Energy and Environment by Paul Scherrer Institut

Energy and Environment

Research at the Paul Scherrer Institute

The Paul Scherrer Institute’s experimental platform ESI – short for Energy System Integration – tests renewable energy alternatives in all their complex interplay.

Contents 4

Energy − the fuel of life

A good and lasting charge

“We work both in the context of Switzerland’s Energy Strategy 2050”

Insights into the atmosphere

High above

Bad air in Delhi

From the big to the small

Mobile monitor

The heart of the matter

The Energy System Integration Platform ESI

Like a sponge for hydrogen

Simulations make nuclear plants safer

Safely sealed away

Storing energy in gas

A question for the future

Producing hydrogen

Methanation

White paper on Power-to-X

Hotlab: Knowledge from the hot cells

High-value hydrogen

Energy systems: The holistic view

Clean energy, courtesy of fuel cells

Energy mix of the future

Tomorrow’s mobility

The facilitators

PSI in brief

Clean emissions thanks to a

Imprint

sponge-like structure

Contacts

Moving away from “dirty diesel”

Splitting water

Green fuels for aviation

Molecular helpers

8 One platform – many energy systems 10

Cover image Fuel cell research at PSI 3

Energy − the fuel of life How to sustainably generate and store energy is a crucial question for the future of every society. Research at PSI helps to find answers to these ques-

• Holistic assessment of energy systems • Effects of energy use on the climate and atmosphere.

tions of tomorrow today. The aim of the PSI researchers is to achieve the highest possible efficiency Every living being needs energy in the

in energy generation, energy use, en-

form of food. In addition to food, hu-

ergy storage, and their environmental

mans consume far greater amounts of

impact while at the same time conserv-

energy: in private households, in the

ing resources. To do this, it is necessary

economy, and for mobility. If the global

to know the materials used in precise

primary energy demand were to be met

detail as well as their behaviour under

exclusively with crude oil, more than

various operating conditions.

135 trillion tonnes would be required.

The research infrastructure at PSI offers

Switzerland’s share of this would be

ideal conditions for this. Large research

more than 26 million tonnes, or just

facilities such as the Swiss Light Source

under 0.2 percent.

SLS, the X-ray free-electron laser SwissFEL, the Swiss spallation neutron

Energy comes in different forms, for

source SINQ, the Swiss research infra-

example:

structure for particle physics CHRISP,

• as electrical energy in

and the Swiss muon source SμS allow

the form of electricity

deep insights into the smallest struc-

• as thermal energy in

tures of materials. The Energy System

the form of heat

Integration Platform, ESI for short, the

• as kinetic energy in

Hotlab, and new high-performance

the form of movement.

computing systems also help PSI researchers achieve crucial advances

The different forms of energy can be

towards securing a sustainable energy

converted into one another. PSI re-

supply.

searchers are working on developing

In addition to physical and chemical

the most efficient methods possible for

research on substances and processes,

generating, storing, and converting en-

the modelling of new materials and the

ergy.

simulation of energy systems are of

They focus on the following areas:

great importance.

• Research into sustainable energy sources such as biomass • Efficient conversion between energy sources for storage and recovery of energy for heat, electricity, and mobility • Safe use of nuclear energy • Safe disposal of radioactive waste 4

Sustainably generating, converting, and storing energy – a research goal for today and tomorrow.

“We work both in the context of Switzerland’s Energy Strategy 2050” In person Andreas Pautz (born in 1969) has headed the Nuclear Energy and Safety Research Division at PSI since 2016 and he is Professor of Nuclear Technology at EPF Lausanne. He studied physics at the University of Hanover and the University of Manchester and received his doctorate in nuclear engineering from the Technical University of Munich. Thomas Justus Schmidt (born in 1970) has been head of the Energy and Environment Research Division at PSI since January 2018. He studied chemistry at the University of Ulm, Germany, where he received his doctorate in the field of electrocatalysis of fuel cell reactions. He is also Professor of Electrochemistry at ETH Zurich.

Professor Schmidt, you head up the

important tasks to perform: the Energy

Pautz: Exactly, our aim is to ensure

PSI Research Division Energy and En-

and Environment Division needs to

optimal interplay with a view to avoid-

vironment, and Professor Pautz, you

push forward with renewables, while

ing potential environmental impacts as

oversee the Nuclear Energy and Safety

we have to solve the problem of how

much as possible and minimising

Division. What are the differences be-

to ensure nuclear power stations con-

costs. We look at this purely from a

tween your two fields of research, and

tinue to operate safely up to 2040 –

scientific angle; we are not engaging

what do they have in common?

possibly even well beyond – and lastly,

in political discussions. The decision

Schmidt: The Energy and Environ-

how to safely dispose of radioactive

not to limit the lifetime of existing nu-

ment Division researches the produc-

waste. We play our part in maintaining

clear power stations effectively makes

tion, conversion and storage of energy

high safety standards throughout and

them an integral part of the country’s

from renewable sources, as well as

minimising the nuclear legacies for

energy strategy. By the way, there is no

addressing the consequences our en-

future generations to deal with.

other scientific institute in Switzerland where so much research is conducted

ergy use has for the environment and atmosphere. Our research does not

So, you don’t see each other as rivals,

into energy as at PSI, in other words

cover nuclear energy, however.

championing different energy sources?

where so many researchers are concen-

Pautz: That is our expertise. But we

Schmidt: Not at all. We work closely

do have some common ground: we

together and in doing so have to keep

always work within the context of Swit-

an eye on time scales when it’s time to

zerland’s Energy Strategy 2050. During

replace one technology with a different

this transition phase, we both have

one.

trated in such a small space. Do you also work on joint projects? Pautz: Certainly. For example, we work together on the SURE project,

Research divisions in comparison Energy and Environment (ENE)

Nuclear Energy and Safety (NES) Employees

220

190 PhD students

whose aim is to determine how we can

build a secure and resilient energy supply for the country over the coming

Third-party industry funding

years. This involves much more than

CHF 2 million

CHF 10 million

just minimising CO2 emissions, but other aspects such as reliability of sup-

Scientific publications/year

ply, network stability, and defence

275

250

against external and internal threats. Schmidt: We carry out this research

Plants in operation

in a joint PSI lab, the Laboratory for

Energy Systems Analysis. This specialises in holistic analyses of the entire energy system. Transport, industry, private households, electricity gener-

