In a world seeking cleaner energy solutions, the concept of renewable energy sources (RES) with storage is becoming central. This article explores the various options available, from solar and wind technologies to innovative storage systems, including hydroelectricity. We will examine the technical challenges, environmental impacts, and implementation rules for a successful energy transition.

Key Takeaways

• The concept of RES with storage is essential for a sustainable energy transition, but current storage technologies, whilst developing, still present limitations in terms of capacity, cost, and longevity. Research and development is therefore crucial to find more efficient and less resource-intensive solutions.
• Hydroelectricity, particularly via pumped-hydro storage (PHS) plants, remains the most proven large-scale storage technology. However, the potential for expansion in France is limited by geography and social acceptance, paving the way for innovations such as coastal storage.
• Sizing RES installations with storage requires significant overcapacity to compensate for the intermittency of sources like solar and wind. This overcapacity, combined with conversion and storage losses, implies installed power requirements far exceeding average consumption.
• The integration of RES poses major technical challenges, notably managing production variability and adapting electricity grids. Smart grids and demand flexibility are key tools for managing these fluctuating energy flows.
• Although more ecological than fossil fuels, RES have an environmental impact. Rigorous planning, minimisation of impacts on wildlife and ecosystems, and adherence to design and safety standards are essential for responsible implementation of photovoltaic and other projects.

The RES concept: an overview of photovoltaic and storage solutions

The concept of Renewable Energy Sources (RES) encompasses a set of technologies aimed at producing energy from inexhaustible natural sources. In the field of photovoltaics and storage, this involves capturing solar energy to convert it into electricity, and being able to store it for later use. This approach is increasingly relevant given climate challenges and the need to reduce our dependence on fossil fuels. Integrating storage is a key step to making these intermittent energies more reliable and available when needed.

The challenges of storage for renewable energies

Intermittency is the main challenge for renewable energies like solar and wind. The sun doesn’t shine at night, and the wind doesn’t always blow. To overcome this, energy storage becomes indispensable. It allows for smoothing production, meeting peak demand, and ensuring a stable electricity supply, even when renewable sources are not producing. Without storage, the contribution of RES remains limited and often requires the use of backup power plants, which can be polluting. The aim is therefore to find solutions to store surplus electricity produced and release it at the opportune moment. This contributes to better electricity grid management and greater energy autonomy.

Global and French storage outlook

Globally, the demand for electricity storage capacity is growing rapidly. Countries heavily investing in renewable energies, such as China or the United States, are making massive investments in various storage technologies. In France, the landscape is slightly different. The existing nuclear fleet and hydroelectric potential play an important role. However, to achieve energy transition objectives, the development of storage is a necessity. Prospects include the deployment of large-scale batteries, as well as the exploration of innovative solutions. The goal is to be able to rely on green and reliable energy production, whilst reducing costs and environmental impact. France seeks to develop solutions adapted to its energy mix, taking into account its geographical and industrial specificities. It is important to note that the development of photovoltaics for businesses is a strong trend accompanied by storage solutions.

The importance of research and development for sustainable solutions

Current storage technologies, whilst useful, still present limitations in terms of cost, lifespan, efficiency, and environmental impact. Research and development (R&D) is therefore crucial for imagining and realising tomorrow’s solutions. We need more efficient, more durable storage systems that are less resource-intensive and easier to recycle. The objective is to find technologies that wear out less quickly and are economically viable on a large scale. This involves exploring new battery chemistries, improving thermal storage systems, and developing hydrogen storage solutions. Innovation in this area is key to enabling a majority share of renewable energies in our energy mix, whilst guaranteeing the stability and security of electricity supply. Advances in this field are eagerly awaited for a cleaner energy future. Companies like Bourgeois Global and Hellio are working on innovative solutions for solar storage.

Renewable energy storage technologies

For renewable energies like solar and wind to truly take over from fossil fuels, reliable ways to store the electricity they produce must be found. The problem is that the sun doesn’t always shine, and the wind doesn’t constantly blow. This is where storage technologies come in, but they are still under development for large-scale use.

