Renewable Energy Systems: A Smart Energy Systems Approach to the Choice and Modeling of 100% Renewable Solutions
About this book
Henrik Lund's "Renewable Energy Systems: A Smart Energy Systems Approach to the Choice and Modeling of 100% Renewable Solutions" is a foundational academic text that charts a rigorous and practical course toward fully decarbonized energy societies. First published in 2010 by Academic Press (Elsevier), revised in 2014, and substantially expanded in its third edition in 2022, the book has become a standard reference for energy planners, engineers, researchers, and policymakers grappling with the enormous challenge of transitioning away from fossil fuels. At its core, the book introduces and systematically develops the concept of "Smart Energy Systems" — an integrated framework that moves well beyond the conventional focus on electricity alone.
Lund argues persuasively that achieving a 100% renewable energy supply requires the coordinated coupling of multiple sectors: the electricity grid, district heating and cooling networks, individual building heating systems, industrial processes, gas distribution infrastructure, and transportation. Rather than optimizing each sector in isolation, a smart energy systems approach seeks cross-sector synergies that make the overall system more efficient, flexible, and cost-effective. This concept, often described in the literature as sector coupling, is treated here not as a technical curiosity but as an operational necessity at the scale of entire national or regional energy systems.
The book dedicates considerable attention to the challenge of integrating fluctuating and intermittent renewable energy sources — particularly wind power and solar photovoltaics — into a stable and reliable energy supply. When renewable generation exceeds instantaneous demand, smart systems must be able to absorb, store, or redirect that surplus. Lund explores the full range of tools available for this purpose: large-scale battery storage, pumped hydropower, hydrogen production via electrolysis, thermal storage in district heating systems, electric vehicles used as distributed storage assets, and the flexible operation of combined heat and power (CHP) plants.
Each of these mechanisms is analyzed both technically and in terms of its systemic contribution to enabling higher shares of renewables. A distinctive and highly valuable feature of the book is the accompanying EnergyPLAN software tool, developed by Lund and his research group at Aalborg University and freely available online. EnergyPLAN is an advanced energy system simulation and analysis tool designed to model complete national or regional energy systems on an hourly basis over a full year.
It enables analysts to compare different pathways toward 100% renewable energy, evaluating trade-offs between technical performance, carbon emissions, and economic costs. The book serves as both a conceptual guide and a practical manual for EnergyPLAN, grounding abstract modeling concepts in worked examples drawn from real-world studies of Denmark, Germany, and other countries. The theoretical backbone of the book rests on what Lund calls "Choice Awareness" — a framework for understanding why societies tend to persist with existing energy technologies even when superior alternatives are available.
This framework examines the socio-political, institutional, and economic barriers that slow energy transitions and proposes strategies — including technical demonstrations, public regulation reform, and democratic engagement — to overcome them. By weaving this social science perspective into an engineering text, Lund produces an unusually holistic analysis that acknowledges the real-world constraints facing energy planners. Organized into logically progressive sections, the text begins with foundational principles of renewable energy sources — covering wind, solar, wave, tidal, hydropower, geothermal, and biomass technologies — and then moves through energy storage options, sector-coupling mechanisms, and the methodology of large-scale energy system modeling.
Results from over fifteen comprehensive national and regional case studies are presented, offering concrete illustrations of how 100% renewable energy systems can be designed and what they would cost. The transportation sector receives particular attention as one of the most difficult to decarbonize. Lund examines the relative merits of battery electric vehicles, hydrogen fuel cell vehicles, and biofuel-based solutions, concluding that direct electrification using batteries offers the most system-efficient pathway for most transport applications, while acknowledging that biomass-derived fuels will remain necessary for heavy transport, aviation, and shipping segments where direct electrification is impractical.
From a green building and sustainable urban infrastructure perspective, the book is highly relevant. Buildings are major consumers of both electricity and heat, and the integration of building energy systems — through heat pumps, solar thermal collectors, on-site photovoltaics, and smart energy management systems — into broader urban energy networks is treated as a key enabling strategy for the energy transition. District heating systems, which can flexibly incorporate surplus renewable electricity through large-scale heat pumps and thermal storage, are presented as particularly powerful tools for decarbonizing the built environment.
Lund's work stands as an intellectually rigorous yet accessible guide to a genuinely complex challenge. Its combination of theoretical frameworks, computational tools, and empirical case studies makes it indispensable reading for anyone engaged in the design, planning, or policy governance of sustainable energy systems at any scale.