Swiss employees is shrinking. But we

Schmidt: Amongst other activities,

ation – everything comes together

have an excellent international reputa-

we have reduced our research into

here.

tion and thus enjoy strong demand.

combustion technology. Although this

Together with EPFL and ETH Zurich, we

used to be an important topic, it now

Is more scientific objectivity necessary

offer a Master’s course in Nuclear En-

has a limited future. On the other hand,

in the discussions about the energy

gineering, for example. Every year on

we have taken on several new topics,

transition and the various ways of

average 15 students start this course,

such as hydrogen production. Another

achieving it?

and more than 20 have enrolled this

issue that has become more important

year. This shows nuclear energy still

is the impact of our energy use on the

has a role to play internationally.

climate. For example, what effects do

Pautz: More objectivity in the energy debate would be extremely help-

aerosols have on the atmosphere and

ful. We simply need to carefully weigh up the facts currently available – such

Do you often hear the criticism: “Swit-

as those concerning climate change or

zerland wants to discontinue nuclear

Pautz: The long-term operation of

security of supply – to reach a lev-

energy, so why is PSI still researching

nuclear power stations tops our

el-headed assessment.

it?”

agenda, as well as the final disposal of

the human health?

Schmidt: This also underlines the

Pautz: Hardly ever. No one disputes

nuclear waste and the dismantling of

importance of the holistic approach we

that specialists are needed for the next

decommissioned plants. Since it be-

adopt at PSI in order to understand

25 years at least, partly to solve the

came clear that Switzerland plans to

energy systems as a whole. Only a few

problem of radioactive waste disposal.

phase out nuclear energy, we have

other places in the world follow this

The need for Switzerland to maintain

suspended activities that are related

approach.

its nuclear expertise is also widely rec-

to constructing new power stations,

ognised in political circles. When it

such as the development of new fuels.

Is it difficult for you to attract young

comes to nuclear technology, Switzer-

We are only marginally involved in in-

scientists in your area of research?

land should also be able to defend its

vestigating new safety systems. In fu-

position as a global player and draw on

ture, I’d really like to see industry and

a deep pool of know-how.

research collaborations becoming

Schmidt: No. Our international outlook helps: people from around 45 different countries work in the Energy and Environment Division. Pautz: The same applies for my division, even though the number of

much more international. We want to What has changed in your field of re-

continue to capitalise on PSI’s strong

search over the past years and what

international reputation in nuclear en-

do you expect for the future?

ergy research. 7

One platform – many energy systems Energy systems around the world are under construction. More and more, this involves the so-called “new” renewable energy sources: sun, wind, and biomass. In Switzerland, too, their share of the energy supply is increasing and should continue to do so. In order to increase efficiency, research and development of new materials and processes will be necessary – both in the production of energy from renewable sources and in its distribution and use.

With its Energy System Integration Platform, PSI offers a unique combination of different energy systems in one place and thus excellent opportunities to investigate processes for efficiently generating, storing, and converting energy. PSI is working in close cooperation with partners from research and industry to investigate and further develop different variants of energy storage as well as the energy-efficient use of biomass, and to assess their technical and economic feasibility (see also “Storing energy in gas” on page 12f.). With the help of the ESI Platform, a process was developed that enables significantly more methane to be generated from biomass, for example from household biowaste. Methane is the main component of conventional natural gas and therefore a proven energy source. Methane is usually produced from biowaste through microbial processes known as fermentation. In this process, however, large amounts of carbon dioxide are also generated. The mixture of the two gases – that is, the raw biogas – consists of 60 percent 8

The ESI Platform enables research on how excess renewable energy from wind and sun can be stored and made available again when required. The individual elements of the ESI Platform are housed in containers so that they can be used flexibly on-site.

methane and 40 percent carbon diox-

methane. The resulting end product is

360° for this important contribution to

ide. The latter is usually separated from

of such high quality and so closely re-

a sustainable energy supply with the

the methane in a costly process and

sembles commercial natural gas that it

Swiss Energy Prize Watt d’Or; they were

not exploited any further.

can be fed directly into the gas network.

jointly named winners in the Renewa-

PSI researchers have succeeded in con-

In a joint project with the Zurich-based

ble Energy category.

verting this carbon dioxide into meth-

energy provider Energie 360°, the PSI

ane by adding hydrogen directly to the

researchers tested the technology they

raw biogas. For this they need, among

had developed under real conditions.

other things, catalysts – substances

With the mobile Cosyma system, which

that make the conversion of one chem-

converts hydrogen and carbon dioxide

ical compound into another possible

to methane, they were able to show

in the first place – so that hydrogen and

that the new process is very well suited

carbon dioxide combine with each

for use on an industrial scale. Even the

other to form methane (see: “The facil-

experts at the Federal Office of Energy

itators” on page 16f.). The carbon diox-

were impressed by the new process for

ide contained in the raw biogas is al-

efficient methane production from bi-

most completely converted into

omass. They awarded PSI and Energie

Synergy in service of energy research In the ReMaP project, led by ETH Zurich, the ESI Platform is virtually interconnected with the demonstrators from the Federal Materials Testing and Research Institute (Empa). Together with the Empa platforms NEST (future buildings), move (future mobility) and ehub (energy networks at neighborhood level), the ESI Platform offers a unique experimental setup for research and industry to provide the knowledge and technical fundamentals needed to develop the energy systems of the future.

The Energy System Integration Platform ESI 1

Mini gas turbine

The miniature gas turbine converts methane into electricity and heat. This makes it possible to generate electricity when the wind isn’t blowing and the sun isn’t shining. Using the mini gas turbine, the researchers are investigating how much hydrogen they can add to the methane while keeping the conversion safe and efficient. That’s because hydrogen is easy to obtain, burns quickly, and could help to react to rapid changes in load.

GanyMeth

In this reactor, methane is produced from hydrogen and carbon dioxide. The product is also called synthetic natural gas (SNG). The reaction takes place in a fluidised bed reactor with the help of catalysts (see “The Facilitators” on page 16f.). In the reactor, solid particles carrying a catalyst are constantly swirled around by an upward flow of gas, creating a good mixing where the reaction can take place.

