Wind Turbine Lifespan: The Power of Repowering
Wind turbines generally have an approximate life span of 25 years. However, with age, their mechanical parts degrade - leading to a decrease in their overall efficiency. Here we will examine the technique of repowering, why it’s a good option for ageing turbines and how it can maximise energy output.
What is repowering?
Repowering is the replacement of an older wind turbine with a newer and more efficient one, on the same site. This involves dismantling and removing the old turbine, including the tower and turbine foundations, before replacing the generating equipment. The turbines we reference to here are generally 50 – 250 kW in size.
Unlike the rest of the UK, in Northern Ireland under the Northern Ireland Renewables Obligation (NIRO), developers were permitted to install second hand machines. At the beginning of the scheme, many developers and landowners installed refurbished machines. Many of these machines were already at least 10 years old and halfway through their 20 year support under NIRO. So, for many turbine owners, now is a perfect time to consider repowering. Let’s look at the benefits…
Benefits of repowering
- Improved performance of generator - taller hub heights and longer rotor blades enable more wind energy to be captured;
- Maximised energy output - power output can be enhanced, with the possibility of doubling annual production. A new machine can be tailored to the local wind resource (from real data gathered on site)
- Improved reliability - modern components tend to be more dependable and allow for more consistent generation. Older turbines tend to have more operation and maintenance issues
- Spare parts - these can be scarce for older machines and some manufacturers are no longer in business, therefore driving up the maintenance and repair costs as they age.
- Easier to insure - some insurers will not insure a turbine after 10 years in operation due to concerns e.g. stress fractures. Seeking insurance elsewhere can be difficult and costly.
What to consider
There are various issues to consider when thinking about repowering:
- Ofgem requirements – Ofgem must be notified of any changes to a generator and have specific processes to follow and information to assess.
- Planning – liaison with Planning NI will be required. However, the extent of this depends on the significance of the changes to the original planning consent.
- Land leases – if the turbine owner is not the landowner, a land lease extension negotiation may be required.
- Legal opinion – as suggested by Ofgem - a third party legal opinion should be sought on implications on the new installation, to ensure any potential issues are identified at an early stage.
The big picture
A large amount of onshore wind generation was installed at the start of the ROCs scheme – for example approximately 23 MW was installed in 2010. These turbines may already be nearing the end of their life, or will be in the next 5 years. This could lead to a decline in the renewable generation from onshore wind, as turbines may be switched off, due to old and unreliable equipment and lack of financial incentives. Looking ahead, to 2037, when NIRO ends for all participants, the operation of these plants may no longer be feasible.
At the moment there is no specific energy policy in Northern Ireland regarding repowering. It is vital that renewable energy targets continue to be included in NI energy strategy and that the repowering of existing sites and wind farms is recognised in our energy policy. Doing so will help maintain the installed capacity of onshore wind and deliver on our renewable targets.
We can provide full project management including project feasibility, economic analysis, Ofgem liaison, guidance and support. To find out more visit our Energy Solutions page or contact our large scale generators team for a quotation.