Wind turbines have seen a steady increase in size since the early 2000s, with both the height of the tower and the length of the blades growing to generate more energy. Wind turbines are typically measured by their “hub height,” which refers to the distance from the ground to the middle of the turbine’s rotor. The average hub height for utility-scale, land-based turbines increased by 59% between 1998 and 2020 – bringing it to 90 meters (295 feet), roughly the same size as the Statue of Liberty.
The hub height of offshore turbines is projected to increase even further. In 2016, they had an average hub height of 100 meters (330 feet) and are set to increase to 150 meters (500 feet) by 2035.
The increased size of the turbines allows for greater energy generation capacity. In 2020, the average capacity of a newly installed wind turbine in the US was between 2.7-3.5MW. An increase of 8% in 2019 and 284% from 1999. This increase in size and capacity means that more power can be generated on any given wind farm, reducing manufacturing and maintenance costs, and maximizing yield on the site.
Fewer Turbines = Greater Risk
It is clear that bigger means better. These larger turbines can generate more energy by harnessing more wind, which is a positive development for the sector’s energy transition. However, increasing turbine size also increases the magnitude of the consequences when it comes to fire risk in wind turbines.
While increasing the hub height increases exposure to higher wind speeds, meaning a turbine can generate higher amounts of energy – it also means investors are putting more capital into singular units. Therefore, more is at risk if anything happens to the asset.
Even at their current hub height, turbines are typically located in remote locations to lessen the impact they have on local communities and to take advantage of better wind resources. While this is very advantageous for projects in regard to permitting, it does mean that if a turbine catches fire, it is unlikely to be extinguished before significant damage occurs.
In addition, there is an element of unknown territory that comes with these larger turbines. Fires occur most commonly at the turbine’s rotor, the highest part of the turbine. As turbines increase in height, so must firefighting equipment to enable firefighters to access the seat of the fire.
During the early stages of larger turbines entering the market, it is even more likely that fires that are difficult to combat will result in total loss of the asset.
Safeguarding a Project’s Financials
Bigger turbines cost more money – the bigger the size and capacity, the bigger the cost. So, to lose one turbine due to fire can be costly, to repair or, more likely, replace. But it also means your project is down on the amount of power it's producing - which is also very costly. This isn't ideal for the financials of a project and can raise concerns from the local community as well as investors.
In order to encourage investors to make these larger investments and increase their own risk, developers need to put their minds at ease by taking relevant precautions to protect these giant assets – including installing fire suppression technology.
Our report, The complete Guide to Wind Turbine Fire Protection, recommends the level of protection should progressively increase based on the capacity/size of the turbine due to the cost of a 1MW turbine being significantly less than an 8MW turbine. Investing in fire prevention for larger, higher risk turbines demonstrates to investors that these projects have been thought about holistically and that all possible risk factors, as well as how to mitigate against them, have been considered.
As turbines get bigger, so does the impact on operations and balance sheets, should one catch fire. It is a little bit like placing all your eggs in one basket – that’s all good and well until that basket gets dropped, and you break all your eggs.
As the global clean energy transition continues apace, and we become more dependent on renewable energy, installing fire suppression technology will become essential as turbines increase in size, to ensure energy providers can serve the demand of their customers, safeguard their own operations, and maximize return for investors.