On my radar with Eize de Vries: Wind power does not need greenwashing to enhance its status

Our new series on wind industry developments and new technologies continues, as Eize de Vries looks at EU plans to tackle greenwashing and why wind power has no need to inflate its green credentials; plus component news from Vestas, Winergy and Aerovide.

 "CO2-free" would mean the end of life on earth (DrPixel/Getty Images)
"CO2-free" would mean the end of life on earth (DrPixel/Getty Images)


The European Commission on 22 March proposed rules to counteract greenwashing practices that would require European businesses and other organisations to back climate-friendly product claims with evidence. These measures are intended to stamp out misleading green labels for products and commodities such as e-fuels, renewable hydrogen, methanol and ammonia, and other claims made in wider societal contexts.

If approved, the EC rules will regulate common labels including "natural", "climate-neutral", "CO2-neutral" "CO2-compensated", "zero-emission", "towards-net-zero" and"‘carbon-negative". 

The aim is to tackle what the commission says is rampant greenwashing among products sold in Europe. 

If companies wish to use such terminology in future, businesses and other organisations must conduct science-based assessments for all significant environmental impacts and prove that their offerings live up to the claims made – or face financial penalties if they don’t.

Greenwashing has become widespread and is harmful for a number of reasons. It creates a false sense of achievemen and promotes a laid-back approach to the energy transition, instead of urging organisations to roll up their sleeves and find real solutions that make a difference.

I come across such claims every day and in all situations. 

A Dutch Tesla driver pledged exemption from the new national 100km/hour motorway speed limit, claiming that his battery electric vehicle (BEV) is CO2-neutral. He clearly "overlooked" that his vehicle-type, according to automotive statistics, uses on average at least 15-20kWh of electricity per 100km, and that non-renewables sources of electricity dominate the Dutch energy mix. 

One could further argue that any large heavy vehicle – electric or conventional – capable of accelerating fast and driving at speed generally contributes to above-average levels of tyre wear and road degradation. And also that collisions with smaller, lighter vehicles put the latter at a disadvantage in accident survival statistics.

Some greenwashing claims are embedded in wider misleading contexts. The title of a recent wind power piece read: “The transition towards a CO2-free society faces substantial resistance.” Taken in its literal meaning, "CO2-free" would mean the end of life on earth, as CO2 is essential for plants and trees growth – and human survival. CO2-free could alternatively mean 100% efficiency of all energy conversion, manufacturing, transportation and other processes involved, without net energy inputs and losses in lifecycle efficiency. However, this would only be possible if we experienced a status of perpetual motion – clearly a non-starter.

I regularly ask organisations behind obviously false greenwashing claims to explain the performance of their product or solution on a lifecycle basis, and where they would place system boundaries. The answers I receive are often vague, sometimes pointing to (or hiding behind) unclear industry standards, and taking direct inspiration from political motives (see below).

Is biomass really a renewable energy?

Image credit: Santiago Urquijo/Getty Images

Opposing views have been held for a long time over whether biomass – and nuclear energy, which is not discussed here – should be considered renewable energy sources. The European Commission and Parliament agreed in late March 2023 on a revised EU Renewable Energy Directive (RED), setting new goals for 2030, that biomass remains “a renewable energy source without exceptions”. Biomass currently accounts for about 60% of renewable energy generation in the EU, and “thus cannot be missed” in reaching the 42.5% renewables goal by 2030, starting from 22% in 2021.

The "renewable" status of biomass within RED rests on a narrowly defined system boundary. It assumes for wood an ideal situation where all the CO2 emitted during a tree’s growth cycle is re-absorbed instantly by a replacement seedling. However, this assumption and reasoning are based on several major omissions. The first and most obvious is that it fails to take into account an average 40–70-year growth period from seedling to full-grown tree and the parallel time lag requiring a gradual reduction of ‘extra’ CO2 still in the atmosphere per cycle, and for each individual burned tree too.

A wider system boundary would include all the energy inputs (and associated CO2 emissions) accumulated during soil preparation up to harvesting, pelleting, land and sea transports, through to handling and preparations until combustion. These are usually processes where mechanisation (mainly with fossil fuels input) has replaced human labour.

A third widening of the system boundary would consider the physics of specific energy sources (and associated CO2 emissions) when burned. The highest CO2 emissions come in descending order from burning wood, peat, coal and natural gas. Wood emits up to three times more CO2 than coal.

When modern wind power produces electricity, it is not CO2-free. And yet, it continues to be claimed – and not exclusively by laypeople – suggesting such CO2-free, or CO2-neutral, or equivalent nonsense status when producing hydrogen with wind, which requires an extra process step known as electrolysis. This additional conversion causes 25-30% additional losses deploying today's state-of-the-art technologies. And converting wind-produced hydrogen further into ammonia or methanol eats away again at any remaining system efficiency.

Wind power does not need greenwashing claims to cherish the fact that it is among the most cost-effective low-carbon renewable generating sources on a lifecycle basis, however it is measured. 

