When will the storage revolution reach your kitchen?

Home front: Will people welcome utilities to use home appliances for energy storage? (Pic source: PhotoMIX via Pexels)


Individual consumers could play a key role in the looming storage revolution. We’ve heard plenty about how a growing number of electric vehicles linked to the grid can help operators to better match energy production with demand, and boost stability.

But grid operators aren’t simply content to harness the storage capacity of the metal horse that sits on your street or driveway. They also want to get in through your front door and control when you produce hot water, chill your food, or wash your clothes – and a pilot project in the northwest of the US shows they may be able to.

This week, Oregon utility Portland General Electric and federal agency Bonneville Power Administration have published the results of a pilot project run over the last two years to use domestic hot water heaters to support the electricity grid. It could have big implications for how operators run electricity grids in the US and beyond; and how much renewable energy capacity that utilities can incorporate on the grid.

What did the study involve?

The study covered 270 homes served by eight utilities in the states of Oregon and Washington. The householders installed devices so that their utility could start and stop the heater when needed, and thus heat the water when production of energy outstripped demand.

The idea is that this makes it cheaper for householders, while allowing utilities to build less peaking capacity and support more renewables.

This isn’t a new idea. For example, London-based consultancy Brattle Group wrote about the potential to use water heaters in this way in February 2016, on behalf of a trio of US organisations. It said: “Electric water heaters are essentially pre-installed thermal batteries that are sitting idle in homes across the US.”

What PGE and BPA have done is to take on that theory and find out whether it would work in practice – and, if it did, how it could transform the market. The pair started on the project, which they called the ‘largest smart water heater pilot ever implemented’, in 2015, and said that in total there were 600 demand response over 220 days. You can get the full report ‘A Business Case for CTA-2045 Market Transformation’ here.

And before we carry on, ‘CTA-2045’ refers to the interface that allows utilities to send request so curtail energy use.

What did the project find?

First, it found the system worked and that customers were satisfied. Eighty percent of customers said they were ‘very satisfied’ with the pilot, and 94% said they would be likely to join a programme using this technology in future. It is worth noting that a study such as this would attract people who were most willing to give the technology a go, and that others might be more resistant, but the result is still impressive.

In our view, this taps into an important element here. I don’t think most people care about whether the utility controls their hot water heater, as long as they get the hot water when they need it and can save a bit of money in the process. Reliability will be key if grid operators and utilities want to roll out this programme further afield.

Second, PGE and BPA said that if 26.5% of households in Oregon and Washington used this system – or 48% of the households covered by the participating utilities – then that would enable the utilities to create capacity equivalent to a 301MW peaking plant by 2039, or the equivalent of 340MWh-800MWh battery storage.

It could save $106m compared to the cost of building new peaking capacity in those two states – and could be worth $2bn if the system was used across the US.

The partners added that there would still be a financial benefit even if as few as 5% of the households in the region actually used it. Clearly, if there is capacity there and the technology works then it makes sense to take advantage of that potential; and it is an easy way for individual householders to support more renewables.

And third, the report also raised the prospect that similar technology could be used in fridges, dishwashers and clothes dryers. All of these have the potential to shift their electricity use to quieter times, and enable individual billpayers to save money. This could be a great example of how a ‘smart grid’ could make life better for real people.

This is where I’ve got a bit of history. Before joining Energy Storage Report sister title A Word About Wind, I worked for a US-headquartered website that focused on smart cities and emerging systems such as the ‘internet of things’. This idea of a network of connected appliances always seemed to focus on gimmicks like a fridge that says if you’re running out of milk. It’s good to see the idea being used for something useful.

That final point might seem like I’m being snarky, but it’s key. If utilities are going to encourage people to hand over control of their cars and household appliances for the benefit of the electricity grid, then there needs to be a clear reason for doing so. For most people, supporting renewables and saving money are both good ones.

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