The expected useful life of US-based utility-scale photovoltaic (PV) projects is growing longer, while the forecast operating expenditures (OpEx) have decreased, according to research from the Lawrence Berkeley National Laboratory.
The study entitled ‘Benchmarking Utility-Scale PV Operational Expenses and Project Lifetimes: Results from a Survey of US Solar Industry Professionals’ draws on a survey of US solar industry professionals and other sources.
It found that solar project developers, sponsors, long-term owners, and consultants have increased project-life forecasts, from an average of about 21.5 years in 2007 to about 32.5 years in 2019.
Current assumptions range from 25 years to more than 35 years, depending on the organisation; 17 out of 19 organisations from which data were obtained use 30 years or more.
Levelised, lifetime OpEx estimates have declined from an average of circa $35/kW per year for projects built in 2007 to an average of about $17/kW a year for projects built in 2019.
The measure of OpEx used was defined to include scheduled and unscheduled maintenance, operations personnel, land lease costs, property taxes, and any other ongoing operation costs.
Across 13 sources, the range in average lifetime OpEx for projects built in 2019 is broad, ranging from $13 to $25/kW a year, the study found.
It added that operation and maintenance costs – one component of total OpEx – have declined precipitously in recent years, to $5-8/kW a year in many cases.
Property taxes and land lease costs are highly variable across sites, but on average are of similar magnitude.
The levelised cost of energy of utility-scale PV projects fell from an average of $305 a megawatt-hour (MWh) for projects built in 2007/2009 to $51/MWh for those built in 2019.
This reduction was largely due to lower upfront capital expenditures, but about 9% ($22/MWh) was due to improvements in project life and OpEx.
Had project life and OpEx not improved, the levelised cost of energy in 2019 would have instead averaged $73/MWh, making it 43% higher, the study said.
The useful life of PV projects and their OpEx serve as indicators of the levelised cost and profitability of utility-scale PV plants, it added.
Lawrence Berkeley National Laboratory said the data can also provide useful benchmarks to the solar industry, helping developers and asset owners compare their expectations for project life and OpEx with those of their peers.
The research was funded by the Solar Energy Technologies Office of the US Department of Energy.