Solar - the first three months

We've had solar for long enough now that we can see the trends. How is it going? Is it everything we hoped and dreamed of?

The good news is - we're saving a LOT of money on our power bill.

The bad news is - we spent a LOT of money on our solar and its payback is pretty slow.

Good news

Look! The black line is our average power spend (in $/day) over the last 6 years. The red line is our spend in 2022. The solar went in in mid February.

In April we had a $40 bill instead of the usual $210 bill. That's pretty awesome.

Bad news

Adding extra Sparky work and the various timers, it's going to take us 8 years to pay off the work from that savings. That's  probably about when we will be selling the house, letting the next owner cream all the profit of our hard work.

That's just extrapolating that $170 per month savings out to the future, since we've only had one power bill with everything set up right. Who knows what will happen over winter - we need a year of data to do this properly. But then, power prices may go up, our usage may change ... it'll all be approximate at best.

It's also not like the good news graph is that robust either. Over the last 6 years we've added roof insulation, underfloor membrane barriers and some double glazing. We bought a beer fridge and changed our washer/dryer. Toby went through his teenage years and then left home. We've moved electricity providers and plans a couple of times. Oh, and there was that thing that happened that changed our habits a lot over the last two years!

But I figured that's the best I have to work with, no need to overthink it. (Um, maybe I've already overthought it.)

It's the dashboard too!

You can see the spikes where we boiled the kettle or microwaved breakfast.
And just how much usage we can shift to 9pm.

Solar or not, I reckon having direct visibility of exactly what power we're using in real time makes a huge difference. Everybody needs it! You can't budget what you can't measure. 

I'm astonished how much you can save running your high use appliances - dishwasher, washing machine, dryer - overnight on cheap power instead of say after dinner when it's convenient to just turn it on without thinking. And it's no change to the usual thing we'd do (for dishes and clothes) of turn it on, go to bed, empty it in the morning. On the other hand, modern lights use next to no power, there's no point turning them off like in the old days with 100W lightbulbs. 

You just don't know these things unless you can see what exactly what happens when you turn things on and off.

Solar Web Dashboard - translating tariff jargon

This Fronius Solar Web Dashboard also lets us estimate our costs and savings, if we enter our import and export tariffs.  The tariff names are really confusing though. Luckily I found a forum where someone had kindly translated the German English to New Zealand English:

• Feed-in tariff (without Fronius smart meter) This is the yield of solar generation, (this is needed only if you do not have Fronius Smart Meter)
• Reference tariff (with Fronius smart meter) This is the cost of electricity you pay to the utility in kwh, ( this is needed if you have Fronius Smart Meter)
• Feed-in tariff (with Fronius smart meter) This is the how much utility pays to for solar going back to the grid, (this is needed if you have Fronius Smart Meter)
• Offset [kWh] The offset Kwh allow you to add in missing kwh hours that the logger has not picked up, eg. you have inverter installed for couple of months and then you start recording the kwh. This allow you add in the total missing kwh here.
• Offset Earning The offset earning allow you to add in missing yield that the logger has not picked up, eg. you have inverter installed for couple of months and then you start recording the yield. This allow you add in the total missing yield here.

It's the Electricity plan too!

The big red bars are FREE FREE FREE

Contact Energy's three free hours of electricity is amazing.

Between the solar during the day, and shifting all possible usage to the free power evenings, we don't have to pay for very much power at all. 

So little in fact that we've been able to move to a 'low use' plan with a base charge of 30c per day instead of $1.70 per day. Break-even is about $160 per month. We'll see how winter goes.

In a year or so we'll see if there are spot price plans that give us better export rates and maybe really cheap overnight power instead of 3 free hours. Maybe it'll be worth it.

It's the timers too!

I've also installed (or started using) all sorts of timers to restrict anything that doesn't have to run on demand, to when power is cheap.

Hot water  (3000W) - Sinotimer - 9pm to 2am

This is the big one and I've written far too much about it already. But if you don't have a timer on your electric hot water cylinder, you're spending hundreds of dollars a quarter that you don't need to.

Beer fridge (some W) - $10 Mitre 10 plug timer - 9pm to 12am, 10am to 4pm

Both Consumer NZ and my mate Gareth from EECA say that beer fridges are one of the biggest power vampires in your house. But (apart from Christmas when it's probably got turkey and ham in it) it's only got beer in it and doesn't have to run 24 hours a day.

Towel Rails (2x 100W)  - Goldair towel rail timer - 9pm to 1am, 9am to 1pm

This simple little box sits inside your plug box and turns your towel rail on for just 4 hours in 12. It's intended to get your towels warm and fluffy in the morning and evening. But I've set it to use cheap power instead. So our towels are cold and clammy, but they're dry at least.

Bathroom heated floor (some W) - Warmup W3115 timer - 9pm to 12am, 10am to 4pm 

This thermostat/timer (that came with our underfloor heating system) was a nightmare to program, I had to study the instructions in detail and write down the algorithm to program in. If it wasn't a one-off job I'd replace this thing for sure.  It's pretty old and there'll be much better ones around now.

It's also heating the floor when it's cheap, not when our delicate feet are walking over it. Oh well.

So, is it all worth it?

We went into this for largely non financial reasons, and that's lucky. Solar is going to save us money, but not for a while and if we sell our house this decade, not at all unless we recoup our investment in the sale price. 

But we're using far less power, far less dirty peak power, and we understand our usage much better. That's what we wanted and that's what we got.