Choosing the right solar rooftop for your needs

 

We see a lots of people installing solar rooftops in today’s time. But still lots of people are still skeptical about going for solar rooftop. The main reason for that is the high initial cost, which is scarring them away from the great benefits which solar energy has to offer.

People who have gone for solar rooftop are definitely witnessing their benefits and are also encouraging other people to opt for it. We will be sharing here some of the basic things which one needs to be aware of while choosing the right solar rooftop for their needs.

Residential Solar Panels: An introduction

Residential solar panels are either monocrystalline, polycrystalline or thin film panels. All of them has their own pros, cons and efficiency rates. In terms of suitability, monocrystalline and polycrystalline panels are most suitable for residential application because of their higher efficiency, longer life, etc.

Choosing the right solar panel for your need

Lots of people has this common question of which solar panel should they go for and for how many kW. For residential application both monocrystalline and polycrystalline panels are suitable. Choosing either single facial or bifacial solar panels will depend on the amount of space available for the kW of solar panels you have chosen. Bifacial solar panels will require lesser space.

Every household has different requirements of electricity in terms of monthly and daily consumption. This will lead to different capacity of solar panels being ideal for use by these individuals. One needs to look into their current consumption and their likely future consumption before choosing to install a particular capacity of solar panels. Here I will be sharing general guidelines to follow before selecting a particular solar panel for your needs. Also we will only be focusing on residential solar panels and not industrial solar rooftops. Also all the calculations discussed here is for on-grid solar plant.

a.       Set your monthly billing amount: Most simplest way to do this is to average out the monthly electricity bills of last 12 months. It will give you general idea about your average consumption. Also it will average out, the higher consumption during summer and lower during winter.

b.       Add buffer to this monthly consumption: Once you have decided your monthly consumption one should add atleast 20% bugger for future increase in demand before selecting your actual consumption.

Lets take an example to understand this concept. Lets assume that your bi-monthly electricity bill is 4000 INR. Number of units consumed will correspondingly be 615 units considering per unit cost to be 6.5 rupees. Now a 3kw solar rooftop is capable of generating approximately 13 units per day. Now lets calculate the amount of solar panels you would require if your bi-monthly consumption is 4000 INR.

Bi-monthly units consumption  = 615 units

20% buffer for future rise in load = 615 x 1.2 = 738 units.

Now daily unit consumption = 738/60 = 12.3 units per day.

As we discussed 3kW of solar rooftops are capable of generating 13 kW of power per day on an average. So for a person having power consumption of house to be 4000 INR bi-monthly could easily go for 3kW of solar rooftop and still maintain zero bill every month. Now lets discuss a general formula which you can use to calculate kW of solar panels which is right for you.

kW of solar panels = ((((B/C)*1.2)/60)*3)/13)

where B = Bimonthly bill you receive in INR,

            C = Cost per unit of electricity in INR.

Above equation will give you an idealistic idea about the kW of solar panels which you should choose for your house requirement.

Choosing the right inverter for Solar Rooftop

Always choose inverter of more capacity than the solar panels installed. It will give you flexibility of increasing the solar panels in future without changing the invertor. So for someone who is opting for a 3kW solar, they should go for minimum 5kW or 6kW invertor for future requirements.

Below image will give brief idea about functioning of solar rooftops

Source: Indiamart

On-Grid vs Off-Grid solar plant

1.         On-Grid Solar Plant:

This is the one which is directly supplying the power generated by solar plant to the grid. In this case, you are getting the benefit of not paying huge investment for the installation of the battery system. Lets discuss few of the pros and cons of on-grid solar power plant system.

Pros

i.                     Benefit of using the units of electricity generated even during night time when there is no availability of solar energy.

ii.                   You can get paid for the excess units of electricity produced as compared to what is being used by you.

iii.                 No worries about availability of power during night time as everything is connected to grid itself.

iv.                 Any kind of excess electricity is not wasted if battery is full like off-grid solar, as it is transferred to the grid directly.

Cons

i.                    Returns received for the excess amounts of units generated against consumed units is very low.

ii.                  There is requirement of installation of 2 separate meter. One for calculating the units of electricity imported to house and other to calculate units of electricity exported.

iii.                Solar plant stops in case of grid power failure.

2. Off-Grid Solar

This kind of solar plant is not connected to the grid. Hence, whatever solar electricity is produced in excess gets stored in the battery installed. During day time whatever excess electricity is produced gets stored in the battery system. This power can then be utilized when solar power isn’t available. Lets now discuss its pros and cons.

Pros

i.                    Better return over excess electricity produced as its stored in battery which can be utilized whenever required.

ii.                  Power availability even during power failure. As power is stored in the battery system, one can have access to power even during power failure.

Cons

i.                    Extra cost of battery to be bear by you during the installation process. This battery cost can be substantially high as normally it is lithium batteries.

ii.                  Excess electricity generated after battery is full will be wasted as one can’t supply the same back to the grid.

Off-Grid Solar. Source: Homescape Solar

Conclusion

As per this discussion, one can say that the most preferred mode of solar installation depends on one’s specific needs. But in general most people opt for on-grid solar installation as it provides benefits in many different forms.