Where will the electricity come from in 2050?

The Swiss Competence Centre for Energy Research - Supply of Electricity (SCCER-SoE) has examined what this goal means for future electricity demand and what contribution can be made by geothermal energy and hydropower in particular. The focus has shifted from the expansion of renewables at the beginning of the project to a much more extensive problem: By 2050, electricity demand will increase by 30 to 50 percent. This increase must be as climate-neutral as possible, which requires much more comprehensive and, above all, more integral solutions. Negative emissions, whereby CO₂ is permanently removed from the atmosphere, are an indispensable part of this. Therefore the SCCER-SoE also analysed the possibilities for storing CO₂ underground in Switzerland. Also, it is not simply more electricity that is needed; energy has to be available in the right place at the right time. The association of 25 Swiss scientific institutions, industrial companies, and federal authorities has carried out numerous research and innovation projects over the past seven years to bring the electricity supply of the future within reach.

Electricity demand will rise by up to 50 percent

In a joint effort, eight Competence Centres under the direction of the SCCER-SoE have used scenarios to model how electricity supply and demand will come together in the future. The results show that electricity demand will increase by 30 to 50 percent by 2050. Most of this is due to electrification in two areas: transportation and heating. To the greatest extent possible, vehicles of all kinds will be powered electrically and no longer with fossil fuels. This applies not only to private vehicles, but also to public and freight transport. Where this is not possible due to user needs, hydrogen vehicles can be used. For heating purposes, the trend continues to use environmentally friendly heat pumps or wood heating instead of oil and gas heating. Together with comprehensive measures to improve the energy balance of buildings, these are efficient and cost-effective means of reducing CO₂ emissions.

"Overall, our analyses suggest that electricity supply costs are likely to rise despite falling costs for renewables," estimates Peter Burgherr, head of the Technology Assessment Group at the Laboratory for Energy System Analysis of Paul Scherrer Institute.

To meet the increasing demand and, in particular, to compensate for the decommissioning of nuclear power plants, the supply of energy from renewable sources must be almost doubled by 2050. The largest contribution can be made by technologies that use the wind and the sun.

"Photovoltaics has by far the greatest potential for electricity production with renewable energy in Switzerland," says Burgherr. "But harnessing the additional potential of wind, biomass, geothermal and hydropower is crucial for an overall resilient power sector." However, their potential can only be fully exploited if, at the same time, investments are made in sophisticated storage systems to cover fluctuations in demand (hydropower, geothermal energy). These technologies also require support from large portions of the population. Furthermore, even under optimistic assumptions, electricity imports or domestic gas-fired power plants would still be needed to cover the demand, in addition to geothermal energy for direct use of heat or for electricity generation.

Efficiency gains and negative emissions

Besides expanding renewable energy, increasing the efficiency of existing technologies, and taking measures to keep energy consumption as low as possible, Switzerland also needs negative emissions in order to hit the net-zero target. Negative emissions can be achieved, for example, through burning of biomass with subsequent CO₂ capture and long-term storage underground. The latest findings indicate, however, that underground storage options in Switzerland are less than originally hoped; this requires further investigations and, in parallel, clarification of options for storage abroad.

"All renewables allow for 'low-carbon' electricity generation by 2050, with hydropower, wind power and photovoltaics performing best," Burgherr said. In the case of biomass, much depends on the starting material. Also, as with natural gas, this requires a solution for capturing the accumulated CO₂ and storing it over the long term. For the future power supply, therefore, it is not only the expansion of renewables that is crucial, but also the interactions between them and the needed support from society. The climate targets that have been set can only be achieved if comprehensive changes to the entire system are rapidly made.

Hydropower remains the most important energy source

Hydropower is, and in the future will continue to be, the most important domestic energy source in Switzerland. In addition to its direct contribution to the electricity supply, hydropower takes on an important role in energy storage. Pumped storage plants can be filled in times when electricity prices are low, and they can be emptied to generate energy when needed. In addition, large reservoirs can be used for seasonal storage, for example to provide electricity for the winter.

A significant expansion of hydropower in the coming decades is unrealistic due to the high demands associated with such projects in terms of environmental protection and social acceptance. The efficiency of existing systems should therefore be optimised and, if possible, they should be expanded in a sensible and acceptable manner. This also applies to the storage potential, which could be increased by raising existing dams. With the retreat of glaciers, there are also new possibilities for reservoirs, which should be considered in a participatory process.

In any case, action should begin early on any expansions or new developments, since such projects usually take 15 years or more. It is especially important to precisely analyse the ecological footprint of these projects and prioritise them accordingly. For hydropower to make its essential contribution to the climate strategy, efforts are required with regard to the optimisation of existing plants as well as their expansion, new plants, and accompanying research.

Geothermal energy with great potential

In Switzerland, geothermal energy has the potential to cover a large proportion of the heat demand in the future: for heating purposes, hot water, and certain industrial processes. On the one hand, subsoil water can be heated and then pumped. On the other hand, the subsurface can be used to store water that has been heated on the surface, for example by means of excess energy from photovoltaics or waste incineration plants. If the potential is fully exploited, geothermal energy can make an important contribution to decarbonisation in this area.

To exploit this potential for meeting the heat demand and to further explore direct electricity generation using geothermal energy, an even better understanding of what the local subsurface looks like and how it reacts will be required. Also needed is further investigation into which processes and techniques are available for heat recovery. Because the efficiency of geothermal energy increases with depth, investigations at greater depths, such as those carried out in the BedrettoLab at ETH Zurich, are of great importance.

The insights gained within the SCCER-SoE framework provide reasons to be optimistic that geothermal energy could play an important role in the future for heat generation and could possibly contribute to the direct power supply. In any case, a step-by-step approach is recommended that continuously provides deeper insights into the subsurface and also provides information to support the selection and/or design of the process.

To be able to achieve the net-zero target, negative emissions are indispensable. For this purpose, CO₂ can be captured either directly from the air or in the course of industrial processes and then pumped into suitable deep geological formations, where it remains permanently. There, over the long term, it can mineralise and combine with the surrounding rock.

It has to be assumed that the potential for CO₂ storage in Switzerland is lower than previously hoped. To be able to estimate the effective potential, however, further detailed analyses of the subsurface are necessary. At the same time, it is advisable to explore alternative storage facilities abroad, because it is becoming apparent that such storage alternatives will be essential for achieving the net-zero target.

Text based on a notice from ETH Zurich