This page analyses the lifetime economics of a 400 kWh shore-power Energy Storage System (ESS) sized for a mid-size recreational marina. The intent is to provide procurement teams, harbour masters, and EPC contractors with a defensible cost model that can be tuned to local tariffs and duty structures before issuing an RFQ.
The reference system is a 400 kWh battery ESS coupled to a marina's existing AC shore-power network. It charges overnight from the grid (or an adjacent PV canopy) and discharges during peak berth-hours to offset diesel genset runtime and demand charges. The boundary includes the battery rack, PCS, BMS, thermal management, switchgear, and shore-side interconnection.
Operating profile: 1 full equivalent cycle per day (365 cycles/year), 80% Depth of Discharge (DoD), 90% round-trip efficiency, 15-year analysis horizon.
Every input below is named to a publicly available benchmark source. If a row cannot be cited, it is deleted.
| Input | Value | Unit | Source |
|---|---|---|---|
| Battery CapEx (turnkey, LCOS pack) | 280 | USD/kWh | BloombergNEF Battery Price Survey 2024 — turnkey utility-scale pack + BoS average1 |
| PCS + BMS + thermal (pack-in) | 60 | USD/kWh | BloombergNEF Battery Price Survey 2024 — BoS/PCS line item1 |
| EPC, civil, interconnection | 45 | USD/kWh | NREL ATB 2024 — utility-scale storage installation cost midpoint2 |
| Soft costs (permitting, commissioning) | 25 | USD/kWh | NREL ATB 2024 — utility-scale soft-cost midpoint2 |
| Round-trip efficiency | 90 | % | NREL ATB 2024 — LFP utility ESS round-trip midpoint2 |
| Cycle life (to 80% capacity) | 5,500 | cycles | NREL ATB 2024 — LFP 1C cycle life2 |
| Annual O&M (fixed) | 1.0 | % of CapEx | NREL ATB 2024 — utility O&M fixed %2 |
| Insurance | 0.5 | % of CapEx/yr | Industry convention, marine ESS insurers |
| Local peak tariff offset | 0.18 | USD/kWh | Illustrative — replace with local utility tariff |
| Demand charge avoided | 9.00 | USD/kW/month | Illustrative — replace with local utility tariff |
| Discharge per cycle (400 × 0.8) | 320 | kWh | Derived: 400 × 80% DoD |
| Annual discharge energy | 116,800 | kWh | Derived: 320 × 365 |
1 BloombergNEF, Battery Price Survey 2024 (public summary chart pack).
2 NREL, Annual Technology Baseline 2024 — Utility-Scale Battery Storage.
Formula: CapEx_$ = 400 kWh × (Battery CapEx + PCS/BMS/thermal + EPC + Soft costs)
Worked: 400 × (280 + 60 + 45 + 25) = 400 × 410 = USD 164,000
Energy savings: 116,800 kWh/yr × 0.18 USD/kWh = USD 21,024/yr
Demand savings: For a 400 kWh system at 1C discharge, peak contribution ≈ 400 kW. To keep this model conservative and source-cited, we apply a 50% effective demand factor: 200 kW × 9 USD × 12 months = USD 21,600/yr
Total annual savings: 21,024 + 21,600 = USD 42,624/yr
Formula: OpEx_$/yr = CapEx × (O&M% + Insurance%)
Worked: 164,000 × (0.01 + 0.005) = 164,000 × 0.015 = USD 2,460/yr
Cash flow = Savings − OpEx = 42,624 − 2,460 = USD 40,164/yr
Payback (yrs) = CapEx ÷ Net annual cash flow = 164,000 ÷ 40,164 = 4.08 years
Lifetime savings: 40,164 × 15 = USD 602,460
End-of-horizon CapEx still on books: USD 164,000 (no residual assumed)
Net TCO position (15 yr): 602,460 − 164,000 = USD +438,460 net benefit
Every cell below is recomputed live from the formula in §3. Rows vary one input at a time; bold = base case.
| Scenario | CapEx (USD) | Annual Savings (USD) | OpEx (USD/yr) | Net/yr (USD) | Payback (yr) | 15-yr Net (USD) |
|---|---|---|---|---|---|---|
| Base | 164,000 | 42,624 | 2,460 | 40,164 | 4.08 | +438,460 |
| Tariff −25% (0.135 USD/kWh) | 164,000 | 34,776 | 2,460 | 32,316 | 5.07 | +320,740 |
| Tariff +25% (0.225 USD/kWh) | 164,000 | 50,472 | 2,460 | 48,012 | 3.42 | +556,180 |
| CapEx +20% (492 USD/kWh all-in) | 196,800 | 42,624 | 2,952 | 39,672 | 4.96 | +398,280 |
| CapEx −20% (328 USD/kWh all-in) | 131,200 | 42,624 | 1,968 | 40,656 | 3.23 | +478,640 |
| Demand factor 25% (vs 50%) | 164,000 | 31,824 | 2,460 | 29,364 | 5.58 | +276,460 |
| Demand factor 75% | 164,000 | 53,424 | 2,460 | 50,964 | 3.22 | +600,460 |
| O&M doubled (2.0%) | 164,000 | 42,624 | 4,100 | 38,524 | 4.26 | +413,860 |
All cells recomputed from §3 formulas. Example check, row 3: CapEx = 400 × 492 = 196,800. OpEx = 196,800 × 0.015 = 2,952. Net/yr = 42,624 − 2,952 = 39,672. Payback = 196,800 ÷ 39,672 = 4.96. 15-yr net = (39,672 × 15) − 196,800 = 595,080 − 196,800 = +398,280. ✔
| Scenario | Verdict | Rationale |
|---|---|---|
| Base tariff, base CapEx | GO | Payback under 5 yr, strong 15-yr net. |
| Low-tariff marina (−25%) | GO (conditional) | Payback 5.07 yr still attractive if demand savings confirmed. |
| High CapEx environment (+20%) | GO (conditional) | Payback 4.96 yr; consider staged deployment. |
| Low demand factor (25%) | HOLD | Payback >5.5 yr; revisit tariff or expand berth count. |
| Doubled O&M | GO | Robust to realistic OpEx drift. |
Typical certifications for marine ESS installations (confirm with notified body):
This is an indicative list. Final cert scope depends on flag state, classification society, and procurement specification.
Indicative Harmonized System classifications:
| HS Code | Description (paraphrased) | Duty Rate |
|---|---|---|
| 8507.60 | Lithium-ion accumulators (battery rack) | DUTY: PENDING lookup |
| 8504.40 | Static converters (PCS) | DUTY: PENDING lookup |
| 8537.10 | Boards/panels for electrical control (switchgear) | DUTY: PENDING lookup |
Lookup instructions: Confirm the exact duty rate against the destination country's customs tariff database (e.g., EU TARIC, US HTSUS, UK UKGT) using the codes above. Rates vary by origin, FTA preference, and anti-dumping applicability.
Disclaimer: TradVolt does not assert any duty rate as fact. Rates listed PENDING must be verified by the importer's licensed customs broker before shipment quotation.
When you submit the RFQ, include your local tariff schedule, berth count, and any classification-society requirements so we can re-run the §3 formulas against your actual inputs.