CENTRALES HÍBRIDAS EN EL CONTEXTO DE LA

TRANSICIÓN ENERGÉTICA

HYBRID POWER PLANTS IN THE CONTEXT OF THE

ENERGY TRANSITION

Vinicius Santos Pereira1, Edmar Luiz Fagundes Almeida2

Marco Antonio Haikal Leite3, Sergio Luiz Pinto Castiñeiras Filho4

Recibido: 28/10/2024 y Aceptado: 12/3/2025

1.- vinicius.pereira@aluno.puc-rio.br

2.- edmar@puc-rio.br

3.- mahaikal@puc-rio.br

4.-sergiocastfh@gmail.com

Las centrales híbridas están ganando protagonismo en el escenario de la transición energética por su

capacidad para integrar múltiples fuentes de energía, renovables o no, en un único sistema de generación.

Este enfoque, a menudo complementado con sistemas de almacenamiento, pretende maximizar la

producción de energía y reducir la variabilidad del suministro, lo que se traduce en un abastecimiento más

able y económico.

Este artículo pretende analizar el atractivo y las posibles aportaciones de las centrales eléctricas híbridas en

el contexto de la transición energética, centrándose en su competitividad económica, sus ventajas técnicas y

sus retos normativos. Se presenta y analiza el concepto de centrales híbridas y su aplicación en la regulación

brasileña. A continuación, el documento señala las principales motivaciones para el uso de sistemas híbridos

de generación, centrándose en los impactos de la difusión de las energías renovables variables, como la

energía solar distribuida, en la curva de demanda de energía despachable se discuten. El precio horario de la

energía debido a la variabilidad de la carga se analiza en la tercera sección, destacando las oportunidades de

las centrales híbridas en el mercado actual. El documento también analiza la popularización de las centrales

híbridas debido a la reducción del coste de las tarifas por el uso de la red de distribución y la contribución

potencial de las centrales híbridas a la descarbonización de los sistemas aislados. Por último, el documento

presenta ejemplos de proyectos de generación híbrida en Brasil y explora la agenda de investigación

relacionada con las centrales híbridas, destacando un proyecto piloto que está desarrollando el Instituto

de Energía de la PUC-Rio. En resumen, las centrales híbridas representan una estrategia prometedora para

afrontar los retos de la transición energética, ofreciendo una solución exible y económicamente viable para

la generación de electricidad.

Hybrid plants are gaining prominence in the energy transition scenario due to their ability to integrate

multiple energy sources, whether renewable or not, into a single generation system. This approach, often

complemented by storage systems, aims to maximize energy production and reduce variability in supply,

resulting in a more reliable and economical supply.

This article aims to analyze the attractiveness and potential contributions of hybrid power plants in the

context of energy transition, focusing on their economic competitiveness, technical advantages, and

regulatory challenges. The concept of hybrid power plants and their application in Brazilian regulation is

presented and analyzed. Next, the paper points out the main motivations for the use of hybrid generation

systems, focusing on the impacts of the diusion of variable renewable energies, such as distributed solar

energy, on the dispatchable energy demand curve are discussed. The hourly pricing of energy due to load

variability is analyzed in the third section, highlighting the opportunities for hybrid plants in the current market.

The paper also discusses the popularization of hybrid plants due to the reduction in the cost of taris for use

of the distribution network and the potential contribution of hybrid power plants to the decarbonization of

isolated systems. Finally, the paper presents examples of hybrid generation projects in Brazil and explores the

research agenda related to hybrid plants, highlighting a pilot project being developed by the Energy Institute

of PUC-Rio. In summary, hybrid power plants represent a promising strategy for meeting the challenges of

the energy transition, oering a exible and economically viable solution for electricity generation.

PALABRAS CLAVE: centrales híbridas, transición energética, energías renovables, almacenamiento de

energía, energía solar distribuida, taricación horaria de la energía, descarbonización, sistemas aislados,

proyecto piloto, generación de energía eléctrica.

KEYWORDS: emissions, methane, natural gas supply chain, mitigation measures, abatement costs.

Resumen

Abstract

1. INTRODUCTION

The global energy transition is reshaping the

electricity sector, driven by economic, regulatory,

and technological transformations. One of the key

developments in this transition is the increasing

deployment of hybrid power plants, which integrate

multiple energy sources to enhance reliability,

optimize costs, and reduce environmental

impacts. Hybrid power plants play a crucial role

in addressing the intermittency of renewable

sources while maximizing the eciency of existing

energy infrastructure.

