How much Solar do I need? Its a basic question and a very relevant one. Why? because it determines how much one would have to invest and what the returns (savings) would be. We have searched hard but have not found a simple answer. Lets delve in.
What is your goal?
Most Solar installers and online sites start with the question “What is your goal?”. Lets take an example: here is a quote (paraphrased) from an online solar developer:
“Determining how much solar you’ll need for your home means first deciding what your goals are. Minimize your carbon footprint? Maximize your return on investment? Save as much money as possible? Most people want to save as much money as possible while minimizing their impact on the environment.”
– Online Solar Developer Site
The question is relevant, and anyone considering solar should answer it to themselves. But notice, the developer has already answered it for you in the last sentence! They want you to save as much money as possible. The question is How? How do I know how much money am I going to save?
In India there is a different tack developers use to push us into buying the largest system they can sell us. Goes something like this: “How many ACs will you want to run from Solar?” (Again the goal is to push us into buying a large system.) The answer is its irrelevant with net metering and a grid tie system.
“Yeh wrong number hai”
– from PK, a favorite movie of mine
The Head Spinner
Then come the other questions:
“You first must determine how much energy your household uses”
There is no shortage of calculators online to help you do that. Some will have you walking in every room noting how many light bulbs you have and estimating how many hours they are on for!
“What is your roof’s usable surface area”
This is of course relevant. And especially when the developer is trying to sell you the largest plant they can! It tells them what the max is, where they should stop.
“How many hours of sunlight, the climate …”
“… the wattage and relative efficiency of the technology of your panels”
“… is net metering available?”
Is you head spinning yet?
The above is designed to confuse and complicate. Lets forget it and start again.
Question 1: What is my goal? Is it to maximize my return, save as much as possible, something else?
Answer 1: I don’t know. I’d like to keep it open if I can.
Question 2: How much money do I want to invest in my solar plant?
Notice, this question was never even asked by the developer, and yet it is the most relevant question.
Answer 2: I don’t know, but I’d like it to not be more than XX, and it will depend on what I get for it (the return on investment).
Which brings us to the third and last question
Question 3: What is the Return on my Investment?
Answer 3: Well, this is what it should be all about. And how many developers tell you that?
That is it! I don’t want to walk around my house counting light bulbs!
Keep it simple. Solar PV is an investment. We should install it because it saves us money, and there are some other benefits like its clean and renewable and doesn’t poison our air, water and land with toxic stuff like coal does.
Like any investment, the decision needs to be based on the return from the investment. Why should solar be any different? We have developed a calculator that will enable you to treat solar as an investment, and decide based on hard numbers how much solar is right for you. You decide, not some developer!
Check it out and see for yourself.