FRANKFURT—Germany’s federal network agency on Wednesday curbed the permitted return on new infrastructure for power and gas networks in the years to 2029 in a move aimed at protecting consumers from higher energy bills. In its equity interest rates for the networks published on Wednesday, the authority proposed a permitted return for new infrastructure of 5.07 percent, versus 6.91 percent now, in the regulated sectors, where costs are recouped through fees levied on prices paid by energy customers. The move, which the authority said was led by the general interest rate environment, comes as a surge in energy prices has left consumers facing an expensive winter heating season. The grid element accounts for just over a fifth of the final bill paid by power consumers, while in gas it is a quarter, industry statistics show. The new rates will apply in the five-year periods starting 2023 and 2024 respectively. Rates …