Research Data Visualizations

Economic Viability of Utility-Scale Battery Storage Co-Located with Renewable Energy Sources — Yuri Naidu

The Duck Curve → Canyon Curve

Illustrative CAISO net load profile showing deepening midday trough (spring day)

Midday min (2024)
~8,000 MW
Evening ramp
17,000 MW in 3 hrs
Net demand decline
−45% midday (2020→2024)

Sources: CAISO OASIS data; FactSet, Aug 2025; REsurety, May 2025. Note: Stylized curves for illustration.

CAISO Renewable Curtailment

Solar accounts for 93% of all curtailed energy in 2024

2024 Total
3.4 TWh curtailed
YoY Growth
+29%
US Total (2024)
~20 TWh across all ISOs

Sources: EIA, May 2025; Yes Energy, Jun 2025; Amperon, Feb 2026. *2025 projected based on Jan–Apr pace.

Illustrative CAISO Hourly Price Profile (SP15)

The arbitrage window: charge at midday lows, discharge at evening peaks

Sources: REsurety, May 2025; Modo Energy; CAISO LMP data. Note: Stylized for illustration.

Negative Pricing Escalation — SP15

Both frequency and depth more than doubled in one year

2023
~530 hrs (6% of year)
Median: −$10/MWh
2024
~1,180 hrs (13% of year)
Median: −$17/MWh
Solar Capture Rate (SP15)
<30%
Solar earns 70% less than baseload generation

Source: REsurety, "Negative Prices in CAISO," May 2025; Ascend Analytics CAISO Outlook.

CAISO Battery Storage Capacity Growth

From 500 MW in 2020 to ~17 GW by October 2025 — a 34× increase in five years

Total Energy Capacity
55.2 GWh
Evening Peak Discharge
>8 GW nightly
Record Day (Apr 21)
9.72 GW / 42.6 GWh
% of Net Load at Peak
~26%

Sources: Amperon, Dec 2025; Modo Energy, Oct 2025; EIA, May 2025; CAISO Battery Storage Report, May 2025.

Storage Technology Comparison: CapEx ($/kWh)

Current mid-range installed cost estimates by technology

Sources: Lazard LCOS v9/v10; IRENA Nov 2025; Ember Dec 2025; iScience Dec 2025; DOE; NREL ATB 2024.

Round-Trip Efficiency (%)

Max Discharge Duration (hours)

Storage CapEx Cost Trends ($/kWh)

LFP costs have fallen dramatically; sodium-ion and CAES are emerging lower-cost alternatives

LFP Pack Price (2025)
$70/kWh
45% fall from 2024 (BNEF)
Total Project Cost
$125/kWh
Outside US/China (Ember)
Na-Ion Cell Target
$40/kWh
IRENA projection
A-CAES (100+ MW)
$120/kWh
Achieved in 2024

Sources: Lazard LCOS v7–v10; Ember Dec 2025; BNEF 2025; IRENA Nov 2025; iScience Dec 2025.

CAISO BESS Merchant Revenue — Price Compression in Action

Year-over-year revenue decline demonstrates storage cannibalizing its own spreads

Sep 2025 Revenue
$2.54/kW-mo
YoY Decline
−45%
TB4 Spread Decline
−44% YoY
Key Implication
Operational α required

Sources: Modo Energy monthly CAISO benchmark reports, 2024–2025.

Poland: "Pre-Storage California"

Surging curtailment on a coal-dominated grid with only 200 MW of BESS deployed

Solar Capacity
~21 GW
+4 GW added in 2024
BESS Online
200 MW
vs CAISO's 14.7 GW
H1 2025 Curtailment
800 GWh record
36% YoY increase
2-hr Arbitrage Potential
+81% YoY (Q2 '25)
Day-ahead market

Sources: Gramwzielone.pl; pv magazine Jul 2025; Pexapark Aug 2025; IEO/pv magazine Jan 2025.