HydroPilot

In a pilot plant, PSI is con ducting research on the hydrothermal gasification of wet biomass with supercritical water. Waste with a high water content, such as sewage sludge, coffee grounds, and liquid manure, is exposed to high pressure and temperature. This creates a high-quality gas from the waste, similar to biogas. The project investigates processes similar to those being studied at Konti-C, but on a larger scale in order to simulate conditions closer to industrial practice.

Gas tanks

hydrogen tank (4) carbon dioxide tank (5) oxygen tank (6)

Electrolyser

Hydrogen and oxygen are produced from water with the help of electricity.

7 8 6 9

Supply lines n biogenic residues n carbon dioxide (CO2) n hydrogen (H2) n oxygen (O2) n electricity n (synthetic raw) biomethane n water (H2O) n air n wet biomass

Cosyma

Raw biogas from a biogas plant contains only about 60 percent methane; the rest is carbon dioxide. The test facility Cosyma (Containerbased System for Methanation) processes raw biogas by adding hydrogen, which reacts with the carbon dioxide. This increases the methane yield. This process is called direct methanation.

Konti-C

This test facility examines how energy can be obtained from wet biomass – liquid manure, sewage sludge, or algae. At high temperatures and pressures, the biomass is converted into synthetic biogas, i.e., methane. The advantage is that the biomass does not have to be dried beforehand, because that requires a lot of energy and often makes processing economically unprofitable.

10 Control room and visitors platform

Gas purification/drying

Here, hydrogen and oxygen from the electrolyser are dried and purified so that they can then be pumped into storage tanks.

Fuel cell

The fuel cell generates electricity from hydrogen and oxygen. This creates water. Since a fuel cell system alone generates too little electricity, four systems, each consisting of 236 individual cells, are interconnected in this container. This is how an industrial environment is simulated.

Storing energy in gas One problem with wind and solar power

drastically reducing its direct emis-

is that their sources are not always or

sions of greenhouse gases. According

uniformly available. When there is

to the Energy Strategy 2050, Switzer-

enough wind, wind turbines produce

land aims to reduce greenhouse gas

plenty of electricity; when it’s calm, this

emissions by 50 percent by 2030 com-

source dries up. Similarly, the irradia-

pared to 1990 levels, and up to

tion of sunlight changes not only in a

85 percent by 2050. After 2050, the

day-night rhythm, but also depending

energy supply in Switzerland should

on the weather and the season.

be completely climate-neutral. In order

A reliable energy supply therefore

to achieve this goal, the new renewa-

needs effective energy storage devices:

ble energy sources – biomass, wind,

They conserve the energy gained during

and solar power – are crucially impor-

high-production phases and release it

tant, as is the question of how the

when there is not enough wind or sun-

energy they produce can be stored.

shine. One method that is used here is

power supply cathode – hydrogen

+ anode

e–

oxygen

e–

membrane

Switzerland has set itself the goal of

H+

e–

In proton exchange membrane electrolysis (PEMEL), electrical current causes water to break down into its components hydrogen and oxygen at the anode. First, oxygen and positively charged hydrogen ions (protons) are created. These migrate through the membrane, which is only permeable to them, and combine with electrons at the cathode to form gaseous hydrogen.

fluctuating electricity production from renewable energy sources H2

ELECTROLYSIS

H2 H2

METHANATION

CH4

natural gas network

gas storage

called power-to-gas. Electric power, for example from wind or solar energy, is used to generate gases such as hydro-

industrial use

mobility

electricity generation

heat supply

gen or methane. These gases serve as energy stores and feed their energy content back into the energy supply when required.

Vehicles with a fuel cell can be operated with hydrogen (see page 15). The gas can also be fed into the natural gas network. Industry, in turn, can use it to maintain its production processes: Hydrogen is an important raw material, for example in the manufacture of nitrogen fertilisers in the chemical industry, or in the “cracking” of hydrocarbons in oil refineries.

Producing hydrogen Hydrogen is produced through the electrolysis of water, among other means. In principle, electricity is fed into water,

which then breaks down into its com-

direct methanation. The hydrogen is

energy systems” on page 8f ). The

ponents hydrogen and oxygen. There

not combined with pure carbon diox-

higher methane yield thus conserves

are different processes for electrolysis.

ide, but with biogas, which already

resources and preserves the environ-

PSI uses proton exchange membrane

consists largely of methane but still

ment.

electrolysis (PEMEL, see page 12).

contains a comparatively high propor-

Both in the production of hydrogen and

tion of carbon dioxide. Additional

in methanation, auxiliary substances

methane can also be generated directly

are used that make the reactions pos-

from carbon dioxide in this gas mixture

sible in the first place. These are cata-

with the addition of hydrogen, thus

lysts, which are also the subject of in-

significantly increasing the methane

tense research at PSI (see page 16f.).

Methanation Another option for temporarily storing

content in the biogas, up to natural gas

energy in gas is called methanation.

quality. PSI researchers have devel-

The gas methane, the main component

oped a new process for this and showed

of conventional natural gas, is gener-

that up to 60 percent more bio-meth-

ated from hydrogen and carbon dioxide.

ane can be obtained from biogas from

One special case of methanation is

biowaste (see “One platform – many

White paper on Power-to-X Scientists at PSI, together with colleagues from six Swiss universities and research institutions, have compiled extensive information on various aspects of Power-to-X technologies. This is the name given to technologies that allow electric power to be stored in other forms of energy, for example chemical energy carriers, in times when there is a surplus of electricity. In a white paper, the researchers have summarised the potential that Power-to-X processes have to help realise Energy Strategy 2050, the challenges the technology is facing, and the key factors favouring its widespread use. The white paper was commissioned by the Swiss Federal Energy Research Commission (CORE), drawn up by the partners of the Swiss Competence Centre for Energy Research (SCCER) Heat and Electricity Storage, Biosweet, Crest, Furies, and Mobility, and financed by the Swiss Agency for Innovation Promotion Innosuisse and the Federal Office of Energy (SFOE). One conclusion: The contributions that Power-to-X can make in individual energy sectors such as transportation and heating or through reconversion are very different. Thus the re-conversion of electricity from energy sources such as hydrogen or methane generated using Power-to-X processes is currently still very expensive. However, the costs for such processes – also known as power-to-power – could fall by up to two-thirds by 2030 due to technological advances and increasing experience in dealing with these technologies. Fuels that are produced using electricity from renewable energy sources in Power-to-X processes can replace fossil fuels such as heating oil, natural gas, petrol, and diesel and thus help to reduce carbon dioxide emissions. However, this will only be economical if appropriate environmental incentive mechanisms come into play.

