Gaining megawatts

The biggest advantage of hydropower is its flexibility. Hydropower plants can not only generate electricity on demand, but can also absorb the electricity produced by other types of renewable energy, storing it in pumped-storage facilities. “With hydropower, we can increase our production and storage capacity for other renewables – and therefore build more solar and wind farms,” says Elena Vagnoni, project head at EPFL’s Technology Platform for Hydraulic Machines (PTMH). This R&D platform was established in 1969 and has since become a center of excellence in its field, with world-leading expertise in testing and certifying hydraulic equipment.

A paradigm shift

“At first, hydropower plants were designed for optimal efficiency and not to provide flexibility to power grids,” says Mario Paolone, the head of PTMH. “But now we’re undergoing a paradigm shift, which means we need to completely rethink the way equipment is designed and used. That said, we obviously can’t tear down all our existing plants and build new ones. So we have to find ways to retrofit existing equipment, in addition to designing next-generation systems.”

EPFL spearheaded the EU’s biggest hydropower R&D program, called XFLEX Hydro, which has just wrapped up. “We developed a range of technology for improving the flexibility of hydropower systems without increasing their installation and maintenance costs,” says Vagnoni. The program included studying ways to optimize the use of existing equipment, analyzing the stresses on equipment in the highly dynamic operating conditions at hydropower plants, and doing research into fluid mechanics and flow control systems.

For example, at pumped-storage plants, the pumps and hydroelectric turbines operate in series. That is, the turbines rotate to generate electricity, and the pumps use the electricity to pump water into a reservoir at a higher elevation, thus storing any surplus energy. When plant operators want to switch the order of operations, the plant has to be shut down for 10 minutes or more. To get around this problem, scientists have designed what they call hydraulic short circuits, or systems that allow pumps and turbines to operate simultaneously. “This mechanism lets plant operators reverse the process instantly, like what happens inside a battery,” says Paolone. “We’ve already tested it successfully at several hydropower plants in Europe.”

The engineers are also examining methods for boosting the output of hydropower plants. “It’s always better to rely on a carbon-free source of energy,” says Vagnoni. They’re exploring various options, such as increasing a plant’s energy-storage capacity by installing additional pumps, placing microturbines within pipes to supply power to small villages, addressing system fatigue, dealing with sediment more effectively, adopting digital processes for monitoring, maintenance and production schedules, mapping out more granular production schedules, and gaining insight into still-obscure physical phenomena.

Of course, environmental preservation is also important. “We’re looking at how we can renovate hydropower plants to reduce their impact on plant and animal life and make them more resistant to the fluctuations in water levels being caused by global warming,” says Vagnoni.

Nuclear economics no longer add up

Will Switzerland still have nuclear power plants in operation in 2050? Not according to the country’s 2050 energy strategy, although Switzerland’s youngest plants – in Gösgen (1979) and Leibstadt (1984) – may in fact still be in service at that point. But for now, constructing any new nuclear capacity is out of the question before 2050, even if the law changes (for instance, if the recent citizen initiative to overturn the ban on new nuclear facilities is successful).

Meanwhile, next-generation nuclear technology is being developed that could gain traction in the coming decades. For instance, thorium reactors – like the one being developed by Geneva-based Transmutex, which just raised CHF 21 million – uses a particle accelerator coupled with fuel made from recycling conventional nuclear waste. The company hopes to build a pilot plant by 2032 and begin constructing commercial reactors by 2040. Will Switzerland be one of its customers? The chances are slim, again owing to the country’s laws. Yet compared with today’s nuclear reactors, those based on thorium are better for the environment (the radioactive waste sticks around for a few centuries rather than hundreds of thousands of years), more reliable (no risk of a chain reaction) and more secure (no risk of proliferation).

Under the most optimistic scenarios, we’ll start to see nuclear fusion plants come online in the second half of this century. Nuclear fusion can generate massive amounts of clean energy and would be an almost inexhaustible power source. But there’s still quite a ways to go. “Especially since the falling costs of renewable energy mean nuclear won’t be able to compete, no matter what kind of technology is used for the reactor!” says François Maréchal, a professor at EPFL’s Laboratory of Industrial Process and Energy Systems Engineering.

Power from a conventional nuclear plant costs approximately 8 cents per kWh. At newer plants, like the EPRs at Flamanville in France and Hinkley Point C in the UK, the cost is around 12 cents per kWh. “But with solar technology, we can generate power in Africa at just 1.2 cents per kWh!” says Christophe Ballif from EPFL’s PV-Lab in Neuchâtel. For wind power, the figure is around 5 cents per kWh.

The math is pretty straightforward – and the cost of renewables hasn’t stopped falling. Even factoring in the intermittent nature of renewable energy and the systems needed to convert and carry it, nuclear power will be priced out of the game.

The untapped potential of geothermal energy

The figure was released in early February: 5% of the heat used in Switzerland in 2022 came from geothermal energy. That’s not much in view of the country’s total energy use. Still, the total heating capacity of Switzerland’s geothermal systems grew by 6% – to 2.6 GW – versus the previous year.