Redox flow battery storage

Redox flow batteries are an interesting option for energy storage. Unlike conventional batteries, they use liquid solutions containing chemical elements that exchange electrons. The advantage is that storage capacity can be increased independently of power, simply by adding more liquid. It’s a bit like enlarging a water tank. They are considered more durable and potentially less expensive in the long term than some other battery technologies, particularly because they use more abundant materials. However, their energy efficiency is not always the highest, and their large-scale deployment still faces technical and economic challenges. Work is ongoing to improve their efficiency and reduce their footprint to make them more practical.

Solar thermal storage

Solar thermal storage is a different approach. Instead of storing electricity directly, solar energy is used to heat a fluid (such as water or another heat transfer fluid) which is then stored in insulated tanks. This heat can later be used for heating buildings or for generating electricity via thermal cycles. This is a well-established technology for heating water in homes, but its larger-scale application for electricity storage remains more complex. Conversion efficiencies from heat to electricity are not always optimal, and managing heat losses over long periods is a point of concern. It is a solution with potential, especially in very sunny regions, but it still needs to prove itself to compete with other forms of large-scale energy storage. For example, integrated systems in solar thermal power plants can be imagined to smooth production.

The limitations of current technologies

Currently, no single storage technology perfectly meets all needs. Batteries, whether lithium, redox, or others, have limitations in terms of lifespan, cost, material availability, and efficiency. Pumped-hydro storage is efficient, but it requires specific geographical sites and raises environmental concerns. Long-duration storage solutions, capable of lasting several days or weeks, are still largely at the research stage. It is necessary to be able to store very large quantities of energy to compensate for periods without renewable production, such as several days without wind in winter. To give an idea, it would take the equivalent charge of billions of car batteries to cover a country’s needs for a few days without wind, which is colossal. We are still far from being able to do this economically and ecologically. Virtual storage is a way to optimise self-consumption, but it does not solve the problem of mass storage for the grid.

It is clear that the development of high-performance, sustainable, and economically viable storage solutions is a prerequisite for achieving a majority share of renewable energies in our energy mix. Research and development must continue to explore new avenues, whilst improving existing technologies to make them more efficient and less dependent on scarce resources.

Hydroelectricity and pumped-hydro storage

Hydroelectricity, and more specifically pumped-hydro storage (PHS), represents the most mature and widely deployed large-scale energy storage technology globally. These installations use water stored in an upper reservoir to generate electricity when demand is high, and pump the water back to this reservoir when renewable energy production is in surplus. It is currently the only solution capable of managing considerable energy volumes over variable durations, ranging from a few hours to several days.

The predominant role of PHS in large-scale storage

PHS plants form the backbone of grid-scale electricity storage. Their ability to respond quickly to demand fluctuations and absorb surplus intermittent production, such as from solar and wind, is unparalleled. In France, the PHS fleet, although ageing for some units, plays an essential role in the stability of the electricity grid. It helps to smooth the production of renewable energies and ensure continuity of supply, even in the absence of wind or sun.

• Global installed capacity: Over 100 GW across approximately 400 sites.
• Typical efficiency: Reaches approximately 80%.
• Storage duration: From a few hours to several days, depending on reservoir size.

The importance of PHS in balancing supply and demand is undeniable, especially as the share of intermittent renewable energies in the energy mix continues to grow. Without these storage capacities, the massive integration of these energy sources would be compromised.

Potential and limitations of hydroelectric installations in France

In France, the potential for developing new large hydroelectric dams is limited. The best sites are already exploited, and new installation projects often face significant environmental and social constraints. Furthermore, most existing PHS plants were built between 1976 and 1985, and their modernisation or extension represents a technical and financial challenge. Hydroelectric energy remains a valuable renewable energy source, offering low operating costs and low greenhouse gas emissions [4a7f].

Current limitations include:

• Saturation of the most favourable sites.
• Environmental concerns and social acceptability of new projects.
• Ageing existing infrastructure.
• The need to strengthen transmission networks to transport electricity produced far from consumption centres.

Innovations in coastal and offshore hydroelectric storage

Faced with these limitations, innovative concepts are emerging to diversify hydroelectric storage applications. One avenue being explored is the development of modular 50 MW units intended for installation along coastlines. These systems would use seawater, pumped to an artificial reservoir located at height on the coast. Another idea, even more experimental, concerns offshore storage using artificial atolls. These projects aim to create significant elevation differences by using underwater or coastal reservoirs, thus offering significant storage capacity whilst minimising visual and environmental impact compared to traditional dams. These innovations could open new perspectives for energy storage, although their economic and technical viability on a large scale remains to be demonstrated [bad9].