Download “Power-to-X: Prospects for Switzerland” at https://bit.ly/3ASe4UC

High-value hydrogen Hydrogen is the most abundant ele-

of the entire conversion chain and

changes with more hydrogen in the fuel

ment in the universe. On the earth it

opening up a wide range of storage

gas mixture. A look into the past shows

plays an important role in life and in

options. Studies with gas burners have

that gas networks can be made fit for

the natural energy cycle. In the energy

shown that up to 20 or even 30 percent

high hydrogen proportions: Up to

system of the future, it will be created

hydrogen can be added to methane

around 50 years ago, municipal gas was

using power-to-gas processes, drive

without the gas burners being damaged

widespread in Switzerland and con-

fuel cells, or be fed into the existing

by local overheating. Therefore, the PSI

tained up to 50 percent hydrogen.

natural gas network.

researchers want to find out if small gas turbines could also handle that much hydrogen, and how they would react to

Hydrogen is already being fed into the

short-term demand peaks with a higher

natural gas network, albeit in a very

hydrogen content. The scientists hope

small proportion. In a further step,

that since hydrogen is very reactive and

hydrogen can also be converted into

burns very quickly, the turbine might

methane – the main component of

even respond better to rapid load

natural gas. PSI researchers are now using a miniature gas turbine to test how the proportion of hydrogen in the natural gas mixture can be increased. In its housing, the system is no bigger than a wardrobe, and it delivers an electrical output of 100 kilowatts. This could cover the power requirements of a small neighbourhood with around five to seven single-family houses – in line with the trend towards decentralising the power supply. The mini gas turbine is a commercial product and a typical system for cogeneration of heat and power that can be used in hotel complexes, residential areas, and campsites to supply the local infrastructure with electricity and heat. In the future, it will be possible to produce hydrogen in an environmentally friendly way with the help of electrolysis (see page 12) if enough electricity is available from new renewable energy sources. If more hydrogen can be used in natural gas, the conversion step from hydrogen to methane would no longer be necessary, increasing the efficiency 14

This mini gas turbine, part of the ESI Platform, converts methane into electricity and heat. PSI researchers are using it to test how the pro portion of hydrogen in the natural gas mixture can be increased.

Clean energy, courtesy of fuel cells gen, can pose a practical problem for fuel cell-powered motors. In colder climates, the water can freeze when the motor is switched off, thus impairing the function of the fuel cells. PSI researchers have directly mapped the distribution of ice and water in a fuel cell with the help of the spallation neutron source SINQ. They also checked how a specially developed material could better drain off the water produced. With the help of the Swiss Light Source SLS, PSI researchers also investigated how the polymer electrolyte membrane of a fuel cell wears out. A better understanding of these processes in fuel cells will help in the development of improved materials and methods for their use in the energy system. When we breathe, we take in oxygen

insights into the interior of the fuel cells

into our body. We need this vital gas to

and the materials used. This gives the

generate energy. One reaction involved

researchers a fundamental understand-

in this is the combination of hydrogen

ing of the processes in the fuel cell and

and oxygen to form water. This is ex-

enables them to improve this technol-

actly what happens in a fuel cell.

ogy in a very targeted manner. For example, water, the waste product from the reaction of hydrogen and oxy-

A fuel cell generates electricity from a fuel and oxygen. The fuel is usually hydrogen, but it can also be methanol, butane, or natural gas. When hydrogen reacts with oxygen, energy is released and water is created. In this way, a fuel cell provides carbon dioxide-free, clean

Anode Hydrogen

–

+ Cathode Oxygen

–

PSI has been involved in various stages

e– PEM e– e– (protonexchange membrane) e–

of fuel cell research for many years: from

H+

the optimisation of individual compo-

nents to the investigation of complete

H+

fuel cell systems. At PSI, researchers can

H+

energy.

carry out studies with the help of large

e–

Principle of the PEM fuel cell: At the anode, under the release of electrons, hydrogen is oxidised to protons (H+), which migrate through the membrane. At the cathode, oxygen is reduced by electrons (e–), and water is created. Anode and cathode are switched on to an electrical consumer; electricity flows.

Water

research facilities – particle generators and accelerators – which provide unique 15

The facilitators

At PSI researchers are developing more efficient catalysts as well as the necessary substrates.

Catalysts are substances that accelerate

carbon dioxide to more energy-rich

a chemical reaction, make it more effi-

methane at moderate temperatures,

cient, or even make it possible in the

you need catalysts. The element nickel

first place. In biology, the role of cata-

is particularly suitable for the reaction

from being able to use time-resolved

lysts is played by enzymes. These are

of carbon dioxide with hydrogen to form

X-ray spectroscopy at the Swiss Light

natural protein molecules that enable

methane. It is used in direct methana-

Source SLS to observe the course of

humans, for example, to convert starch

tion, a technology developed at PSI to

chemical reactions. This has a crucial

into sugar. Catalysts are also invaluable

significantly increase the methane

advantage over conventional methods:

in industry.

yield in the fermentation of biowaste

Instead of just snapshots, the progress

(see pages 8, 9 and 13). The catalyst

of the reactions can be captured and

ensures that carbon dioxide and hydro-

shown. It is important to understand

As the end product of many combustion

gen combine to form methane and

exactly how the processes change over

processes, carbon dioxide is a compar-

water.

time, because temperatures and the

atively inert gas that does not like to

In the investigation and optimisation

quantities of precursor materials can

react with other substances. To convert

of catalysts, PSI researchers benefit

vary during a chemical reaction.

Clean emissions thanks to a spong-like structure

of surface area. If the palladium is finely

to the catalytic converter in order to

distributed in it, it can react even better

keep nitrogen oxides in the exhaust gas

with the exhaust gases – the pollutant

as low as possible at all times.

