Volume 3 — Valuation and Risk Metrics © Copyright 2002, CCRO. All rights reserved. 45 For some long-term valuations, the monthly spark spread values can be computed for direct comparison with contract prices (e.g., $/kW-month). The NPV of the monthly cash flows is computed. Fixed-Price Calculations For fixed-price deals, the spread between the contract and market prices is used to value the contract volume. Option Calculations For European options, the Black valuation model is used.