There are two broad types of geothermal energy. First, there’s the surface energy used for residential heating – and here, Switzerland is a leader in Europe. These systems are often installed in people’s yards and contain probes extending as much as 400 meters deep. A heat-transfer fluid circulating inside the probes captures the underground heat and carries it up to the surface. The systems are attached to a heat pump, allowing the pump to operate all year long with a low environmental impact. It’s a promising method for decarbonizing Switzerland’s heating sector which, along with cooling systems for buildings, accounts for a third of the country’s energy demand. And 75% of the energy used for heating and cooling currently comes from fossil fuels.

Surface geothermal energy can be sourced even without digging holes. Enerdrape, a company spun off of EPFL’s Soil Mechanics Laboratory, has developed technology for this purpose. Its geothermal panels can be installed in underground structures to capture residual geothermal heat, providing a supplement to heat pumps. The firm recently raised CHF 1.3 million. Meanwhile, EPFL professor Lyesse Laloui, who heads the Soil Mechanics Laboratory, has developed a geothermal-pillar system that’s steadily being adopted in the construction of new buildings. The system involves installing heat recuperators on a building’s support pillars or aprons, with no additional drilling required.

The other type of geothermal energy is deep energy, sourced more than a kilometer underground where temperatures can exceed 100°C. These systems extract heat and can even generate electricity. They’re used extensively in Iceland – but not in Switzerland. Drilling through the hard rocks in our soil would require sophisticated technology and comes with its share of risks, including seismic ones.

Wind power helps fill the winter gap

Switzerland’s first wind turbine went into service in 1986. Today, the country has around 40 of them – mainly in the Bernese Jura, the Rhone valley, Entlebuch in the canton of Lucerne and Gütsch in the canton of Uri – with a total capacity of some 100 MW. These wind turbines generated a record 169 million kWh of power in 2023, covering the household needs of approximately 153,000 residents, which is more than the population of Lausanne. The main advantage of wind power is that it’s more productive in the winter, when Switzerland is short on electricity, than in the summer. However, this type of renewable energy currently generates just 0.3% of the electricity used in the country.

A combination of solar and wind

Solar power will make up a sharply growing share of the world’s energy mix, which is good news. In Switzerland, the government has introduced targets for transitioning to solar and other kinds of renewable energy by 2050. The goal is to have renewables supply 45 TWh, or more than half of the country’s total power demand based on current levels. Experts agree that the most effective way to reach this target is to combine solar with other forms of clean energy: hydropower, of course, but ideally also a sizable amount of wind power.

To be employed with power grids, both solar and wind power need to be coupled with one or more storage systems such as batteries, dams and synthesis gas. For batteries in particular (including EV batteries), China is once again the world’s manufacturing powerhouse. Here too, the country has made massive investments in new facilities. “China is flooding the market and overproducing to the point where prices are collapsing, for both batteries and solar units,” says Ballif. “That’s good for consumers and the energy transition in general, but it will create a form of dependency that we don’t want. Governments in other regions, including in Europe, need to build and expand their manufacturing capacity in order to make the market more resilient.”

NEUCHÂTEL: A hub of yield-boosting technology

That said, it’s not easy to invest in capacity when you’re up against that kind of competition. But it is possible to find ways of doing things better, or differently. Engineers at Ballif’s lab and at the Centre Suisse d’Électronique et de Microtechnique (CSEM) in Neuchâtel, where Ballif also heads a research group, have developed methods for considerably increasing the yields of PV cells. Some of their technology is being implemented in China’s new factories. For instance, the engineers designed “tandem” cells consisting of a perovskite layer deposited on a silicon cell. These devices set a new world record for power conversion efficiency and broke through the symbolic 30% yield barrier.

A number of solar-energy startups have popped up in and around Neuchâtel, building on the research conducted by researchers there. Some of those companies are developing systems for integrating PV cells into a building’s architecture through panels and tiles with customizable colors (these firms include Freesuns, Solaxess and SwissINSO), while others are creating systems specifically for farming applications (Insolight and Voltiris). “It’s true that these startups operate in niche markets,” says Ballif. “But as far as Switzerland is concerned, their technology can go a long way towards meeting the government’s targets.” They’re also proof that Swiss businesses aren’t about to throw in the towel. Just look at Thun-based 3S, which recently built a new 200 MW/year production line for solar panels that can be integrated into buildings, and Meyer Burger, which now has a total production capacity of 1 GW/year at sites in Europe. Both these companies leverage technology developed in association with CSEM and EPFL.

Forecasts by the Swiss Federal Office of Energy indicate that solar power will be a key component of the country’s energy mix in 2050 (see infographic). “The potential for solar is definitely there,” Ballif explains. “PV cells can be integrated into buildings’ architecture, placed on top of supermarkets and their parking lots, for example, and installed on mountains, where models with bifacial panels – which can also capture the sunlight that reflects off snow – are particularly effective during the winter. Switzerland’s total installed capacity was 1.5 GW in 2023, which can generate 1.5 TWh of solar power per year. This renewable energy should reach 10% of our energy mix in 2024. So it’s on track to make a major contribution to the government’s goal of having 45 TWh of power come from renewables.”

