightning arrestors installed.

More technically, here is an NIST paper:
http://www.eeel.nist.gov/817/pubs/spd-anthology/files/Protect%20solar%20cells.pdf

There is some really good information in that paper.

The possibility of getting a pretty strong electric pulse in 10 years is not that low, based on what you are describing. The probability of a direct strike is probably very low. Therefore good grounding of the frames and mounts, controlling exposed wires, and lightning arrestors on cabling is important. The risk of picking up a strong pulse does increase because of the area covered by the mounts and frames on the roof, so grounding with multiple rods is a good idea. Especially if the ground gets dry. Wet ground sucks up the electricity, dry ground doesn't very well.

Finally, here is an article from Germany on this topic. I would consider installing a lightning rod system if I were you (e.g. evaluate the need), but this paper (excuse the German-English) is very understandable and explains the considerations:
http://www.dehn.de/pdf/blitzplaner/Chapters/BBP_E_Chapter_09_18.pdf

Especially important is the part of this article that explains the necessary space between the lightning rod and closest piece of the solar system. The cones of protection issue is covered in the NIST article.

If your building is sited relatively close to higher buildings, you may not need the lightning protection system. But if you feel the electricity from discharges already, my guess is that you will need multiple-point grounding and the lightning arrestors. You are making an investment that should last for 30 years, so the extra cost for the protection is well worth it.

[CRH]

6. Thank You for your reply and links, ...

I'll read the papers. Another factor is that all the roofs around me are near the same height, and all are metal. Thanks again for the links, much appreciated.

[Yo_Mama]

7. I would go with the lightning rod too then

It's a lesser risk, but it's a risk. The other stuff will not suffice for a direct hit. But then you need to plan your system carefully so that it is within the protection zone and totally excluded from contact with the lightning rod and that does mean that the necessary distance should be maintained and that there should be no points of conductive contact.

[CRH]

8. Thanks again, you give a wealth of information, ...

and several avenues of research.

[CRH]

11. I think your second link (NIST paper), ...

has possibly saved me considerable investment, and at very least tempered my entrance into the proposed project described in the original post.

Many people would not face the same problems I have come to realize, could very serious for my situation. Not only is my location very active for potential strong electric pulses, but the location of my house to others, the relative height, and the materials of construction; all add risk to the situation.

The problem that arises, is my home is one of many running in a a north/south direction on the street I reside. To the east is over a thousand yards of open space, to the west is the road and commercial electric service. The houses are built with very little distance to the road, but huge back yards. The houses are also very close together, often with less than a meter in between when not sharing walls. Therefore the roofs are often less than a meter apart when not slightly overlapping. The roofs are all metal of varying designs. The basic construction is concrete block.

So a lightening strike affecting my southern neighbor would easily through arcing travel through my roof if the current could not find a suitable conductor to the ground. The same would be true of my two nearest northern neighbors. All the houses in this area were constructed near the same time, 1960's, and unless remodeled, the electrical systems are not grounded to anywhere near today's standards. So, even if my house is remodeled with new code electrical grounding standards, that in noway protects me from transference from neighboring homes.

Lightening masts creating 'attractive points of termination' for lightening step leaders would need to be more than fifty feet from ground level and could only be positioned on the east side. The cone of protection would then be only partially effective.

On the west side, the grid service has a concrete service pole five meters from the corner of my house, and a large metal transformer just three meters above roof level. It makes me wonder if some of that hair raising static electricity after a flash/bang strike, might be that transformer and the existing service lines are acting as a lightening mast of insufficient height, to properly cone my house, and are instead lighting me up.

At any rate I have read enough to come to a decision. In view of my individual high risk situation, it is best to start out with a smaller investment of a thermosyphen pressurized evacuated tube system with an auxiliary heat element for a roof mounted 200 liter tank for the hot water, and see how that works out first. Then in a few years if I see roof top PV start appearing in this location with similar circumstances to mine, perhaps pursue the more ambitious project of a grid tied generation system.

Again, thank you for the links the information I was have trouble locating. hrh

[kristopher]

12. The primary risk is from the grid connection

And that can be easily managed with surge protectors. I've lived in thunderstorm prone areas and I have trouble believing the risk of direct lightening strike is so abnormally high there. Then again, it is your pocket the money is coming out of so our perceptions are based on different stakes.
Insurance is a routine part of the cost of solar installations (annual premiums about 0.25-0.5% of the cost of the system IIRC) so I wouldn't give up on that avenue. However, as you obviously know solar is just now taking off so it may be a case where you need to become the instrument of education for the local insurance reps.

