OVRB Transaction Map¶

Phase 4, step 4.2 (reviewed). One business transaction interface per buy/sell link in the OVRB base case. Each interface transfers value between two units — buyer's cost is seller's revenue, one shared price and quantity — and defines how profit pools between them.

A business transaction interface is one link where value changes hands between two modeled units: the buyer's cost line and the seller's revenue line must carry the identical price × quantity. Cost lines with no counterparty unit are exogenous overheads (see below), not interfaces.

The transaction interfaces¶

#	Buyer	Seller	Good / service	Quantity basis	Price basis
H0	RIDER	(vehicle market — exogenous)	Vehicle, one-time	1 vehicle	purchase price (cash or financed, ADR 0004 parity)
H1	RIDER	SNS	Battery swap service	swaps/day × kWh/swap	composite tariff (see H1)
H2	SNS	BCS	Charged-battery availability	per swap served	availability fee (implicit degradation)
H3	SNS	EPS	Energy for charging	kWh charged	$/kWh (grid tariff + backup blend)
X0	RIDER	(outside ecosystem)	Delivery income	exogenous	exogenous

Transaction interface details¶

H0 — vehicle purchase (boundary event)¶

One-time; enters RIDER balance sheet, depreciation schedule starts.
No counterparty BUFM in the OVRB base case (VSP only for rent modalities).
Financed purchase: higher effective total cost; ownership still RIDER's from day one (Amendment 1, ADR 0004).

H1 — swap service (RIDER ↔ SNS)¶

RIDER's operating cost line = SNS's revenue line. Same quantity, same price.
Quantity driver: swaps/day (from daily energy demand ÷ kWh/swap), the ecosystem's demand anchor.
Composite tariff: real-world swap pricing has up to three components, each weighted 0–100%:
monthly subscription (fixed access)
energy transferred ($/kWh)
per-swap fee (per transaction)
The tariff mix is a scenario dimension, not a fixed convention. For cross-unit comparability (petrol parity, price wedge), every mix normalizes to $/kWh delivered: monthly fees amortize over expected monthly kWh; per-swap fees divide by kWh/swap. The normalized figure is the comparison basis; the component weights are the pricing lever.

BCS sells availability of a charged battery at the moment of swap, not energy (energy is H3's good).
Degradation is priced implicitly: the rider-facing and SNS-facing charges bundle wear-and-tear into the service price; it is never itemized to the customer. The financial model must still book it — inside BCS as an explicit equipment wear-and-tear accrual per EFC, offset by residual/second-use recovery (eMe function, deviation register).
SNS margin = H1 normalized price − (H2 fee + H3 energy cost + opex/swap).

kWh drawn ≈ kWh swapped × (1 + charging losses) — the loss factor is explicit, not hidden in price.
EPS value proposition is anchor load (predictable nightly charging curve), not commodity margin.
Charging location is an operational variant, not a structural one: base case charges batteries in-situ on station racks. Alternative: stations act as pure swap points (LPG-canister style) and discharged batteries are collected and charged at a central depot via shuttle trucks. Collectively every battery must be charged either way, so the transaction map is unchanged — SNS remains the single energy buyer. The variant reallocates cost lines (shuttle logistics, depot opex) and is modeled as a scenario toggle, not a new interface.
Contract structure — PPA: the SNS↔EPS link is naturally a power purchase agreement: fixed-tariff supply against a predictable anchor load. The PPA tariff is the value-transfer mechanism; it shapes how energy margin pools between SNS and EPS.

Exogenous overheads (no counterparty unit)¶

Cost lines that appear in one unit's P&L with no modeled seller. They are inputs from the environment/parameter layer, not transaction pairs:

RIDER: vehicle maintenance, insurance, depreciation (from H0)
SNS: labor, property rent, station opex
BCS: fleet rotation logistics where not bundled into H2
EPS: generation/grid procurement cost

The price wedge (vertical identity)¶

At equilibrium, one identity holds across the chain (all legs in normalized $/kWh):

H1 price  =  H2 fee  +  H3 energy cost/swap  +  SNS opex/swap  +  SNS margin

If H1 is market-capped (rider affordability, petrol parity), the wedge determines who squeezes whom: BCS fee and SNS margin compete for the remainder. This is the core negotiation the model quantifies.
The composite tariff (H1) changes how H1 revenue is collected, not the identity — the wedge is evaluated on the normalized basis.

Shared state variable¶

Utilization is set by H1 quantity (swaps/day) against SNS's integer station capacity.
It drives: SNS break-even, BCS fleet utilization (each battery rotated per station throughput), EPS anchor-load profile.
One variable, three consumers — modeled once, referenced everywhere (DS coupling, step 4.3).

Value-transfer check (modeling contract)¶

For any period, each interface must satisfy:

Pair	Buyer debit	Seller credit	Must match
H1	RIDER swap cost	SNS swap revenue	price × quantity identical
H2	SNS availability fee	BCS availability revenue	price × quantity identical
H3	SNS energy cost	EPS energy revenue	price × quantity identical

Next step (4.3): demand-supply coupling spec → Delivered: DS Coupling Spec