Reshaping geopolitics

Looking at the bigger picture, the pressure that Chinese manufacturers are putting on the prices of PV and wind components, batteries and electrolyzers could substantially alter the geopolitical playing field. “At these prices, operators could build plants in Africa’s deserts and generate power at less than 1.3 cents per kWh. That’s five to ten times cheaper than the cost at newly built nuclear plants. This would make it more economical to produce clean hydrogen by water electrolysis than to produce grey hydrogen from natural gas,” says Ballif. “Another option could be to turn the hydrogen into ammonia, initially for use in crop fertilizer and later for transporting energy to Europe.”

If renewable energy gets that cheap, many governments and businesses could be tempted to ramp up their support for the energy transition, simply because it makes financial sense. That would be a blow to oil-exporting nations like Russia and Saudia Arabia. “China may be saving the planet – but that will create other challenges!” says Ballif.

The Swiss Army Knife of energy carriers

Research into hydrogen as an energy carrier surged in the 1990s, says Züttel. “When I entered the field 32 years ago, we thought hydrogen would replace all fossil fuels. In those days, we weren’t yet hoping to combat global warming, we were trying to address the fear that fossil fuels would soon run out.” As new fossil fuel deposits were discovered and increased production drove down their cost, the hydrogen hype cooled down.

But now, the pendulum has swung right back. Hydrogen is once again in the spotlight, says Züttel. This time it’s for its potential to help curb global CO₂ emissions. While burning carbon produces heat-trapping CO₂, burning hydrogen produces nothing but water. If renewable electricity is used to produce hydrogen, for example through the electrolysis of water, the resulting hydrogen becomes an effective way to store renewable energy.

“Hydrogen is the key element on the path from renewable electricity to chemical energy carriers such as methane, methanol, synthetic oil or ammonia,” explains Züttel. “While these can be produced using carbon from captured atmospheric CO₂ or from biomass, the hydrogen carries the renewable energy.”

This makes hydrogen a valuable energy carrier for a variety of applications. Pure hydrogen can be used to generate electricity to meet peaks in demand, and it can power cars, busses, and heavy vehicles. If we managed to solve the storage, distribution and handling puzzle, then we could start using it as a carbon-neutral fuel for shipping and aviation.
Combined with carbon extracted from the atmosphere, biomass or industrial emissions, it could be further transformed into methane, synthetic oil, ammonia, methanol or other net-zero-emissions fuels. This would, again, come at the cost of overall energy efficiency. But in a world awash with renewable electricity, the increased volumetric energy density and safety of handling that these synthetic fuels provide help cut the carbon footprint of applications that are difficult to electrify.

Accelerating market adoption

Fortunately, says Züttel, there have been several breakthroughs on the path to market adoption of green hydrogen in transportation and electricity production, the two sectors responsible for more than half of the world’s greenhouse gas emissions. They begin upstream of hydrogen production, where renewable electricity has already achieved price parity with standard electricity, decades earlier than initially predicted by the International Energy Agency, bringing down the cost of clean hydrogen with it.

Market forces have been a key driver in road vehicle applications, accelerating the development of fuel cells and safe high-pressure hydrogen storage cylinders. Despite these advances in technology, adoption of hydrogen-powered vehicles has been frustratingly slow. In fact, the main obstacle has been the lack of roadside infrastructure. Switzerland currently has eight hydrogen refueling stations, says Züttel. “People won’t buy a hydrogen car if they can’t fuel it. And who wants to run a fueling station if no one wants to buy the hydrogen? That’s the reason why Toyota is not selling their fuel cell electric vehicles here.”

As the share of intermittent renewable electricity carried by the power grid increases, power plants will likely become increasingly reliant on stored hydrogen to match the supply and demand for power. “If you have a lot of volatile electricity, say from solar or wind power, you can produce hydrogen and store it underground, for example. Then, you can use that in the wintertime to produce electricity with a high efficiency in combined cycle power plants that have a hydrogen fired turbine and a steam turbine,” he says.

“For this to work, the whole market — and our expectations — will have to adapt. We are used to buying electricity at an almost constant price. To make storage attractive, the price of electricity during the night would have to be more expensive than during the day. And in the winter, we would have to be prepared to pay more than in summer months. But the more attractive it becomes to store electricity using hydrogen, the more such storages will be installed,” he says.

To stimulate market growth on both the supply and the demand side, the industry has come up with a colorful solution — at least in name. Hydrogen is now being marketed on a color spectrum ranging from black to green based on carbon footprint. When developing new applications, hydrogen users can now make a conscious choice whether to prioritize carbon footprint or cost. This strategy will eventually nudge consumers up the spectrum towards greener hydrogen as it becomes more and more affordable.

However, as Züttel emphasizes, this only makes sense as a temporary strategy, in place long enough to build up demand for hydrogen and the infrastructure to distribute it. “Once we start using a lot of hydrogen, it will have to be renewable hydrogen only. Anything else would not really make sense.”