Good luck, the thermal sounds good in any case.

[CRH]

13. Can you then, refer me to, ...

an insurance that is a routine part in the cost of Costa Rica installations? I don't intend to be antagonistic. I don't want to give up on that avenue, I want to help. But how, within the current restraints of the system?

As far as the belief of direct lightening being a risk, it doesn't have to hit you to be a risk. If it makes the hair on you arms stand up, you might want to pay attention.

I'm not giving up on anything, I'm waiting to be convinced, that in my situation, prudence will be out measured by hope.

[kristopher]

14. Are you telling me they don't have insurance companies operating in Costa Rica?

I can accept they may not have any expertise with solar, but if that is true it is also true that someone somewhere there will soon be the first policy written.

This isn't rocket science.

[CRH]

19. Reply #4, no there are insurance companies, ...

but as I said, I am checking. It is not as easy here to just call someone up and get a quote or discuss coverage of a new technology. First there is the language barrier, and second there is a different way of doing business in CR. Just try banking here, your will soon notice within the different culture there are different business methods and expectations as well.

The largest insurance company here is INS, I have queries in to determine if there is a reasonable priced insurance for residential solar arrays and systems. In due time, I will have the answer. If the price were reasonable, I would certainly go ahead with the plan I described in the OP. The problem will be having a large enough pool of clients to average the risk. Like I said, residential rooftop solar is in its infancy, and grid tied systems are still in a pilot program.

[kristopher]

22. Actually the only insurance company in CR is INS

I just spoke to an agent who assured me that solar panels are covered (against lightening and other hazards) by the standard homeowners insurance which you are required to have. You should present the bill (and plans?) from the installer to the agent to have the panels incorporated into the policy.

If your agent doesn't speak english let me know and I'll PM you the name and number of the person I spoke to.

[CRH]

25. Great that solves that problem, ...

I am still waiting for a reply from the local office, as of this afternoon. And english is not spoken in this location, so if you could PM me the name and number of the person you contacted, that would be great. Thank's so much, and now on with the project!

[Yo_Mama]

17. I'm sure you're right about the source of the pulses you get in the house

That makes absolute sense. Those are the high points and metal, and you get bleed-off. I've noticed that metal frame windows in buildings pick up enough of a pulse to transfer charge to near-by wiring with any exposed metal.

The solar water heater sounds like a good idea.

If you have a very large back yard, what about a rack-mounted ground system? One of the things I've been thinking about are "tree" systems, because they have the potential to produce a longer, steadier flow of electricity.

Solar cells are pretty cheap, and I've thought about experimenting with those myself.

I think that the next few years are the golden time for working with solar stuff. The cost of manufacture will stay low for a few more years and then I think it will go up. Right now it's artificially suppressed due to overcapacity in China and an absolute neglect of the costly but necessary step of safely handling the toxic manufacturing waste byproducts. So I am trying to figure out how to use this window of opportunity to do some things myself.

[CRH]

20. The ground based array, ...

you mention might well be a solution. All I've read of lightening indicates most of the danger is in situations of high metal strike points above surrounding structures. It would also be easy for multiple grounding sites. Thanks.

[kristopher]

23. High metal strike points?

All homes in CR are required to have lightening rods - AKA a "high metal strike point".

[CRH]

26. By new code Yes, in practice, ...

few older homes have lightening rods separated from the house in cities. Usually just weather heads for the electrical service, which rarely extend as high as the ridge beam, which is covered with metal shingles. When houses are remodeled they are then required to upgrade to new code requirements.

[kristopher]

21. Your understanding of the situation in China isn't accurate

Right now it's artificially suppressed due to overcapacity in China and an absolute neglect of the costly but necessary step of safely handling the toxic manufacturing waste byproducts.

The price is expected to continue to decline as the new plants are far more efficient than the older plants. One of the sources of that efficiency is recycling the waste materials you are "concerned" about since the recycling process costs less than purchasing the equivalent raw input materials.

[Yo_Mama]

24. The new companies are going bust too

That's even with very low component costs, because there was major oversupply there as well.