Catalytic converters perform valuable

emissions are significantly reduced.

services in filtering exhaust gases. Researchers at PSI are working to develop catalytic converters with higher performance for petrol-burning cars. In a vehicular catalytic converter, the exhaust gas is routed through a large

Getting away from “dirty diesel”

Splitting water One energy carrier of the future is hydrogen: It can be stored in tanks and

number of parallel ceramic ducts. Their

In diesel engines, harmful nitrogen

later converted back into electrical en-

surface is coated with the actual cata-

oxides are produced when the fuel is

ergy, for example in fuel cells. Hydrogen

lyst. It usually consists of finely distrib-

burned. To reduce this, gaseous am-

is obtained from water in so-called

uted particles of precious metals, often

monia is added to the exhaust gas,

electrolysers with electricity (see page

palladium on a carrier substance. De-

which, activated by a catalytic con-

12). PSI researchers have developed a

pending on the type of engine, how-

verter, reacts with the nitrogen oxides

new material that acts as a catalyst and

ever, quite large amounts of the main

to form harmless nitrogen and water.

accelerates the splitting of the water

component, methane, can be left over

The catalyst in this case is copper on a

molecules.

after burning natural gas or biogas. This

zeolite framework. However, the pro-

The PSI researchers’ goal is to create a

is not easy to break down using con-

cess does not yet work optimally at low

catalyst that is both efficient and inex-

ventional catalysts.

temperatures.

pensive because it works without pre-

In tests conducted by the PSI research-

The researchers investigated the struc-

cious metals. To do this, they are going

ers, zeolites proved to be the most

ture and function of a copper-zeolite

back to a well known material: per-

suitable for this purpose. These are

catalyst under realistic operating con-

ovskite, a complex compound of the

highly porous substances based on

ditions at SLS. The most important

elements barium, strontium, cobalt,

silicon dioxide. Under the microscope

finding: A stepwise addition of ammo-

iron, and oxygen.

they look like a sponge: criss-crossed

nia allows a faster reaction than a con-

They were the first to develop a process

by many tiny holes that are connected

stant dose. From this, recommenda-

that produces perovskite in the form of

to one another by channels. Such a

tions can be derived as to when and

tiny nanoparticles. This is the only way

structure offers an enormous amount

how much ammonia should be added

it can work efficiently, because a catalyst needs the largest possible surface area. If the particles of the catalyst are

Due to their sponge-like structure, zeolites are excellent substrates for catalysts. Metals finely distributed within their scaffolding can react particularly effectively with exhaust gases.

made as small as possible, their surfaces add up to a larger total surface. The new manufacturing process yields large quantities of the catalyst powder and should be easy to adapt to an industrial scale.

Green fuels for aviation In the “SynFuels” initiative, scientists at PSI and its partner Empa are jointly developing a method of producing kerosene from renewable resources. They aim to produce top-quality liquid fuel mixtures that burn with as few residues as possible, making them suitable for aircraft propulsion.

Together, the two Swiss research institutes are looking for ways to combine carbon dioxide and hydrogen to form longer-chain molecules and thus produce synthetic fuels. Making such fuels suitable for an aircraft engine is an ambitious but very worthwhile goal: aviation fuels are the highest quality fuels around. If they can be manufactured from renewable resources, it will also be possible to synthesise all other types of fuel using the same method. Kerosene is a mixture of hydrocarbons with very precisely specified chemical and physical properties, which must be strictly maintained in order to ensure economical and safe flight operations. A synthetic fuel must of course

Molecular helpers

Another important part of the project is analysing the ecological footprint of

have the same properties. The starting materials for the manufac-

The key to success will be catalysts (see

the fuels produced, determining how

turing process to be developed are

page 16, The facilitators). These are

much they can contribute to reducing

carbon dioxide and hydrogen. The car-

designed to enable the step-by-step

greenhouse gas emissions in Switzer-

bon dioxide comes from various

conversion of carbon dioxide and hy-

land and how economical they are to

sources, such as biomass, directly from

drogen into liquid hydrocarbons at the

manufacture.

the surrounding air or from industrial

molecular level.

processes, such as cement production.

The Swiss Light Source SLS is an indis-

The hydrogen required is produced

pensable tool in the “SynFuels” pro-

from water with the help of renewable

gramme. This large research facility

electricity. The liquid fuel is synthe-

provides insights into the reaction

sised via one or more intermediate

mechanisms, or scientists can use it to

products, such as methane, carbon

study how the catalysts change during

monoxide, methanol, ethene or dime-

use and how these changes affect the

thyl ether.

range of products.

A good, long-lasting charge Electricity provides light and warmth,

graphite, the material most commonly

A deep look inside a completely differ-

powers most household appliances,

used for electrodes in commercially

ent type of battery, so-called solid-state

and supplies our entertainment de-

available batteries. By cleverly optimis-

batteries, also revealed potential for

vices with energy. Electricity is also

ing the graphite anode – the negative

improvement. This type of battery

gaining in importance because of

electrode – in a conventional lithi-

works completely without liquids,

changes in mobility and new transpor-

um-ion battery, the researchers tripled

which in conventional batteries are

tation concepts. Electricity can be

the storage capacity that can be used

responsible for transporting the charge.

stored in batteries, also known as ac-

at high currents under laboratory con-

Since these liquids are flammable,

cumulators, and thus can also be used

ditions. Adding silicon further in-

solid-state batteries have the potential

on the move. This poses challenges for

creased the usable storage capacity.

to make electromobility significantly

electricity storage systems, which PSI

PSI researchers also achieved a sub-

safer. X-rays at PSI’s Swiss Light Source

researchers are working to solve.

stantial increase in performance with

SLS gave researchers unparalleled in-

another type of lithium-based battery.

sights into the processes that take

Lithium-sulphur batteries can theoret-

place in a solid-state battery during

One problem that arises with all mobile

ically deliver significantly more energy

both charging and discharging. This led

energy storage systems – whether in

than conventional lithium-ion batter-

to better understanding of the damage

smartphones, tablets, laptops, or elec-

ies, but today’s prototypes exhibit a

that such batteries sustain, which in

tric vehicles – is their storage life. The

noticeable loss in capacity after just a

turn should help in the development of

question is not only how rapidly energy

few charging cycles. The researchers

better energy storage systems for the

can be stored and accessed, but also

found that optimisation of the elec-

future.

how often, how reliably, and how much.

trode structure could increase the num-

Researchers in the PSI Laboratory for

ber of charging cycles considerably.