From natural gas to its substitute

Renewable gases are on a roll. Green hydrogen, green ammonia and green methane (synthetic natural gas) have many of the same properties as its fossil-fuel counterparts but is produced artificially. What’s more, through a process known as power-to-gas, all these substances can be used to store and transport the surplus power generated by renewable energy. In the power-to-gas process, the first step is to produce green hydrogen from water using electrolysis, with renewable electricity as the power source. Then CO or CO₂ are added to the hydrogen to produce synthetic natural gas through a catalytic reaction. The mixture of CO, CO₂ and hydrogen can also be converted to liquid fuels such as methanol. Another catalytic reaction can also be used to create ammonia from hydrogen, through the addition of nitrogen.

Methanol and ammonia are the two most widely produced chemicals in the world, with some 200 million tons of each gas manufactured per year. But today, most of this production releases large amounts of carbon. Oliver Kröcher, a professor at EPFL’s Catalysis for Biofuels research group and at the Paul Scherrer Institute (PSI), is exploring the potential of green ammonia – how it can be synthesized carbon-neutrally, decomposed (see article on page 28) and used as a fuel. He’s testing out novel ideas that can be developed further at PSI. One such idea is to create a small reactor that can synthesize ammonia dynamically right where hydrogen is produced from renewable energy. “The reactor has to be extremely dynamic so that it can respond to the intermittent nature of wind and solar power,” says Kröcher. The system he’s studying would use induction heating to trigger the catalytic reaction that forms ammonia. “The advantage is that we could apply this heat very quickly, without having to heat the whole reactor. That saves a lot of energy,” he adds.

Kröcher also notes that “We’re in a really interesting transition period. As scientists, our role is to explore all the options available and then supply data to businesses and policymakers so they can make informed decisions. In reality, of course, we’ll probably end up using several different options in parallel. The optimal fuel, the optimal method for transporting it, and the optimal system for using it will depend a lot on local conditions.”

Mario Paolone, a professor at EPFL’s Distributed Electrical Systems Laboratory, explains: “Renewable gases will be essential for storing the surplus power generated by photovoltaics during the summer months.” The catch is that the efficiency of gas production is low. And it is even worse for liquid fuels. Kröcher says, “It takes five times as much electric power to produce synthetic fuels than what you can obtain from using it. We’ll therefore need a lot of green electricity in the future. That’s why synthetic fuels should be used only in cases when there’s no alternative, like for aviation.”

Carbon capture

Another challenge is that the production of synthetic natural gas is directly linked to the development of carbon capture technology. “For now, CO₂ isn’t easy to come by because many carbon capture systems are still in the experimental stage,” says Kröcher. But there’s no shortage of sources of CO₂, such as in the construction industry or from waste incineration – places where combustion occurs with high carbon concentrations.” Switzerland plans to equip at least one household-waste incineration plant with a carbon capture system with a rated minimum capacity of 100,000 tons CO₂ per year by 2030.

So carbon can thus be captured at the source, and also by “scrubbing” the air as part of efforts to reach net zero. EPFL has just kicked off a six-year project to build a demonstrator for a large-scale carbon capture, use and storage system near the Valais Wallis campus. This project, which is geared towards sustainability and the circular economy, brings together several EPFL labs with complementary skill sets. The system will capture CO₂, store it for short periods and convert it into energy carriers, high-added-value chemicals and the catalysts needed for the energy transition.

A closed-loop process

“We need to close the carbon loop – that is, capture CO₂ so it can be used to make synthetic natural gas, which in turn is fed to combined gas power plants,” says Paolone. If clean hydrogen is used to make that synthetic natural gas, and if the carbon coming out of power plants is captured to make more gas, then we’ll achieve carbon-free power generation. EPFL has been working with Gaznat for the past five years to develop enhanced carbon-capture technology and systems for producing green methane from clean hydrogen, particularly in Sion through the research groups headed by EPFL professors Kumar Agrawal and Wendy Queen.

Getting hydrogen out of ammonia

Kevin Turani-I-Belloto has developed a low-cost method for breaking down ammonia to produce hydrogen. He’s just been awarded a BRIDGE grant to develop a proof of concept for his technology.

Without hydrogen, Kevin Turani-I-Belloto surely wouldn’t have chosen hydrogen storage as the topic for his PhD thesis, and he probably wouldn’t even have come to EPFL. But today, it’s hydrogen’s cousin ammonia – NH₃, a combination of hydrogen and nitrogen – that’s keeping him busy. Turani-I-Belloto is an associate researcher at EPFL’s Catalysis for Biofuels research group headed by Prof. Oliver Kröcher, and he’s developed a catalyst that can break down ammonia at a lower cost than existing methods, and without the need for rare-earth metals. Last fall he received an Ignition grant from EPFL’s Vice Presidency for Innovation and an Enable grant from EPFL’s Technology Transfer Office to help him build a prototype. And now, he’s been selected for a BRIDGE Proof of Concept grant, offered through a joint initiative by the Swiss National Science Foundation and Innosuisse.