Then add in the eventual costs of paying for proper waste handling, and you have a recipe for real price rises:
http://www.dailyfinance.com/2012/12/13/china-saving-itself-from-solar-disaster/
http://www.eenews.net/public/climatewire/2013/01/02/1

However this isn't going to happen immediately, and right now pricing is very favorable, so why not do it now?

The loans given are being rolled with interest included, and eventually at least some of that principal must be paid back. Right now China is willing for the state to subsidize below cost sales in order to grab the market. That will not continue forever, and the change will begin to happen in the +3-5 year range.

So I am looking to buy the panel and cells while I still get the subsidy from the Chinese government.

The only thing that could change this picture is if India tries to jump in the market and China continues the subsidy program longer in order to prevent that.

Some of the new technologies coming along look great too. But right now we have a rare opportunity (if your local site has good sun) to get in at a remarkably low cost. The cost on some of the other system components may come down more (like inverters), but I think the base case is that we have a great time frame here to profit from overbuilding.

All the companies that are actually making money right now off solar seem to be building projects, not manufacturing solar panels.

[kristopher]

27. You are just making things up as you go along...

The new companies are already recycling - that's because it saves money and helps reduce costs, it doesn't raise costs. They are also expecting to continue lowering costs for a number of years into the future. However, a further 25% reduction in panel costs is hardly a blip compared to the soft costs that are caused by the policy framework here. You'll see major future savings on solar system cost come from national policies that force utilities (like the one you admire so much in GA) to stop obstructing the installation of solar (and to a lesser degree wind).

[broiles]

9. Thanks for posting this,

We have a solar company coming out today and I'll be sure to ask about this.

[CRH]

10. Good Luck, I hope they have, ...

an informative response. Please post if it would have a bearing on this thread. Thank You.

[quadrature]

15. what does 'two way meter' mean?

two meters, different rates in different directions,
or a meter that runs backward?
(you may already have a meter that runs backward)
.

is 22cents, an average, or for each additional KWh.
(if the latter, that is a lot)

do you really want to pay to change meters, and then go into competition with the local power company?

I think a better approach is to get an array that
is just big enough to zero your use of grid
power when the array is at max output.

[ProgressiveProfessor]

16. Depends on the utility/jurisdiction

In the US most grid tie systems trade watt for watt. You settle up at the end of the accounting period, in my case a year. If you were to install a zero net system, you would over produce in the summer and under produce in the winter. Depending on the jurisdiction, you can get paid for any net overproduction.

[CRH]

18. As I understand the meters, ...

allow for the excess energy of an array to be fed into the power grid. So in the daytime when I am generating far more than I am using, my excess is used by the grid and I am being given credit for when I am drawing from the grid. The grid tie allows the array to produce electricity during the day and offset the electricity used in the night, without having maintain batteries. The panel also needs the capability to restrict the flow of electricity into the grid when the grid is down. Otherwise energy from my system could charge the grid while it is thought to be down for repair. I'm not sure of the actual function of the meter.

22 cents is the cost per kwh after all taxes and other charges have been added in. If I take the kwh's for the billing cycle and divide them into the total payment, it comes out to a little more than 22 cents. 80% of the national grid here is clean renewable energy, and investment is ongoing to accomplish 100% clean renewable energy grid by 2021. Also there is a lower base rate for people who use less and have less financial means. There are also higher rates for people who use more. I am sure the actual cost of generating the energy is far below what is being charged.

No I definitely do not what to compete with the power company. Here people do not receive money for generation from roof top arrays, they receive credit toward their future use during the billing cycle. What I am trying to accomplish is to offset the future cost of electricity by reducing the net kwh's I am charged. Grid requirements here are expanding rapidly, and as demand rises faster than supply the prices per kwh will rise even more. No telling what the future cost of the grid could be if the rainfall patterns change the capacity for hydro production. I am trying to hedge against the future cost of living within a fixed income.

[quadrature]

28. is 'third world discount' electricity service available...

in your area?

many people worldwide get
electricity for free

[CRH]

29. I am unaware of a ' third world discount' , ...

available in CR. If there were such a program available, I would not take advantage of it. I don't consider my desires anywhere near the needs of most 'third world' citizens. If I can afford a solar array, own a home, and am typing on the internet, for me it would be fraudulent to accept free electricity in a program designed for those in need. That's just me of course, different strokes for different folks.