Solar powered street lighting 1

[pavement]

Im investigating the possibility of using PV arrays to feed some lighting columns all the name of sustainability, I was just wondering if anybody off the top of there heads may indentify some issues that may arise that i may miss further down the line.Or to reinforce any points that should be considered.


Many Thanks.

 

[ScottyUK]

Hi Pavement,

The ballasts associated with HP and LP sodium lighting, among others, are awkward high-inrush loads with heavily distorted current draw which will make things hard for the device you want to power it from. Not an insurmountable problem, but you may find yourself designing ballasts as well as the PV system.

You will find no customers in my locale, as the sun doesn't shine here very often!


Hope this helps,


Scotty.





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Do it right, or don't do it at all.

 

[jbartos]

Suggestion: More information about the lighting designed hardware and concept is needed, e.g. will PV supplies be distributed or concentrated to power batteries implying DC-AC inverters powering lights?

 

[IRstuff]

You might check out some commercially available systems:

http://www.alphasolar.com/alpha_solar_050.htm

BUT, street lights can run 2 to 3 times the power of the bulbs in the aforementioned system, which would put that kind of system at a negative power flow.

The initial investment is pretty high, but might be worth it to not have to dig trenches to run power.

TTFN

 

[EEJaime]

The only systems I have come across using photovoltaic arrays power only low wattage flourescent or led lamps. These have very limited output and very few municipalities would allow them. Most areas have standard luminaires they require be used. We've used these in small parking lots, but with marginal success. Good luck!

 

[quark]

I am not an expert in this field but had a bad experience in the past with deep discharged batteries(I don't know whether it is a correct technical term or not). You will have problems if you have 3 consecutive cloudy days. We could have milked 50% subsidy from the government but my electrical engineering colleagues were dead against it from the beginning and they finally proved it.

Regards,


Eng-Tips.com : Solving your problems before you get them.

 

[jghrist]

I have a solar powered floodlight on my back porch (turned on by motion detector). Unless I get a full day of sunshine, the %#%& thing only flashes on for a second at night when I walk past. I haven't tested to see how long it would stay on after a full day of sunshine (it goes off with a timer after 30 minutes).

I'd really be concerned that the streets would be dark all night after cloudy days. As far as sustainability goes, I'd be interested to see if the energy saved during the lifetime of a solar powered streetlight is more or less than the energy it takes to produce the thing in the first place.

 

[ScottyUK]

Thinking on the same lines as the above few posts, what happens in winter? Long nights, lighting required for 16 hours a day, no sunshine to speak of, and what there sun there is will be weak. I think your idea will be limited by geograhical and prevailing local meteorological conditions. Round here, we get mild winters.... instead of summers! Brrrr...




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Start each new day with a smile.

Get it over with.

 

[jbartos]

Suggestion: Solar Power supply requires a careful load study to be prepared and a plenty of spare capacity in solar cells and batteries. On the other hand, the energy is then for free for a long time to come.

 

[ScottyUK]

Hi jB,

I agree with the gist of what you are saying, but the replacement cost of the storage battery needs to be factored in over the battery service life of, say, 10 years when calculating the energy saving from the 'free' power.

Do PV cells have a finite sevrice life? What sort of period do they operate for before requiring replacement?



-----------------------------------

Start each new day with a smile.

Get it over with.

 

[jbartos]

Comment: The solar free energy is to be properly interpreted in context with the nuclear energy, fossil energy, etc. E.g. the nuclear power plant can generate 1kWHr for about 2 cents(US), fossil plant for about 3 cents(US), and PV cells for ? cents(US) (probably for 0 cents(US)) when the investments in hardware are disregarded.

 

[davidbeach]

For larger systems, PV equates to $5000/kW installed. By comparison Diesel Reciprocating engine driven generators can be had for $400/kW-$600/kW installed. On a purely economic basis, PV only makes sense for either very, very small loads or where the grid is very, very far away. When you add in an owner who really wants to have PV then the economic justification is no longer necessary.

 

[IRstuff]

Just for giggles, let's see if there is a possible solution:

assumptions:
>> 4 continuous overcast days ~10^3 lx available (10^5 max with direct sunlight)-- equates to about 11 W/m^2 total available irradiance.
>> average of 66 W-hr/m^2 -- assumes triangular function over 12 hrs
>> approximately 67% in-band for PV array -- results in about 44 W-hr/m^2
>> 50% efficiency -- 22 W-hr/m^2
>> therefore, sunny day -- 2200 W-hr/m^2
>> 4/1 distribution -- 2288 W-hr/m^2 supply

>> 12 hrs operation with 300 W bulb -- 3600 W-hr needed per day -- 18000 W-hr demand

Final answer -- ~8 m^2 of PV to support above scenario.

>> Not to mention a 1500 A-hr 12V deep discharge battery to store all the energy


TTFN

 

[advidana]

We use pv power lighting for a 50 parking space area. it worked very well excepted we mounted the pv cells and battiers on the ground. Well after about two years, someone stole the pv cells but left the battiers. The pv cell were replace but place on top of the lighting pole were they are now. The installation went in about 12 years ago. The city grid as now past the solar installation since las vegas is growing so fast. So the point of using this pv lighting does not matter now. The weak spot of the pv system is the battiers. We need better and cheaper battiers. Or some better way to store the pv energy.

 

[busbar]

Aside — Some shoreline xenon(?) beacons on the Columbia River {OR/WA} are powered with close-by PV cells prominently labeled “US Coast Guard”.

 

[jbartos]

Comment: PV power supplies need somewhat selected modern loads, e.g. a neon bulb that has 26Watt power consumption, and it is equal to a 100Watt incandescent lamp. It costs over 7US$.