Sizing of renewable installations with storage

To effectively integrate intermittent renewable energies like solar and wind, it is essential to provide adequate storage capacity. This helps to compensate for periods when production is low or non-existent, thus ensuring a more stable electricity supply. Without these storage systems, conventional power plants would have to be kept on standby, which would go against the decarbonisation objective.

Need for overcapacity to compensate for intermittency

The intermittency of renewable sources necessitates oversizing production facilities. In France, for example, for an annual production equivalent to average consumption, the installed wind or solar power should be more than ten times higher than the average power consumed. This overcapacity is necessary to both supply the grid and charge storage systems during peak production. Without this margin, frequent power cuts would be risked during periods of combined low production.

Comparison of power requirements for solar and wind

Installed power requirements vary depending on the renewable technology and its utilisation rate. Wind power, with a higher average utilisation rate, requires less overcapacity than solar photovoltaics to achieve the same annual production level. For example, for a stable supply via batteries or PHS, wind power might require an installed capacity approximately 6.7 times higher than average consumption, whilst solar might require 10.7 times more. The use of hydrogen as a storage vector further modifies these ratios, demanding even greater overcapacity.

Energy Source	Utilisation Rate (%)	Installed Power Ratio (with batteries/PHS)
Wind	20.1	≈ 10
Solar	12.8	≈ 16

Impact of different storage systems on sizing

The choice of storage system has a direct influence on the overall sizing of the installation. Batteries and PHS (Pumped-Hydro Storage) offer higher storage and discharge efficiencies than hydrogen, which translates into a reduced need for production overcapacity. However, PHS, whilst efficient, is limited by geography and environmental constraints. Batteries, which are increasingly efficient, are an increasingly considered solution for renewable energy storage. Hydrogen, whilst promising for long-duration storage, has lower energy efficiencies, implying greater production overcapacity to compensate for losses during production, storage, and discharge cycles. Research continues to optimise these different systems.

Technical challenges of renewable energy integration

Integrating renewable energies into our current energy systems presents a set of technical challenges that must be addressed for a successful transition. These challenges are primarily related to the very nature of these energy sources.

Managing variability and intermittency

Solar and wind energy production, whilst clean, is inherently variable. It depends on weather conditions and the day-night cycle. This intermittency makes production forecasting complex and poses a problem for ensuring a constant electricity supply. To overcome this, the development of high-performance energy storage solutions is absolutely necessary. These technologies allow surplus energy produced during peak production to be stored and then released when demand is high or production is low. Without adequate storage, the massive integration of these variable sources can destabilise the electricity grid.

• Improved weather forecasting: More precise models to anticipate solar and wind production.
• Flexible storage systems: Batteries, hydrogen, and other technologies to smooth production.
• Demand management: Encouraging consumers to adapt their consumption to periods of high production.

Adapting existing infrastructure is a key step to accommodating a growing share of renewable energies. This involves significant investments to modernise the grid and make it more resilient to production fluctuations.

Adapting electricity grid infrastructure

The traditional electricity grid was designed for a unidirectional flow of energy, from large power plants to consumers. The integration of renewable energies, often decentralised (solar panels on roofs, small wind turbines), creates a bidirectional and more complex flow. The grid must be modernised to manage these multiple flows, ensure stability, and prevent overloads. This includes strengthening transmission lines, improving transformers, and installing more sophisticated control systems. The goal is to make the grid smarter and capable of reacting in real-time to variations in production and consumption. A good understanding of sizing rules, such as those relating to Enedis connection power, is therefore essential.

Smart grids and demand flexibility

Smart grids are an essential component for addressing these challenges. They use information and communication technologies to monitor, control, and optimise the electricity grid in real-time. They enable better integration of renewable energies by facilitating energy flow management and improving predictability. Furthermore, smart grids promote demand flexibility. This means encouraging consumers to adjust their electricity consumption according to the availability of renewable energy. For example, scheduling the charging of electric vehicles or the operation of household appliances during hours when electricity is abundant and cheaper. This approach helps to balance supply and demand, thereby reducing the need to resort to backup fossil fuel sources. Large solar installations, such as solar farms, play a role in this transition by feeding the national grid with green electricity production.

