INGENIEUR
Figure 19 : Past Trend and Forecast Average Electricity Tariff vs Solar PV Electricity Generation Cost Source : MPIA Proposal for Net Energy Metering Programme 2016-2030 . [ Ref . 8 ]
As mentioned earlier , with the anticipated large-scale integration of solar PV renewable variable generation in the electricity infrastructure grid network , future power systems need to have higher levels of flexibility requiring challenging MW ramping rates in the operational time frame . Characterising these ramping rates within the planning domain is becoming increasingly necessary . Operational flexibility is related to the system ’ s ability to deal with variability within system operation time scales — normally from a day ahead to real time . The type of operational flexibility required will depend on the time scale :
● Increased frequency response and reserves from seconds to minutes ;
● Increased ramping capability from minutes to hours ; and
● Scheduling flexibility from hours to a day ahead .
The time scales of flexibility , from the systemplanning perspective down to very short-term operation , and the impacts of VG on flexibility can be seen in Figure 20 .
Figure 21 depicts how each part of the system affects the need for and supply of flexibility . Variability sources drive the need for flexibility to restore a system ’ s power balance , while the flexibility sources respond to restore that balance .
While flexibility resources are commonly found on the supply-side , there is also the possibility of harvesting flexibility from the demand-side ( Demand Response , DR ). Large-scale industrial processes and direct control of certain loads have been utilised for many years . Recent advances in information and communication technologies ( ICT ), together with the large-scale rollout of advanced smart meters , have created a new window of opportunity to make better use of DR to increase flexibility .
The flexibility required can be obtained by scheduling and dispatching certain loads ( either individually or as an aggregation of smaller loads ) according to system needs while respecting a set of pre-conditions , such as comfort levels . Alternatively , price-responsive demand can be used with price signals that reflect flexibility
62 VOL 87 JULY-SEPTEMBER 2021