arXiv subjects

Silvia Romagnoli

Publications and source records attributed to Silvia Romagnoli.

4 recordsLinked to original sources

arXiv2026

Renewing Reliability: Valuation and Credit Risk Adjustments for Renewable Power Purchase Agreements

Power Purchase Agreements (PPAs) are bilateral over-the-counter contracts central to renewable energy financing. While their capacity to stabilise revenues and hedge price risk is well recognised, their OTC structure exposes both parties to counterparty credit risk. This is a dimension yet to be explored in the literature, particularly given the dual price and volumetric uncertainty inherent in renewable sources. This paper develops a framework for the pricing and valuation of wind power PPAs and for quantifying this risk through Credit Valuation Adjustment (CVA) and Debit Valuation Adjustment (DVA). We model the joint dynamics of electricity spot prices and renewable output, incorporate default probabilities, and compute valuation adjustments that reflect the fair value of bilateral credit risk. The framework provides market participants with a transparent metric for PPA valuation under counterparty risk. While initiatives such as the European Investment Bank's pilot guarantee scheme aim to mitigate credit risk for certain offtakers, such interventions do not cover all PPA transactions. Rigorous internal credit risk assessment therefore remains indispensable for lenders, producers, and offtakers alike.

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arXiv2026

Beyond the Fixed Price: Valuation and Risk of Non-Standard Renewable PPAs

Renewable Power Purchase Agreements have become increasingly important instruments for supporting the energy transition, as they offer revenue stability to renewable energy producers and price certainty to electricity consumers. This paper develops a financial framework for the valuation and risk assessment of fixed-price renewable PPAs. We formalize the payoff structures of the main PPA designs adopted in practice for wind and photovoltaic generation and derive fair contract prices based on financial valuation principles. We further propose a market risk-assessment methodology based on Monte Carlo simulation and introduce a parsimonious continuous-time model for solar irradiance suitable for financial applications. An empirical analysis of the Italian electricity market shows that fair prices and risk profiles vary substantially across technologies and contractual structures, highlighting the trade-off between downside protection and participation in favorable market outcomes. This framework provides practical tools for the pricing and risk evaluation of renewable PPAs.

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arXiv2021

The SINC way: A fast and accurate approach to Fourier pricing

The goal of this paper is to investigate the method outlined by one of us (PR) in Cherubini et al. (2009) to compute option prices. We name it the SINC approach. While the COS method by Fang and Osterlee (2009) leverages the Fourier-cosine expansion of truncated densities, the SINC approach builds on the Shannon Sampling Theorem revisited for functions with bounded support. We provide several results which were missing in the early derivation: i) a rigorous proof of the convergence of the SINC formula to the correct option price when the support grows and the number of Fourier frequencies increases; ii) ready to implement formulas for put, Cash-or-Nothing, and Asset-or-Nothing options; iii) a systematic comparison with the COS formula for several log-price models; iv) a numerical challenge against alternative Fast Fourier specifications, such as Carr and Madan (1999) and Lewis (2000); v) an extensive pricing exercise under the rough Heston model of Jaisson and Rosenbaum (2015); vi) formulas to evaluate numerically the moments of a truncated density. The advantages of the SINC approach are numerous. When compared to benchmark methodologies, SINC provides the most accurate and fast pricing computation. The method naturally lends itself to price all options in a smile concurrently by means of Fast Fourier techniques, boosting fast calibration. Pricing requires to resort only to odd moments in the Fourier space. A previous version of this manuscript circulated with the title `Rough Heston: The SINC way'.

q-fin.PR↗

arXiv2016

Granger Independent Martingale Processes

We introduce a new class of processes for the evaluation of multivariate equity derivatives. The proposed setting is well suited for the application of the standard copula function theory to processes, rather than variables, and easily enables to enforce the martingale pricing requirement. The martingale condition is imposed in a general multidimensional Markov setting to which we only add the restriction of no-Granger-causality of the increments (Granger-independent increments). We call this class of processes GIMP (Granger Independent Martingale Processes). The approach can also be extended to the application of time change, under which the martingale restriction continues to hold. Moreover, we show that the class of GIMP processes is closed under time changing: if a Granger independent process is used as a multivariate stochastic clock for the change of time of a GIMP process, the new process is also GIMP.

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