Joint effect

The joint electricity demand of washing machines, tumble dryers and dishwashers is shown in Figure 8.7. The effect of delaying the starts on the joint demand is visible. Not allowing starts reduces the electricity demand drastically after half an hour. However, it takes long before the electricity demand of the appliances is gone.

At the moment the appliances are allowed to start again, power demand goes up. For a delay of one hour, the total power demand is 53.3 % higher. A longer delay (two hours) results in an increase by 142.5 %. One hour after the first peak, the power drops again. Dishwashers are responsible for this drop. The second peak is also caused by dishwashers.

A more detailed view on the effect of using the flexibility is depicted in Figure 8.8. For a delay of half an hour, the peak demand is relatively low because of the cycles that would have operated. The power demand before 19h15 is negative (Table 8.8). After 19h15 the power rises and remains about the same the next fifteen minutes. Half an hour after allowing starts, the power drops to slightly negative (412 kW), most dishwashers only require base load power after half

00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 5

10 15 20

Time of the day

P o w er (MW) no 1h 2h

Figure 8.7: The effect of using flexibility on the total demand of wet appliances

Table 8.8: Peak before and after delay of wet appliances

delay participating power before power after

[#] [kW] [kW]

30’ 3999 -3977 1723

60’ 7158 -5543 4141

90’ 10166 -7311 7542

120’ 13070 -7573 11073

an hour. The base load combined with no power demand of cycles that would have operated explain the negative power.

A delay of one hour resulted in a higher negative just before and a more positive power just after 19h15 (Table 8.8). The double peaks are visible as well. The negative power is restricted to the avoided electricity demand, hence the same magnitude of negative power for one and a half hour and two hours (Table 8.8).

16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 −8 −6 −4 −2 0 2 4 6 8 10 12

Time of the day

P o w er (MW) 0.5 h 1.0 h 1.5 h 2.0 h

Figure 8.8: The impact of using wet appliances’ flexibility

8.3

Conclusions

The impact of wet appliances on the total electricity demand is limited and ranges from 28 W (average business-consumers) to 87 W (relatively large day-consumers) on average. The wet appliances’ electricity demand of the various customer groups is combined with the attitude towards active demand participation of the groups to estimate the potential. Only the most positive attitude is assumed to be willing to participate. The potential is found to be ranging from 11 W (large day-consumers) up to 44 W (relatively large day-consumers) on average.

The potential for active demand, i.e. flexibility, in Belgium is estimated by combining the probability of each customer group with the potential per group and multiplying this with the number of households. 29 % of the households are considered to be participating in active demand based on the most positive attitude.

The average potential for flexibility is expected to be 92 MW, with peaks up to 353 MW and is not negligible compared to the power reserves. However, it seems likely that the flexibility will only be used as a last resort for balancing because of the reserves’ requirements regarding availability and response time.

The effect of using flexibility of wet appliances is tested by simulating 100 000 households for a Tuesday. The appliances are not allowed to start until 19h15, the disallowance varies from half an hour up to two hours with steps of a half

hour. The effect in terms of power reduction when the devices are delayed and the effect when the appliances are allowed to start again is described.

The peak demand when the appliances are allowed to start again is influenced by the delayed cycles, resulting in a relative lower peak for a small (fifteen minute) delay. The lower peak is encountered for every wet appliance. The power demand of dishwashers has an extra effect. Because of the two heating cycles during a dishwasher cycle, there is a peak first, followed by a drop in power, to end with a peak.

Longer delays involve more appliances. The negative power before starts are allowed again is however limited to the power demanded by the appliances which would have been started. The positive power on the other hand, scales up with an increasing delay and the increasing number of appliances.

The potential for active demand and the results of the simulations are based on multiple assumptions. The dimensions to cluster upon are assumed to be correct. The cluster membership is relaxed to spread the data over multiple customer groups, introducing errors. The customer group membership weight is used to scale up measurements of appliances. The number of appliances is limited, impacting the estimations based on measurements. Models are created to represent appliances and again assumptions are made. The results presented in this chapter are thus not exact, but the magnitude of the numbers is correct and give insights about the possibilities for active demand.

Toolset

The Linear project, the major data source for the thesis, gathers data from different sources. Making data mining possible for multiple partners requires a specific software infrastructure, especially because of the confidentiality requirements of the parties providing data providing [151].

The requirements are listed in Section 9.1, the major ones being are related to security and functionality. Thereafter, an overview of the infrastructure is given (Section 9.2). How security and functionality are tackled, is described in Section 9.3. Some aspects of the work recently got improved by Strobbe et al. [14].