Friday, 1 April 2016

Sunlight and Solar

In our subtropical part of the world, we have an abundance of sunlight streaming down from the warm sun in the sky. 

Sunrise off our back deck this morning.

Over a year ago, we put a 3 kilowatt solar panel system on our roof to take advantage of nature's solar energy. This was in addition to our already existing solar hot water system. We took a long time to decide on the size of the system suitable for us and we are so glad that we didn't jump in and put the largest system we could afford on the roof. That would've been a 5 kilowatt system and many more panels than what we eventually decided upon. Without even seeing our bills or visiting our site, a couple of energy companies were recommending larger systems but one small installer took the time to go through our bills with us, looked at our roof and talked with us about the times of day when we use electricity the most. That installer recommended a 3 kilowatt system with capability, through our inverter, to add further panels later when battery storage becomes more affordable. I was a bit confused by this advice at first. Wouldn't it be better to just put a big system up there? In short. For Us. No. 

As I was driving to the market the other morning, listening to a talkback radio caller telling the radio host how he wished he hadn't put a 5 kilowatt system on his roof at a cost of around $8,000, I felt very grateful that we had listened to our installer. That poor talkback caller felt he would've been better off not having solar at all and putting his $8,000 in the bank instead! Because he and his wife both work during the day, they use the bulk of their electricity at night when there's no sunlight hitting their panels and so their system isn't producing anything. The tariff, at around 6 - 8 cents per kilowatt, down from around 40c per kilowatt initially, is what they get paid for the excess they generate from their system. They have to pay around 24c per killowatt for the electricity they use at night.  Their very expensive system saves them very little compared to their investment with the talkback caller estimating savings of between $60-$70 each quarter.

Our system, with high quality panels and inverter, cost us $4,800 and saved us $577 last year. That saving comes from less usage of electricity from the grid and from the 6c we get for each kilowatt we return to the grid. We think our investment will take between 7-8 years to pay for itself and the life of our panels extends well beyond that to approximately 20 years.

Our solar panels.

We are paying for the electricity that we use at night. We have 'tweaked' our patterns of usage by making little changes to try to reduce the amount of electricity we use after the sun goes down. So, the dishwasher is packed at night but isn't started until the sun hits our panels in the morning. The washing machine lays idle at night and is started up later in the morning. And I am constantly reminding our young boy to turn the light off after he leaves a room! These are small changes but each helps to reduce the amount of electricity our family uses at night. Those small changes add up to savings.

What we saved by not choosing a 5kilowatt system is sitting there waiting for when battery storage becomes a cost-effective reality for ordinary folk like us. And that time is getting closer.

Do you have solar on your roof? Are you happy with your choice of system? Why/why not?



  1. We have solar water panels but that fills our roof! We have a small house in the UK, we love to have PV panels but we don't have the room. We had the solar water panels installed twelve years ago and they have saved us a lot of money and we have been really pleased with them.

    1. It's great that your solar hot water panels are saving you money and that you are still happy with them after more than a decade. Such things are not only great for supporting the environment but are also an investment of your money and it's nice to see a return on that.

  2. Great points Meg. We are considering solar in NZ and it is a costly thing to get wrong.

    1. I think solar, if a family can afford it, is a great thing but it's so important to really look at the system size and whether that works for your family's patterns of energy usage. We are looking forward to the day when we can get battery storage. It's prohibitively expensive for us right now but it's predicted to come down in price over the next 5-10yrs. You must be looking forward to heading to NZ and setting up a new home there, Fiona. Thanks for visiting here. Meg:)