Every year, offshore wind looms bigger. The industry saw its second largest growth year last 2022. Oil majors are snatching up leases to build, sensing the winds shifting in favour of greener energy sources.
At the other end of the chain, a critical need is surfacing. To date, less than ten offshore wind farms have been decommissioned globally. Expertise is limited. Few operators have experience in the process, and there is currently no standard breakdown of how much it’ll cost.
In the next three years, about 50,000 tonnes worth of machinery is set to be decommissioned. Most of that will end up in landfills or incinerated, despite 80 to 85 percent of the weight of turbines being recyclable. This option also presents a negative cost to developers, as there are no known ways to generate revenue from completely removing a site.
Growing Pains
While the industry tries to figure out how to dispose of turbines, the machines are only growing larger, consuming more raw materials to produce and transport. Late last year Siemens Gamesa’s first SG 14-222 DD prototype was completed and first put to the test, setting a new bar for the world’s largest turbine after GE’s Haliade-X.
More orders are coming down the pipeline as markets continue to mature. By 2030, there may be more than 30,000 turbines installed globally. More can only follow as emerging wind markets work towards building the necessary infrastructure needed to unlock the 16,000GW capacity these regions are capable of opening up.
Faced with rapid growth and limited experience for retiring aged equipment, how is the industry planning to make wind even cleaner?
Creating A Cycle
Among green energy sources, wind energy has one of the lightest carbon footprints. Yet it still stands to be considerable given the rising demand for offshore wind globally.
Experts believe the pressure can be reduced by recycling instead of building components from scratch. Recycling can cut offshore wind’s carbon emissions per kWh by 35 percent, according to one study. Turbine recycling can potentially be a massive sub-industry in itself, generating around 20,000 jobs in offshore wind.
Innovations are already being deployed. Late last year Siemens Gamesa introduced a new kind of turbine that’s easier to break down into raw materials at the end of its lifetime, its parts to be used for new applications. A ten partner consortium that includes Ørsted, Vestas, and GE Renewable business LM Wind Power have announced a three-year project to develop cost-effective solutions for breaking down composites into reusable raw materials.
The bigger challenge is in finding what those applications are. “Recycling is only of benefit when the recovered materials have saleable end-products that prevent deployment of virgin materials,” says Chris Hill, Director of Operational Performance at research centre ORE Catapult.
A few intriguing and creative projects are emerging from the field. Re-wind, a joint research project funded by the US-Ireland Tripartite Research Agreement, has developed proposals for use of recycled blade components in civil engineering and architecture. In Denmark, some blades are living a second life as bike sheds. US-based startup Global Fiberglass Solutions breaks down the fibreglass from blades into raw materials for construction.
Keeping The Lights On
The new generation of turbines may be larger, but they’re also much more efficient than early models. This gives wind farms the opportunity to “repower”, which is essentially upgrading turbines instead of decommissioning and taking apart the entire structure.
Higher efficiency and reduction in manufacturing costs are some of the advantages of repowering that offshore wind can reap. Between 2012 and 2019, Denmark was able to increase capacity while dropping more than a hundred turbines from their fleet.
The technology is already in use in onshore wind, but in its infancy in offshore wind. It was only in 2018 that the first offshore wind farm was repowered in Sweden. But results are promising. Momentum Gruppen A/S, the owner of the said farm, estimates that repowering extended its lifespan by at least 15 more years and doubled annual production capacity from 5,000MWh to 11,000MHw.
Repowering also helps solve another increasingly pressing problem in the growing offshore wind industry: limited space. There’s only so much viable shallow seabed where farms can be constructed. Refurbishing existing installations optimises land use. “From a societal and economic point of view, it makes a lot of sense to repower–it’s a quick, easy and cheap way to take advantage of the sites with the best wind and reduce carbon,” says Ben Backwell, the Global Wind Energy Council (GWEC) CEO.
Extending The Lifespan Of Turbines
Early model turbines have an average lifespan of 15 to 20 years. But manufacturers and developers are hard at work to push that limit. With close monitoring and regular upgrades, a turbine can be made to operate up to 30 years.
Squeezing more years out of existing equipment places less strain on logistics. ORE Catapult senior analyst Angeliki Spyroudi estimates that extending the lifespan of turbines can produce the least emissions from vessels, as crews will only travel to farms for routine maintenance and minor repairs.
Life extension is expected to produce the lightest carbon footprint at 63 tonnes of carbon dioxide equivalent (tCO2e) per annum. In comparison, full repowering and partial repowering resulted in 2,707 tCO2e and 1,417 tCO2e, respectively.
Of course, decarbonising offshore wind is more about reducing vessel use. Repowered sites can offset emissions through higher energy production rates. Extending the lifespan of farms gives us more clean energy for longer whilst skirting emissions and the consumption of raw materials.
Ultimately, cleaning up offshore wind will be an effort that involves the entire supply chain. New turbines can be built to last longer, reducing carbon emissions from the considerable transport vessels it requires to put it together. Existing wind farms can be given a new lease in life with larger, more energy efficient equipment. Turbines that need to be retired can be broken down and repurposed for either new turbines, or other industries.
