Doing the Math on Solar Power in New Zealand: An Introduction

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The problem with solar power is, all too many people are looking for quick fix calculators that will tell them at a glance whether solar is affordable for them or not.

The reality is, return on investment calculations for solar power will depend upon your home or business’s specific circumstances.

This reductive thinking often leads people to overestimate the benefits of solar, or even, and perhaps worse, miss some of the critical benefits that would have made solar power worthwhile.


Over the next few weeks, we’ll be looking at some of the key ingredients to formulating a highly specific solar power proposal. We’ll be talking to some industry experts about how it all fits together, realistic risks you may encounter, and how these risks might flow through to bottom line financial analysis suitable for a household and separately for a business.

In short, we’ll be looking at the financial specifics of a solar power proposal, and using the case study of our motel for why we should or why we shouldn’t go solar.

Calculating the specific value of a solar power proposal is a highly complex exercise. It requires all of the below.

Evaluating the Arguments Against Solar Power in NZ: Too Much Green Energy Already Comes Off the Grid
Why It’s Important to Calculate Your Own Power Consumption Before Buying Solar Power
Why It Helps to Start Planning a Year in Advance When It Comes to Solar
Interview: Solar Power from the Actual Experts
Specific Tools – Reading Smart Meters
Specific Tools – Using Ammeters
Why Peak Use Power Consumption Should Be Excluded From Solar Power Generation Calculations
Planning for Future Growth
Summer vs Winter Power Consumption
How to Estimate Daylight Hours in NZ
The Importance of Facing the Right Direction
Why Your Roof Angle Affects Your Solar Efficiency
Why Less Is Sometimes More
Solar Power Batteries: Are They Worth It?
Anecdotal Experience: Solar Battery Longevity
Industry Forecasts on Solar Battery Replacement Timelines
Daytime Occlusion and Impact on Power Generation
Understanding Your Energy Bill
Hidden Costs – Energy Levies
Should the NZ Government Sponsor Solar?
Selling Back to the Grid: The Basics
Reliance on Wholesale Energy Prices
An Accountant’s Perspective: Tax Benefits of Solar for Businesses
Does Depreciation Apply to Solar Power Equipment?
Saving GST on Energy Consumption
How Does GST Work on Power Sold to the Grid?
Leasing Solar Power Equipment – the Pros and Cons
Hire Purchasing Solar Power Equipment
Putting It All Together: Solar Power Calculation Spreadsheet
Otaki Motel: A Solar Power Case Study
Who Can Afford Solar

One thing is for sure. You should read up and make yourself aware of all the risks before going into solar.

As I go through I will add to the list, and as the articles get written I’ll link the text below through to the corresponding article.

Author: Richard Christie

Richard Christie runs a small motel on the Kapiti Coast and also writes the Balance Transfers blog. He is interested in how businesses can play a role in improving environmental outcomes, and the challenges associated with doing so. Although this is a blog nominally about the topic of inflation, one of the key recurring questions this blog covers is 'what will be the financial cost and financial impact of climate change?' The blog covers micro economic and business-specific topics relating to the business landscape in New Zealand.