How to beat the rising electricity prices?

11/11/2016

"Sun-sun everywhere and solar on my roof, I make my own electricity, here is the proof. I beat the electricity demand and the rising grid price by making my solar roof oversize.

People say that it is better to buy or install things as per the requirement as this will save you money, but the parameters are opposite in the case of your solar roof. Actually, installing over-sized solar power system at your rooftop could prove to be a better investment choice for you.

Do I need to explain it further?

Okay, no problem let us start with the basics of the sizing of the solar power system.
Before starting with the concept of the over-sizing, you should first know the sizing & the feasibility of your solar power system. You can go through to my article "How to design the solar power system by yourself?" for better and the deep understanding and look at my solar feasibility spreadsheet to know know the complete techno-economic viability of your residential solar roof.
Let us say that I have the following facts and the figures:

Location of solar roof: Delhi/NCR (India)
Coordinates: 28.6139° N, 77.2090° E
Average solar Insolation: 5.35 KW/m2/day

Please see the solar insolation levels in the different months of the year in the following chart:

(The intensity/insolation of the sun is one of the very important factors in sizing your solar roof)

Daily average load: 1 KW
Daily average usage in a day: 4 hours

On the basis of the above facts and the figure, the required solar roof size would be 1.4 KW (including all the conversion and other losses in the system. It means that 1.4 KW of your solar roof will power your 1 KW load for 4 hours daily. Or I can say that the sizing of my solar power system is 1.4 KW.

Why the concept of over-sizing?

When my requirement are getting fulfilled then why should I buy extra panel or oversize my solar power system, which will also result in over-sizing of all the components attached like solar charge controller & solar inverter?

The demand for the electricity in every household in only increasing with time and you are no exception
Solar panels are the almost on time investment with very little maintenance required. Moreover, the other electronic & electrical components like solar charge controller and the solar inverter are very durable and have long life
The cost of installing an oversized solar roof right now is very less as compared to the cost of adding extra panels, extra solar charge controller and the extra solar inverter later in the future to the rightly sized solar roof when your demand for the electricity increases. In some cases, if your demand increases more, then you end up installing new solar inverter having higher electrical rating by discarding the old one as it has now become an undersized device which results in the energy loss to the whole system unless you replace it with new one.
By installing an oversized solar roof you can sell the unused solar units to the grid and earn money through Net metering system. Many states in India offer the facility of the Net-metering
The larger size solar roof is costs comparatively less per watt as compared to the per watt cost of the smaller solar roof. It is obviously due to the economies of the scale.

How much extra do I need to add to my present requirement?

I think we should at least consider and foresee our needs at least for next 5 years.

The rate of rise in the residential grid electricity prices are 5% per year
I further assume that my electricity consumption is increasing at the rate of 5% per year
Adding both the rates 5% + 5% gives me 10% growth rate
If consider this growth rate for another 5 years, then the total increase in the size of my solar roof is 10% x 5 = 50%.

Therefore, I should install and add at least 50% extra to my present requirements in order to avail the above mentioned benefits, beat the rise in electricity rates & meet my future electricity needs.

Conclusion:

By looking at the benefits, durability of the solar power systems, incentives by the government, increasing electricity demand and the rising grid prices, installing a oversized solar power system at your rooftop is obviously a smart move.

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