Hybrid power plants combine dierent primary

energy sources, such as solar, wind, hydro,

biomass, and fossil fuels, often incorporating energy

storage systems to improve supply stability. This

integration allows for better adaptation to uctuating

energy demand, reducing supply disruptions

and optimizing the utilization of transmission and

distribution networks. Consequently, hybrid power

plants contribute to system resilience, economic

eciency, and the overall sustainability of electricity

generation (Wichert, 1997; Manwell, 2004; Lazárov

et al., 2005).

The Brazilian electricity sector is undergoing

signicant changes to incorporate hybrid power

generation. The regulatory framework established

by the National Electric Energy Agency (Aneel),

particularly Normative Resolution No. 954,

provides guidelines for implementing hybrid and

associated power plants in the country. These

regulations aim to facilitate the integration of

renewable energy sources, improve grid stability,

and reduce costs associated with energy

generation and distribution. In this context, hybrid

power plants have emerged as a strategic solution

for both interconnected and isolated power

systems.

This article aims to assess the role of hybrid

power plants in the energy transition by analyzing

their technical, economic, and regulatory

aspects. Specically, it explores how hybridization

strategies can be optimized to improve

energy reliability, reduce costs, and support

decarbonization eorts. The study also examines

how hourly energy pricing, network usage costs,

and regulatory incentives inuence the adoption

of hybrid power plants, providing insights into

their economic competitiveness and potential for

widespread implementation.

To achieve this objective, the article is structured

around the following key topics:

• Denition and regulatory framework of

hybrid power plants in Brazil – An overview

of hybrid power plant congurations and

their regulation under Aneel’s Normative

Resolution No. 954.

• Impact of renewable energy penetration

on dispatchable generation – Analysis of

how the expansion of variable renewable

energy sources aects the demand for

dispatchable energy and grid stability.

• Hourly energy pricing and hybrid power

plants – Investigation of how hybrid

generation systems can optimize energy

sales and system operation under hourly

pricing mechanisms.

• Reduction of network usage costs

through hybridization – Assessment of

how hybrid plants can lower transmission

and distribution costs by optimizing energy

generation proles.

• Decarbonization potential of hybrid power

plants in isolated systems – Evaluation of

how hybridization can replace fossil-fuel-

based generation in remote areas, reducing

carbon emissions and operational costs.

• Economic competitiveness and feasibility

of hybrid power plants – Examination of

key factors inuencing the nancial viability

of hybrid systems under dierent market

conditions.

2. CONCEPT OF HYBRID POWER PLANTS

A variety of technological combinations may be

employed to facilitate the hybridization of existing or

novel generation systems. Potential combinations

include a wind power plant with photovoltaics and

batteries; a hydropower plant with photovoltaics;

a biomass thermal power plant with a gas power

plant and photovoltaics; among others. The

specic combinations to be pursued will depend

on the opportunities for reducing generation

costs by leveraging common infrastructures

and the complementarity of generation sources.

Furthermore, there may be signicant gains

associated with the ability to adapt energy supply

to the characteristics of demand.

The generation hybridization strategy can

be adapted to the specic characteristics of

the demand curve of a region or consumer,

considering the availability of natural resources

and local needs. The combination of dierent

energy sources in a single installation has the

potential to enhance operational eciency,

improve the reliability of electricity supply, and

reduce dependence on a single energy source.

For a power-generating plant to be considered

hybrid, the project must contain a single metering

• Case studies of hybrid generation projects

in Brazil – Presentation of real-world hybrid

power plant implementations, highlighting

their benets and challenges.

• Research agenda and pilot projects –

Discussion on ongoing research initiatives,

including the pilot hybrid power plant project

at the Energy Institute of PUC-Rio, which

aims to validate hybridization models and

assess their performance under real-world

conditions.

The article is organized into seven sections.

Following this introduction, Section 2 provides an

in-depth discussion on the concept and regulatory

landscape of hybrid power plants. Section 3

examines the impact of variable renewable energy

sources on dispatchable generation requirements

and explores the role of hybrid plants in adapting

to hourly energy pricing structures. Section 4

discusses how hybridization can reduce network

usage costs. Section 5 evaluates the potential

of hybrid power plants in decarbonizing and

reducing the costs of generation in isolated

systems. Section 6 outlines the research agenda

on hybrid power plants, with a particular focus

on experimental models and pilot projects being

developed to advance this eld. Finally, Section 7

presents the study’s conclusions.