Electrochemistry are working to improve existing systems, for example those based on lithium, while also developing new storage systems based on other elements such as sodium. With the help of the large-scale research facilities at PSI, scientists can look inside materials and track the processes that occur during charging and discharging, for example, down to the level of individual atoms. In doing so, they take into account all components of a battery, from the contacts through which electricity flows in or out to the storage material that holds the electrical energy. Thus one research group at PSI, in cooperation with researchers from ETH Zurich, succeeded in developing a new

The Swiss Light Source SLS enables direct insights into the processes inside a battery.

process to significantly improve the performance of electrodes made from 19

Insights into the atmosphere When we produce or use energy, we

the earth as a unique climate archive,

always influence our environment, es-

PSI researchers are participating in the

pecially the earth’s atmosphere. That

international Ice Memory project.

is why PSI is doing research on pro-

Within the framework of this project,

cesses in the air – both close to the

ice cores are being extracted worldwide

earth’s surface and at an altitude of

and then stored in a warehouse in the

several thousand metres. Knowing

Antarctic, protected against climate

about this helps to make the right

change and rising temperatures.

decisions when it comes to controlling

With the help of ice cores from the Alps,

air pollution.

PSI researchers have shown for the first time that industrial soot can hardly be responsible for the melting of the Al-

What do the Arctic and Antarctic, big

pine glaciers, which mainly took place

cities like Beijing or New Delhi, and the

between 1850 and 1875. It was not until

Swiss Jungfraujoch have in common?

around 1875 that the soot content in the

PSI researchers work at all of these lo-

air exceeded its natural level and could

cations. They measure environmental

therefore be traced back to human ac-

factors and collect data to get a better

tivities. Before that, the soot came

picture of what is going on in the atmos-

mainly from natural sources, especially

phere.

from forest fires.

In the Alps, PSI researchers extract ice cores from glaciers. These contain trace substances from the atmosphere of times long past. By analysing their com-

High above

position, researchers can determine trends in climate history. This in turn

At around 3,500 metres above sea level,

enables them to make forecasts for the

in the research station on the Jungfrau-

future development of our climate. In

joch, PSI researchers examine, among

order to preserve this cold memory of

other things, aerosols that are generally

PSI’s smog chamber is a partner within the infrastructure programme EUROCHAMP-2020, an international programme for the integration of European simulation chambers in order to investigate atmospheric processes. This programme supports researchers in gaining access to state-of-the-art smog chamber facilities in Europe, including the PSI smog chamber. EUROCHAMP-2020 offers researchers the opportunity to bring their instruments and their specialist knowledge to various simulation chambers for measurement campaigns and instrument tests. www.eurochamp.org

In the smog chamber at PSI researchers can study how particulate matter is produced from gases and solid particles and how it changes in the atmosphere.

Aerosol research on the Jungfraujoch helps, among other things, to better understand how soot particles turn into cloud droplets at different times of the year.

better known as particulate matter.

lises like Delhi in India. There they

These, too, influence the climate. Un-

measure 20 to 30 times higher concen-

like the greenhouse gases carbon diox-

trations of pollutants than in Switzer-

chamber can be irradiated with ultravi-

ide and methane, they do not always

land – mainly from human sources.

olet light, which corresponds to the UV

contribute to warming, but can also cool

With their devices and analyses, the

component of sunlight. In this way,

the climate. Some absorb sunlight,

scientists uncover which sources and

scientists can observe and analyse pro-

heating themselves up as a result, and

processes produce how much particu-

cesses that normally take place in the

thus contributing to the warming of the

late matter and what steps could there-

atmosphere under controlled condi-

atmosphere. Others scatter light back

fore improve the situation.

tions.

into space, so they have a cooling ef-

This has already been achieved in

fect. In addition, cloud droplets form

China: There PSI researchers have

on aerosol particles. Thanks to the high

shown that the smog in Beijing consists

altitude of the Jungfraujoch, it is very

to a large extent of secondary particu-

easy to study how the short-lived par-

late matter, to which distant sources

Energy production goes hand in hand

ticles change on the way from the

also contribute. In addition to on-site

with emissions in the form of particu-

earth’s surface to the higher layers of

measurements, they also carried out

late matter and gases. The climate and

the atmosphere and ultimately influ-

experiments in the “smog chamber” at

health effects that arise as a conse-

ence the formation of clouds there.

PSI and imported a Chinese stove and

quence result from an enormous num-

coal for this purpose. Their findings

ber of complex processes in the atmos-

helped to improve air quality in Beijing

phere. To assign the effects of energy

through government measures.

production to specific sources or pro-

Bad air in Delhi

From the big to the small

The heart of PSI’s smog chamber is a

cesses or to project effects into the

PSI researchers work at a location with

27-cubic-metre cube made of thin Tef-

future, we need not only the diagnosis

much higher temperatures than at the

lon film. Specific gases can be directed

in the atmosphere but also experiments

poles of the earth or in the Alps when

into this space. To simulate the natural

in the laboratory that make it possible

they study the air in gigantic metropo-

environment as well as possible, the

to understand individual physical and

chemical phenomena in detail. This

it was archived in a glacier. Finally, they

Mobile monitor

involves not only smog chambers, but

come to understand the interaction of

To study the environment not only in

also reactors in the laboratory that are

dissolved substances on the surface of

individual locations, researchers can

equipped with the latest analytical

the water, for example when a cloud

use the so-called smogmobile. This

methods.

droplet forms. Another experiment

vehicle can be equipped with many

That’s where the large research facili-

makes it possible to take an X-ray view

different measuring instruments. Dur-

ties at PSI come into play. PSI research-

inside particulates to see how they are

ing measurement runs, it can be used

ers have set up infrastructures at the

structured, or how they change their

to examine the spatial as well as the

Swiss Light Source SLS to investigate

structure under the influence of a chem-

temporal distribution of pollutants in

processes on the surfaces of particulate

ical reaction or changed environmental

the air.

matter, ice, or water at the molecular

conditions. These experimental facili-

level. In this way, they come to under-

ties are also available to external users

stand how water molecules organise

to address questions at the interface

themselves on the surface of an ice

between environmental research and

grain. Or they gain insight into the fate

physical chemistry.

of nitrate, a breakdown product of nitrogen oxides, on the ice surface before

PSI’s smogmobile. Various devices, including an apparatus that draws air through the pores of a filter, can be installed in it. Researchers can then analyse the accumulated material.

The heart of the matter Switzerland will phase out nuclear energy – this is what the Energy Strategy 2050 stipulates. The last nuclear power plant is expected to go offline in around 25 years. Beyond this point in time, knowledge about dealing with nuclear energy and all safety-relevant aspects is expected to be preserved and improved through research. Only in this way can valid facts be kept available in the future so that Switzerland can continue to make good decisions with regard to nuclear energy, nationally and internationally, and have a say as a competent discussion partner.

