The government has started many different projects to end load shedding. However, due to financial constraints or unavailability of equipment, the projects have been... Ownership Costs of Solar System versus Generator versus UPS

The government has started many different projects to end load shedding. However, due to financial constraints or unavailability of equipment, the projects have been delayed with their completion date being pushed further and further. The government has acknowledged that these projects won’t be completed anytime soon and load shedding would continue till 2018, when the current government’s term finishes. This will result in excessive load shedding during summers because the demand of electricity is much more than the supply. The best way to handle load-shedding during summer or any other time is by installing a UPS, generator or a solar system. Each system has its benefits, and choosing one depends upon the requirements and finances.

UPS is the basic solution to handle load shedding. It is cost effective and easy to maintain. The only disadvantage is that it can’t handle heavy voltage items like a refrigerator or air conditioner.

Generator is a better solution since it can handle high voltage items. Its disadvantage is that it requires lots of maintenance, causes pollution, and is very noisy.

Solar system is a relatively new way to handle load shedding. It saves on electricity bill and its disadvantage is that it requires a lot of money upfront.

The following table summarizes the load handling capacity of each system of equal wattage.

Items Supported UPS

750 Watts

Generator  750 VA Solar System

750 VA

UPS

1000

Watts

Generator 1 kVA Solar System

1 kVA

UPS

2000

Watts

Generator 2 kVA Solar System

2 kVA

Energy Saver 6 4 4 8 10 4 14 14 10
Fan 3 3 3 4 6 3 8 8 6
Tube light 1 3 1 5 5 2
Water Dispenser 1 1
Laptop 1 1 2
LCD TV 1 1 1 1 2
Water pump 1

0.75HP

1

1.5 HP

The following table summarizes the equipment required for each system and the cost of it.

Additional Items Required UPS

750 Watts

Generator  750 VA Solar System

750 VA

UPS

1000

Watts

Generator 1 kVA Solar System

1 kVA

UPS

2000

Watts

Generator 2 kVA Solar System

2 kVA

Battery 9000 72,000 9000 144,000 18,000 144,000
Solar Panel 86,250 115,000 230,000
Hybrid Inverter 85,000 85,000 85,000
Installation + Cabling 52,000 52,000 52,000
Solar Panel Stand 7000 7000 7000
Total Cost (main equipment + additional items) in Rs 17,000 23,000 302,250 20,000 28,000 403,000 32,000 35,000 460,500

Maintenance –

UPS: A UPS’s battery water level needs to be regularly checked. In most cases, batteries need to be replaced after a year, 1 ½ years or even 2 years. If a battery is well maintained, it can last up to 3 years. Some consumers, who maintained their battery well, didn’t need to replace it for 3 ½ years thus it depends on how well it is maintained.

Regularly checking the water level and cleaning the connectors increases the battery’s life. Every year the battery connectors and the Ups connectors should be cleaned to ensure maximum utilization of the battery. The battery needs to recharge, and clean connectors will help it to recharge quickly. A good battery will charge in less time than a slightly old battery which will take a relatively longer time to recharge. The amount of time a battery takes to charge is equivalent to the electricity consumed by a 100W bulb. An average recharge time of a battery is about 75-90 minutes. The longer it recharges, the more electricity it will consume and higher the bill will be.

Some imported UPS, especially from China, are made from low quality materials. They are named disposable UPS by technicians. If any part malfunctions, the UPS can’t be repaired, but needs to be replaced. This increases ownership costs of UPS. If you plan to buy a UPS, then buy a reputable company’s UPS.

Generators: Most people install generators because of their load capacity. A powerful generator can support the entire house including refrigerator, television, and air conditioner. It is much cheaper than a solar system, but requires more maintenance.

A generator will be either petrol or diesel or a gas generator. Since the price of petrol fluctuates, the amount of money spent on petrol or diesel depends upon the latest price. Similarly, during winter there is gas load-shedding which will hinder the use of the generator.

Oil needs to be changed regularly in a generator. For a petrol or diesel generator, oil needs to be changed after 100 hours, while for a gas generator it needs to change after 70 hours. The cost of oil change is between Rs 1000-1500 for a 1.5kVA to 2 KVA generator. As the VA increases, the cost of oil change increases too.

A generator also needs to be tuned up. Tune up is done after every 2 to 3 oil changes. The cost of a tune up is between Rs 300-400 for a 1.5kVA to 2 KVA generator. As the VA increases, the cost of tune up increases too.

Solar System: A solar system is maintenance free and doesn’t require any tune up or oil change. It consists of dry batteries which don’t have water; hence the batteries don’t need to be checked for water level. The batteries need to be replaced every 4 years.

