The pursuit of a stable, year-round supply of renewable energy is no longer just an environmental goal: it's an economic, business, and social necessity. Spain is at a pivotal moment in its energy transition, with record-breaking clean energy generation, new certification systems, and ambitious future plans that will shape how electricity is produced and consumed in the coming decades.
At the same time, very reasonable doubts arise: can we rely solely on renewables without experiencing energy shortages? Which technologies are more stable? What role do storage, interconnections, and certifications like Guarantees of Origin play? We will break down, using very recent data, how Spain is building a renewable, reliable, and secure electricity system 365 days a year.
Stable renewable energy all year round: much more than installing solar panels and wind turbines
When we talk about stability, it's not enough to simply say that an energy source is clean; it needs to be supplied continuously, reliably, and measurably throughout the year. Several elements come into play here: the type of technologies (solar, wind, hydroelectric, biomass, geothermal, etc.), storage, the transmission network, international interconnections, and market mechanisms such as PPAs and Guarantees of Origin.
For businesses, stability also translates into price certainty and environmental traceability . It's of little use to sign a long-term power purchase agreement (PPA) if it cannot then be rigorously demonstrated that the electricity is of renewable origin and that the declared emission reductions are valid according to standards such as the GHG Protocol or initiatives like RE100.
Therefore, today it is impossible to talk about stable renewable energy without mentioning Guarantees of Origin (GoOs) , the massive deployment of renewables in Spain and macro-projects such as La Robla Green , the new objectives of the PNIEC and the revolution of storage and smart grids, which allow balancing variable production with real demand at any given time.
Furthermore, official data shows that Spain is no longer simply “testing” renewables: renewables are the central pillar of the electricity system , with more than half of the annual generation coming from clean sources and a growing presence of technologies capable of providing stability, such as hydropower, biomass or geothermal, supported by batteries and pumped hydro storage.
PPA 365 and Guarantees of Origin: how to certify year-round renewable
For many organizations, the key is not just consuming renewable electricity, but being able to demonstrate 365 days a year that their electricity consumption is linked to clean generation. This is where Power Purchase Agreements (PPAs) and Guarantees of Origin (GoOs) come in, functioning as the renewable energy "ID."
A 365 PPA aims to ensure a continuous supply of electricity at an agreed price, while Guarantees of Origin certify that this energy comes from renewable sources . These GoOs can be contracted alongside the PPA itself or independently, to "green" existing electricity consumption and align it with internationally accepted renewable credentials.
Thanks to this system, a company can support its climate objectives in different methodologies: Scope 2 emissions accounting of the Greenhouse Gas Protocol (GHG Protocol), the requirements of initiatives such as RE100 or sustainability reports aligned with European and international standards.
Among the most relevant benefits of combining PPAs and GoOs are the possibility of complying with Scope 2 emissions reporting , aligning corporate strategy with frameworks such as RE100, and strengthening the credibility of public sustainability commitments, avoiding the risk of greenwashing thanks to a recognized and traceable certification system.
Spain: record-breaking renewable energy generation and a cleaner system
The latest official data shows a change in scale: Spain ended 2024 with 148.999 GWh from renewable sources , representing an increase of just over 10% compared to the previous year. This is the highest annual figure recorded to date by Red Eléctrica and represents no less than 56,8% of the entire national electricity generation mix.
This surge is not due to a single factor: on the one hand, the installed capacity of renewables has grown significantly ; on the other, 2024 was accompanied by very favorable weather conditions, especially for hydropower and solar photovoltaics. As a result, hydropower production increased by around 35,5% compared to 2023, and photovoltaic production soared by nearly 18,9%, marking its sixth consecutive annual record.
In terms of energy generation by technology, wind power has consolidated its position as the leading source, accounting for over 23% of the national total. This is followed by nuclear power, with around 20%, solar photovoltaics at approximately 17%, combined cycle gas turbines with slightly over 13%, and hydroelectric power with a contribution slightly above 13%.
