Setting the right goals for climate protection

The transition to a new energy mix is technically feasible and less expensive than many had feared. But we need to think and act more holistically than before.

Almost half of the electricity in Germany is already generated from renewable energy sources. At certain times, it is even possible to meet the entire German electricity demand using renewable energy. This sounds like a success and an energy transition milestone, but despite these figures and substantial investments Germany will not achieve its climate targets for 2020. Energy is much more than just electricity for example transport and heating still rely mainly on fossil energy.

“We have to think differently than before, more holistically,” explains Hans Jörg Heger, head of the Energy System Modeling research group at Siemens Corporate Technology. “It’s not a matter of promoting or condemning certain technologies. The goal is to reduce CO2 emissions, and there may be very different ways to achieve this. We need to set transparent CO2 targets and then be open to different types of technology when it comes to implementing them. Sector coupling is an important mechanism to reduce CO2 holistically across transport, building and industry sectors.”



Heger and his team have specialized in this holistic view of the energy transition. They use mathematical models to replicate our infrastructures and energy systems in all their complexity. With the help of simulations, they develop measures that are as inexpensive as possible to effectively reduce CO2 emissions. “Siemens is firmly committed to the Paris climate targets. With our simulations, we’re showing how the energy transition can be implemented both technically and cost effectively,” says Heger. “We all know that time is of the essence.”

Time is of the essence

The experts all agree: We burn too many fossil fuels, such as coal, oil, and natural gas. In 2017, we generated around 37 gigatons of CO2 annually worldwide, and the trend is upward (source: European Commission). If we continue like this, in 26 years the atmosphere will have already warmed by more than two degrees. (Source: A 2018 study by the Intergovernmental Panel on Climate Change, a body that works on behalf of the UN If it becomes even warmer, then we have to assume that a climate characterized by drought, heat, and extreme weather conditions – one that will dramatically change people’s lives – will prevail on our planet for the long term.

With digital twin and simulation

Countries and communities are facing a mammoth task, because they have to convert their entire infrastructure – power supply, heating supply, mobility, etc. – while continuing to provide a stable supply to industry and the population. “We use our system models to identify scenarios showing how the energy transition could take place. To do this, we use a digital twin to replicate the energy supply of a region. This gives us a picture of where and how much energy – power, heat, and mobility – is needed,” explains Michael Metzger, also from Siemens Corporate Technology. “Our model takes into account forecasts of how the net energy demand will develop as well as all of the technologies known to us – such as solar installations, wind turbines, electrolysis, etc. – and then uses optimization algorithms to determine measures designed to minimize CO2 emissions as quickly as possible.”


For Germany, for example, the complete energy supply structure of the future was depicted in cooperation with RWTH Aachen University. It was shown down to the last detail, with spatial resolution down to the zip code and municipal level.

“It’s not a matter of promoting or condemning certain technologies. The goal is to reduce CO2 emissions."

The transition to new models for energy, heating and traffic

According to these simulations, the initial steps for the German energy timetable could be roughly outlined as follows: The power grid has to be further expanded. Renewable energy technologies will become increasingly important within this context. The capacity of gas-fired power plants will also need to be increased significantly, as a back-up for periods with insufficient wind or sun. This may seem surprising at first because they generate CO2 emissions as well, but their CO2 emissions are significantly lower than those of coal-fired power plants. Furthermore, they can be decarbonized gradually by using more and more green hydrogen, generated by renewable power.  Siemens has made a commitment that its gas turbines can be co-fired by 20% hydrogen in 2020 and 100% hydrogen by 2030. This approach buys time for the further development of zero-emissions power generation and the electrification of heating and transportation. In this regard, investments should first be made in the modernization of the heating supply. New houses can be equipped with climate-friendly heat pumps at reasonable costs. Since houses are used for many years, it would be preferable for the overall CO2 balance if this type of heating become the standard as quickly as possible. Cars are much more short-lived than houses, which is why the simulation recommends transitioning to e-mobility only after the power generation system has undergone more extensive decarbonization. “All our simulations are optimized for total costs,” clarifies Heger. “This means that the optimizer reviews all the offered technologies and selects the most favorable CO2 reduction measure for each step. The results show that the total system costs for achieving a climate target are not significantly higher than for continuing with business as usual, providing the right measures are implemented at the right time and in the most favorable sequence.”

Flexible adaptation

“The simulation naturally doesn't give us the ability to see into the future,” notes Metzger. “Many assumptions in the models are fraught with uncertainty. Oil prices, for example, are influenced by global economic developments and can hardly be predicted over a period of decades. Our goal therefore is not to predict the future as accurately as possible, but rather to identify the essential levers for achieving our goals that are resilient to these uncertainties.”

“This enables us to sketch out a variety of realistic scenarios of what the energy future could look like,” continues Heger. “From this we can determine how we can properly position ourselves as a technology supplier with a future-oriented portfolio. In addition, we can better advise our customers, and naturally not just in Germany. Our model can be flexibly adapted to other regions as well. We have already received inquiries from France, Australia, Canada, and the Middle East, a region that has made a lot of money selling fossil fuels and is now planning its own energy transition.”

Aenne Barnard 2019-09

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