EE FORUM JULY 2014
• MAIN TOPIC – CHANGE TO TOU TARIFF, THE
CAVENDISH EXPERIENCE
• CONCLUSION – AN INSIGHT INTO FUTURE
ENERGY SAVING INITIATIVES FOR
CAVENDISH
CHANGE TO TOU TARIFF – WHY?
• Very Large Power User tariff falling away in July 2011
• Choice between two tariffs – LPU (MV) & TOU
• TOU tariff offered the opportunity to be pro-active about load
management in order to further save on electricity costs
• TOU tariff offered a cheaper kWh rate vs VLPU or LPU (MV) tariffs
during standard and off-peak times for 9 months of the year
• TOU tariff peak time only constitutes approximately 27% of retail
operating hours during the week and 0% over weekends, which is
the peak operating time for retail with kWh consumption at its
highest
• For retail, the kWh consumption is at its lowest during the 3 winter
months due to reduced HVAC loads, which constitutes the high
season for the TOU tariff
• Reduce operating costs for the centre and combat high electricity
tariff increases
CHANGE TO TOU TARIFF – COST ANALYSIS
AND CALCULATIONS TO INFORM DECISION
• Compared LPU (MV) tariff vs VLPU tariff to
calculate the variance in cost
• Compared TOU tariff vs VLPU tariff to calculate
the variance in cost
• LPU (MV) tariff was slightly easier due to bulk
kWh and kVA figures being readily available from
Council bills
• TOU was harder due to MV bulk metering data
not being available for Cavendish for the
purposes of calculating TOU kWh figures
CHANGE TO TOU TARIFF – COST ANALYSIS
AND CALCULATIONS TO INFORM DECISION
• Results for LPU (MV) vs VLPU tariff – pay R700k
more for electricity p.a. mainly due to VLPU low
kVA charge (almost half)
• Calculation for TOU figures - typical week load
profile for Cavendish and applied % for off peak,
standard and peak kWh consumptions for high
and low seasons
• Results for TOU vs VLPU tariff – pay R70k less for
electricity p.a. due to TOU having lower kVA and
service charges
CHANGE TO TOU TARIFF – COST ANALYSIS
AND CALCULATIONS TO INFORM DECISION
City of Cape Town: Draft Electricity Tariffs
To Be Implemented With Effect From 1 July 2011
Average 19.94 % Increase
(All values exclude VAT)
Commercial Tariffs
Large Power MV
Very Large Power
Time of Use
2010/11
2011/12
%Incr
Service
R/Day
23.90
28.67
19.96
Energy
c/kWh
37.85
45.40
19.95
Demand
R/kVA
112.69
135.16
19.94
Service
R/Day
5000.00
n/a
n/a
Energy
c/kWh
37.85
n/a
n/a
Demand
R/kVA
69.95
n/a
n/a
Service
R/day
3900.00
4680.00
20.00
Energy
High-Peak
c/kWh
191.88
230.14
19.94
High-Standard c/kWh
50.74
60.86
19.94
High-Off Peak c/kWh
27.62
33.13
19.95
Low-Peak
c/kWh
54.48
65.34
19.93
Low-Standard c/kWh
33.80
40.54
19.94
Low-Off Peak
Demand
c/kWh
R/kVA
23.97
60.87
28.75
73.00
19.94
19.93
Notes to the TOU
Tariff:
High Demand season is from June to August, Low Demand season is
from September to May.
Hours of Operation:
Peak
Standard
Off Peak
Weekdays 07:00 to 10:00, 18:00 to 20:00
Weekdays 06:00 to 07:00, 10:00 to 18:00, 20:00
to 22:00
All other times
Note also that demand is only measured during the Peak and
Standard periods, and not off peak times, and that public holidays
are considered normal days due to metering constraints.
