Achieving global climate goals requires a transformative shift in decision-making, investments, and policy adjustments. Energy system models play a crucial role in this process, enabling informed decisions for optimizing investments, forecasting trends, and shaping regulations. This policy brief highlights the importance of open-source energy modeling as a key driver of the energy transition. Open models offer transparency, flexibility, and cost-effectiveness, ensuring a collaborative and data-driven approach to tackling climate challenges. By fostering innovation and inclusivity, open energy modeling provides robust tools for policymakers, regulators, and investors to navigate the complexities of modern energy systems. The document outlines the benefits of open-source models, their potential applications, and the steps needed to integrate them effectively into global energy planning.

Summary

To achieve global climate goals and unlock opportunities for innovation and sustainable, equitable economic growth, the world needs unprecedented levels of investment and major policy adjustments. This requires a step change in decision-making. Energy system models already play an essential role, making a major positive contribution to the success of the energy transition. They enable investors, policymakers and regulators to optimize investments, forecast trends, and shape policies. The next generation of these tools is open-source, offering transparency, flexibility, speed, and cost-effectiveness. This is needed now more than ever, as our energy systems are becoming more complex. Model users, model builders, investors, policymakers, and regulators need to work together to realize the full potential of open-source models as complements to or replacements for existing methods. Promoting open solutions fosters collaboration, innovation, and ultimately a more effective, efficient and equitable energy transition.

The climate transition requires a step change in decision-making

Meeting international climate goals and achieving net-zero emissions will require annual global investments of €4.4 trillion by 2030 and €4.5 trillion by 20501. These investments are essential for a successful energy transition with new technologies, upgrades to existing infrastructure, regulatory adjustments, and shifts in behavior and consumption habits. They are also unprecedented. Never before have we made such a large transition in such a short time.

We are making progress. The use of renewable energy resources is rapidly growing across the world. Costs of solar and wind power have decreased massively and are now the cheapest technologies for electricity generation in many locations. Renewable energy reached 16% of global energy production in 2020. There are also increasingly affordable and mature technologies to decarbonize heating and transport. However, to align with the Paris Agreement’s target of limiting global warming to 1.5°C, we must accelerate our efforts and increase the share of renewable energy in the global energy mix to at least 77% by 20502. Conversely, investments in several locations show clear signs of slowing down, with, for instance, failed offshore wind auctions in Denmark and the UK. Energy storage investments are also lagging behind. Estimates show the need for 200 GW of storage in Europe alone by 2030 and 600 GW by 2050, while current levels are below 100 GW3.

Meanwhile, 1.18 billion people worldwide still live in energy poverty4, and there is evidence that energy poverty is increasing in many parts of the world as a result of current high energy prices. Unprecedented challenges require unprecedented actions. Achieving climate goals must be a collective global effort. We need a step change in decision-making, leading to a step change in investment, in policy, and in regulation, while continuing reliable system operation. The good news is that this will make the climate transition possible, and unlock opportunities for innova- tion and sustainable, equitable economic growth. The bad news is that decision-making in the climate transition is highly complex, with many interactions between energy carriers and coun- tries, with many uncertainties and potential for unintended consequences. Decision-makers, both in the public and private sectors will need to navigate multiple, interdependent changes simultaneously if we are to achieve the step change towards a sustainable world we urgently need.

Energy models are key tools to improve decision-making

In this complex decision-making landscape, energy system models are essential tools. They help investors simulate markets to quantify risks and returns and inform choices. They help system operators keep our electricity and gas systems secure by giving the ability to simulate and optimize short- and long-term system operation. They form the basis for assessment of energy and climate policies in many countries, and help regulators identify market failures. Offering data-driven insights, these models play a crucial role in shaping sustainable and resilient energy systems.

What are energy system models?

Energy system models are mathematical models that are designed to reliably represent particular parts of the energy system. They are simplified representations of the energy system (or its sub-systems) at different temporal, sectoral, and spatial resolutions, and include mathematical descriptions of energy resources, conversion technologies, transport, and energy use. Starting from the 1980s, when models such as TIMES and WASP became popular, particularly through their use by the Organisation for Economic Co-operation and Development (OECD) and International Atom- ic Energy Agency (IAEA), a wide range of different models have been developed to address different challenges. These include simulating current or future systems, optimization of systems to recommend policy or investment decisions, forecasting of future developments, and the construction of consistent scenarios that form the basis for policy or collaboration. Because models have been developed for different uses, they have different structures, from bottom-up agent-based models that capture the behavior of individual investors, producers, or consumers in detail, to large-scale top- down optimization or equilibrium models.

Energy system models enable decision-making in complex settings through:

01

Simulation of Events, Investments, and policies: Energy system models help assess the impact of various events, investments, and policies in current and future energy systems. For example, an electricity dispatch model can be used to show the effects of adding a particular type of energy storage facility on power flows, prices, and system reliability, or a gas system model could show the effects of increasing LNG imports.

02

Forecasting of Future Developments: Energy system models help uncover interdependencies within the energy system, forecasting how systems as a whole might develop. For example, whole-system models might be used to forecast how the use of different conversion technologies might develop as a result of global trends in prices of primary energy carriers and end-user demand.

03

Optimization of Investments and Policies: Energy system models can identify the most efficient allocation of resources in time and space, improving cost-effectiveness and decreasing unintended side-effects. For exam- ple, a multi-country energy system model could show where investments reduce overall system costs or carbon emissions the most.

04

Generation of Consistent Future Scenarios: Energy system models can create sets of projections for future energy systems in which the mix of technology is consistent with technical and economic boundary conditions, serving as a shared foundation for decision-making among stakeholders. For example, an electricity capacity expansion model might be used to generate future scenarios for expansion of interconnection capacity between countries.

