The other renewables
Invested in renewables
Renewable energies such as geothermal, wave and biomass offer a promising back-up for solar and wind.
[Geothermal, wave and biomass: Promising renewable energy alternatives]
[A geothermal project in Germany, a wave energy project in Portugal and a biomass project in Czechia are good back-ups to the main renewable energies, solar and wind.]
The other renewables
Invested in renewables
Renewable energies such as geothermal, wave and biomass offer a promising back-up for solar and wind.
[Geothermal, wave and biomass: Promising renewable energy alternatives]
[A geothermal project in Germany, a wave energy project in Portugal and a biomass project in Czechia are good back-ups to the main renewable energies, solar and wind.]
Daniel Mölk first worked in the Bavarian town of Geretsried in the early 2010s, on a project seeking hot subsurface water reservoirs for a plan by the local utility to generate hydrothermal energy. They didn’t strike water, but Mölk and the team learnt almost everything there was to know about the earth and rock formations around the town, which is 40 kilometres south of Munich. It laid the foundations for a pioneering geothermal endeavour in the same spot 13 years later.
Mölk is now the managing director of Eavor Germany, which is drilling a giant underground radiator in that same spot. It's an innovation that will provide clean, renewable heat and electricity to 30 000 households in the region.
“Since I drilled here the first time over a decade ago, I had the opportunity to work on many other hydrothermal projects in other places around the world,” Mölk says. “It’s really something, to be back in Geretsried now and to show – with Eavor’s technology – that generating geothermal energy on a large scale also works without thermal water.”
Extreme weather events and record temperatures in recent years have highlighted the urgency of climate action in Europe. To reach the EU goal of climate neutrality by 2050, member states must cut greenhouse gas emissions by at least 55% by 2030. The switch to renewable energy is key to achieving this goal.
While solar, wind and hydropower have so far been the most efficient sources and are the most developed and widely adopted, they are not available everywhere or every day of the year. This article highlights other renewable energies that can make a big contribution to meeting climate goals.
For the moment, these other renewables are not as widely used as solar and wind, but the technologies are improving. Here are three of them:
Geothermal energy is derived from the natural heat of the earth’s interior. Conventional geothermal solutions mostly involve capturing heat from subsurface water or steam reservoirs that are accessed through drilling. However, in Geretsried and many other places, underground water is not available or accessible.
Eavor-Loop, the innovative solution developed by the Canadian company Eavor, is different, because it does not rely on water reservoirs. Instead, the company (whose name is pronounced “ever”) drills deep into the earth and harvests the heat from the rock itself.
The first commercial-scale Eavor-Loop is being built in Geretsried with the help of a €91.6 million grant from the EU Innovation Fund and €45 million in financing from the European Investment Bank.
The Eavor-Loop system resembles a giant underground radiator. Eavor drills two vertical wells to a depth of between 4 500 and 5 000 metres. Then they drill 12 pairs of horizontal lateral channels 3 000 to 3 500 metres long from the base of each well, making a total of about 80 km of drilling per loop. (Geretsried’s system will have four such loops.) The giant radiator is then filled with clean water.
A pump initiates the flow of water. When the pump is switched off, the system continues to operate naturally on a “thermosiphon.” That means the water in the bottom of the system is heated by the underground rock through conduction and naturally rises to the surface, where it can be used directly for district heating or to generate power.
The system emits less greenhouse gas than conventional geothermal systems, since there is no need to reinject new fluids and because it does not require the extensive use of pumps.
Although underground water is not necessary for this system, geological conditions must be right for drilling.
“You need the kind of rock formation that enables you to drill the loop safely and efficiently,” explains Laurie-Anne Michnick, an engineer at the European Investment Bank. “And you need to have thermal conductivity.”
Before starting the commercial Eavor-Loop in Germany, Eavor built a pilot, the Eavor-Lite, in Alberta, Canada, in 2019. With only one loop, instead of Eavor-Loop's four, the pilot has been in operation without interruption for five years.
Meanwhile, the company tests its technology in Animas, New Mexico, where the temperature of the Earth’s subsurface increases rapidly with depth.
