What does household electrification look like in reality?

Stock image ex Canva for use as feature image for Wattwatchers blog post about home electrification

DATA AND STORIES FROM THE GRID EDGE

For most people, until very recent years, having electricity for your home was mono-dimensional. 

Your home was connected to the poles and wires of a distribution network. A billing meter was installed between your site and the grid. Electricity flowed one-way into the home and power bills followed, quarterly or monthly in arrears. Paying it was more like a tax than consumer discretionary purchasing.

Now, for many customers, if not all, they can be energy market participants, not just price-takers, and it’s poly-dimensional.

This is the brave new world of customer energy resources (CER), and one way or another we can all play in the space: increasing energy efficiency, choosing optimal tariffs, generating solar from rooftops, providing flexible demand, adding battery storage, and electrifying everything, our cars included.

At Wattwatchers we see an energy future where approximately 10 million Australian households have 10 million different ways of solving their electricity needs and wants.

Using Wattwatchers data from our fleet of 5000-plus households, approved for anonymised sharing through our MyEnergy Marketplace initiative, we’re profiling what household electrification is looking like for several different Australian households.

These are all ‘journeys’, and data is supporting, enabling and verifying what’s happening at each household.

Household 1

SNAPSHOT: Older-style (1980s) freestanding house in Sydney, bought in 2021 with a combination of old appliances and gas-ducted heating. Home for five people with high energy usage. Recently renovated, including energy upgrades via a ‘green loan’ for solar and battery (10kw solar/11kWh battery). EV purchased in 2022. 

This journey has been one to eradicate gas and some petrol, with a recently added EV and the removal of gas-ducted heating and gas cooking, although it still has gas hot water which will be replaced at some point with an electric heat pump solution.

After receiving a $20,000 ‘green loan’ which was used in its entirety on solar and battery installation, the electrification self-consumption journey began in earnest.

Unfortunately, the battery was not working properly for many months, which adversely impacted on the results this household could have achieved (but that’s the real-world experience of emerging technologies).  

The graph below shows that, even with this battery hiccup, the total cost spent on electricity and gas this year versus last year is now under the previous year. This includes the $175 per month ‘green loan’ repayment and also the most recent big electricity price hikes in July 2023.

The graph above also includes six months of fuel prior to the EV arrival. It has been interesting to note that it is hard to see the impact of the EV on the daily/monthly energy usage as the majority of its charging is done by solar generation (see below).

Source: Wattwatchers web dashboard

The only way this household can manage this is with granular real-time data and control. For example, the EV is not allowed to charge from 4pm to 9pm on weekdays for two reasons: firstly, peak time of use pricing is in place; and secondly, the house battery is in operation (as can be seen in the above graph), so there is no point in transferring power from one battery (stationary) to another battery (mobile).

Even with this electrification journey there is still ample solar generation headroom to be utilised as self-consumption, and this is where electric heat pump hot water could sit once the gas system is replaced.

The beauty of the ‘green loan’ initiative is that the cost is built into the monthly utility spend, so there is no asset payback period required.

Household 2

SNAPSHOT: Older-style home (1980s) in south-east Melbourne. Mostly unrenovated. Home for three people with relatively low energy usage. No solar.

The home has high ceilings – and thus little if any insulation – in the living areas, but lower, more standard ceilings and insulation in the bedrooms. 

It started out with the typical Melbourne configuration of gas central heating and gas storage hot water, which were upgraded to heat pump hot water in October 2022 and reverse cycle air-conditioning split-systems in March 2023.

Old gas storage hot water unit (left) replaced with an EvoHeat Evo 270-1 Heat Pump Hot Water system in October 2022.

New split reverse-cycle air conditioning units installed to replace the unused old wall cooling unit (left) and the central gas heating (right) in March 2023.

This year (2023) was the first winter without using gas for heating, which had a clear impact on total energy bills even before accounting for substantial increase in gas rates in 2023. Combining the gas and the electricity bills results (see graph below) in over $600 of savings already accumulated, and that’s closer to $1,000 if the 2023 rate increases are taken into account.