By providing a comprehensive analysis of hybrid

power plants, this study contributes to the

understanding of their potential to accelerate

the energy transition, enhance grid stability, and

improve economic eciency in electricity markets.

system and a single license (Aneel, 2021). There

are also associated generating plants that also

integrate two or more energy sources, but with

dierent licenses and metering, which share the

same energy transmission system.

In Brazil, the National Electric Energy Agency

(Aneel) enacted Resolution regarding hybrid and

associated plants in 2021 through Normative

Resolution No. 954. This regulation involves power

plants with a capacity exceeding 5 MW, including

associated plants. A hybrid power plant is dened

as a facility that produces electricity from a

combination of dierent generation technologies,

with dierent metering per generation technology

or not, subject to a single grant. In contrast, an

associated generating plant is dened as a facility

that produces electricity from a combination of

dierent generation technologies, with dierent

licenses and metering systems, which physically

and contractually share the infrastructure for

connecting to and using the transmission system.

Figure 1 provides a schematic representation of

the hybrid and associated plant concepts.

Figure 1 - Hybrid and Associated Plant Arrangements (Aneel, 2021).

As illustrated in the initial chart of Figure 1, the

associated plants are organized according to a

scheme that encompasses two or more licenses

and the shared utilization of the connection.

Consequently, the aforementioned plants are

subject to two distinct metering but have a single

contract regarding the use of the transmission

system. In contrast, hybrid plants, as illustrated

in the second table, possess a single license

but employ two or more power generation

technologies. These plants can be classi ed in

two distinct manners:  rstly, each technology is

associated with a distinct meter; secondly, a single

meter is utilized, with the technologies sharing the

same transmission system.

It is also important to note that separate

measurements by generation technology are

required for hybrid power plants that employ

technologies centrally dispatched by the

National System Operator (ONS). Furthermore,

it is imperative to underscore that in instances

of hybridization or association of generating

plants, there must be no compromise in meeting

contractual obligations within the regulated

framework. This is to ensure the stability and

reliability of the electricity supply.

As stated by EPE (2018), the primary advantages

of hybrid plants can be summarized as follows:

• Increased utilization of available

transmission and/or distribution system

capacity

• Optimized use of available land area

• Enhanced logistics and implementation

planning through synergies

• Operational synergies

• Shared utilization of system equipment of

restricted interest

• Reduction of generator costs with network

usage tari s

One of the  rst projects to receive approval from

Aneel was the Neoenergia Renewable Complex,

comprising the associations of Neoenergia

Chafariz and Neoenergia Luzia in Figure 2.

These two solar and wind renewable energy

generation facilities are associated with the

objective of supplying energy to Paraíba. The

plants have an installed capacity of approximately

620 MW, distributed between solar panels and

wind generators connected to the National

Interconnected System, which integrates the

production and distribution of electricity in Brazil.

The total output is su cient to supply 1.3 million

homes per year (Neoenergia, 2022).

Figure 2 - (a) Neoenergia’s Chafariz Wind Farm with 467.77 MW of installed capacity. (b) Solar complex of 228,780

photovoltaic panels installed at Neoenergia Luzia. ((a) Neoenergia/Divulgação, 2022. (b) Envato Elements, 2022)

Figure 3 - Veredas Sol and Lares  oating solar power plant, in Minas Gerais (Cemig/Divulgação, 2023)

The Companhia Energética de Minas Gerais

(Cemig) has announced plans to invest over R$1.8

billion in the construction of  oating photovoltaic

plant projects within the reservoirs of hydroelectric

facilities in the state of Minas Gerais as can be

seen in Figure 3. The aforementioned photovoltaic

plants will be installed at Três Marias, Cajuru,

Theodomiro Carneiro Santiago, and another yet

to be announced, with the latter scheduled for

installation in the middle of the year. The projects

are scheduled to commence in 2024 and are

anticipated to become operational between the

end of 2024 and the beginning of 2026 (Eixos,

2023).

The photovoltaic panels will serve the function of

integrating the hydroelectric plants into a hybrid

system. The main advantage of this system is its

capacity to generate energy during the daytime,

thereby enabling the hydroelectric plant to serve

as a form of energy storage during periods of

heightened demand that exceed the capacity

of the modules. Moreover, given the inherent

variability in the supply of photovoltaic panels, it is

essential to utilize hydroelectric power as a means

of supplementing this instability.