The next generation of energy modeling tools is open-source

The next generation of energy modeling tools is open-source. A wide range of existing energy modeling tools is currently available. These tools have played a crucial role in the creation and operation of our past and present energy systems, contributing to the early stages of the climate transition to date, and continue to be useful in many areas today. At the same time, the next generation of modeling tools has now arrived, ready to enable the step change in decision-mak- ing that is needed. This next generation is open-source. This change is needed to allow the rapidly developing state of art in energy technology to be matched with equally rapid develop- ment of models that are used to make decisions. By opening the models to all relevant users, the impact of newer technologies can be accurately calculated with fewer risks for expensive errors. The characteristics of open-source energy modelling tools are transparency, flexibility, speed, and quality, offering a cost-effective complement or alternative to proprietary solutions.

What is open-source ?

Open-source tools are free to study, modify, use, and share. Their source code is Findable, Accessible, Interoperable, and Reusable (FAIR). This allows users to tailor the framework to their needs while gaining insight into the underlying calcu-lations. Because the code is openly accessible, users benefit from reproducibility across different tools. Examples of open frameworks with complementary features include PyPSA, Sienna, GenX, PowSyBl and pandapower. Open-source tools can be used with proprietary data and proprietary software packages. They can also be combined with open data and open-source software for a fully open workflow.

Open-source energy modeling tools can support decision-makers with the next generation of energy decision-making, offering transparency, flexibility and speed, collaboration for quality, at comparably low costs.Transparency Open-source software is built on principles of openness and transparency. In energy modeling, this means that users can access and validate the underlying assumptions and calculations, enhancing trust in the tool. Studies can also be repeated and reproduced. Transparency is vital in today’s increasingly complex energy systems, with more variability, flexible technologies, and more interactions between energy vectors and markets. In these complex systems, modeling assumptions and choices have a big impact. Consequently, it is necessary to be able to see and understand them. This facilitates innovation that matches the needs of the users, and promotes an informed societal dialogue in which all parties can participate. Ultimately, this also leads to stronger and broader support for the energy transition.

Transparency

Open-source software is built on principles of openness and transparency. In energy modeling, this means that users can access and validate the underlying assumptions and calculations, enhancing trust in the tool. Studies can also be repeated and reproduced. Transparency is vital in today’s increasingly complex energy systems, with more variability, flexible technologies, and more interactions between energy vectors and markets. In these complex systems, modeling assumptions and choices have a big impact. Consequently, it is necessary to be able to see and understand them. This facilitates innovation that matches the needs of the users, and promotes an informed societal dialogue in which all parties can participate. Ultimately, this also leads to stronger and broader support for the energy transition.

Flexibility & Speed

Open-source modeling tools offer flexibility and speed, enabling users to adapt models to their specific and rapidly changing needs without needing to wait for lengthy approval or support processes, offering the potential for quick exploration of new technological innovations. Open-source modeling tools facilitate:

• Immediate customization to fit with projects or local requirements;
• Seamless integration with existing workflows and systems,including proprietary software; • Automation of workflows, reducing manual effort and increasing accuracy;
• Access to the latest scientific methods that can reduce model runtimes.

This adaptability is particularly valuable in dynamic energy markets, where rapid adjustments and innovations are crucial.

Collaboration for Quality

Open-source modeling tools belong to open-source communities, where experts from around the world can contribute improvements, share documentation, and refine the software collab- oratively, regardless of their location or affiliation. This collaborative development means that tool development is not restricted to the ideas from or capacity of a single development team. Instead, open-source tools benefit from:

• Peer review and global collaboration, ensuring robust and reliable codebases;
• Continuous innovation, as developers worldwide enhance functionality together;
• Rapid evolution, as the energy modeling community collectively advances the field.

This collaborative approach leads to more resilient and high-quality energy models tailored to the needs of policymakers, investors, system operators, and other users.

Lower Cost

Open-source models are free to use, without licensing fees, making them accessible to all users regardless of their financial capacity. This is a particular advantage to users in smaller organizations and/or in the Global South. Services such as training, implementation, and support may still need to be purchased from software providers specializing in open-source solutions. Because open-source tools are vendor-neutral, users can select their preferred providers to supply these services. This enables a healthy, competitive market, with cost-re- flective prices. This cost-effectiveness, both through the absence of licensing fees and free choice of support providers, makes open-source tools an attractive choice for organizations looking to reduce reliance on proprietary software while maintaining high-quality modeling capabilities.

We need to work together to realize the full potential of open-source

Open-source energy models can contribute to the step change in decision-making about investment, system operation, policy, and regulation that we need, both to meet climate target sand to drive sustainable growth. We need to work together to realize their full potential. Whether you are a model user, model builder, manager, investor, policymaker, or regulator, you can plan your part.

• Already have a functioning modeling setup? Proprietary software used for energy modeling can be complemented with open-source tools, enhancing modeling capabilities, streamlining pre-processing, and increasing flexibility.
• Looking to start modeling? Consider open-source solutions. Explore whether they meet your requirements—they offer cost-effective, transparent, and adaptable options for energy planning.

• Want to invest in solutions that will accelerate the energy transition? Invest in open-source modeling and model support to ensure continued development, maintenance, and usability.
• Want to encourage broader adoption? Advocate for open-source energy modeling. If you are a policymaker, advocate for transmission system operators, energy regulators, and energy planners to integrate open-source tools into their workflows whenever possible.

Promoting open solutions fosters collaboration, innovation, and more effective energy transition strategies.