0885-8950 (c) 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TPWRS.2018.2869626, IEEE Transactions on Power Systems 1 Abstract-- This paper presents an advanced market bidding and operation strategy for the joint participation of a solar plant with storage in Energy and Secondary Reserve Markets (SRM). A linear optimization is applied in order to calculate the optimal day-ahead and intraday market bids through a Model Predictive Control (MPC) approach, considering solar generation forecast, hourly market prices as well as battery acquisition, operating and degradation costs. Moreover, several rule-based strategies are selected to participate in secondary reserve markets, focused on more profitable and reliable hours through the estimation of market prices and the expected operation of the battery. Finally, the real-time operation tackles all the uncertain parameters, such as the reserve requirements and solar forecast errors, with the objective of achieving an optimal trade-off between market profits, battery costs and market technical fulfillments. Several market strategies have been compared in techno-economic terms with annual real market data. Regarding the most advanced strategy, market benefits are improved 6.42% from base case and non-fulfillment level of SRM is reduced up to 1.49%. Index Terms-- Ancillary Services, Day-Ahead Market, Energy Storage System, Intraday Markets, Secondary Reserve Market, Optimization method, Photovoltaic plants, Rule-based strategy. NOMENCLATURE Subscripts/Superscripts: DM Day-ahead market IM Intraday market SRM Secondary Reserve Market curr Current step of the optimization day end Last step of the optimization day h Hour of the day k Simulation step Parameters:   Acquisition and operation battery costs A. González-Garrido is with the Energy Storage and Management Area, IK4-IKERLAN Technology Research Centre, Arrasate-Mondragon 20500, Spain, and also with University of the Basque Country, Alda. Urquijo s/n, 48013 Bilbao, Spain (e-mail: amaia.gonzalez@ikerlan.es). A. Saez-de-Ibarra, H. Gaztañaga and A. Milo are with the Energy Storage and Management Area, IK4-IKERLAN Technology Research Centre, Arrasate-Mondragon 20500, Spain (e-mail: asaezdeibarra@ikerlan.es; hgaztanaga@ikerlan.es; amilo@ikerlan.es). P. Eguia is with the Electrical Engineering Department, University of the Basque Country, Alda. Urquijo s/n, 48013 Bilbao, Spain (e-mail: pablo.eguia@ehu.eus)   Acquisition inverter costs m Number of steps k in one hour (6 steps)  Optimization time step (10 min = 1/6 h) Variables:  Reserve rate (%)   Battery nominal capacity (MWh)   Battery reference capacity (MWh) CRR Regulation Required Contribution in real-time (MW) DA TSO Downward secondary reserve assignment (MW) DR TSO Downward secondary reserve requirement (MW)   Energy battery profile (MWh)    ( Real battery power in real-time operation (MW)   Secondary reserve band of the PV+ESS system (MW)   − Downward secondary reserve band (MW)   + Upward secondary reserve band (MW)   Optimal battery power (MW)   Converter power (MW)   Delivered power into the grid (MW)   +/− Positive and negative energy imbalances power (MW)   Optimal market bidding power (MW)   Secondary reserve penalty term (MW) PC PV Participation Coefficient of the PV+ESS system (%)   PV generation forecast profile (MW)   Real PV generation (MW)   Expected lifetime of the battery (year) SOC State of charge of the energy storage system (%) SOH State of health of the energy storage system (%) UA TSO Upward secondary reserve assignment (MW) UR TSO Upward secondary reserve requirement (MW)   Maximum solar generation error (%)   Secondary reserve band price (€/MWh)   Downward secondary reserve price (€/MWh)   +/− Positive and negative energy imbalance price (€/MWh)   Day-ahead or intraday market price (€/MWh)   Upward secondary reserve price (€/MWh)  ℎ/ℎ Charge and discharge overall battery efficiency (%) I. INTRODUCTION he growing penetration of Renewable Energy Sources (RES) will contribute to achieve the targets toward a low carbon economy. However, the uncertainty in energy forecast and the power generation intermittency and variability [1] Annual Optimized Bidding and Operation Strategy in Energy and Secondary Reserve Markets for Solar Plants with Storage Systems A. González-Garrido, A. Saez-de-Ibarra, H. Gaztañaga, A. Milo, P. Eguia T