Hydrogen holds just as much promise for storing the surplus power from renewable energy as for being used as fuel. It’s the smallest molecule in the universe and can escape through even the tiniest hole. Owing to its ultra-low density, it has to be stored at a pressure of 350 or 700 bars – depending on the standard – for use in gas form, or at a temperature of –252°C for use in liquid form. Distribution networks for hydrogen remain scarce and therefore expensive. Operators of ships and aircraft – vehicles for which electric batteries are not yet viable – are placing their bets on hydrogen or synthetic fuels made from hydrogen, although the production of these compounds isn’t very energy efficient.

That’s where Turani-I-Belloto’s new method comes in. He proposes using ammonia to transport hydrogen. “Today, half of the hydrogen that’s produced goes into the manufacture of ammonia, which in turn is used as the main ingredient in fertilizer,” he says. Ammonia is a colorless gas but not odorless, meaning leaks can be detected fairly easily. It can be liquified at a relatively low pressure (8.5 bars) and a reasonable temperature (–33°C), making it a good candidate for transport. Liquid ammonia also has a higher energy density than liquid hydrogen. “What’s more, distribution networks for ammonia are already well-developed around the world,” says Turani-I-Belloto. “Hence my idea for using it to transport hydrogen.”

“What I want to do is leverage the benefits of each gas: ammonia for transport and hydrogen for energy, producing it from ammonia right where it’s needed,” says Turani-I-Belloto. “That’ll make it possible to meet demand for clean energy, both for cargo vehicles and in an array of other industries.” Turning ammonia into hydrogen requires the use of a catalyst. “Catalyzing agents do exist, but they’re either not effective enough or they’re too expensive, like ruthenium, an extremely rare metal. My system delivers high yields, uses abundant raw materials and cuts the catalyst cost by a factor of over 200.”

Funding agencies clearly see potential in Turani-I-Belloto’s technology, although he’s keeping the details of his process under wraps. “It’s my magic formula,” he says. So we won’t get a peek into the black box. However, his compact demonstrator is now set up in the research group’s laboratory, and it has demonstrated the potential of his innovative catalyst. He’s filed for a patent for his invention. “If we’re successful in using ammonia to store hydrogen, that will unlock an entire value chain,” says Turani-I-Belloto, who’s working tirelessly to reach that goal.

Demonstrating renewable hydrogen’s potential in a closed loop

To showcase the viability of converting renewable energy to synthetic fuels, a team led by Andreas Züttel, who heads EPFL’s Laboratory of Materials for Renewable Energy, has developed a pilot plant, which they built in at the EPFL Valais Wallis campus in Sion. “Our demonstrator includes everything from solar power production and storage, hydrogen production and storage, and the synthesis of hydrocarbons, all in the size of the average energy consumption of a single person in Switzerland,” explains Züttel. The small-scale installation provides a unique proof of concept, allowing researchers to evaluate and optimize every aspect of the synthetic fuel production cycle under real-world conditions.

The demonstrator integrates all steps of the synthetic fuel production process into a closed-loop cycle with no net CO₂ emissions, comprising four sequential steps. In the first step, solar panels covert solar energy into electricity, which, in step two, is stored in two batteries or, when needed, converted to alternating current and fed into the grid. In step three, electricity stored in the batteries is used to electrolyze water and compactly store the resulting hydrogen in a metal hydride cell. In the final step, the hydrogen retrieved from the metal hydride cell is combined with CO₂ captured from the atmosphere to produce around 100 grams of synthetic methane and 200 grams of methanol per hour.

Concentrating sunlight to produce hydrogen (and more)

A team lead by Sophia Haussener, head of EPFL’s Laboratory of Renewable Energy Science and Engineering, has achieved a significant breakthrough in solar hydrogen production. Their innovative system allows a production rate of about half a kilogram of hydrogen per sunny day – the energetic equivalent of 1.5 liters of heating oil. By combining a photovoltaic cell and an electrolyzer into a single unit, the system enhances its efficiency while also reducing costs. Additionally, its local, decentralized production alleviates pressure on the power grid and avoids costs related to transporting hydrogen.

Their installation is made up of an “artificial tree” — a parabolic dish seven meters in diameter. By concentrating sunlight close to 1,000 times and directing it at a photochemical cell located at its focus, the solar energy is used to split water into its constituent elements — hydrogen and oxygen. These gases, and the heat generated in the process, can all be used in downstream applications. The hydrogen can serve as renewable energy carrier for carbon-neutral synthetic fuels or as feedstock for the chemical industry, for example, for the production of ammonia. Meanwhile, the oxygen could be used for medical applications, while the heat can be used for ambient heating, for example.

Exploring fuel cells

Fuel cells have become a household name in the world of clean energy solutions, but they’ve done so in the shadow of solar panels, wind turbines, and lithium-ion batteries. With Swiss production capacity of green hydrogen expected to reach 300 MW by 2030 – up from 3MW in 2022 – fuel cells are poised to play a growing role in our clean energy future. We sat down with Jan van Herle, senior researcher in EPFL’s Group for Energy Materials, to explore this important technology.

What are fuel cells, and how do they differ from batteries?

