photovoltaic energy usage for cellular base stations (gsm and umts)

System

Hello,

i need some documents, advice, guidance, etc about the subject (photovoltaic energy usage for cellular base stations (gsm and umts)).

- what components needing ac/dc energy (such as radio, conditioner etc) are there in a typical gsm/umts base station ?

- what is the amount of needed energy (ac/dc, volt, amper, watt, etc) for each component and for all?

- what pv system should be used for this base station and why? and

thanks a lot

BB.

Re: photovoltaic energy usage for cellular base stations (gsm and umts)

That is a very wide open question...

A "site" could run from a small cell repeater to a full site with uplink to microwave or satellite.

This can push the power requirements upwards of 2-10 kWatts, and larger cell cites in the US can have a 40kW diesel genset for backup.

The power requirements, in the end, depend on your local cellular provider's requirements and the specific needs of the site.

To a large degree, successful use of solar/alternate power sources will depend to a great extent on the design of the equipment--hopefully designed to use the least amount of power possible, and use as little cooling too.

Guessing that you are in Turkey--I will use this website / program and pick Greece (Athens) as being close to you (just a handy program--you can possibly find data that is closer to your installation location).

You can see that the PV Watts website has quite a few options that you can pick that affect your overall power generation capabilities... For now, lets use 1kW of solar panels (easy to scale), use a derating factor of (0.77 default * 0.9 for AGM/Sealed batteries * 0.9 for inverter efficiency=) 0.62 over all solar->AC output efficiency. Also leave defaults in the rest of the data fields (Fixed Mount, tilted for latitude):

Results

Month
Solar Radiation (kWh/m2/day)
AC Energy (kWh)
Energy Value (euro; 0.0860 euro/kWh)

1      3.22          58     4.99 
2      3.77          62     5.33 
3      4.68          85     7.31 
4      5.35          92     7.91 
5      5.84          102     8.77 
6      6.74          111     9.55 
7      6.97          117     10.06 
8      6.82          114     9.80 
9      6.43          106     9.12 
10      4.65          81     6.97 
11      3.04          51     4.39 
12      2.83          50     4.30 
======================================
Year  5.04hrs of sun  1031kWh/month  88.67euro/yr

So, if you assume solar power for at least nine months of the year, Month #2 (February) is the minimum month we would plan for.

1 kW of solar panels gives us 62 kWhrs per month.

If you assume your cellular base station uses 1kW of power 24 hours per day, 30 days per month:

1 kW * 24 hours/day * 30 days/month = 720 kWhrs per Month

For February, the "average" size of solar panels would be:

720kWhrs per month need / 62 kWhrs per month per 1 kWatt of panels = 11.6 kWatts of solar panels

That is no small system... In the US, that would cost you (just a guess) of USD $100,000-$150,000 (complete power system, solar panels, mounts, wiring, batteries for 3 days of no-sun, inverter, charge controller, installation, etc.).

If your site uses 5kW of power 24*7, then your solar panels would need to be 5x larger.

And if this is a remote site, you will have security issues (breaking of glass panels with rocks/etc., stealing of panels, batteries and copper wire.

Of course, your needs may change by season (no AC in winter). And, you may choose to only run the site 6 months of the year when you have close to 100 kWhrs per month per 1kW of solar panels (and when AC loads are highest)--and make up the rest of the power with a diesel generator.

If you can find/use a cellular base station that uses much less power (say 100 watt 24*7)--then the amount of power required is 1/10th as large.

Hope that helped.
-Bill

niel

Re: photovoltaic energy usage for cellular base stations (gsm and umts)

i'm not sure why it is you are asking this as most cell phone facilities are designed with a backups for power failures. are you the engineer of such as site or curious or what? when one goes to add pvs to help charge the battery bank of a cell backups system it is usually supplementary to a utility type charger. if no such utility type charger is in place then pv is going to provide all power necessary for the worst case conditions in that location and would be sized accordingly. i am not sure of the backup time capabilities most cell towers battery banks utilize, but i would imagine it to be enough to run things for 3 days minimumly. high quality batteries are used in cell systems and are usually agms.
i can see the possible need of solar for some cell systems where the utility power is not reliable or available. whatever the wattage requirements would've been from that system being run by the utility over a day is the pv requirement too. obviously, the sun doesn't shine 24hrs a day so it must be during the sunny periods pvs will produce making the pv power source that much more in wattage. the pv wattage needed would most likely be the wattage needed by the system for a day divided by the number of full sun hours on average during the worst month and add up to 50% more for losses, efficiencies, conversions if any, temperature effects, and some extra. if the battery bank is so large that the previous statement i made would make the charge percentage fall short of 5% then the system must be enlarged further to properly charge those batteries.

System2

Re: photovoltaic energy usage for cellular base stations (gsm and umts)

Thanks a lot for all,