This renewable energy push has a direct impact on the climate: CO₂ equivalent emissions from the electricity sector have fallen to historic lows , around 27 million tons, a decrease of approximately 16-17% compared to the previous year. Overall, roughly 76-77% of all electricity generated in Spain in 2024 was free of direct emissions.
Photovoltaics takes the lead in installed capacity
Looking at installed capacity, solar photovoltaic energy has become the dominant technology in Spain's power generation sector . In 2024 alone, some 7,3 GW of new renewable power was added, primarily from photovoltaics and wind, representing the largest single-year increase to date.
Of that total, approximately 6 GW correspond to new photovoltaic installations, which have allowed this technology to reach approximately 25,1% of all installed generation capacity in Spain. Wind power has also grown, with around 1,3 GW of additional capacity, reaching a share of approximately 24,9% of the national generation capacity.
The energy landscape has also shifted in terms of fossil fuel technologies: the definitive closure of the As Pontes coal-fired power plant in Galicia has resulted in the removal of approximately 1,4 GW of non-renewable capacity. Thus, by the end of 2024, Spain had nearly 129 GW of total installed capacity, of which around 66% was renewable.
Photovoltaics is currently the fastest-growing renewable energy technology. It relies on panels that convert solar radiation into electricity and can be installed in large-scale plants as well as on residential rooftops, industrial buildings, or parking lots. Its cost has fallen dramatically in the last decade, making it highly competitive; international examples like the new solar plant in Germany illustrate this global trend.
Its advantages include its inexhaustible nature, the ease with which it can be scaled from small installations to large farms, and relatively low operating and maintenance costs . Disadvantages include its dependence on sunlight (it loses production on cloudy days and at night) and the need for available space, either on a rooftop or on the ground.
The typical efficiency of commercial modules ranges from 15-22%, although technologies exceeding these values are being developed. For photovoltaics to contribute to a stable year-round renewable energy supply, it is crucial to combine it with batteries, pumped storage, or other forms of energy storage , as well as sound grid planning.
Wind energy: high power, but limited by the wind
Wind power harnesses the kinetic energy of the wind using onshore or offshore wind turbines . Spain is one of the European leaders in this technology, with a well-established wind farm sector that contributes a significant percentage to the annual energy mix, and initiatives such as the record-breaking offshore wind energy auction stand out in the European context.
Its main strength is that, in areas with good wind resources, it offers significant production at competitive costs , with efficiencies typically ranging between 35 and 50% in modern turbines. However, it is subject to wind variability, which necessitates complementing it with other technologies and energy storage.
The combination of wind and solar power is particularly interesting because their peak production doesn't always coincide : there are times with more wind and less sun, and vice versa. This helps to smooth the renewable energy generation curve throughout the year and reduce dependence on backup fossil fuels.
The key role of hydropower: a very stable renewable energy source
Within the renewable energy sector, hydroelectric power stands out for its ability to provide stability and manageable power to the grid . On the Iberian Peninsula, hydroelectric production in 2024 reached approximately 34.900 GWh, representing an increase of nearly 35,5% compared to 2023.
Thanks to this increase, hydropower reached approximately 14% of the Iberian Peninsula's electricity generation, gaining several percentage points in the energy mix compared to the previous year and consolidating its position as the fourth largest source of generation across the peninsula. This technology has a clear advantage: it can modulate its production according to demand , within the limits imposed by the availability of water stored in reservoirs. Furthermore, there are incentives available to promote wind and hydroelectric power in Spain, facilitating investment and improvements in resource management.
The comparative data from 2023 and 2024 show that, except for November and December, hydroelectric production was higher in almost every month of 2024. The most striking month was April, with a growth of close to 159%, while December saw the largest year-on-year drop, with production around 39% lower than in the same month of the previous year.
The experience of this exceptionally wet year leaves an important lesson: hydropower, well managed and combined with other technologies and with storage, is one of the great allies to have stable renewable energy all year round , provided that the weather cooperates and adequate water reserves are maintained.
