Here's the difference, Pub 5695...

"Residential clean energy credit. The residential energy efficient property credit is now the residential clean energy credit." Clean Energy property is an energy consuming component.

"Energy efficient home improvement credit. The nonbusiness energy property credit is now the energy efficient home improvement credit." Energy efficiency is things like insulation, storm doors and windows, heat pumps.

The change in description is the first way to tell if you are reading something current.

"Residential energy property costs are costs of new qualified energy property that is installed on or in connection with a home...Qualified energy property is any of the following...
• Certain electric or natural gas heat pump water heaters; electric or natural gas heat pumps; central air conditioners; and natural gas, propane, or oil water heaters.
• Natural gas, propane, or oil furnaces and hot water boilers.
• Certain biomass stoves and biomass boilers.
• Certain improvements or replacements of panelboards, subpanelboards, branch circuits, or feeders."

"Qualified energy efficiency improvements are...
• Any insulation material or system and air sealing material or system that is specifically and primarily designed to reduce heat loss or gain of a home when installed in or on such a home.
• Exterior windows and skylights.
• Exterior doors."

Solar is nowhere on any of this, because it is generation property.