Fuel cells are electrochemical cells in which the electron donor is a fuel. In hydrogen fuel cells, that fuel is hydrogen. Each cell is made up of two catalysts separated by an ion conducting membrane. On one side, the catalyst extracts electrons from the fuel, which circulate through an outer circuit, generating a DC that can be used. Then, the electrons are injected into the other electrode and picked up by the oxygen from the air. The product of the reaction is simply water.

What types of applications can fuel cells enable?

The most obvious is electric mobility, where fuel cells are much more efficient than standard combustion engines. In large electric vehicles, fuel cells can increase the range of a smaller battery pack and extend battery longevity by recharging them on the fly and reducing deep cycling. Because they are modular, fuel cells can scale to tens of megawatts to enable applications such as maritime shipping and stationary co-generation of power and heat. Co-generation plants running on natural gas are available for individual houses. And at smaller scales, fuel cells can replace batteries in portable electronics applications.

What are the current challenges facing the widespread adoption of fuel cells?

Improving performance, increasing durability and longevity, and bringing down their cost. There’s been enormous progress in all three areas, cost remains the main challenge. It’s mainly a matter scaling up manufacturing, which is why we are seeing the construction of fuel cell giga-factories.

Which specific challenges are you addressing in your research?

Questions related to durability are currently at the heart of our research. There are a whole range of phenomena that cause fuel cells to degrade, from catalyst loss, delamination between layers, and accumulation of contaminants over time. We’re also working on optimizing the design of large systems at the megawatt scale to bring down cost. Equipping each fuel cell with its own heat exchanger, plus all the electronics would simply be too expensive. That’s why we need to find ways for them to optimally share these supporting resources.

A matter of timing

“The more we rely on renewables with unpredictable power generation, the more we’ll also need to rely on reserves,” says Mario Paolone, the head of EPFL’s Distributed Electrical Systems Laboratory (DESL). Especially since today, it’s demand that sets the pace. Demand is seen as immutable, and so it’s the supply part of the equation that must be adjusted accordingly. People want to be able to switch on a light, heat up the oven and charge their vehicles at any time of day or night, in the summer or in the winter. As a result, grid operators keep reserves of electricity on hand that can be tapped into at different time intervals. These include a primary reserve deployable in a few minutes, a secondary reserve deployable within 15 minutes and one hour, and a supplemental reserve for periods beyond that. Each type of reserve comes with the appropriate power storage system.

Fortunately, Switzerland isn’t alone. Our power grid is connected to the rest of Europe, allowing us to pool resources, storage systems and costs with other countries. “The dream of becoming self-sufficient in terms of our power supply is neither technically nor financially optimal if we limit our view to Switzerland,” says Paolone. “It’s Europe as a whole that needs to become energy independent.”

Electrifying our processes and transitioning to renewables will impact power grids in two ways. First, it will change how operators balance the load on their grids and store reserves. “For now, synthesis gas made from renewable energy is the most promising method for storing power and responding to seasonal fluctuations,” says Paolone. Gas-fired power plants can step in to meet excess demand. Operators can also set up power-to-gas systems, which use surplus power to produce clean hydrogen, which in turn is processed to make synthesis gas. “Natural gas companies are really interested in power-to-gas technology because it will let them keep using their existing transmission and distribution infrastructure,” says Mario Paolone. “But for that, engineers will need to develop efficient, large-scale carbon capture systems.”

He also points out that “as we decarbonize Switzerland, hydropower will play an important role in providing this kind of flexibility to power grids. It’s the only completely renewable energy source that we can control. That’ll be a crucial advantage going forward.”

Hydropower plants provide the flexibility to cover load variations throughout the day or across seasons. Their flexibility depends in part on the type of plant – for instance, whether it’s an impoundment plant (i.e., one that collects precipitation and glacier runoff) or a pumped-storage plant. EPFL recently coordinated the EU’s biggest R&D program on hydropower facilities, called XFLEX Hydro. The program studied small-scale modifications that can be made to hydropower plants to increase their capacity, so as to improve the overall reliability of Europe’s power grids. The technology developed under the program can enhance the ancillary services provided by grid operators – the services that continually match supply with demand – which will help keep local and regional grids reliable and make them resilient to fluctuations in the energy supply, both now and in the future.

Batteries to the rescue

When it comes to intraday load balancing, batteries can be a powerful ally. Paolone believes that lithium batteries will be a key feature in tomorrow’s decarbonized power grids. “They deliver very high yields and can quickly switch between absorbing and injecting electricity,” he says. “These capabilities will be essential for managing primary reserves. In addition, lithium batteries will soon be able to complete tens of thousands of cycles. That’s a huge benefit for grid operators. The power stations they build are intended to last 10 or 20 years, and the technology is starting to be compatible with that time frame.”

What’s more, the potential is already out there. “The world’s power grids will need a total battery capacity of around 180 GWh/year by 2035,” says Paolone. “And at roughly the same time, some 100 GWh to 200 GWh of capacity will become available as electric vehicle (EV) batteries reach end-of-life. It’s a perfect match.” There are still some technological hurdles to overcome, however. Engineers at DESL are developing methods for measuring car batteries’ residual capacity in order to give them a second life. “We can now determine how many and which cycles second-life batteries can run through within a power grid cycle,” says Paolone. “Given that a grid’s cycles are much less intense than those in cars, these batteries could be useful for several more years.”

