What this simulation does not model -- known gaps and simplifications before optimization
11 known limitations identified
This simulation models energy flows, battery cycling, PV production, and hourly price arbitrage for a single ADS-TEC CP320 ChargePost on a typical summer Saturday. The following factors are not yet included in the financial model. They should be considered when interpreting results and before using the optimizer output for investment decisions.
Estimated Impact
With ~300 kWh daily battery throughput and 88% RTE, approximately 36 kWh/day is lost to heat. At avg procurement of ~13.4 ct/kWh, this is ~4.82 EUR/day hidden cost.
Recommendation
Add a batteryRoundTripEfficiency parameter (default 0.88) to the store. Every kWh discharged should cost 1/RTE kWh on the input side. The optimizer must account for this -- sometimes it is cheaper to use grid directly than to cycle through battery at a loss.
Estimated Impact
Estimated daily OpEx for a single HPC unit: - Eichrecht backend (has-to-be, Plug Surfing, etc.): ~2-4 EUR/day - CPMS software license (ChargeCloud, Wirelane): ~3-5 EUR/day - Payment processing (e-clearing, card terminal): ~2-4% of revenue - Maintenance / service contract: ~5-14 EUR/day (for 320 kW HPC) - Insurance (liability + equipment): ~3-8 EUR/day - Connectivity (IoT SIM, VPN): ~0.50 EUR/day - Total estimate: 15-35 EUR/day or ~5,500-12,800 EUR/year
Recommendation
Add a flat dailyOpEx field to the cost model. Even a rough estimate of 20 EUR/day would make the P&L far more realistic.
Estimated Impact
Estimated CAPEX components: - ADS-TEC CP320 ChargePost: ~150,000-200,000 EUR - PV system (150 kWp rooftop): ~120,000-180,000 EUR - Grid connection upgrade (80 kW NS): ~15,000-40,000 EUR - Installation, civil works, signage: ~20,000-40,000 EUR - Total: ~305,000-460,000 EUR - Over 10 years: ~84-126 EUR/day amortization - Over 15 years: ~56-84 EUR/day amortization
Recommendation
Add CAPEX inputs (equipment cost, installation cost, depreciation years) and compute daily amortization. This is essential for any investor/business case evaluation.
Estimated Impact
- Roaming settlement: CPO typically receives 70-85% of the end-user price - Hubject/intercharge platform fee: ~0.50-2.00 EUR/session - Card payment processing: ~2-4% of transaction value - On 59 ct/kWh retail: effective revenue could be 42-52 ct/kWh via roaming - Typical CPO revenue mix: ~40% roaming, ~30% ad-hoc, ~30% subscription
Recommendation
Add a blendedRevenueDiscount factor (default ~15%) or model separate revenue streams for ad-hoc, roaming, and subscription users.
Estimated Impact
If ad-hoc market rate is 69-79 ct and you charge 59 ct, you leave 10-20 ct/kWh on the table. On 600 kWh/day throughput, that is 90 EUR/day potential uplift.
Recommendation
This may be an intentional pricing strategy. Document whether 59 ct targets subscription users, is a volume-attraction strategy, or should be raised to 69 ct market rate.
Estimated Impact
On summer Saturdays in 2024, EPEX DAM prices in Germany reached -5 to -10 ct/kWh for several hours. This means the optimizer could benefit from aggressively charging the battery during negative-price windows (you get paid to fill the battery, then sell that energy to EV drivers at 59 ct). Missing this underestimates the battery arbitrage opportunity by ~2-5 EUR/day on sunny days.
Recommendation
Allow negative values in the EPEX price input. Add preset profiles for different day types (sunny weekend with negatives, cloudy weekday, winter evening peak).
Estimated Impact
Potential Netzentgelt reduction of ~30-60% on the Arbeitspreis component. With current Netzentgelt ~5.0 ct/kWh, savings could be 1.5-3.0 ct/kWh on all imported energy. However, the curtailment to 4.2 kW could disrupt HPC charging sessions during grid events (rare, typically < 100h/year).
Recommendation
Evaluate with local DSO whether 14a is compatible with battery-buffered HPC (the battery can likely absorb curtailment events without impacting EV charging).
Estimated Impact
With 25 daily sessions, if even 20% of users overstay by 10 minutes at 10 ct/min, that is 5 sessions * 10 min * 0.10 EUR/min = 5 EUR/day additional revenue. Actual data from German CPOs suggests idle fee revenue is ~3-8% of total charging revenue.
Recommendation
Add an optional idle fee parameter. This is a minor revenue source but helps with realistic P&L.
Estimated Impact
Summer PV output ~6-8 kWh/kWp/day vs winter ~1-2 kWh/kWp/day in Germany. Annual extrapolation from a summer day overestimates PV savings by ~40-60%. Winter EPEX prices are typically higher (more gas-fired generation), which means higher procurement costs but also higher grid arbitrage potential.
Recommendation
Add representative profiles for 4 seasons or at least summer/winter. Weight annual projections: ~5 months summer-like, ~4 months shoulder, ~3 months winter.
Estimated Impact
5-10% of energy drawn from the charger does not end up as usable SOC in the EV. This means the CPO sells slightly more kWh than the EV actually stores, which is actually favorable for revenue but means the kWh-per-session estimates are slightly low (the meter bills the gross, not net).
Recommendation
This slightly underestimates billed kWh per session. For accurate billing simulation, add a dcChargingOverhead factor of ~5-8%.
Estimated Impact
Grid connection costs: - NS 80 kW (if transformer has capacity): ~5,000-15,000 EUR - NS 80 kW (if transformer upgrade needed): ~20,000-50,000 EUR - New dedicated MS connection: ~50,000-150,000 EUR These are one-time costs rolled into CAPEX.
Recommendation
Include in CAPEX amortization when that module is added.