The added benefits of hydrogen, ammonia and methanol as essential building blocks in the energy transition towards low-carbon societies remain huge, despite their inevitable inherent conversion losses. These advantages should be used wisely, however: not wasted on applications such as domestic heating, but used instead to provide clean shipping fuels and fertilisers, and future ‘green steel’. Combining electricity and hydrogen production with wind additionally offers great grid-stabilising and energy storage opportunities, especially in circumstances where electricity supply regularly exceeds power demand and turbines would have to be switched off. Total system efficiency in these instances takes second place to the value added.

The wind industry should persist with efforts to get closer to ‘net zero’ at systems level by adding promising ‘carbon-negative’ elements. One example that continues to stand out and inspire me is the ground-breaking Blancair turbine concept developed by Hamburg engineering consultancy Spitzner Engineers (WPM 11/2018). This genuine out-of-the-box solution combines wind power generation, CO2 harvesting and removal, passive systems and sustainability enhancing benefits – although Blancair’s current status is not clear.


Innovative gearbox sun gear with advanced hollow composite shaft 

Geislinger gearbox sun gear shaft in carbon-reinforced composite was developed with Winergy and Vestas (pic credit: Geislinger)

Turbine supplier Vestas, drivetrain and drive components supplier Winergy and composite shaft and coupling provider Geislinger joined forces in 2020 to develop an innovative steel gearbox sun gear with advanced hollow composite shaft combination. Geislinger displayed a ground-breaking full-scale prototype assembly – a genuine wind industry novelty – at a German high-level drivetrain conference in March. Experts from the three project partners presented a paper on joint technology transfer, considerations regarding component design and lifetime prediction, manufacturing challenges and validation processes at the component, system and turbine levels. 

The main objective of this collaborative effort was the development and validation of a new, highly integrated driveshaft solution capable of encountering potential noise and tonality challenges with future onshore wind turbines. The combination of growing turbine sizes and ever-increasing power densities could make current and future drivetrains sensitive to tonality, in essence annoying audible tones caused by gear mesh excitations. 

Since drivetrain eigenmodes are susceptible to vibrations (excitations) induced by gear mesh, it is important to finetune its frequency behaviour. One option for tuning eigenfrequency behaviour is by changing the characteristics of the sun shaft’s torsional stiffness by – as is the case for the current development project – introducing carbon-fibre reinforced plastics (CFRP) for the shaft. 

This makes it possible to drive down torsional stiffness significantly, with a positive impact on drivetrain vibrations. Composite driveshafts are rather new in wind applications, except for at least one use example in a two-bladed upwind turbine where a shaft of this kind links the rotor and rear-mounted generator. However, composite shafts have been used in aerospace and marine propulsion for many years.

Advances for 25-year-old journal bearing, plus new main shaft expansion

Aerodyn’s 5MW offshore turbine pioneered drivetrain journal bearings (pic credit: Aerovide)

At the 1998 Hannover Messe industry fair, German consultancy aerodyn-engineering (now Aerovide) presented a fully integrated low-speed geared 5MW Multibrid turbine for offshore wind. The much-delayed 2004 prototype of a pioneering stepped planetary gearbox incorporated ‘first-generation’ journal bearings. 

The first Multibrid-type prototype with such journal bearings was a 1MW Winwind prototype of former Finnish OEM and licencee Winwind, followed by a 3MW WWD-3 prototype in 2004. Both were produced in modest numbers. 

Research projects into new-generation journal bearings for wind gearboxes by leading gearbox suppliers followed in 2008–2012, leading to prototypes and pre-series testing and validation from roughly 2013–2014. 

Journal bearings became serial fitting elements from around 2018, with leading gearbox brands now incorporating them as semi-standard in low and medium-speed gear stages. They are considered key enablers of today’s high torque densities of 200–220 Nm/kg. 

In several presentations at the March 2023 Aachen conference on wind power drives, drivetrains and systems engineering, single-blade installation was shown as a highly challenging operating environment for journal bearings. Largely stationary conditions with asymmetric peak loads make for a very unfavourable lubricating environment, especially challenging in terms of retaining a sufficient oil film between inner and outer bearing rings in the absence of rotation.

Deployment of journal bearings for main shaft applications is novel for the wind industry but could become a major trend. Many research projects on main shaft journal bearings that had started before the global financial crash of 2008 were later discontinued. 

RWTH Aachen Technical University developer the conical FlexPad journal bearing concept

Aachen’s TWTH technical university engaged in two PhD projects in 2019 investigating journal bearings for main shaft applications. The first involves development and validation of a conventional non-integrated four-point drivetrain layout with main shaft, two bearings and a gearbox layout with side torque support arms. The frontal journal bearing, as in the four-point solutions deploying roller elements, absorbs radial loads only, while the rear bearing typically absorbs radial plus axial loads. The second PhD project is on a disruptive conical journal bearing concept. A drivetrain conference participant hinted at a large-scale turbine model fitted with rotor/main shaft journal bearings, but asked for strict confidentiality and would say no more that I can reveal on the matter.


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