Five decades of energy efficiency and energy system analysis

Jochem, E.; Bradke, H.; Dütschke, E.; Klobasa, M.; Wietschel, M.; Plötz, P.; Fleiter, T. (2024): Energy Demand and Modelling of Energy Systems: Five Decades from Little Knowledge to Differentiated Know-How. In: Edler, J.; Walz, R. (Ed): Systems and Innovation Research in Transition. Research Questions and Trends in Historical Perspective. Cham: Springer.

Using energy is never an end in and of itself. Rather, it always serves to fulfill other needs such as heating a home, making a hot meal, moving around, communicating with others, producing industrial goods and so on. Although — with a few exceptions — there has never been a shortage of energy in recent decades and it has been available at a relatively low cost, energy has always played a major role in politics and, consequently, in research too, in part due to geopolitical factors, but also because it is so important for national economies.

From limitless energy consumption to “The Limits to Growth”

The early 1970s were characterized by the “economic miracle” and the idea of unbridled economic growth, which therefore meant unbridled energy consumption. This world view was shaken by the report titled “The Limits to Growth”, commissioned by the Club of Rome, in 1972, then again by the first oil crisis in 1973. The first maverick institutes working in the energy sector began recognizing the need to decouple economic growth from the demand for energy, for example by being more energy-efficient, and started working on solutions.

The second oil crisis in 1979, which came with political measures that affected the public such as bans on Sunday driving and slogans like “Conserving energy is the best source of energy”, intensified research efforts not only into nuclear energy, but also in the fields of energy efficiency, demand simulations (including the structural transformation of industry) and policy measures, along with initial concurrent evaluations of said research. The optimization models that were around in the early 1980s, initially developed and used to configure optimum structures for electricity generation and other energy supplies, were increasingly expanded by add-ons covering the demand for final energy.

The oil price halved during the 1990s, which meant the market was therefore less interested in energy efficiency and renewable energies. At the same time, however, arguments for mitigating the effects of climate change were getting louder thanks to events such as the 1988 Toronto Conference on climate protection and Enquete Commission recommendations like those put forward by the German Federal Ministry for the Environment under Klaus Töpfer (25 percent reduction in greenhouse gases by 2005), the Rio Summit in 1992 (on sustainable development) and the Kyoto Protocol of 1997 (climate protection targets of 2 °C). These events ensured that the fields of science and politics kept forging ahead on energy issues. A growing number of publications began looking at the obstacles standing in the way of using energy more efficiently and how energy savings were being canceled out by additional consumption (the “rebound effect”).

Rising prices and new forecasting methods

The scarcity of conventional oil came into focus during the 2000s with the notion of “peak oil” and an increase in the oil price to over 100 US dollars per barrel (nominal). Energy efficiency and renewable energies experienced something of a renaissance in the worlds of politics, society and research. Changes in behavior and also technological developments were difficult to predict.

So, to build a better scientific foundation on which to make such predictions, various methods for making technological forecasts were now combined: For example, by analyzing literature and patents together, it becomes possible to determine the speed at which individual technologies reach maturity, from the initial idea through market readiness. Joint publications also looked at topics such as the regions in which developments were taking place and how stakeholders were interlinked in the early stages. The number of patents in individual regions provided more information on penetration speed.

Given the increasing use of fluctuating renewable energies, electricity demand models were adjusted to respond faster and be more granular in terms of location so they would better suit the increasingly fluctuating, decentralized electricity supply and the options for load transfer. Energy demand models (both optimization and simulation models) based on technology were also refined, taking into account the machines and plant of the future.

The expectation of further increases in energy prices and in greenhouse gas emissions steered research away from purely analyzing what obstacles were hampering an efficient use of energy and toward an examination of which instruments could be used to remove those obstacles.

Price decline and climate targets

Fracking, a new method of extracting oil and natural gas, prevailed in the USA during the 2010s. The excess supply of oil caused its price to drop to around 50 US dollars per barrel and the insights gained from climate research had an even greater influence on energy research and energy policy accordingly. The Fifth and Sixth IPCC Assessment Reports and the Paris Accords, with their goal of limiting global warming to 1.5 °C, were the driving forces behind this. It is not enough to just decarbonize the process of generating electricity — instead, sustainably produced electricity or synthetic sources of energy made from such electricity need to come in as substitutes for fossil fuels in all sectors.

As a result, analyses and models relating to the energy sector were expanded to include sector coupling. Familiar examples are substituting combustion engines with battery-powered electric drives or the blast furnace route in the iron and steel industry with hydrogen direct reduction technology.

The early 2020s have been marked out by Russia’s attack on Ukraine and the profound uncertainty this has unleashed on the energy markets, where prices have risen by as much as four times amid a great deal of volatility, the fear of gas supplies from Russia being disrupted over the winter months, and discussions over whether Germany’s last remaining nuclear power stations should continue running.

It is becoming clear at present that Germany has relied much too heavily on natural gas from Russia and has wantonly neglected its climate change obligations to rapidly expand renewable energies and energy efficiency measures. Expertise within the energy sector is currently laser-focused on how to get through the coming winter without cold homes and industrial shutdowns, with the serious implications they would have for the national economy. Short-term energy efficiency measures, but especially changes in behavior, could have a significant impact here.

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