Cost Reduction Presentation

Bulk Supply Cost Reduction

Strategic Energy Solutions for Dr Beyers Naudé Local Municipality

137.61

MWp Solar Capacity

121.94

MWh BESS Capacity

R155k

BESS Cost/MWh/mo

15,000

Total Households

Annual Energy Consumption Profile (Eskom 30-min Interval Data)

Total Annual Consumption

71.6

GWh / year

71,600,000 kWh

TOU Consumption Distribution

Peak

Standard

Off-Peak

Time-of-Use Period Details

Peak Period

07:00-10:00 & 18:00-20:00

19%

Annual Consumption

13.57 GWh

13,570,000 kWh

Avg Rate

R3.635/kWh

Standard Period

06:00-07:00, 10:00-18:00, 20:00-22:00

51%

Annual Consumption

36.52 GWh

36,520,000 kWh

Avg Rate

R1.705/kWh

Off-Peak Period

22:00-06:00, Weekends & Public Holidays

30%

Annual Consumption

21.48 GWh

21,480,000 kWh

Avg Rate

R1.08/kWh

Annual kWh by TOU Period

13.6 GWh

Peak (19%)

36.5 GWh

Standard (51%)

21.5 GWh

Off-Peak (30%)

Total: 71.6 GWh annual consumption from Eskom 30-minute interval metering data

Eskom Time-of-Use (TOU) Period Definitions

2025/2026 Tariff Structure - MunicFlex

High-Demand (June - August)

Winter Peak Period

Peak

07:00 - 10:00 & 18:00 - 20:00

R6.47/kWh

Standard

06:00-07:00, 10:00-18:00, 20:00-22:00

R2.14/kWh

Off-Peak

22:00 - 06:00, Weekends & Public Holidays

R1.08/kWh

Low-Demand (September - May)

Standard Period

Peak

07:00 - 10:00 & 18:00 - 20:00

R2.69/kWh

Standard

06:00-07:00, 10:00-18:00, 20:00-22:00

R1.56/kWh

Off-Peak

22:00 - 06:00, Weekends & Public Holidays

R1.08/kWh

Key Insight: During High-Demand season (winter), peak tariffs are 6x more expensive than off-peak (R6.47 vs R1.08/kWh). This is why BESS arbitrage generates maximum value during June-August, providing R12M in savings during just these 3 months.

Detailed Calculation Breakdown

Monthly BESS Cost

BESS Capacity:121.94 MWh

Cost per MWh/month:R155,000

Monthly BESS Cost:R18.9M

121.94 MWh × R155,000 = R18,900,700/mo

Monthly PV Savings

PV Capacity:137.61 MWp

Generation:150 kWh/kWp/mo

Derivation: 5 Peak Sun Hours/day × 30 days = 150 kWh/kWp/mo

PV Cost:R1.25/kWh

Monthly PV Savings:R25.8M

137.61 MWp × 150,000 kWh × R1.25 = R25,801,875/mo

PV Savings

R25.8M/mo

BESS Cost

R18.9M/mo

Net Benefit

R6.9M/mo

→

Annual Benefit

R82.8M/yr

Monthly BESS Cost vs PV Savings (Utility Scale)

BESS Cost Rate

R155k/MWh/mo

Monthly BESS Cost

R18.9M

Monthly PV Savings

R25.8M

Net Monthly Benefit

R6.9M

Three Strategic Cost Reduction Interventions

Utility-Scale BESS & PV

137.61 MWp Solar + 121.94 MWh BESS

Annual Savings

R50.96M

Households

Municipal

Nano-Grid PV+BESS

3kWp PV + 10kWh BESS per unit

Annual Savings

R44.4M

Households

10,000

BESS Only Solution

10kWh BESS @ R1.05 dispatch, R1.079 charge, R10/kVA to provider

Annual Savings

R105M

Households

15,000

Household Deployment Overview

Total Available Households

15,000

PV+BESS & PV-Only Eligible

10,000

Due to roof constraints

BESS-Only Eligible

15,000

No roof requirements

Key Outcome

PV Generation Fully Offsets BESS Operating Costs

At R155,000/MWh/month BESS cost and R1.25/kWh PV generation cost, the 137.61 MWp PV system generates sufficient savings to cover the 121.94 MWh BESS operating cost with R6.9M/month surplus.

Annual BESS Cost

R226.8M/yr

R18.9M × 12

Annual PV Savings

R309.6M/yr

R25.8M × 12

Net Annual Benefit

R82.8M/yr

R6.9M × 12