Solar PV power plant lifespan

Assessing and monitoring the expected lifespan of a solar power plant is a complex task that involves an in-depth analysis of the many different factors that can impact the facility. In terms of a standard solar farm, this analysis is mainly based on a cross-cutting study that covers the design values and the useful life of the main equipment (predominantly modules and inverters) combined with an analysis of the condition and execution of the building and electromechanical work, as well as the facility’s ancillary components.

There are also other aspects that have an impact on the longevity of a solar power plant, such as the quality and frequency of preventive and corrective maintenance work, the availability of spare parts, the rate of replacement of damaged parts, and environmental conditions.

There are several types of maintenance that keep solar farms working in optimal condition:

• Predictive maintenance: This involves regular monitoring to analyse the state of the installations. Based on the results, targeted follow-ups are conducted for equipment with abnormal behaviour and preventive maintenance of the facility is scheduled.
• Preventive maintenance: These are basically regular facility inspections and overhauls, scheduled to minimise the impact on production and are conducted based on the manufacturer’s specifications, to keep the plant working in optimal, efficient condition.
• Corrective maintenance: This is scheduled or unscheduled (in the event of an uncontrolled incident) work to correct any malfunctions in the solar power plant’s operations.
• Engineering maintenance: Relevant assessments are conducted according to the applicable industry regulations, mainly due to updates to the regulations.

Industry stakeholders try to anticipate the evolution of business models that involve increasing the lifespan of solar power plants. While current market conditions allow building and electromechanical works to comfortably reach a 40-year lifespan with adequate O&M services, PV assets (modules and inverters) require an upfront provision of spare parts (MRA) to bridge the gap between their lifespan and that of the rest of the plant’s components.

Let’s take a hypothetical plant as an example, where modules and inverters have product warranties for 25 and 5 years, respectively. If the goal is for all components to reach 40 years of operation, an MRA for modules and inverters should be factored in starting from year 26 and 6, respectively, which will continue until the year the plant is decommissioned. Approximately 5% of the modules and 175% of the inverters will be replaced over this period.

However, as the industry matures, its major stakeholders have been able to offer longer and more extensive product guarantees (up to 30 and 15 years for modules and inverters, respectively) and performance guarantees (up to 12 years for modules), further boosting the lifetime projection of facilities that were unthinkable until very recently. There has been a change in business models over the last 10 years that implies an increase in the lifespan of solar power plants from 25 to 35 years, even to 40 years in the most ambitious models, thus shifting the paradigm of many renewable arrays and value chains in different markets. This paradigm shift will directly affect solar PV project developers, who will have to revisit, adjust and improve processes under a legal framework that now supports this durability of a solar farm.

It is worth noting that the change in life expectancy for PV projects does not limit its impact on new projects or projects under development. For those operating assets with modules that have reached a certain degree of output degradation, re-powering the plant is common. Again, the aim is to maximise the productive capacity within the limits of the legal framework.

With that in mind, it is interesting to see how the technological frontier has been pushed to align solar power plants with their useful life so that projects can reach their full potential.

Vector Renewables, through its Site Engineering service, verifies that plant design meets the lifespan stated in the contract with the property. Services also include the testing and analysis of operating solar farms so that the overall condition can be assessed, and realistic lifespan expectations can be provided.