Storage: the great driver of renewable stability
For a system based primarily on renewables to function stably, it's not enough to simply generate large amounts of clean energy during periods of sunshine or wind; it's essential to be able to store the electricity and feed it back into the grid when needed . This is where battery storage and pumped hydro storage come into play, among other emerging solutions such as green hydrogen.
Spain has already begun to reflect these technologies in official electricity system reports, incorporating specific storage indicators. According to Red Eléctrica, the country currently has an installed storage capacity of approximately 3.356 MW , which has allowed for the integration of around 8.666 GWh of stored energy over the past year.
Batteries and pumped storage plants play a dual role: they facilitate the integration of large volumes of variable renewable generation and provide flexibility and stability services to the grid , helping to control frequency, manage peak demand and reduce renewable energy spills during periods of low demand.
Looking ahead to 2030, the Integrated National Energy and Climate Plan (PNIEC) sets a very ambitious target: to reach approximately 22,5 GW of storage capacity , combining different technologies. For this to materialize, the sector is awaiting clear regulations that will attract investment and accelerate the deployment of battery storage, pumped storage, and other advanced solutions.
Electricity demand, transmission network and interconnections: stability at system scale
Renewable energy stability depends not only on how much is generated, but also on how demand evolves and how robust the electricity grid is . In 2024, Spain's electricity demand grew slightly: adjusted for temperature and calendar effects, it was around 1,4% higher than the previous year. In gross terms, it stood at around 248.800 GWh, slightly less than 1% above the previous year.
These levels are in line with those of other European countries, where electricity consumption is growing at a moderate pace due to efficiency improvements, industrial changes, and economic conditions. Even so, the National Integrated Energy and Climate Plan (PNIEC) forecasts that demand will reach 358 TWh in 2030 , around 34% higher than current levels, driven by the electrification of transport, heating, and parts of industry.
The Spanish transport network has also continued to be strengthened: in 2024, approximately 487 kilometers of new lines were added, bringing the total length to approximately 45.674 km. The availability rate of this network is around 98% across the national system, with slightly higher figures in the Balearic and Canary Islands.
In addition to all this, there are the electrical interconnections with France and Portugal , which allow for the export and import of energy as needed by the system. Spain has now ended the year as a net exporter of electricity for three consecutive years, with a surplus of approximately 10.227 GWh in 2024, thanks in large part to its renewable energy surplus at certain times of the year.
Objectives of the National Integrated Energy and Climate Plan (PNIEC) and renewable growth forecasts
The framework guiding Spain's energy transition is the Integrated National Energy and Climate Plan (PNIEC ), recently updated with more ambitious targets. The PNIEC sets a target of approximately 81% renewable electricity generation by 2030 and Spain achieving climate neutrality by 2050.
Regarding the target capacity, the aim is to reach approximately 76 GW of solar photovoltaic energy, 62 GW of onshore wind power, nearly 4,8 GW of concentrated solar power (CSP), and around 1,4 GW of biomass electricity by the middle of the next decade. According to the sector, photovoltaics is the technology most aligned with the projected growth trajectory , while other renewable technologies will need to accelerate their deployment to meet the established targets.
Market forecasts point to very solid growth. According to specialized analyses, Spain's cumulative renewable capacity is estimated to exceed 218 GW by 2035 , with an annual growth rate of close to 9% between 2024 and 2035. During this period, renewable generation would increase from around 131 TWh to more than 313 TWh, with particularly strong expansion in solar photovoltaics.
According to these projections, photovoltaic capacity could scale from around 21,5 GW in 2021 to nearly 152,8 GW in 2035, while onshore wind power would increase from approximately 28,7 GW to around 56,3 GW over the same period. Furthermore, offshore wind and green hydrogen are emerging as new pillars of growth , supported by European and national funding.