The researchers in PSI’s Nuclear Energy and Safety Division are working on the following tasks: • acquiring new scientific knowledge on nuclear safety • further developing the most modern simulation methods for safety assessments • assessing and/or updating nuclear safety criteria to reflect changes in power generation strategies, technological developments, modernisa-

fuel rods, especially the cladding tubes

tion, and long-term operation

that enclose the actual uranium oxide

Like a sponge for hydrogen

• developing experimental facilities

fuel, behave during operation and after

For example, the Nuclear Fuels group

together with the most modern in-

their use? What would happen in the

found out how the integrity of the clad-

strumentation technology for the

event of a serious reactor accident?

ding tubes of nuclear fuel rods could

design, execution, and interpretation

How would the fuel material react in

be influenced. To do this, the research-

of measurements on real physical

the event of a core meltdown, and how

ers used neutron imaging, a process

phenomena of high relevance to

can it be ensured that radioactive sub-

perfected at PSI that is regularly carried

safety, which are required for the

stances do not get into the environ-

out by its own PSI working group at the

verification, validation, and qualifi-

ment?

local large research facility SINQ, the

cation of computational methods.

Swiss spallation neutron source. SINQ has one of the world’s best neutron

Specific questions are, for example:

microscopes. It can be used to illumi-

How does the material that is used in

nate a wide variety of types of objects.

nuclear power plants age? How do the

In their investigations, the researchers

coating, which stops it there. The liner

dents in complex nuclear facilities, that

acts like a sponge for the hydrogen. It’s

are extremely unlikely but should still

as if a person in a bathrobe walked into

be studied for safety reasons. The re-

drizzling rain: The terrycloth would up

searchers in the Laboratory for Scien-

the water, and the person’s skin would

tific Computing and Modelling at PSI

stay dry. Evidently the coatings, which

benefit from rapid advances in com-

were originally introduced for mechan-

puter technology.

ical protection, also make the cladding tubes more stable over the long term.

Safely sealed away

Using computational models and simulations, researchers closely study the processes that take place in nuclear power plants and thus make the plants safer.

Simulations make nuclear plants safer

In Switzerland, the Nuclear Energy Act

Computer simulations make a crucial

waste from nuclear power plants and

contribution to the safe operation of

other sources. PSI researchers are con-

nuclear power plants. Supervisory

tributing to this important social un-

authorities also use them to check the

dertaking by investigating the natural

safety of the systems. Almost every

processes that are important for the

thing, from the installation of new com-

safety of a deep repository.

prescribes deep geological disposal of high-level, low-level, and medium-level

ponents to tests and measures to maintain security, has to be calculated and analysed on the computer beforehand. To this end, researchers at PSI develop computational models and computer programs that simulate components and subsystems in the nuclear reactor, as well as their interactions, with ever

A question for the future

concentrated on hydrogen that pene-

greater precision. In doing so, PSI acts

By supporting students, doctoral

trates the metal of the cladding tubes

as an independent research partner of

candidates, and young scientists, PSI

and forms so-called hydrides with the

the Swiss supervisory authority, the

and its partners ETH Zurich and EPF

metals, which can compromise the

Federal Nuclear Safety Inspectorate

Lausanne are contributing to the

stability of the tubes. The group then

ENSI, and thereby contributes to guar-

long-term maintenance of specialist

looked into the effects of an additional

anteeing and continuously improving

expertise in matters of nuclear en-

protective layer on ducts, the so-called

the safety of Swiss nuclear power

ergy in Switzerland: In the cross-lo-

liners. These are used worldwide and

plants.

cation master’s course in Nuclear

especially in Switzerland. They protect

For several years now, the trend has

Engineering, engineers learn how to

the ducts against mechanical damage.

been towards realistic computational

operate nuclear power plants effi-

The researchers found that liners do

models called best-estimate models.

ciently and safely, as well as how to

have a positive effect: Cladding tubes

The aim is to describe and quantify the

decommission them and dispose of

that have such a protective layer have

processes in a reactor as precisely as

radioactive waste.

fewer hydrides underneath. The hydro-

possible on the basis of physical laws.

gen penetrates more and more into this

hypothetical events, for example inci25

Hotlab: Knowledge from the hot cells All of Switzerland’s scientific expertise

Irradiated and therefore radioactive

out experiments with the radioactive

on the behaviour of materials and the

materials, whether from nuclear power

material inside these chambers.

ageing of nuclear power plants is con-

plants or research facilities, may only

Around 35 staff members oversee the

centrated at PSI. From the nuclear fuel

be examined under strict safety precau-

security and analytical infrastructure of

itself to the cladding tubes of fuel rods

tions. Such tests are carried out in the

the Hotlab – and also work on other

and on to the reactor pressure vessels

PSI Hotlab, a facility that is unique in

research topics, for example in medi-

and coolant lines – researchers at PSI

Switzerland. The radioactivity is her-

cine. In the hot cells, PSI scientists

are investigating how materials change

metically enclosed and shielded in so-

produce some of their radiopharma-

under the harsh conditions they are

called hot cells, behind concrete walls

ceuticals – radioactive drugs against

subjected to during the operation of a

up to one metre thick and leaded glass

cancer, which irradiate tumours directly

nuclear power plant.

windows. This protects employees and

inside the body. In the future, the radi-

avoids contamination of the environ-

oactive isotope required for this, ter-

ment. With externally controlled gripper arms, the researchers can safely carry

The PSI Hotlab has been examining spent fuel rods from Swiss nuclear power plants in its shielded hot cells for many years, in order to detect any damage at an early stage.

bium-161, is to be produced at PSI’s

at the possible embrittlement and ox-

operation, such as corrosion or the

spallation neutron source SINQ and

idation of the fuel rod cladding. The

ingress of hydrogen. If too much hydro-

then separated from the element from

focus is on continuously improving fuel

gen penetrates into the cladding tube,

which it is created in the shielded cells

rod design so that as much energy as

hydrides can be formed; compounds

of the Hotlab.

possible can be obtained from the

of hydrogen and the metals that make

The main task of the PSI Hotlab is to

safely enclosed fuel. These findings

up the cladding tube material, hydrides

carry out detailed examinations of irra-

help the nuclear power plant operators

can make the cladding more brittle and

diated fuel rods in order to understand

enhance the efficiency and safety of

promote the growth of existing cracks.

how they change during operation or

their power plants.