Another noteworthy consequence is the

prevention of evaporation from the reservoir bed.

The capture of solar radiation by photovoltaic

panels has the potential to signi cantly reduce this

phenomenon. According to a recently developed

research method by the National Water and

Basic Sanitation Agency (ANA), launched in

2021, evaporation in the South and Southeast is

estimated to be around 300 to 1000mm/year. The

implementation of  oating plants has the potential

to reduce this evaporation by approximately 70%,

according to ANA studies.

The potential of hybrid plants to facilitate the

acceleration of the energy transition is well

documented. A primary characteristic of the

energy transition process in the electricity sector

is the proliferation of intermittent renewable energy

sources. In other words, these are sources whose

generation cannot be controlled and depends on

the primary source of energy, such as the sun or

wind. In particular, the signi cant proliferation of

distributed solar generation has a considerable

impact on the load curve characteristics of

electricity systems. The generation of electricity

from distributed solar sources results in a

signi cant reduction in centralized energy

3. INTRODUCTION OF HOURLY ENERGY PRICING

AND HYBRID POWER PLANTS

demand during the daytime hours. However, this

has led to a notable challenge in the ramping up

of centralized generation between 4 p.m. and

8 p.m. This alteration in the demand curve has

become known as the Duck Curve (Figure 4). The

illustration of the transformation in energy demand

characteristics with the spread of distributed

solar energy is provided by the evolution of the

daily energy demand curve in California. As solar

capacity in California continues to grow, the

midday drop in net load is decreasing, presenting

challenges for grid operators, as can be seen in

Figure 4.

Figure 4 - Illustration of the evolution of the net load in California with the

spread of distributed solar energy (GW) (CAISO, 2023).

Another illustrative case of the transformation

of the electricity demand curve is that of Spain.

Figure 5 illustrates the emergence of a negative

residual demand in May 2023. In other words, the

supply of renewable energy exceeded total energy

demand for a few hours of the day. Indeed, the

residual public electricity load reached -1.3 GW on

the afternoon of May 16. Just a few hours later, the

In addition, the case of Australia can be referenced

as a further example. As reported by the Australian

Energy Market Operator (AEMO), on December

31, 2023, negative demand was observed in

South Australia and Victoria. As illustrated in

Figure 6, distributed solar generation surpassed

total demand by 26 MW. This phenomenon

occurred on a day with temperate temperatures

Figure 5 - Net electricity generation in Spain in May 2023 (GRIDX, 2023)

Figure 6 - Electricity generation in May 2023 in South Australia (AEMO Energy, 2024).

residual load (total load minus energy generated

from variable renewable sources) increased to

almost 15 GW, with renewables only covering

62% of demand.

and clear skies, providing optimal conditions for

solar energy generation by photovoltaic panels.

Daily wholesale electricity prices on the same day

exhibited negative values, averaging -$66.54 ($/

MWh) and -$73.02 ($/MWh) in South Australia and

Victoria, respectively.

In the case of Brazil, the proportion of solar and

wind energy in the system remains insu cient to

meet the total load. Nevertheless, the in uence

of renewable energy sources on residual energy

demand is already considerable. The report,

entitled “Deep Dive Petrobras 2024,” examined the

The advent of the Duck Curve has had a profound

impact on the design of electricity markets, with a

consequent shift towards a greater emphasis on

the valuation of generation  exibility and energy

storage. In other words, di erent countries have

altered how energy is priced on the wholesale

market, with the implementation of hourly pricing

systems. In this system, the price of energy tends

to  uctuate in accordance with the load curve,

with the greatest  uctuations occurring during

periods of peak demand (i.e., the duck’s neck).

This is due to the necessity of dispatching more

expensive sources of energy or storing energy

during these periods. The introduction of new

data provided by the National Electricity System

Operator (ONS) regarding energy demand and

consumption in Brazil on November 23, 2023.

Figure 7 illustrates the  uctuations in demand for

thermal generation throughout the day.

Figure 7 - Residual demand for thermoelectric generation on November 23, 2023 (Petrobras, 2024).

Figure 8 - Hourly energy prices on the spot market in Portugal and Spain - February 21, 2024 (OMIE, 2024).

pricing mechanisms for ancillary services to

guarantee supply during periods of high demand

represents an additional aspect of the trend to

revise electricity market designs.