Environmental impact of renewable energies

Although renewable energies are considered a cleaner alternative to fossil fuels, their deployment is not without consequences for the environment. It is therefore essential to assess these impacts for thoughtful and sustainable integration.

Comparison with fossil fuels

Renewable energies, by their very nature, offer a major environmental advantage: they emit little to no greenhouse gases during operation. Unlike thermal power plants that release significant amounts of CO2, solar and wind installations directly contribute to the fight against climate change. This difference is fundamental for air quality, particularly in urban areas, and for biodiversity preservation.

Ecological considerations related to hydroelectric dams

Hydroelectricity, whilst being a mature renewable energy source, raises specific ecological questions. The construction of large dams can lead to the submersion of vast land areas, thus altering ecosystems and displacing animal and plant populations. Furthermore, dams alter the natural flow regime of watercourses, affecting aquatic wildlife, particularly migratory fish, and modifying downstream sedimentation. Water management and the impact on aquatic habitats are therefore major points of vigilance for this type of installation.

Impact of wind installations on avian wildlife

Wind farms, whether onshore or offshore, can pose a risk to birds and bats. Rotating blades can cause collisions, and the presence of masts can disrupt migration corridors. Careful site planning, taking into account migratory routes and nesting areas, is therefore paramount. Thorough impact studies and the implementation of mitigation measures, such as detection systems or temporary turbine shutdowns during periods of intense migration, are necessary to minimise these risks. Integrating these technologies into the energy landscape is a challenge that requires constant attention for a successful energy transition.

Planning and minimising ecological impacts

For the deployment of renewable energies to be truly beneficial, a proactive planning approach is essential. This involves:

• Rigorous environmental impact assessments before any project implementation.
• Selection of optimal sites that minimise conflicts with sensitive ecosystems and land uses, as proposed by ground-mounted photovoltaic fields.
• Implementation of compensatory and avoidance measures to preserve biodiversity and landscapes.
• Continuous monitoring of installations to adjust practices and improve environmental performance over time.

Reconciling the growing need for clean energy with the preservation of our natural environment requires a balanced approach and rigorous planning. The benefits of renewable energies, such as reducing the carbon footprint through photovoltaics, are undeniable, but they must be achieved by taking into account the ecological specificities of each territory.

Design and implementation rules for photovoltaic installations

The design and implementation of photovoltaic installations must follow precise rules to guarantee their safety, performance, and compliance. It’s not just about installing panels in the sun; several technical and regulatory aspects need careful consideration.

Technical evaluation of integration processes

The integration of solar panels, whether superimposed on an existing roof or replacing roofing elements, requires a rigorous technical evaluation. It is necessary to ensure the compatibility of materials, the mechanical resistance of the supporting structure, and the watertightness of the system. Current technical opinions, issued by recognised bodies, provide valuable information on validated processes and the actors involved in this evaluation. Good integration is key to the longevity of the installation.

Electrical standards applicable to photovoltaic systems

Adherence to electrical standards is absolutely fundamental for the safety of property and people. In France, the UTE C 15-712-1 guide is the main reference. It details the requirements for circuit design, protection sizing, and the decoupling devices necessary for grid connection. Product standards, meanwhile, guarantee the quality and reliability of the components used. A CONSUEL certificate and a control report are often required to validate the conformity of the installation.

Fire safety considerations

Fire safety is a major concern for photovoltaic installations, particularly when integrated into buildings. It is imperative to be aware of specific normative and regulatory provisions. This includes implementing appropriate safety measures, such as emergency shutdown devices, and considering the fire behaviour of the modules. Firefighter intervention procedures must also be anticipated to minimise risks in the event of an incident.

The RES concept: towards sustainable energy autonomy

The idea of achieving energy autonomy through renewable energy sources (RES) is no longer a mere utopia. It is increasingly becoming a reality, driven by technological advancements and a collective awareness of climate issues. The goal is to build a resilient energy system, independent of fossil fuels and respectful of our environment. This implies a profound transformation of our energy production and consumption methods.

The growing need for high-performance storage solutions

The intermittent nature of certain renewable sources, such as sun and wind, makes energy storage indispensable. Without effective storage solutions, it is difficult to guarantee a constant and reliable supply. Progress in this area is therefore essential to maximise the use of locally produced energy. Regions or businesses can now benefit from innovative storage solutions to stabilise their energy supply. This helps to smooth production peaks and meet demands even when natural sources are not available. Collective self-consumption, for example, allows groups of people to share locally produced electricity, often from solar panels, thereby reducing their dependence on the traditional grid and their electricity bills [b571].