Policies, regulation and incentives: how renewable stability is promoted
This massive deployment of renewables and storage is not happening by inertia: it is supported by a set of specific public policies and regulatory frameworks . Among these are the Renewable Energy Economic Regime (REER), which establishes competitive auctions for new installations, and the Climate Change and Energy Transition Law, which sets targets for emissions reductions and renewable energy penetration.
The regulation of self-consumption also plays an important role , facilitating distributed generation on rooftops and in small installations, allowing individuals, businesses, and energy communities to generate and consume their own electricity. This reduces grid losses, alleviates some of the demand, and contributes to greater system resilience in the face of peak consumption or occasional outages.
However, the sector faces several challenges: delays in connection and construction permits , capacity limitations at certain network nodes that force the injection of unused renewable energy, and still low levels of interconnection with the rest of Europe, which makes it difficult to make the most of renewable surpluses during periods of high generation.
Even with these obstacles, the incentive framework, the availability of solar and wind resources and the diversification of gas imports (with little weight of Russian gas and strong LNG capacity) put Spain in a very favorable position to move towards a decarbonized, stable and competitive mix both at the European and global level.
Will renewables alone provide us with enough energy year-round?
This is the million-dollar question. The answer, in light of the data and recent experience in Spain, is that it is indeed possible to meet demand with a system based primarily on renewables , but only if several key elements are combined: technological diversity, storage, reinforced networks, interconnections, and demand flexibility.
On the one hand, technologies like hydroelectric, biomass, and geothermal offer more stable and manageable energy production than solar or wind power, which are more directly dependent on weather conditions. On the other hand, energy storage and smart demand management (for example, by shifting consumption to peak renewable generation times) are essential for solving the puzzle on a daily basis.
Data from 12 consecutive months in which Spain has maintained more than 50% of its electricity generation from renewable sources demonstrates that renewable energy stability is not a theory, but a reality in progress . In some periods, the annual renewable share has hovered around 56-57%, driven by a strong increase in photovoltaics and, in very wet years, by an extraordinary increase in hydropower.
Looking to the immediate future, the major challenge is not so much whether there will be enough renewable energy, but how it will be integrated and managed to avoid grid bottlenecks, energy spillover, or price imbalances. This requires intensive investment in storage, grid reinforcement, digitalization, and incentives for flexible consumption.
Types of renewable energy and their contribution to stability
To better understand how to achieve a stable year-round supply of renewable energy, it's helpful to review each of the main clean energy technologies and their role in the system. Each has its strengths and limitations, and stability is achieved precisely by combining their production profiles.
Solar photovoltaic energy: the main protagonist of growth
Photovoltaics is currently the fastest-growing renewable energy technology. It relies on panels that convert solar radiation into electricity and can be installed in large-scale power plants as well as on residential rooftops, industrial buildings, or parking lots. Its cost has fallen dramatically in the last decade, making it highly competitive.
Its advantages include its inexhaustible nature, the ease with which it can be scaled from small installations to large farms, and relatively low operating and maintenance costs . Disadvantages include its dependence on sunlight (it loses production on cloudy days and at night) and the need for available space, either on a rooftop or on the ground.
The typical efficiency of commercial modules ranges from 15-22%, although technologies exceeding these values are being developed. For photovoltaics to contribute to a stable year-round renewable energy supply, it is crucial to combine it with batteries, pumped storage, or other forms of energy storage , as well as sound grid planning.
Hydropower: the most efficient and one of the most stable
Hydropower is based on harnessing the energy of moving water , generally through dams and reservoirs that allow the flow to be used to generate electricity through turbines. It is one of the most efficient forms of energy, typically reaching efficiency levels of 80-90% in large power plants.
Its main advantages are its continuous production capacity and flexibility to adapt to peak demand, in addition to low operating costs and a long infrastructure lifespan. However, it can have a significant environmental impact on river ecosystems, and its performance depends on water availability, which is closely linked to weather patterns and reservoir levels.
In terms of stability, hydroelectric power is a key component, especially when combined with pumped storage plants that allow energy to be stored by raising water to a higher reservoir during off-peak hours or when prices are low, and then generating electricity through turbines during peak hours.