PSI scientists use the large research

in the interim storage phase. Research-

Special attention is paid to the clad-

facilities in-house and the hot cells of

ers in the Hotlab regularly examine the

ding tube of the fuel rods. This first

the Hotlab to better understand how

spent fuel rods from the Swiss nuclear

protective cover against the leakage of

hydrogen is absorbed and then distrib-

power plants using modern analysis

radioactivity from a nuclear reactor is

uted in the cladding tube, thereby

methods. They take a very close look

exposed to very high stresses during

weakening it mechanically.

Energy systems: The holistic view

At PSI, scientists study energy systems

ical guidelines, social trends, and tech-

nership with the World Energy Council

in all their complexity, on both national

nological developments could most

(WEC), whose framework is used to

and global levels. To do this, the re-

strongly influence the overall frame-

create scenario analyses of the global

searchers carefully examine the indi-

work conditions. Their results are not

power supply. An updated version of

vidual areas – electricity, heating, and

predictions set in stone, but rather

the world energy scenarios is published

transportation – as well as their inter-

well-founded answers to the question:

every three years. In three different

actions. They also look into the eco-

“What if?”

scenarios, researchers describe the

nomic sustainability of these net-

global energy system and provide an

worked systems.

idea of how it could develop further up

Energy mix of the future

to 2040 and beyond under specific framework conditions.

The researchers develop scenarios and

The proven economic expertise at PSI

The scenarios have musical names that

make assumptions about which polit-

has led, among other things, to a part-

express a certain basic mood. Modern

example through laws, framework con-

most environmentally friendly? In a life

ditions with long-term stability, and

cycle assessment commissioned by the

subsidies. In this scenario, climate

Federal Office of Energy, the Laboratory

policy decisions and other sustainabil-

for Energy Systems Analysis at PSI an-

ity aspects carry much more weight.

alysed how the various types of pas-

Hard Rock, on the other hand, assumes

senger cars affect the environment. The

lower economic growth than the other

researchers took into account the entire

two scenarios; there is less cooperation

vehicle life cycle, from production

among individual states as well as less

through operation and disposal. Their

innovation.

results included, for example, green-

Over the past few years, the Laboratory

house gas emissions, primary energy

for Energy Systems Analysis at PSI has

requirements, and the accumulation of

built up and continuously developed a

ground-level ozone or particulate mat-

computer-based model of the global

ter.

energy system. It applies this to the

One finding: From a climate protection

world energy scenarios. This model –

perspective, alternative vehicles and

the Global MARKAL Model, GMM for

fuels – battery and fuel cell vehicles as

short – maps out today’s structures of

well as those that can run on synthetic

the energy system as well as their in-

methane – only make sense if the elec-

teractions, and it integrates many pos-

tricity to operate the electric motor or

sible future options for the energy sup-

to produce hydrogen and methane

ply. The researchers calculate how

comes from low-carbon sources. This

development goals and framework

is true today and in the future. With

conditions will affect the energy mix,

electricity from nearly carbon diox-

access to energy, carbon dioxide emis-

ide-free production (hydroelectric,

sions, and economic and population

wind, and nuclear power plants), bat-

growth. One finding that holds true for

tery vehicles, fuel cell vehicles, and

all three scenarios: Electricity is becom-

motors that burn synthetic methane

ing increasingly important. Also, the

make it possible to reduce greenhouse

average per capita energy consumption

gas emissions by around half compared

will reach a maximum in the next ten

to conventional petrol and diesel cars.

years and then decrease again. Total

However, if the additional electricity

energy consumption will not decrease

demand due to electromobility is met

in any of the three scenarios; in two of

by natural gas power plants, green-

Jazz assumes that the markets will de-

them, it is projected to more than dou-

house gas emissions will not decrease.

velop relatively freely and that con-

ble.

Therefore, renewable electricity pro-

Researchers at PSI perform detailed comparisons of the environmental impacts of passenger cars with different power systems and determine their ecological balance.

sumer behaviour will change drastically

duction must always be expanded in

by leaps and bounds – seen, for exam-

parallel with the expansion of electro-

ple, in a rapid switch to the purchase

Tomorrow’s mobility

mobility.

of large numbers of electric cars. In Unfinished Symphony, governments

Petrol, diesel, or natural gas, electric

exert significantly more influence on

cars, hybrids, or fuel cell vehicles –

how the energy system develops, for

which fuels and technologies are the 29

Bird’s eye view of the Paul Scherrer Institute.

PSI in brief The Paul Scherrer Institute PSI is a research institute for natural and engineering sciences, conducting cutting-edge research in the fields of future technologies, energy and climate, health innovation and fundamentals of nature. By performing fundamental and applied research, we work on sustainable solutions for major challenges facing society, science and economy. PSI develops, constructs and operates complex large research facilities. Every year more than 2500 guest scientists from Switzerland and around the world come to us. Just like PSI’s own researchers, they use our unique facilities to carry out experiments that are not possible anywhere else. PSI is committed to the training of future generations. Therefore about one quarter of our staff are post-docs, post-graduates or apprentices. Altogether PSI employs 2200 people, thus being the largest research institute in Switzerland.

Imprint Concept/texts/editing Sebastian Jutzi, Brigitte Osterath Photos Scanderbeg Sauer Photography, Markus Fischer, Mahir Dzambegovic Design and layout Monika Blétry Printing Paul Scherrer Institut Available from Paul Scherrer Institut Events and Marketing Forschungsstrasse 111 5232 Villigen PSI, Switzerland Tel. +41 56 310 21 11 Villigen PSI, October 2021

Contacts Division Head Energy and Environment Prof. Dr. Thomas J. Schmidt Tel. +41 56 310 57 65 thomasjustus.schmidt@psi.ch Division Head Nuclear Energy and Safety Prof. Dr. Andreas Pautz Tel. +41 56 310 34 97 andreas.pautz@psi.ch Department Head Communications Mirjam van Daalen Tel. +41 56 310 56 74 mirjam.vandaalen@psi.ch

Paul Scherrer Institut :: 5232 Villigen PSI :: Switzerland :: Tel. +41 56 310 21 11 :: www.psi.ch

Energie und Umwelt_e, 2/2024