Figure 8 illustrates the hourly energy prices on the

spot market in Portugal and Spain on February

21, 2024. The graph demonstrates that the price

of energy in the early morning, late afternoon, and

early evening can be more than double the price

of energy during the daytime, when solar energy

generation is high.

In January 2021, the Brazilian electricity market

introduced hourly pricing, with the CCEE

calculating the daily Di erence Settlement Price

(PLD) for each hour of the following day. This was

based on the Marginal Operating Cost (CMO),

considering the application of the maximum (hourly

and structural) and minimum limits in force for

each calculation period and for each submarket.

The PLD serves as a reference price for the

settlement of discrepancies between contracted

and actual energy generation and consumption.

However, due to the prevailing surplus of structural

generation capacity in Brazil, the hourly PLD has

exhibited minimal variation over the past two

years. PLD values have consistently remained at

the minimum level for all hours of the day.

The advent of hourly energy pricing has caused

a signi cant economic impact on electricity

generation. Generation systems that are capable of

o ering energy at times of higher prices possess a

markedly di erent economic value than those that

are only able to generate at times of low prices.

One method of increasing the value of electricity

generation plants is to hybridize the system,

which entails integrating generation capacity from

A signi cant bene t of generating and distributing

energy through hybrid systems is the reduction

in the cost of utilizing the transmission and

distribution system (TUST, or Tari for Use of the

Transmission System, and TUSD, or Tari for Use

of the Distribution System). The aforementioned

tari s are calculated based on the contracted

transmission and distribution capacity. It is

imperative that the contracted capacity is su cient

to meet the generation peak. A generator with a

low capacity factor will result in an increased cost

of TUST and TUSD per MWh produced.

The combination of two energy sources, such

as wind and solar, whose generation curves are

considered to be almost opposite, especially in

the case of Brazil, allows the generator to produce

a greater amount of energy with the same

disparate technologies or even energy storage

systems Hybridization can facilitate the provision

of continuous energy supply, enhancing resilience

and enabling the sale of energy at times of high

prices.

One of the primary advantages of hybrid power

plants is their capacity to generate energy during

periods of peak demand, when energy prices are

typically higher. For instance, solar energy can be

generated during the daytime, when electricity

demand is typically high and prices are elevated,

considering local climate variations and the time

of day. Similarly, wind energy can be generated

at night, when demand still exists. This ability to

generate or store energy at strategic times allows

hybrid power plant owners to optimize energy

sales, supplying excess energy precisely when

prices are highest or saving it when the price is

lowest. This not only increases revenue but also

enhances the pro tability of the venture. Therefore,

hybrid power plants represent an attractive option

for investors seeking to maximize their return on

renewable energy investments.

4. HYBRID SYSTEM AS AN OPTION TO REDUCE NETWORK

USAGE COSTS

contracted transmission and distribution capacity.

Figure 9 illustrates de coupling of solar and wind

power generation. Solar power generation exhibits

a distinct diurnal pattern, with the highest output

occurring during the day, starting around 9:00

a.m., and declining around 5:00 p.m. In contrast,

wind power generation occurs between 6:00 p.m.

and 6:00 a.m. the following day.

Figure 9 - Average hourly generation pro les of typical wind and solar energy units in the

northeastern region of Brazil as a percentage of their historical average

(historical records from July 1, 2019 to September 20, 2021) (LAMPS PUC-Rio).

It is thus possible to combine the two technologies

in a hybrid plant in order to create an optimized

energy curve, which demonstrates that it is feasible

to meet daily demand throughout the 24 hours

of the day, rather than just at speci c times. By

optimizing the generation process, it is possible to

enhance the Transmission System Usage Amount

(MUST), thereby facilitating an optimized demand

for energy production and distribution.

Another potential avenue for exploration is the

integration of batteries in conjunction with solar

and wind technologies. This approach could

lead to a reduction in the Distributed Energy

Power provided for in the Transmission System

Use Contract (CUST), with the surplus energy

being stored in batteries. This would allow for the

optimization of energy sales throughout the day,

irrespective of the time.