The total upgrade costs were about $15,000, however, so the payback period is probably in the 10-12 year range when accounting for further energy rate increases. But the home only previously had an evaporative cooling system that was ineffective in extremely hot weather, so there is added value from the comforts of the much more effective cooling now available.

Winter electricity consumption more than doubled from around 340kWh per month in 2022 to 776kWh in 2023 due to use of the RCAC units for winter heating. The consumption of the heat pump hot water system averages 2.5kWh per day, which is harder to see the impact of – except for the lowest usage days, without any heating or cooling, that have gone from 6-8kWh per day to 8-10kWh per day.

Gas bills are now currently around $25-$30 per month – of which 90% is just the daily service charge. This is just for the kitchen stove as the last gas appliance left in the home and is expected to be replaced with an induction cooktop in the next 12 months.

Household 3

SNAPSHOT: Newer-style freestanding house in Wollongong area bought in 2022 with solar already installed. Empty-nester couple with plenty of visitors. Medium energy usage. Complex three-phase site. Already has an electric oven and induction cooktop (but also a gas wok burner), and there’s a large three-phase reverse-cycle air conditioning unit. Hot water heating is instantaneous gas with two separate units, one either side of the house, and the swimming pool has a non-working gas heating unit. EV arrived in September 2023.

The overlapping aims for this household are a combination of energy efficiency, solar optimisation by maximising self-consumption, electrification, bill minimisation and being Net Zero for electricity across the year.

On sunny days, a majority of solar generated was being exported to the grid – until the EV arrived – with the house lacking many options in terms of discretionary day-time loads, as can be seen in the left hand side of the graphic below. 

Source: Wattwatchers MyEnergy mobile app

The pool pump (green in the pie chart below) is timed to run under the solar curve wherever possible, and the occupants manually run the dishwasher and clothes washing machine during solar hours when they can.

The large reverse-cycle air conditioning unit (grey in the pie chart below) is rarely used in autumn and spring, but is a significant 24/7/365 load even in standby mode (1-2kWh per day!). It received more but not excessive use for heating in winter, and the occupants are yet to do a full summer to fully understand the cooling side of the equation.

But the EV is the game changer in discretionary load terms, filling out the solar curve on the right hand side of the graphic above, and dominating the pie chart in the graphic below (aqua on the right hand side). 

Source: Wattwatchers MyEnergy mobile app

As expected with the electrification path, and especially the addition of a load as consequential as EV charging (it’s a Polestar 2), overall electricity usage has immediately increased. This will be reflected in future bills to some as yet unquantified extent, although this is offset significantly by greater self-consumption of solar and reduced exports to the grid. 

The graphic below shows the three weeks before the EV arrived on the left hand side, and three weeks after it arrived on the right hand side. Total usage from all sources (grid and rooftop solar) rose by about 13%, solar used on site rose by about 24% and solar exported to the grid fell by about 20%.

Source: Wattwatchers MyEnergy mobile app

Still to come for this home’s electrification journey are:

Medium term – electric hot water heat pump or pumps (one large and one small), a big electric heat pump for pool heating, removal or replacement of the gas wok burner, a Level 2 EV charging point (currently trickle charging from a 15 amp circuit, although currently this is slower than it could be because the EV’s manufacturer- supplied charging cable is restricted to only 10 amps).

Longer term – full disconnection and removal of the gas infrastructure including metering, possible second solar system if justified by the data as electrification progresses, and further consideration of a stationary home battery (although there’s a preference to wait for vehicle-to-load/home/grid capable EV model).

Household 4

SNAPSHOT: This is a vacation property in regional NSW with rooftop solar and a home storage battery installed. The property is mostly vacant, and thus has low energy consumption for extended periods, with substantial solar export opportunities. This is a simple single-phase property with electric hot water and a small pool.

As we have seen in this round-up of electrification sites, the aim is to cover off different types of houses, use cases and spend ratios.

The last in the series, a vacation property, is mainly used on weekends. It is a great example of effectively taking a property completely off-grid whilst nobody’s there, and supplying solar to the grid at the same time.

The hot water and pool are specifically set to operate as much as possible under the solar curve to minimise spend and carbon emissions.

The balance of the time the property runs off the battery when the sun is not shining.

Source: Wattwatchers web dashboard