Building a stronger grid

The second way that the transition to renewables will impact power grids relates to the grid infrastructure itself. Paolone explains: “We need more power transmission lines. Today, transmission lines at all levels – from very high voltage to distribution – are currently operating at full capacity during certain periods, and this issue will continue to worsen over time.” In Switzerland, assuming nuclear power is phased out and all personal vehicles and residential heating units are electric, we’ll need around 40 GWp of photovoltaic power. But the DESL model shows that medium-voltage power lines start getting congested at 13 GWp. So the country will need to make hefty investments to upgrade its power infrastructure.

Local, decentralized power storage systems – or in other words, batteries – would help reduce the need for new power lines. DESL engineers have designed optimization algorithms that, based on the solar power generated within a community and the load on the local grid, can precisely identify where storage systems should be installed and where grid capacity needs to be expanded to minimize the community’s electricity costs.

Yet there’s another problem standing in the way of finding the optimal energy mix, power storage system and load balancing strategy. “Today, our grids remain stable and reliable due to effective control over power generation, as well as robust grid planning and operational processes,” says Paolone. “That’s possible because we have relatively few power stations to manage. But what will happen when we have millions of decentralized power generators that are outside the control of grid operators? When 1 GW of today’s nuclear power is replaced by 5  GWp of distributed solar panels, how will that be managed? There’ll be an explosion in the number of variables that grid operators will have to juggle. Technically, we could supply all our power needs with photovoltaics, but that would require making major changes to our grid control systems, transmission and distribution systems, and electricity market.”

Of course, there’s still the demand part of the equation. Another way to reduce our need for power storage is to gain better control over variations in demand. “If we’re able to effectively modulate the load on the grid, then we can do just about anything,” says Paolone. Technology being developed in this direction includes control systems for EV charging stations, bidirectional EV charging and real-time variable electricity pricing.

He adds that another, often underestimated, obstacle relates to the coordination and synergies that are crucial for any industry in transition. “New technology requires an entire ecosystem around it: companies to make the parts, assemble them and ship them, and then to take the end product to market,” says Aklin. “The more innovative a technology is, the harder it is to convince businesses to get on board. They’re afraid of being the only ones to invest and take the attendant risks, and that other companies in the supply chain won’t follow. We’re seeing that with hydrogen, for example, where businesses are still dragging their feet.”

Illustration Éric Buche

Standardizing the standards

Maria Anna Hecher, a researcher at EPFL’s Laboratory for Human Environmental Relations in Urban Systems, is looking specifically at the challenges associated with coordination. She’s studying the factors that encourage consumers to switch to renewable energy, whether by purchasing solar panels, heat pumps, electric vehicles or energy management systems. A study she and her colleagues carried out in 2022 revealed that part of the problem lies with the many different standards used in today’s systems. “You can find a lot of experts for any one given technology, but few that can link all the technologies together,” she says. “It should be pretty straightforward to hook up your electric vehicle to your solar panels, for example, but it’s actually quite difficult.”

The third obstacle – and it’s no small one – relates to our behavior as a society. Fear of change and the unknown can create a lot of inertia, especially on a group level. And there’s the prospect of losing part of your wealth and being faced with a higher cost of living. Aklin points to the largely unpopular carbon tax as one example.

Hecher’s study determined the profile of people who are more likely to adopt clean energy. They’re generally homeowners with children, a good income and a high level of education. They tend to be well-informed, interested in new technology, engaged in societal issues and keen to increase their energy independence. These are people with the financial and decision-making capacity to do so – which is hardly the case for everyone.

“Our study sheds light on the factors that could both encourage and impede the energy transition,” says Hecher. “This is valuable information for breaking down barriers and reaching more of the population.” It’s already clear that energy utilties and public policymakers can play a pivotal role, such as by introducing subsidies. In Switzerland, given the high percentage of people who rent their homes, property developers and landlords can also be key enablers.

The study additionally found that information and trust among consumers will be essential for driving adoption. “Early adopters usually speak with their friends, family members and colleagues before making a decision,” says Hecher. “And the more often they speak with these individuals, the more trust that’s created. Trust can be enhanced further if the companies providing the technology have a local presence and reach out to the community. Finally, events open to the public – like conventions, conferences and industry fairs – can be effective at putting the different energy-transition stakeholders in touch with each other.”

The mighty carbon interest groups

And then there are the political obstacles. Some of them are inherent to the political system – such as Switzerland’s referendums, which give citizens a way of putting pressure on policymakers. “There’s also the fact that special interest groups have an undue influence on how policy is shaped,” says Aklin. “These groups have deep pockets or can mobilize high numbers of people to get their voice heard.”

It’s simplistic to think that introducing new public policy will be enough to spur the energy transition. Aklin believes that policymakers should take their cue from what’s politically feasible and acceptable to citizens. “The energy transition will be extremely slow without popular support,” he says. “We need to design policies that will benefit the key segments of society, thus increasing the policies’ support and creating the conditions for that support to continue.”