“The deeper down you drill, the higher the temperature gets, and the better the efficiency of the system,” says Bailey Schwarz, director of North American projects at Eavor. “So it’s a great test bed for us to prove and trial these technologies that allow us to cool our drilling assembly and test the proprietary technology we’re developing.”
The first loop of the Geretstried Eavor-Loop project is scheduled to be operating by the end of 2024. All four loops are expected to be running by 2026.
Germany is in the midst of its Energiewende, or energy transition. The transition was introduced in the early 2010s, with the goal of moving away from nuclear power and towards renewable energy.
“The combination of wind, solar and deep geothermal solutions is very attractive for the secure supply of energy for a big economy like Germany’s,” says Alexander Land, Eavor Germany's head of public affairs.
Heating is one of the energy transition’s greatest challenges in Europe, since it consumes the most energy and produces the most carbon dioxide.
The Eavor-Loop in Geretsried will generate heating for 30 000 households in the winter. In addition, a power station at the site will convert the geothermal heat to electricity year-round.
Eavor’s total investment in Geretsried is expected to reach €350 million. The return on investment will come over 30 years.
“The project and others like it will contribute to the stability of energy prices and energy autonomy,” says Eavor's Land.
The European Investment Bank loan is provided on a project finance basis, which means that it goes directly to the project without recourse to the shareholders. Because of the project’s innovative nature, its financial structure is complex and involves a consortium of lenders and a higher risk for the Bank.
“This is a first-of-a-kind project with an efficient financial solution. We are confident about Eavor’s ability to deploy other such projects in Europe and globally,” says Vincent Mansour, a loan officer at the European Investment Bank.
Eavor Germany has also begun working on a second project, in Hanover, which will supply 15% to 20% of the city’s district heating.
Wave energy harnesses the power of the ocean to generate electricity. With an estimated 1.8 terawatts of exploitable power capacity, waves are a promising renewable energy source that could play a role in meeting future global electricity demand.
CorPower Ocean, a Swedish wave-power technology company, has developed a large-scale solution to make wave power viable and economical. The power produced is complementary to wind and solar power and can add stability to the clean energy mix.
Founded in 2012, CorPower Ocean developed the wave energy converter, a technology inspired by the pumping principle of the human heart.
The heart uses stored hydraulic pressure to force its muscles to pump in one direction. CorPower’s solution uses the pressure stored when the wave pushes CorPower's buoy upwards to push the buoy back down. The result is smooth and equal production of energy in both directions.
The system features a buoy on the ocean surface, which is anchored to the seabed using an innovative mooring, anchor, and connectivity kit. “Our system offers more than five times the energy per tonne of installed equipment compared with other wave technologies,” says Kevin Rebenius, commercial director at CorPower Ocean.
A major hurdle for wave energy over the years has been rough weather.
“The challenge has always been building devices that are robust enough to withstand the harshest storm conditions, but at the same time are able to produce enough electricity compared to their size, weight and cost to make a viable business case,” says Rebenius.
Over the years, many wave-energy installations were either destroyed by storms or found not to be cost-effective. The key is to create infrastructure strong enough to withstand the power of the ocean at its roughest and to remain functional regardless of weather and wave conditions.
VianaWave, CorPower Ocean’s first project off the coast of Aguçadoura in northern Portugal, was inaugurated in August 2023. “We’ve faced four storms since it began operating, with the harshest storm exposing the buoy to 18-metre waves,” Rebenius says. “It was an important milestone for us, proving that the technology works even in the roughest conditions.”
During a storm, the buoys go into a protective setting called “detuned mode.” It's similar to the survival function of wind turbines, which pitch their blades to prevent overspinning. In normal sea conditions, the buoy is set to optimal timing with incoming waves, amplifying the motion and power captured.
“This is thanks to our innovative WaveSpring technology, which acts like a negative spring and multiplies the energy production by three,” Rebenius says.
CorPower Ocean has received project development assistance through the EU Innovation Fund for its pre-commercial wave energy project in northern Portugal. The European Investment Bank is providing the company with advisory assistance for capital structuring, to prepare fundraising materials, and to develop a new financial model to facilitate fundraising.