Furthermore, an increased capacity factor directly

contributes to a reduction in transmission and

distribution costs. This phenomenon occurs

because the infrastructure utilized for transmission

and distribution is sized to accommodate peak

generation. Consequently, a generator with a

low capacity factor incurs costs associated with

a substantial contracted capacity that is only

utilized during limited periods. By enhancing the

capacity factor through hybridization or integration

with storage technologies, the same contracted

infrastructure is more e ciently utilized, thereby

reducing the cost of energy transported per

unit. This enhanced e ciency in network asset

utilization leads to a reduction in the per-MWh

cost of TUST and TUSD, thereby enhancing the

overall economic viability of hybrid power plants

and contributing to an improvement in grid stability

and resilience.

Another signicant application of hybrid power

plants is their use in the decarbonization of isolated

electricity systems. The prevailing technological

standard for meeting energy demand in isolated

systems is the utilization of fuel oil or diesel-based

generation. Hybrid power plants can play a crucial

role in the decarbonization of isolated systems

by integrating renewable energy sources with

storage solutions. These systems can reduce

diesel dependency, lower operational costs, and

contribute to sustainability goals.

The Ministry of Mines and Energy (MME) has

established the “Energias da Amazônia” program

with the objective to reduce the utilization of

diesel oil in the isolated power systema in the

Amazon Region, which will consequently lead to

a diminution in greenhouse gas emissions. These

systems provide electricity to cities and towns that

are not connected to the National Interconnected

System (SIN), as is the case for the majority of the

country.

Moreover, the program strives to ensure the

reliability and security of the electricity supply for

over 3.1 million individuals who rely on isolated

systems. These systems provide electricity to

cities and towns that are not connected to the

National Interconnected System (SIN), as is the

case for the majority of the country. This measure

represents one of numerous actions undertaken

within the context of the energy transition, with the

dual objective of enhancing the quality of life for the

population and facilitating the development of the

Amazon region, while simultaneously contributing

to a reduction in greenhouse gas emissions.

The Ministry of Mines and Energy (MME) has

initiated a new auction process to contract supply

solutions for isolated systems, aiming to enhance

energy reliability while integrating more renewable

sources. The auctions, scheduled for December

2025, will contract 49 MW of power to serve

approximately 169,000 people in the Amazon

region. The contracts will be valid for 15 years,

5.HYBRID POWER PLANTS AS A WAY TO DECARBONIZE AND

REDUCE COSTS OF ISOLATED SYSTEMS

with energy delivery starting on December 20,

2027 (CanalEnergia, 2024).

A key innovation in this auction is the requirement

that at least 22% of the contracted energy must

come from renewable sources. This encourages

hybrid solutions that combine thermal generation

with solar, wind, or energy storage technologies.

Additionally, project developers must consider

load modulation, fuel logistics, and environmental

impact. Another provision allows for the

decommissioning of thermal plants after ve

years if the region is later connected to the SIN.

The auction will be conducted as a competitive

process where bidders submit technical and

economic proposals, with contracts awarded to

the most cost-eective and sustainable solutions

(CanalEnergia, 2024).

The initiative is of great importance for the

sustainability and energy eciency of the region,

and it also contributes to a reduction in the

costs of the Fuel Consumption Account (CCC), a

subsidy to cover all or part of the cost of the fuel

used to generate electricity in isolated systems,

thus guaranteeing aordable taris for consumers

in these remote regions.

The deployment of hybrid power plants

represents a promising approach for integrating

intermittent renewable energy sources and

storage technologies (solar, wind, biomass, mini-

hydro, batteries) with thermoelectric power. In

other words, the hybridization strategy can be

employed to minimize thermoelectric generation

and emissions, while guaranteeing energy security

and reliability for the system.

The competitiveness of hybrid systems with

batteries is contingent upon the cost of energy

storage, which can present a signicant challenge.

Nevertheless, there are locations where this

solution can be cost-eective due to the high cost

of thermal generation. In numerous locations, the

nancial and logistical costs associated with fuel

supply are considerable, while generation e ciency

is relatively low. This creates an opportunity for the

implementation of hybrid renewable solutions that

o er a cost-e ective alternative, as highlighted in

the report developed in partnership with World

Bank (WORLD BANK, 2023).

An example of this context can be found in the

Paci c Islands, the Caribbean, and Cayman, where

the price of energy ranges from approximately

$0.20 to $0.60 per kWh. It is also noteworthy that

sub-Saharan Africa represents another location

where the majority of energy generation is based

on fossil fuels, and where energy tari s are

comparatively favorable in comparison to those

observed in island contexts. In both cases, the

use of solar power plants with batteries, despite

their high cost, can be considered commercially

competitive in comparison to the energy provided

by fossil fuels (WORLD BANK, 2023).

