Which Appliances are Best to Time-shift?

It is sometimes said that there is not enough energy consumed by wet appliances to eliminate 7GW of peak consumption by time-shifting them alone. I leave you to judge.

The trend of wet appliances’ consumption has been inexorably upwards, and is now second only to consumer electronics. Much of the increase is due to an undesirable increase in the use of tumble dryers, but I am not here to preach austerity. If you live in a flat or gardenless house, it may be the only realistic option.

Reading off the above graph, we have a Mtoe figure for each appliance type:

APPLIANCE TYPE	Mtoe 2014	GWh (Mtoe x 11,630)	PERCENT OF TOTAL
Light	1.0	11,630	14.2
Cold	1.1	12,793	15.7
Wet	1.3	15,119	18.5
Consumer Electronics	1.8	20,934	25.7
Home Computing	0.6	6,978	8.5
Cooking	1.2	13,956	17.1
TOTAL	7.0	81,410	100

There are around 80 winter days when it is desirable to reduce peak consumption by up to 7GW and by around  18GWh spread over the 5 hours of the peak, so by a total of 80x18=1440 GWh/year. This is 1.7% of total annual domestic consumption, and 9.5% of total annual wet consumption.

There are of course other candidates for time-shifted consumption as well as wet appliances.  Cold devices (mainly fridges and freezers in UK) and increasingly home computing (laptops, smartphones and tablets all have batteries) are if anything even less time-sensitive in direct grid consumption than wet appliances, and are now already 24% of the total vs wet appliances 18.5%. 

The reason we are not focussing on them is the relatively low consumption per device. A typical house may have three wet appliances and ten or more cold and computing ones.

Would you rather go for the wet or the cold and computing!

 It’s up to you. Both is best!

Demand Response and storage - how much of each do we need? Wattstor may have part of the answer.

                                             

A new company in Cornwall - Wattstor - has a useful piece of kit which enables PV system owners to dramatically reduce the amount of electricity they need from the grid in summer. It stores surplus electricity during the day - up to 6kWh - which is then available in the evening.
I spent over £12,000 on a 4kW PV system , so I am a prime candidate for Wattstor.
Will it make any difference  to peak winter electricity demand - when there is very little daytime PV generation?
The Wattstor system costs several thousand pounds - mainly for batteries. If it shifts sufficient summer electricity from day to evening, it will pay for itself.
Delay timers and time switches will have the effect in winter of reducing peak demand at low cost with high reliability.
Perhaps someone could do the sums to calculate the ROI and carbon reduction of each approach?