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Solar Energy House Blog

Welcome Solar Energy House blog


I will be blogging interesting tips and hints, visits by clients and why they come to the Solar Energy House here in Meadowbank, Auckland etc. Please comment and join in!

Have Solar PV on my roof is now BETTER than money in the bank

By Simon Cope, Feb 23 2012 06:42AM

I thought I would do some simple math on whether is it now worth it to put solar PV on a building in NZ (in particular Auckland).

So using the stats from my house: Simon & Kristina Cope’s house

Feb, 2012

• 70 modules @ 65 W each. ~ 4.55kW, made up of 4 separate arrays feeding into 2 separate SMA inverters with MPP modules.

• Based on 25c/kWh unit and average peak sunshine hours of 3.37 per day throughout the year, this produces ~$1400/year of electricity.

• 8 years ago same system cost $70,000, giving a payback of 50+ years with no interest.

• Today (2012) to purchase modules of equivalent output (but different technology), would cost ~$21,000, with a 15+ year payback.

If you had $21,000 cash to invest, you have a couple of choices - put money in the bank, or purchase solar PV modules.

- BANK: you would get ~4% ROI from ASB bank – i.e. ~$900 per annum…

- SOLAR PV: you would get a ROI of ~ 6% (excluding tax etc). i.e. $1400 per annum...

You could argue this is better than having the money in the bank…

• If you have to borrow the money, then you pay 6.9% on that money, so although this will cost you slightly more than what you are borrowing, you have two advantages… 1/ price of electricity is going UP (so ROI can only improve), and 2/ It will pay for itself within ~15 years – which is not bad.

Interested in learning more? Contact Simon and come on a tour of the Solar Energy House in Meadowbank, Auckland

Mar 12 2012 09:31PM by Kristy Hoare

Hi Simon,
We agree with you, we reckon putting a solar power system on your roof is better than putting money in the bank. Check out this article we wrote on the issue

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