The Barbers Point project in Hawaii, which is

coordinated by the Department of Hawaiian Home

Lands (2018), achieved a levelized tari of $0.112/

kWh. This was achieved under a single capacity

contract model that integrates 15 MWp of solar

energy with 15 MW/60 MWh of four-hour battery

storage capacity. In Morocco, the Noor Midelt

project, which combines solar photovoltaics with

concentrated solar power and  ve-hour thermal

storage, achieved a tari of $0.07/kWh under a

mixed contract.

The energy supply on the island of Fernando

de Noronha is currently maintained by a variety

of sources, including diesel, fuel oil, and natural

gas. The primary source of energy is the diesel

thermoelectric plant, designated as UTE Tubarão.

It is comprised of three 1,286 kW generating units

and a 1,120 kW diesel generator set, resulting

in a total capacity of 4,978 kW. Furthermore, a

contingency generator park (capacity of 2,293

kW) may supply power when needed. In addition

to the energy generated by UTE Tubarão, the

island also bene ts from photovoltaic solar energy

(EPE, 2021).

The Noronha I plant commenced operation in July

2014, contributing with an installed capacity of 402

kWp. Subsequently, in July 2015, the Noronha

II plant was inaugurated, increasing the installed

capacity to 550 kWp. Currently, the Aeronautics

Command and the island’s administration are

responsible for the plants, respectively. Figure 10

illustrates the spatial distribution of photovoltaic

plants in Fernando de Noronha. The energy

generated by these plants is integrated into local

demand and deducted from the amount of energy

to be supplied by the local distributor, Neoenergia.

Figure 10 - Location of photovoltaic plants and solar panels in Fernando de Noronha (Iberdrola/Divugation, 2022).

Vila Restauração is a municipality located

on the border with Peru in the state of Acre.

Before the implementation of a more robust

electric infrastructure, the electricity supply was

characterized by signi cant de ciencies and

limitations. The town was previously supplied by

a diesel generator, the cost of which was borne

by the residents and the town hall of Marechal

Thaumaturgo (557 km from Rio Branco). The

lack of electricity resulted in signi cant challenges

for the 200 families residing in the village. These

challenges included the disruption of refrigeration

systems used to preserve food and the reliability of

healthcare systems in hospitals. In 2019, Energisa

assumed responsibility for the Vila Restauração

Microgrid project.

The hybrid microgrid addressed the supply

security concerns of a remote community through

the implementation of a photovoltaic solar energy

system (325 kWp, 580 panels) coupled with lithium-

ion batteries (3 modules, 828 kWh of storage

capacity), biodiesel emergency generators, and

biodigesters (RENEEGISA, 2023). This solution

has resulted in a 60% reduction in energy costs for

the community, along with a guaranteed supply

24 hours a day.

In summary, while the logistics of implementing

hybrid systems in isolated regions may be complex,

the aforementioned projects have demonstrated

Figure 11 - Remote system installed in Vila Restauração, Acre (REENERGISA, 2023).

Figure 11 depicts the hybrid system that was

implemented as part of this initiative. Given the

project’s location, it was necessary to transport

the system components by truck from ports in

the southern and southeastern regions of Brazil

to the city of Cruzeiro do Sul (AC). Subsequently,

the components had to be transported by ferry to

Vila Restauração.

e cacy in addressing energy reliability concerns,

reducing costs, and contributing to greenhouse

gas emission reduction.

6. TECHNICAL CHALLENGES FOR IMPLEMENTING HYBRID

POWER PLANTS AND PRACTICAL RESEARCH AGENDA

Implementing hybrid power plants across diverse

energy systems presents several technical

challenges. These include the integration of

multiple energy sources, the need for advanced

control systems to manage variability, and

the requirement for signicant infrastructure

investments. Pilot plants serve as experimental

strategies to address these challenges by

allowing for the testing and validation of hybrid

congurations under controlled conditions,

thereby facilitating the optimization of system

performance before large-scale deployment.

The integration of hybrid power plants into the

national electricity system presents a promising

avenue for innovation. This is because the optimal

hybridization strategy for generation systems

must be determined through an analysis of

demand characteristics, hourly energy prices,

and available generation sources. In light of the

ndings presented in this study, future research

should focus on rening hybridization models

to enhance energy eciency, environmental

attributes, and economic viability. Additionally,

further investigation of regulatory frameworks

in which plants may be inserted is necessary

to ensure that hybrid systems can be operated

optimally, facilitating their widespread adoption

and scalability. It is thus imperative to develop

simulation and optimization models that facilitate

the dimensioning of hybridization strategies.

