Maximising the output of ageing solar farms

Owners of ageing solar farms should look to partner with expert operations and management companies to squeeze every last megawatt-hour out of their assets, says Matthew Harnack.

Recent research from Aurora Energy predicts that there will be 18GW of unsubsidised renewable energy in northwest Europe by 2030. That’s more than five Hinkley Point Cs. But to make this forecast a reality, maximising the return of ageing solar farms has to be prioritised.

In solar’s early years, profitability was typically achieved by simply looking at outgoings, such as the costs of construction, and driving them down. Now, operations and maintenance (O&M) teams have to find new and innovative ways to maximise the output of solar farms. The focus has shifted: the industry is well established, unsubsidised solar is on the cusp of becoming viable, and profits are now more important than ever before.
During times of downward pressure on costs, simple power generation profiling shows it is vital to deploy quality O&M, rather than relying on a low cost approach.

The numbers speak for themselves: shaving £500 off the cost per megawatt per year of the O&M service will provide initial cost savings but could also significantly reduce the availability of the sites. The result? Reduced returns for the owner.

Modest estimates suggest this initial cost saving could ultimately result in a 1 per cent loss of availability, equating to around £1,300 of unrealised generation – an overall loss of £800/MW per year. Owners of solar parks should therefore implement quality O&M that does not compromise where it matters: excellent service, health and safety, regulatory compliance, and plant availability.

Technology, data and expertise

A comprehensive O&M outfit will employ a number of innovative technologies in order to lower costs and improve output – ultimately enabling profitability in a post-subsidy environment. This might include mechanical cleaning of panels, which is faster and more efficient than hand cleaning. Imagine hand-cleaning all 280,000 solar panels at our Bradenstoke park for example.

Technology has also unlocked highly effective ways to test panels for reduced performance or other degradation. For example, micro-cracks, which may not be visible to the human eye, can impact performance. Formed during transport and installation, these miniscule cracks can grow as panels are buffeted by wind over the years. An IV curve plots current against voltage for each panel. Any disturbance in that curve allows the micro-crack to be located and a solution to be found. Electroluminescence testing and fluorescence testing can also be effective methods of finding micro-cracks.

These innovative methods, alongside others such as thermography and insulation resistance testing, mean output can be significantly boosted by identifying and replacing defective or underperforming panels.

Increasingly, drones are the vehicles of choice when conducting thermography and electroluminescence tests on whole solar parks, and are able to cover numerous panels over a large area far more effectively than any specialist team on the ground.

An O&M A-team that has the ability to effectively roll out these technologies and that proactively works to squeeze out every drop of availability and profit will be essential as unsubsidised solar becomes the norm.

The owner should have 24/7 access to a single, named point of contact in the O&M team. This person should take responsibility for delivering quality O&M across the owner’s site or portfolio, understand each site’s specific requirements and respond quickly to any issues, championing their resolution within the team.

Quality, skilled engineering staff to improve the output of the solar parks is also essential. They can not only review test result data and recommend solutions but can also analyse site performance and propose new output-enhancing measures.

As solar parks age and out-of-date equipment fails, these expert engineers will need to find and install new quality alternatives. They will also often need the expertise to redesign and reconfigure the solar park in the process.

Ideally, an O&M team will pre-empt failures before the warranty ends by conducting regular stress testing on ageing equipment. Inspecting a cable or transformer for a fault, for instance, and discovering unsatisfactory performance can be used as the foundation for warranty claims that may deliver significant cost savings. Quality O&M will also rely on experienced legal and commercial support to aid with warranty and insurance claims.

The future

Looking ahead, O&M will be central to the success of subsidy-free solar. Cost reductions can be made, but solar park owners should look for a balance between short-term cost reduction and long-term quality and performance. New technologies and data capabilities, backed up by a qualified and experienced team, will enable both cost reductions and improved outputs. Only then can solar park owners and asset managers be sure to reap the benefits.