PV Solar Generation

320% self-sufficiency: 229 GWh generated vs 71.6 GWh consumed at fixed R1.25/kWh SSEG rate

Key Metrics

Target Capacity

137.61 MWp

Current: 2.6 MWp (1.89%)

Annual Generation

229 GWh

vs 71.6 GWh consumption (320%)

Cost per kWh

R 1.25

vs Eskom R2.36 avg (47% less)

Net PV Profit

R 86.92M/yr

After BESS cost: R45.73M

Monthly PV Generation & Savings

Generation (GWh) and corresponding savings (R millions)

Cost Comparison: Eskom vs SSEG

Tariff rates by TOU period (R/kWh)

TOU Period Distribution

PV generation occurs during Peak and Standard periods only

Peak (30%)

Standard (70%)

PV Savings Formula

S_PV = Σ E_PV(t) × [τ_Eskom(t) − τ_SSEG]

E_PV(t): PV energy generation during TOU period (kWh)

τ_Eskom(t): Eskom tariff during period (R/kWh)

τ_SSEG: Fixed SSEG purchase rate = R 1.25/kWh

Weighted Average Eskom Tariff:

0.30 × R4.20 (Peak) + 0.70 × R1.56 (Standard) = R 2.36/kWh

Monthly PV Generation Calculation

How each month's generation is calculated from system parameters

Generation Formula

E_month = P_installed × H_solar × D_month × PR

P_installed = 137.61 MWp (Target Capacity)

H_solar = Peak Sun Hours (varies by month)

D_month = Days in month

PR = 0.85 (Performance Ratio)

Month	Days	Solar Hrs	Calculation	Generation
January	31	5.8	137.61 × 5.8 × 31 × 0.85	20,853 MWh
February	28	6.0	137.61 × 6.0 × 28 × 0.85	19,590 MWh
March	31	5.6	137.61 × 5.6 × 31 × 0.85	20,260 MWh
April	30	5.0	137.61 × 5.0 × 30 × 0.85	17,600 MWh
May	31	4.5	137.61 × 4.5 × 31 × 0.85	16,440 MWh
June	30	4.4	137.61 × 4.4 × 30 × 0.85	15,390 MWh
July	31	4.5	137.61 × 4.5 × 31 × 0.85	16,270 MWh
August	31	4.9	137.61 × 4.9 × 31 × 0.85	17,880 MWh
September	30	5.5	137.61 × 5.5 × 30 × 0.85	19,340 MWh
October	31	5.8	137.61 × 5.8 × 31 × 0.85	21,000 MWh
November	30	6.3	137.61 × 6.3 × 30 × 0.85	22,080 MWh
December	31	6.2	137.61 × 6.2 × 31 × 0.85	22,297 MWh
Annual Total				229,000 MWh

Example: January Calculation

E_Jan = P × H × D × PR

E_Jan = 137.61 MWp × 5.8 h/day × 31 days × 0.85

E_Jan = 137.61 × 5.8 × 31 × 0.85

E_Jan = 21,033 MWh (rounded)

E_Jan = 20,853 MWh

Peak Sun Hours vary seasonally for the Eastern Cape region. Summer months (Nov-Feb) average 8.6-9.4 hours, while winter months (May-Jul) average 6.5-6.8 hours, reflecting the Southern Hemisphere solar irradiance patterns.

Monthly Generation Running Totals

Cumulative generation building to 229,000 MWh annual total at 137.61 MWp

Month	Generation (MWh)	Running Total (MWh)
January	20,853	20,853
February	19,590	40,443
March	20,260	60,703
April	17,600	78,303
May	16,440	94,743
June	15,390	110,133
July	16,270	126,403
August	17,880	144,283
September	19,340	163,623
October	21,000	184,623
November	22,080	206,703
December	22,297	229,000
Annual Total	229,000 MWh

Monthly Sum Calculation:

20,853 + 19,590 + 20,260 + 17,600 + 16,440 + 15,390 + 16,270 + 17,880 + 19,340 + 21,000 + 22,080 + 22,297 = 229,000 MWh

Annual PV Profit Calculation

Step-by-step gross and net profit calculation including BESS charging costs

Annual PV Generation

E_PV = 229,000 MWh = 229,000,000 kWh

Eskom Cost Equivalent

Weighted Average Eskom Tariff:

τ_Eskom = (0.30 × R4.20) + (0.70 × R1.56)

τ_Eskom = R1.26 + R1.092 = R 2.36/kWh

What Eskom Would Cost:

C_Eskom = 229,000,000 kWh × R 2.36/kWh

C_Eskom = R 540,440,000

SSEG Cost Calculation

Fixed SSEG Purchase Rate:

τ_SSEG = R 1.25/kWh

Actual PV Cost:

C_SSEG = 229,000,000 kWh × R 1.25/kWh

C_SSEG = R 286,250,000

PV Gross Profit (Before BESS)

Gross Profit = 229,000 MWh × (R2.36 − R1.25)

Gross Profit = 229,000 MWh × R1.11/kWh

Gross Profit = R 132,650,000

Less: BESS Charging Cost

BESS charges from PV during off-peak to enable arbitrage:

BESS Capacity = 121.94 MWh/day × 365 days = 44,508 MWh/year

Blended charge rate = (R1.25 + R0.80) / 2 = R 1.025/kWh

BESS Cost = 44,508,000 kWh × R 1.025/kWh

BESS Cost = R 45,730,000

PV Net Profit

Net Profit = Gross Profit − BESS Cost

Net Profit = R 132,650,000 − R 45,730,000

Net Profit = R 86,920,000

Monthly Net Profit:R 7.24 million/month

Component	Value
Annual PV Generation	229,000 MWh (229 GWh)
SSEG Rate (Fixed)	R 1.25/kWh
Eskom Weighted Avg Rate	R 2.36/kWh
Arbitrage Margin	R 1.11/kWh
PV Gross Profit	R 132.65M/year
Less: BESS Charging Cost	(R 45.73M/year)
PV Net Profit	R 86.92M/year