Biomass and biogas: renewables that can be managed 24 hours a day
Biomass and biogas obtain energy from organic matter derived from agricultural, forestry, livestock, or urban waste , including projects like the Logrosán biomass plant . Combustion, anaerobic digestion, or other processes allow for the generation of electricity and heat with much more controllable production than solar or wind power.
Among its advantages are the possibility of reusing waste and reducing landfills , as well as its ability to operate continuously, regardless of the weather. However, if not managed properly, it can produce emissions, and its sustainability depends heavily on the origin and logistics of the raw materials.
In terms of efficiency, biomass plants typically operate in the 20-40% range. While not the most efficient, their great value in a renewable energy system lies in their ability to provide firm and programmable power , which is very useful for reinforcing system stability and covering periods when other renewable energy sources produce less.
Geothermal energy: a constant source where the resource allows it
Geothermal energy harnesses the Earth's internal heat to produce electricity or heating/cooling . In areas with significant geothermal activity, it can offer a virtually constant source of energy, with high load factors and very high availability; for example, geothermal energy accelerates its expansion in specific regions.
Its main strengths are its stable production, reduced visual impact, and small footprint . On the other hand, it is only viable in regions with adequate geothermal resources and requires high initial investments, in addition to presenting certain technical risks associated with deep drilling.
The efficiency of geothermal power plants typically ranges from 45 to 60%. Where feasible, it can become a solid foundation for renewable energy generation , complementing other, more variable technologies and contributing to greater system stability.
Why accelerating the transition to renewables is key to a stable and sustainable system
Beyond security of supply, the transition to year-round, stable renewable energy also responds to climate and public health concerns. Energy production using fossil fuels is responsible for a vast majority of GHG emissions, more than 75% of all greenhouse gases and around 90% of CO₂ globally.
Science indicates that, to avoid the worst impacts of climate change, global emissions must be reduced by almost half by 2030 and net zero achieved by 2050. This implies phasing out coal, oil, and gas and investing massively in clean energy sources and energy efficiency.
Renewable energy sources also have a direct impact on air quality. Burning fossil fuels is one of the main sources of air pollution, responsible for millions of premature deaths each year and enormous economic costs. Replacing them with technologies like wind, solar, and hydropower drastically reduces the harmful particles and gases we breathe every day.
From an economic perspective, renewables also fare well: in most regions of the world, they are already the lowest-cost option for new electricity generation . The price of solar electricity has plummeted by around 85% in the last decade, while onshore and offshore wind power have reduced their costs by about half or more.
Economic impact, employment and opportunity costs
Investing in renewables and related technologies not only has environmental benefits. Every dollar invested in clean energy generates approximately three times more jobs than the same investment in fossil fuels, boosting local manufacturing, installation, maintenance, and technology services industries.
Looking ahead to 2030, the transition to net-zero energy systems is estimated to result in the loss of approximately 5 million jobs linked to fossil fuels , but in return, it could create around 14 million new jobs in clean energy. An additional 16 million jobs are also expected in related sectors, such as electric vehicles, high-efficiency equipment, and hydrogen technologies.
Therefore, the net result would be more than 30 million new jobs associated with the energy transition. However, it will be essential to guarantee a just transition that leaves no one behind , supporting the most vulnerable regions and workers with reindustrialization policies, training, and social protection.
Regarding the necessary investments, it is estimated that the world spent around $5,9 trillion on subsidies and hidden costs linked to fossil fuels in 2020, while approximately $4 trillion per year would need to be invested in renewables until 2030 to meet climate goals. Although these figures may seem daunting, the savings from reduced pollution and climate damage could exceed $4,2 trillion annually by 2030.
Everything suggests that building a system based on stable year-round renewable energy, supported by a combination of clean technologies, storage, reinforced grids, certifications such as Guarantees of Origin and more flexible demand, is not only technically possible, but also safer, healthier and economically smarter than continuing to depend on fossil fuels in the coming decades.