Moreover, there is an opportunity to assess and

implement decarbonization strategies for the

hundreds of isolated systems throughout the

country.

The Energy Institute of PUC-Rio is dedicated to

making a signicant contribution to the research

agenda on hybrid power plants. Studies have

been conducted on the development of expert

systems capable of modeling their behavior and

performance under various load conditions and

tari modes. An investigation of the experimental

performance of a hybrid power plant pilot plant

with solar photovoltaic (SPV) generation, natural

gas (NG), battery storage, load banks, and grid

coupling, utilizing a variety of simulations and load

conditions has been carried out, to validate models

in specialized software, taking into account a

range of operational load scenarios. To this end,

a hybrid pilot plant is being constructed on the

premises of PUC-Rio in Xerém in collaboration

with GALP and Petrogal Brasil. This pilot plant

will be equipped with a 328 kWp SPV plant. A

320 kW load bank will be employed to simulate

dierent load proles, and a 138 kWh lithium-ion

battery bank with a Battery Management System

(BMS) that will communicate with the inverter and

the supervisory system will be utilized. In regard

to the natural gas system, a motor-generator of

approximately 320 kW in continuous operation will

be employed, which will also communicate with

the supervisory system. The supervisory system

is highly robust and will facilitate a multitude of

experiments, including those conducted in island

mode.

7. CONCLUSION

The increasing adoption of hybrid power plants

represents a strategic advancement in the

energy transition, providing a exible, ecient,

and economically viable solution for electricity

generation. The integration of dierent energy

sources within a single system helps mitigate

the intermittency of renewable sources, optimize

the use of existing infrastructure, and reduce

operational costs and environmental burdens.

The following conclusions can be drawn.

The Duck Curve has been identied as a

signicant prot opportunity for hybrid power

plants, as it underscores the necessity for exible

generation to meet demand during periods of

high consumption variability.During daylight

hours, high solar generation reduces the demand

for energy from other sources, resulting in low or

even negative electricity prices in certain markets.

However, in the late afternoon and early evening,

when solar generation experiences a decline

and demand surges, electricity prices undergo

a substantial increase. Hybrid power plants that

integrate renewable sources with storage or

thermal generation can optimize their prots by

strategically storing energy during low-cost periods

and releasing it during high-demand hours, when

electricity is more expensive. This operational

strategy enables revenue maximization, ensures

reliable supply, and contributes to grid stability,

making it a compelling solution from both technical

and economic standpoints.

Additionally, the capacity factor of hybrid power

plants plays a crucial role in reducing operational

costs and increasing the eciency of the electrical

system. By combining dierent energy sources,

such as solar, wind, thermal, and storage, these

plants can operate at a higher capacity factor

than standalone plants, optimizing the use of

installed infrastructure. This increased utilization

reduces the need for additional investments in

backup generation and lowers costs related to

transmission and distribution system usage fees.

Additionally, by improving generation predictability

and reducing dependence on intermittent

sources, hybrid power plants provide greater

stability to the electrical system, decreasing the

need for dispatching more expensive sources,

such as fossil fuel-powered thermal plants. As a

result, in addition to making energy generation

more competitive, these plants contribute to a

more ecient and sustainable power sector.

Additionally, hybrid power plants can play a

crucial role in decarbonizing isolated systems

by decreasing fossil fuel dependence and

promoting a more sustainable energy supply. The

technical, regulatory, and economic challenges

that remain can be overcome through improved

simulation models, optimized public policies, and

technological advancements, positioning hybrid

power plants as a denitive solution for future

power systems.

The study presented reinforces the importance

of research and the development of experimental

projects, such as the pilot plant at the Energy

Institute of PUC-Rio, to validate hybridization

models and strategies. Through controlled

experiments, it is possible to analyze the

technical and economic feasibility of dierent

hybrid congurations, ensuring their large-scale

application with more reasonability than just

counting on simulations already widespread in

literature. Furthermore, regulation must evolve

alongside these advancements, promoting

incentives for hybrid technology integration and

ensuring these systems remain competitive in the

energy market.

Thus, the adoption of hybrid power plants

can accelerate the global energy transition,

contributing to a more resilient, sustainable, and

accessible future for all.

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