The importance of technology durability and efficiency

Beyond performance, technology durability is a key factor. It is not enough to produce clean energy; the means of production and storage must themselves be designed with a circular economy logic and low environmental impact. This concerns the choice of materials, the lifespan of equipment, and their recyclability at the end of life. Energy efficiency is also paramount: every watt saved is a watt that does not need to be produced. The integration of these energies into the existing grid also poses complex technical questions, but infrastructures are adapting to accommodate these new forms of energy without compromising grid stability thanks to smart grids and the flexibility of electricity supply and demand [b9b7].

Towards a majority share of renewable energies

The ambition is clear: to make renewable energies the main source of our energy supply. Countries like Costa Rica are leading the way by producing a majority of their electricity from renewable sources. Island communities, such as Samsø in Denmark, have already achieved remarkable energy autonomy. These examples demonstrate that a complete transition is technically feasible and economically beneficial. To achieve this, a combination of solar, wind, and hydraulic technologies, supported by innovations in storage, is necessary. Public policies play a decisive role in encouraging investment and offering incentives for the adoption of these sustainable solutions.

Decentralised and local storage

Small-scale energy storage, whether at neighbourhood or individual household level, is gaining increasing importance. It directly addresses fluctuations in local consumption, offering flexibility that complements centralised storage solutions. These systems allow for absorbing peak demand or smoothing the intermittent production of local renewable installations, such as rooftop solar. Self-consumption, whether individual or collective, finds a major ally in decentralised storage for maximising the use of locally produced energy.

Responding to local consumption variations

The energy needs of a residential area or a small community are not constant. They vary according to the time of day, seasons, and activities. Local storage allows electricity produced during periods of low demand or surplus renewable production to be stored, and then released when demand is higher. This reduces dependence on the main grid and can improve supply stability at the local level. For example, a domestic battery can store the day’s solar surplus to power the house in the evening, when the sun is no longer shining. For isolated areas or overseas territories, where grid access is limited or non-existent, these solutions are particularly relevant, as highlighted by an analysis of the specific constraints of Non-Interconnected Zones (NIZs).

Complementarity with centralised storage

Decentralised storage is not intended to entirely replace large centralised storage facilities, such as pumped-hydro storage plants. Rather, it is a complementary approach. Whilst centralised storage manages large-scale imbalances on the national grid, local storage optimises energy use as close as possible to its production and consumption points. This combination allows for finer and more resilient management of the entire energy system. Smart grids play a key role in this synergy, enabling effective communication and coordination between different storage levels and consumers.

Examples of applications for individual and collective use

The applications of decentralised storage are numerous:

• Residential: Domestic batteries coupled with solar panels for self-consumption, reducing electricity bills and carbon footprint.
• Collective buildings: Shared storage systems for co-ownerships, allowing the benefits of collective self-consumption to be pooled.
• Small businesses and crafts: Storage to smooth electricity consumption and optimise the use of on-site solar energy, an important aspect in the development of the French photovoltaic market.
• Rural or isolated areas: Autonomous solutions for electricity supply, often combined with renewable energies, offering an alternative to traditional grids.
• Electric mobility: Integration of storage for charging electric vehicles, for example by using surplus solar energy.

The trend is towards increasingly integrated storage closer to production and consumption points. This not only allows for better management of renewable energy intermittency but also strengthens the resilience of electricity grids against hazards and provides greater autonomy to consumers.

Future prospects for energy storage

The future of energy storage is a complex subject, full of promise but also challenges. We are actively seeking solutions that are both high-performing, sustainable, and do not deplete our natural resources. Current technologies, such as pumped-hydro storage, are already doing a remarkable job for daily, even weekly, storage. But to truly shift towards a society where renewable energies dominate, we need to go further. We are talking about storing energy for several days, or even weeks, to get through periods without wind or sun, especially in winter. Imagine, to cover part of French consumption during five days without wind, a phenomenal amount of energy would need to be stored. It’s a bit like wanting to store the equivalent charge of millions of large car batteries, or several times the capacity of France’s largest dams. Clearly, we do not yet have the large-scale miracle solution for this.

