The global energy industry is no stranger to headlines shouting about environmental damage. Usually these stories talk about problems caused by fossil fuels, but last month saw a flurry of headlines about the surprisingly high environmental cost of wind turbines. Reports surfaced that the decommissioning of over 8,000 turbines in the US and 3,800 in Europe has created huge amounts of unsalvageable refuse – particularly the gigantic fibreglass blades.
Because turbine blades are exceedingly long – offshore models have reached 107-metres in length but onshore units are pushing 70 metres – are also built to withstand hurricane-level winds, they’re virtually impossible to recycle or repurpose: the only way to dispose of them is to chop them up and bury them.
This ‘solution’ is not only counterproductive from a sustainability perspective but overlooks the fact that this many of these turbines could still have decades of safe service in them, so with the number of machines due for decommissioning set to rise significantly in the next decade, the industry urgently need to find ways to manage and mitigate the problem. Innovative technology like digital twins could be key to this.
Although most turbines are sold with a 20-year recommended operating life, many are dismantled and buried after only ten, often as operators repower projects with newer, more efficient models. In many cases though, the overriding rationale is concern over the condition of the blades. Worn out blades are a safety hazard that leads developers to use over-conservative judgements to disassemble turbines earlier than necessary, artificially limiting our renewable energy production levels. Its worth noting too, that even a 20-year field-life is in itself likely to be conservative estimate, based on worst-case environmental scenarios factor in at the design stage.
And this is all about to get worse both because more turbines than ever are hitting their recommended end-of-life dates, and the fact that new blades are twice the size they were a decade ago. In Europe, thanks to stricter waste management regulations, operators are already running into major problems disposing of old blades. And if the issue continues to hit headlines in the US, then developers could soon face new regulatory obligations there as well.
Here is where digital twinning can come in. In the long-term, the challenge will be addressed by developments in material science that allow for either better recycling of existing blades, or the creation of new turbine designs, engineered to be broken down and reused. But In the meantime, the industry needs to take pre-emptive action by investing in technology that can help reduce the rate of decommissioning by extending the life of assets.
Extending the life of wind turbines requires operators to have visibility of the entire asset, with a detailed and accurate view of each individual component – detailed structural analysis of every part provides a far more accurate estimate of fatigue life.
The industry urgently need to find ways to manage and mitigate the problem of blade waste
Decisions about whether to decommission a turbine, usually made after a physical inspection, could be comprehensively improved using a physics-based digital twin that uses data from sensors across the asset to build a near real-time digital replica.
This would be far more detailed than a one-off inspection, allowing operators access to the real-time condition of the turbine 24/7, and enabling highly configurable simulations to address uncertainties in loading conditions and material properties. If the wind conditions at the site are lower than initially anticipated, for instance, this can be incorporated into the model, allowing operators to more accurately understand the remaining life of the asset.
Such insight becomes even more valuable when considering a turbine’s 20-year lifespan is only a recommendation. Introducing a digital twin allows guesswork to be replace by an unprecedented level of understanding of the real structural life of machine. Having a holistic view of real-time asset condition means that engineers can quickly identify any elements that are in danger of wearing out and carry out pre-emptive repairs, at once helping to avoid early decommissioning and reducing operating cost.
Managing the energy transition is the biggest challenge facing humanity today. We need to enable wide-spread renewable energy generation. A key part of that transition is ensuring that renewables – especially wind – is as efficient and as a result, as cheap as possible, which means eliminating unnecessary decommissioning and preventing additional waste.
Giving engineers the digital twining tools that provide full visibility of structural integrity will prevent many turbines from being pulled down and buried in the ground before their time. It’s up to operators to invest in this technology to help strike the precise balance between efficiency and caution and decommission assets at their true end-of-life – which could be up to 25 years later than planned.
· Jonas Ballani is core technology developer at wind power sector software specialist Akselos