“Projects like VianaWave help drive innovation, scalability and market confidence in wave energy technology,” says Andrea Alessi, an engineer at the European Investment Bank. “They play a vital role in transitioning to a sustainable and resilient energy future.”
Wave energy has several advantages:
“Wave energy offers unique advantages across various power demand scenarios, including bulk systems, isolated distribution networks, and remote communities,” says Alessi. “It provides power in challenging locations, bolsters local resilience, synergises with other resources like solar, wind, and energy storage, and circumvents land limitations.”
“Investing in wave energy is crucial,” he adds, “as it adds diversity to the renewable energy mix, reducing dependence on fossil fuels and contributing to a more resilient and sustainable energy system.”
The benefits are clear. But since wave energy is still young compared to other renewables, the environmental effects of large-scale power stations have not yet been studied in-depth.
Building plants along the coast or laying electrical wires under water to harness the energy might have adverse effects on marine life and ecosystems. More research is needed to determine the environmental impact of wave energy infrastructure and to develop strategies to minimise potential negative effects.
In addition, harsh ocean environments, particularly in the Atlantic and the North Sea, raise challenges for the durability and maintenance of the infrastructure.
The success of CorPower Ocean’s project might be a turning point in deploying wave energy worldwide.
"We have demonstrated that wave energy is a viable option among renewable sources," says Rebenius. "The next step is to see more wave energy project developers and major energy firms adopt and develop wave energy farms, enabling us to accelerate the rollout on a global scale."
Compared to fossil fuels, biomass is a plentiful, renewable and eco-friendly source of useful energy. Biomass-based fuel can be produced from organic materials such as certain categories of wood and from agricultural waste. Unlike fossil fuels, biomass can be replenished through responsible forestry, waste management and recycling initiatives.
In addition, when biomass is burned, carbon dioxide released into the atmosphere is part of the natural carbon cycle. As trees and plants grow, they absorb carbon dioxide from the atmosphere, offsetting the carbon emissions released in the burning. This cycle creates a closed-loop, resulting in net-zero carbon emissions.
The utility company Teplárny Brno has embarked on a 15-year project to ensure a reliable and sustainable energy supply for Brno, Czechia’s second largest city, which has a population of nearly 400 000.
With the help of €75 million in financing from the European Investment Bank, the utility plans to upgrade its heat generation and distribution systems to cut emissions and lower the city’s dependence on gas imports.
“It’s a cogeneration system, which will provide not only heat for residential buildings but also electricity, which is crucial especially during peak demand periods,” says Jan Morawiec, a loan officer at the European Investment Bank who is based in Prague.
As part of this programme, Teplárny Brno will build a new biomass-fuelled combined heat and power unit that will cover 15% of Brno’s heating demand. The heat and electricity will be cogenerated by burning wood chips brought in by rail from sustainably managed forests around the city.
The project contributes to the REPowerEU plan of eliminating Europe’s dependence on fossil fuels and is aligned with the European Investment Bank’s Energy Lending Policy and its Climate Bank Roadmap 2021-2025. It also supports EU cohesion policy by investing in economically weaker regions to raise living standards.
“Biomass is expected to replace approximately 11% of natural gas in Brno by 2025,” says Petr Fajmon, Teplárny Brno’s managing director. “Modernising our power plant is the first big step towards an independent and sustainable energy system for the city. It will lower the price of heating and help ensure a stable supply.”
Teplárny Brno has been supplying the city’s heat since 1930 and is a European pioneer in combining heat and power generation. With the Bank’s help, the utility plans to modernise 5 km of pipelines, build 5.5 km of new pipelines, modernise 16 transfer stations, and build 105 new ones.
“We expect there to be a reduction in CO2 emissions of approximately 38 000 tonnes per year, a reduction in nitrogen oxides emissions of six tonnes per year, and a reduction in the use of non-renewable primary energy of 612 000 gigajoules per year,” Fajmon says.
Energy technologies like geothermal, wave and biomass are not as developed or as widely available as solar, wind and hydropower. “But these renewable energies are available all year round,” says Christos Smyrnakis, an engineer at the European Investment Bank’s renewable energy division. “They can provide a baseload to ensure a constant supply of energy.”