The only maintenance, suggested by us, is to regularly check the solar panel. You should make sure that the glass of the panel is clean and not dirty. The cleaner the glass, the more sun it will absorb. Another thing to check is the condition of the glass. Make sure the glass isn’t cracked or damaged. This could result from hail storm damage or kids playing cricket and the ball accidently hitting the solar panels.

 

In summary, you should install the system that you can afford. A UPS is affordable and easy to maintain system. A generator is a little expensive and requires maintenance. It is dangerous too since its smoke can suffocate people. A solar system doesn’t require any maintenance and saves on electricity bill, but its upfront high cost forces the people away. These are the choices available in the market today, and with load shedding to continue, a system needs to be installed.

  • Munir Raza Waris

    Nice comparison between different energy sources, would like to make one comment that UPS does not have a high upfront cost but if you compare it with Solar Solution , the break even is reached in 3-4 years as the cost of charging batteries from the grid ( in the case of UPS ) is high . after this period ( 3-4 years ) Solar becomes cheaper.

    • loadsheddingpk

      Thanks Munir sb. Valid points.

  • We must know that VA is not equal to Watts, or KVA is not equal to KW.

  • After doing some web reading, I have concluded that residential PV systems are NOT cost effective. Pure solar PV KWh (units) currently cost in excess of Rs.20 per unit, which is much higher than the units charged to residential properties. Yes life is unaffected by loadshedding, but one has to pay a lot for this comfort. Net metering does not help, at current repurchase rates. Large residential and commercial societies can install a solar power project to provide uninterrupted low cost electricity, due to scale economies. Any expert comments????

    • Jehanzeb Ahmad

      I agree with your analysis, but let me add that a unit of electricity from battery costs around Rs 25-30 calculated on the base of total units a battery provides in its lifetime and the price of the battery. This equation holds for all types of batteries. So even if charging is “free” from solar you are still paying Rs 30 per unit which is more expensive than Wapda. If you charge a battery through a UPS running on wapda, the cost of that one unit goes to Rs 45 or more. Most solar inverters have a conversion efficiency of only 70% while the claimed efficiency is 95% or more. One problem regarding net metering that you did not mention is that during load shedding it shuts down and does not provide power to the grid or to the house (unless you use a system with batteries..which makes the equation even worse). So yes I agree its not a viable option. Secondly when you install a 1KW system and add the losses in PV, inverters, batteries, the final power that gets to the load is only 500W. Everyone should plan systems accordingly.
      Prof. Jehanzeb Ahmad.

      • Thanks Professor sahib for the detailed analysis. Is it correct that in Pakistan, domestic consumers do not have different rates for peak and non peak consumption? One needs to have digital meters. Right?

        • Jehanzeb Ahmad

          Well a lot of meters atleast in Islamabad are digital with peak and off peak rates. Peak rates are from 6PM to 11PM and charged at Rs 15 whereas off peak are charged at Rs 10. This is excluding taxes. All new meters are digital and wapda is in the process of replacing the old meters.

  • Jehanzeb Ahmad

    One point that I disagree with in this article is mentioning that battery life is 3 year or 4 or 1 year. This is meaningless. The life of a battery depends on three factors..1. Depth of discharge in each cycle. 2. discharge current 3. temperature. A battery that is discharged to 50% of its capacity will have around 600 cycles. Depending on the daily cycles it could last 2 years or just 3 months. A battery discharged to just 10% can have 2000 cycles. so it all depends on the way it has been configured in the system.

  • BMM Solar

    Again a good effort to get a rough idea for general public but there are some fundamental mistakes in the comparison and requires more research and inputs from some real experts.
    To begin with cost of an inverter for 1kva and 2kva are not same, similar is the case with installation cost i.e stands and cables.
    Secondly a 9k battery will give better performance on a solar system as charge/discharge cycles will be half of that of UPS as in day time your system will run on solar power directly.
    Comparison with generator is a totally different story, if we assume that both the systems generate same amount of electricity (both sized accordingly) everyday and include total running cost and installation cost for a period of 20 years. You will be surprised to know that the generator will be 3-4 time costlier than solar power system. https://uploads.disquscdn.com/images/c4ae39e36fbc4a9b657d5d4e66b8aa6fee33ef8cb9bc454e6247eb8bcf46a9a9.png

    In the end I would say that solar is a long term investment and would take around 5 years to payback the initial cost and after that you can reap the benefits without the need to invest further except for battery replacement and minor maintenance cost.