New home, old appliances: Our data-driven journey to solar electrification

As part of the Wattwatchers founding group I’ve had access to our real-time energy monitoring since early prototypes over a decade ago. Then my wife and I sold our home of three decades, rented for a year, before finally moving into our second-ever house. Now ‘energy sight’ has been restored and it’s a whole new world of home energy management systems (HEMS) and ‘electrification’ possibilities.

On my Watts

When my wife Natalie Isaacs first figured out that we could proactively cut electricity waste and therefore household carbon emissions, it changed our way of living and her career.

A businesswoman with her own cosmetics business, hands-on energy saving helped to inspire her founding of 1 Million Women, now an international movement of over a million women acting on the climate crisis in their daily lives.

Along this journey we’ve been helped mightily by some tiny metering devices – various iterations of the Auditor series of real-time monitors – sourced from my day job, and my ClimateTech passion, Wattwatchers Digital Energy.

So I got a bit excited when our trusty electrician-installer Glenn Beames (Beames Electrical), who may well have installed more Wattwatchers than anyone else on the planet, arrived at our new-for-us home near Wollongong to restore our ‘energy sight’.

Let the data flow!

Know your energy sources

Data for electricity at least, because by my reckoning, counting home and vehicle, we currently use energy from a surprising number of sources: grid electricity, solar electricity, mains gas, bottled gas (BBQ), firewood for the fireplace, petrol for the car, and a combination of sun, wind and ambient air temperature (for the clothesline, and arguably partly for the reverse-cycle air conditioning too).

I’ve realised that where once we just focused on reducing electricity consumption, and any carbon emissions savings flowed from that (at the rate of roughly 1kg CO2-e per 1kWh of electricity from the grid), there’s now a lot more happening.

Take action on multiple fronts

In our new abode, 24/7/365 electricity visibility will be driving the information and insights we need to achieve several things in technology-enabled harmony:

Energy efficiency, led by energy waste elimination without seriously diminishing our quality of life (we do pass up on some appliances, especially a clothes dryer, but seem to manage just fine with our sun and wind powered clothesline).

Solar optimisation, which is all about self-consuming as much of our rooftop photovoltaic (PV) generation and minimising (but importantly not eliminating) exports to the grid. We micro-manage this one a bit, because solar output changes day to day, and season to season.

Decarbonisation, with an immediate focus on ensuring that our home is ‘Net Zero’ for electricity, which we can achieve by ensuring that over time our total solar production – whether we use it ourselves, or export it to the grid for our neighbours to receive extra green electrons courtesy of our PV panels – outweighs our total electricity usage (both grid imports and self-generated solar).

Electrification, the exciting new kid on the home energy management block, which for us will mean that over time we will electrify everything we reasonably can, led by mains gas de-gasification (and ultimately mains gas supply disconnection) that will target two instantaneous gas hot water units, a no-longer working gas-fired pool heater, and a single gas burner for wok-cooking (sitting next to an electric induction cooktop).

Stretch out the costs

The electrification part won’t come cheaply, and it will take time, but energy cost savings from the energy efficiency and solar optimisation bits will help to pay the way, and decarbonisation is good for our souls (not to mention the futures of our children and grandchildren).

This means 2-3 electric heat pump units for water heating, depending on what we do for the pool; plus of course there’s the not-so-minor matter of replacing our internal combustion engine (ICE) motor car with an electric vehicle (EV), and various other electrified bits and pieces (I’ve already purchased the lithium ion battery-powered lawn mower and line-cutter).

Reinforcing the electrification theme, the day after ‘Beamsey’ installed our Wattwatchers monitoring ‘The New Joneses’ filmmaking crew arrived at our place to film with Natalie (see feature image for this post) for their 2023 series focused on electrifying everything, a key focus for 1 Million Women through its forthcoming ‘Electrify My Life’ campaign.

For my work, I’ve been sharing screenshots from the first three days, and the first week, in our new home to help other people understand how a HEMS solution like Wattwatchers can work for them. We still have a long data journey ahead, as we get to know the home electricity-wise across changing seasons, a full year, and multiple years (because climate patterns change too, as we are now seeing with the slide out of prolonged and very wet La Nina, and most likely now heading back into at least one dry and fiery El Nino year).

Get into the data detail

Here are the first three days, courtesy of the Wattwatchers MyEnergy App:

MY NOTES: Poor solar day (cloudy), but still covered nearly all of the main day-time load, the pool pump, which is set on timer to optimise solar self-consumption (note to self: change timer as the seasons change); the first six hours of usage over the 24-hour period is the house at rest, when everyone is asleep, and it’s too high for my liking and has work to be done (getting the 24/7/365 ‘baseline’ down really helps to cut bills); the big spike in the afternoon (blue in the middle screenshot) was ‘The New Joneses’ putting their Polestar EV on to charge on the garage 15 amp plug; and, like wow, the grey-coloured item in the usage screenshots is the ducted-system, reverse-cycle air-conditioning unit on standby mode (i.e. not actually doing any cooling work) – got to mull this hungry beast over, as we’ve never had any air conditioning before.

MY NOTES: Better solar day, which revealed that the former owners of the home who installed the solar system undersized the inverter at 5KW (see how it flattens at the top), which left some generation potential unavailable to us and the grid; captured the whole day-time load under the solar, with the pool again the dominant load by far, and the air conditioning still chewing electricity (over 1kWh a day) on standby mode.

MY NOTES: Good solar day again, with the gap in the morning being when the electrician came back to connect remote switches to the air conditioning unit, pool pump and garage 15 amp outlet; decided to actually turn on the ducted air conditioning, initially across all three zones, which blew away our day-time ‘solar self-consumption only’ target, and changed the scale of the ‘History:Solar’ chart; subsequently wound the air-con back to one zone, covering bedrooms and home office, then turned it off altogether later in the afternoon (anecdotally, noted that pre-cooling lingered for hours and think the house has good ‘thermal mass’; pool pump is no competition in load terms when the air-con is running, which currently is rarely for cooling purposes, but we’ll need to see what happens in warming mode when we get to our first winter.

FOOTNOTE: Across the first week we achieved our overarching objective of being net zero for electricity in the household, using a total of 174.27kWh over the seven days (average of 24.9kWh per day, although because of our solar it only looks like 10.24kWh a day to our electricity retailer’s billing meter) while generating 247.41kWh from the rooftop (and could have been more with a bigger inverter). Of the solar produced, 102.58kWh (less than half) was used on-site, leaving 144.83kWh being exported, and more than offsetting our 71.68kWh of imports from the grid (I can’t tell you the $ costs involved yet because we are still waiting on our first quarterly electricity bill to arrive with the tariff rates we are being charged – which I hope won’t be estimated!)

MY NOTES: Solar generation beat total usage across the week and on every day except for 6 March, which is when the air-con went on for part of the day; otherwise the pool is by far the dominant ‘available for solar’ load and needs to be watched and adapted as the seasons change (need to run for 8 hours in summer, but expect to get away with less through winter). Looking ahead, in the short-term test turning air-con unit off using the app’s remote switching, to eliminate its stand-by consumption and trim the 24/7/365 baseline by circa 1.09kWh a day; and mid to long-term, evaluate options such as home storage battery (not keen at this stage), a second solar system (if planned new loads justify this), and timing on an affordable EV.

Murray Hogarth is head of impact and communications for Wattwatchers, having joined the company’s founding team in 2007.

This article was originally published by Wattwatchers. Read the original version here.