Development of promising new technologies

Research is progressing, and several avenues are being explored. Redox flow batteries, for example, show interesting potential for electricity grids and homes. Their advantage is that storage capacity can be increased simply by enlarging the volume of electrolyte tanks. The main challenge remains the longevity of the membranes that separate these electrolytes. Other research focuses on synthetic fuels, such as hydrogen or methane, but current efficiencies are not yet good enough to avoid excessive energy waste. Major breakthroughs are truly needed for these technologies to become viable. Innovation in this area is therefore more than just an improvement; it is an absolute necessity.

Costs and economic viability of storage solutions

Currently, cost remains a major barrier. The most mature solutions, such as lead-acid batteries, are the cheapest, but they raise environmental concerns and have a limited lifespan. New technologies, whilst promising, still require considerable investment to move from the laboratory to mass production. Solar panel prices, however, continue to fall, reaching record lows in Europe, which is good news for solar energy production. But without affordable and efficient storage solutions, the intermittency of these energies remains an obstacle. An economic balance must be found so that storage becomes an attractive option for individuals as well as for large infrastructures.

The role of public policies in innovation

Governments and public bodies have a key role to play. They can support research and development through funding, encourage pilot experiments, and establish favourable regulatory frameworks. Without strong political support, the development of truly sustainable and economic storage solutions risks taking much longer. It is also important to consider installation planning, by evaluating available solar resources and choosing the best sites to maximise photovoltaic energy production. Public policies must therefore accompany this transition, helping to overcome technical and financial obstacles, and guiding the market towards more environmentally friendly technologies. The future evolution of solar panels will also depend on these global factors.

Energy storage is an exciting and rapidly evolving field. There are many ways to store energy for future use, and technologies continue to improve. It is a key topic for the future of energy. To learn more about the latest advancements and how they might affect you, visit our website today!

Conclusion

To summarise, the path towards a predominantly renewable energy future, especially with solar and wind, is still fraught with challenges. Energy storage is somewhat the Holy Grail we are still searching for. Current solutions, like PHS, are certainly there, but they will not be enough to cover all needs, especially during long periods without wind or sun in winter. Promising technologies, like flow batteries, are still under development and have their own challenges. It must be said that manufacturing these systems requires a lot of resources, and we do not yet know how to make them truly sustainable and less costly. We need to find new, more efficient ideas that use fewer rare materials. Without these major advancements in storage, transitioning to 100% renewable energies is still a distant goal. Research and development must truly intensify to find these solutions that will allow us to store energy reliably and economically, so that the sun and wind can truly power us continuously, day and night, whatever the weather.

Frequently Asked Questions

What is energy storage for renewable energies?

Energy storage is like putting electricity aside when there’s a lot of it (for example, when the sun is shining brightly or there’s a lot of wind) so you can use it later, when there’s less. It’s essential because the sun doesn’t shine at night, and the wind doesn’t always blow.

Why do we need to store renewable energy?

Energies like sun and wind are not available all the time. Storage allows us to have electricity when we need it, even if the main source isn’t producing. This helps to ensure a stable and reliable electricity supply, without needing to use polluting power plants.

What are the different energy storage technologies?

There are several ways to store energy. The most well-known are batteries (like those in our phones, but larger), pumped-hydro storage in dams (water is pumped up when there’s too much electricity, and allowed to flow down to generate electricity when needed), and thermal storage (heat from the sun is kept for later use).

Is energy storage already used on a large scale?

Yes, pumped-hydro storage in dams (called PHS) is the most widely used technology for storing large quantities of energy. For batteries, their use is growing, particularly for homes and businesses.

What are the challenges for developing energy storage?

The main challenge is to find solutions that are cheaper, last longer, and use fewer rare materials for their manufacture. These technologies also need to be efficient and environmentally friendly.

How does energy storage help make electricity greener?

By storing electricity produced by the sun and wind, we can use these clean energies more often. This reduces our reliance on power plants that run on fuels like gas or coal, which cause a lot of pollution.

What is decentralised storage?

Decentralised storage is when smaller storage systems are installed directly in people’s homes, neighbourhoods, or businesses. This allows for better management of locally produced electricity and meets the specific needs of each location.

What are the future prospects for energy storage?

Researchers are working on new, more efficient and cheaper storage technologies. Public policies also play an important role in encouraging innovation and helping to deploy these solutions, in order to achieve a more sustainable energy future.