Towards a greener Switzerland

Even the Swiss government’s most ambitious target for switching to clean energy by 2035 is realistic. That’s the main takeaway of a report issued by the SWEET EDGE consortium, which is composed of the University of Geneva, the University of Bern, the UNIL-EPFL CLIMACT Center and ETH Zurich.

The scientists evaluated scenarios with different levels of renewable energy production, ranging from 17 TWh/year to 35 TWh/year – against the current output of approximately 6 TWh/yr. Their model was based on new forms of renewables, including a mix of solar, wind, wood and biogas. The highest production target corresponds to around half of Switzerland’s expected power demand.

The report puts forth three strategies for reaching that target: adopting a range of technology, encouraging consumers to use solar power, and optimizing the use of wind- and solar-power infrastructure. All scenarios would require a sizable investment, but they’d also create new jobs.

See consortium’s website for further infomation: www.sweet-edge.ch/en

Link to the PDF

Won’t that cause the cost of the paper produced to soar?

No, on the contrary! This would be a win-win system – the end product would be cheaper, the fuel and transportation would cost less, and there’d be no need to purchase heat from a supplier. What’s more, this approach could be used just about anywhere, in a whole range of industries. We’re working on a similar project with Novelis, the world’s largest aluminum recycler, at its Sierre plant. And we installed a large demonstrator at the Energypolis buildings in Sion to circulate heat at 17°C using CO₂ as the fluid. It works perfectly well.

Are businesses ready to come on board?

That’s the point of our calculations – to show companies that it’s in their interest. Many people still think the energy transition will come at a high cost. But that’s because they fail to factor in the social costs of carbon emissions. That’s what the next generation will have to pay to repair the damage caused by climate change. And the bill will be high: between CHF 100 and CHF 600 per ton of CO₂ released into the air. That’s the amount we’re “borrowing” from our children, and they’re the ones who will have to pay the cost of restoring out planet and keeping it inhabitable. Also, in 2022 we saw how volatile energy prices can be when we’re largely dependent on countries like Russia for oil, natural gas, uranium and other resources. But it’s only by considering the entire value chain as an integrated system that we’ll be able to properly assess the full advantages of the energy transition.

What do you mean?

We need to take a step back and accept the idea of a return on investment over a 20- to 25-year time horizon. Over that period, industrial plants will be able to not only generate their own energy, but also produce fuel and heat, store power to meet seasonal demand, and recover their “losses” by optimizing process flows. All that will ultimately reduce the amount of energy they’ll need. We won’t have to put up as many wind turbines! But this should be done by taking a systems-based approach, where everything is interconnected. And energy-saving measures should be adopted at all levels of society – including in terms of our individual behavior.

How can we break away from silo thinking?

The transition will open up formidable opportunities for engineers, managers, and financers, but we need to teach them to consider systems in their entirety, to measure the interactions taking place at each point in a power grid and to tap into their creativity. That’s exactly what we aim to do with EPFL’s new Master of Advanced Studies in Sustainable Energy Systems Engineering. In that program, we’ll explain the links among purely energy-related issues, systems-based approaches (like life-cycle assessments), clean technology and urban systems. We believe it’s essential to train engineers who can lead projects of that scale.

But there’s still the issue of timing. 2050 is right around the corner, and not all countries are able – or willing – to invest in the energy transition.

Here too, technological progress will change the playing field. Five years ago, nobody would have invested in bringing electricity to isolated villages in Africa. But today, such villages can generate their own clean electricity with a few solar panels hooked up to batteries – at a trivial cost. China has taken note and is flooding the market with such systems.

In poor countries, diesel trucks are kept in service for decades. And maritime transport is one of the biggest polluting industries there is. How can we decarbonize these sectors?

These examples illustrate what’s known as a technology cycle. It’s true – we can’t upend an entire industry from one day to the next. But little by little, polluting vehicles will be replaced by their clean counterparts. That’ll take a while, though. In the meantime, we can mitigate the vehicles’ impact with technology like that being developed right here by Qaptis. Its system captures the CO₂ in trucks’ exhaust pipes and stores it at a station in liquid form so it can be converted into renewable fuel. By retrofitting existing trucks in this way, we won’t have to replace them. We can also start replacing diesel with carbon-neutral synthetic fuels, as another way of extending existing vehicles’ useful life.

What about the political resistance and the fossil fuel lobby’s efforts to undermine the transition?

The oil majors are now starting to explore these issues. We carried out a project with TotalEnergies to think about what refineries will look like in the future. They won’t produce gasoline but instead probably synthetic kerosene and especially other synthetic compounds – which could turn out to be extremely valuable – by recovering what’s now considered waste. That’s just one example. Our research group has put together a huge open-access database, called AIDRES, that illustrates how heavy emitters like steel and cement plants can reach net zero. We presented the database to the European Parliament along with a map indicating where such plants are located and how they could be converted into sources of CO₂ for making synthetic compounds, for carbon-capture systems, and for mineralization. The road ahead is long, but I’m sure that the findings of our models – which show that these companies can remain profitable while moving towards the goal of net zero – will eventually change the minds of policymakers.