Property, plant and equipment was comprised of the following as of September 30:
(Thousands)Estimated
Property ClassificationsUseful Lives20252024
Distribution facilities
10 to 54 years
$3,642,492 $3,436,308 
Transmission facilities
28 to 40 years
662,801 656,098 
Storage facilities
26 to 87 years
86,448 86,329 
Solar property
15 to 35 years
988,445 885,518 
Storage and transportation property
5 to 55 years
960,547 929,850 
All other property
5 to 40 years
66,298 62,248 
Construction work in progress547,347 440,164 
Total property, plant and equipment6,954,378 6,496,515 
Accumulated depreciation and amortization(1,144,279)(1,093,292)
Property, plant and equipment, net$5,810,099 $5,403,223 

About PP&E Disclosures

The PP&E disclosure details a company's physical asset base — land, buildings, machinery, and equipment — along with the depreciation methods and useful life assumptions that determine how these costs flow through the income statement. Capitalization policy thresholds reveal management's judgment on the boundary between expense and asset, directly affecting both reported earnings and asset values.

Key signals: changes in estimated useful lives or depreciation methods can materially shift reported earnings without any operational change. Compare capital expenditures against depreciation expense — when capex consistently trails depreciation, the asset base may be aging and underinvested. Watch for large asset impairments or write-downs that signal overvalued carrying amounts. Asset retirement obligations reveal future environmental or decommissioning costs that are often underappreciated. Compare PP&E intensity (PP&E-to-revenue) against industry peers to assess capital efficiency and competitive positioning.