CHANGE TO TOU TARIFF – CHALLENGES TO
EFFECT THE CHANGE IN TARIFF
• New meter installation – co-ordination between
the electricity department and metering
department
• Getting the correct documentation from the City
as well as getting signatures
• Deposit that became applicable according to the
max allowable demand, that was not applicable
in the past
• Timeline for change to TOU tariff from date of
first application – 8 to 9 months
CHANGE TO TOU TARIFF – ACTUAL RESULTS
FROM FIRST YEAR OF TOU IMPLEMENTATION
• First year of measurement was from Feb to
Dec 2012
• With the VLPU tariff no longer applicable, the
comparison turned to TOU vs LPU (MV)
• For 11 months in 2012, Cavendish saved
R177k by being on the TOU tariff
CHANGE TO TOU TARIFF – ACTUAL RESULTS
FROM FIRST YEAR OF TOU IMPLEMENTATION
50
45
40
35
30
% Off-peak kWh's
25
% Standard kWh's
% Peak kWh's
20
15
10
5
0
February
March
April
May
June
July
August September October November December
CHANGE TO TOU TARIFF – LEARNINGS AND IMPROVEMENTS
FROM FIRST YEAR OF TOU IMPLEMENTATION
•
•
•
•
•
Budgets had to be changed to accommodate the winter high season as the electricity cost
increased dramatically – between 50 to 80%
Even though Cavendish saved money in 2012 by being on the TOU tariff vs the LPU (MV)
tariff, more could be done to reduce electricity costs
There is a balance that needs to be struck between saving energy and compromising your
centre e.g. turning off lights during the winter high season
More energy saving initiatives means less kWh’s during peak time hours (high and low
season):
– lighting energy saving initiatives implemented
– renewable energy saving initiatives implemented
More investigation would have to go into HVAC efficiency and reducing kWh’s during the
winter high season especially:
– major maintenance of HVAC equipment to be conducted before June to ensure optimal
operational efficiency of equipment during the winter months
– Maximise free cooling from outside air temperature conditions
– Try to start HVAC plant (chillers, cooling towers) only after the morning peak time period
– Increase chilled water set point temperature by 1 or 2 degrees
– Increase diffuser temperature set points by 1 or 2 degrees
CHANGE TO TOU TARIFF – ACTUAL RESULTS
FROM SECOND YEAR OF TOU IMPLEMENTATION
• Second year of measurement was from Jan to
Dec 2013
• For 12 months in 2013, Cavendish saved
R253k by being on the TOU tariff
CHANGE TO TOU TARIFF – ACTUAL RESULTS
FROM SECOND YEAR OF TOU IMPLEMENTATION
50
45
40
35
30
25
20
15
10
5
0
% Off-peak kWh's
% Standard kWh's
% Peak kWh's
CHANGE TO TOU TARIFF – ARE WE IMPROVING?
Graph of variance between TOU
and LPU (MV) in 2013 (Rands)
% Variance between TOU and
LPU (MV) - 2012
% Variance between TOU and
LPU (MV) - 2013
-20
December
November
October
September
August
-10
July
0
June
0
May
10
April
10
March
20
February
20
% Variance between
TOU and LPU (MV) 2012
-10
-20
-30
-30
-40
-40
-50
-50
January
February
March
April
May
June
July
August
September
October
November
December
Graph of variance between TOU
and LPU (MV) in 2012 (Rands)
% Variance between
TOU and LPU (MV) 2013
CHANGE TO TOU TARIFF – CAN IT
WORK FOR RETAIL ENVIRONMENTS?
• YES, IT HAS CERTAINLY BENEFITTED
CAVENDISH
• HOWEVER, CONSIDERATION MUST BE GIVEN
TO THE DYNAMICS OF YOUR CENTRE – LOAD
PROFILE, ABILITY TO SAVE MAXIMUM ENERGY
DURING WINTER HIGH SEASON MONTHS
AN INSIGHT INTO FUTURE ENERGY
SAVING INITIATIVES FOR CAVENDISH
AN INSIGHT INTO FUTURE ENERGY
SAVING INITIATIVES FOR CAVENDISH
Trial voltage optimisation system
• Guaranteed savings – 123700kWh’s p.a. & 46kVA p.m.
for a 1 MVA VO unit
• ROI – 4 years
AN INSIGHT INTO FUTURE ENERGY
SAVING INITIATIVES FOR CAVENDISH
Replacement of T5 flourescents with LED alternative
• Anticipated savings – 868517kWh’s p.a. & 112kVA p.m.
• ROI – 58 months
AN INSIGHT INTO FUTURE ENERGY
SAVING INITIATIVES FOR CAVENDISH
Solar and wind
QUESTIONS?
THANK YOU