Solar 84% cheaper since 2009 according to IRENA

The reposted publication states that utility scale solar costs fell about 84% since 2009 and that, in 2024, solar was the second cheapest source of new power generation worldwide, behind onshore wind.

The text does not say what falling costs do to the residual value of assets already installed. In Renewable Power Generation Costs in 2024, published by IRENA in July 2025, the global weighted average total installed cost of utility scale solar projects fell 11% in a year, to USD 691 per kW, while the levelised cost of electricity stood at USD 0.043 per kWh, up 0.6%.

A plant commissioned a year earlier competes with new capacity that costs less per kW installed. That compresses the asset's resale value and the price it obtains on recontracting, with no change in physical output. On a financed asset, the effect shows up in collateral and in exit value.

The value of an operating solar plant is measured by the cost of the plant that comes after it.