At the height of the storm Thursday night, close to 45-thousand Ameren customers lost electricity.
The rate increase approved Wednesday could mean an extra $10 a month on an average residential bill when it takes effect in January.
The statute forces investor-owned utilities to use increasing amounts of renewable resources to produce electricity.
Missouri utility regulators say there have been 30 electricity-related incidents in the state in the past two years.
7,800 outages at the height, still some 3,000 without power at 8:15.
Investments made since outages of 2006 will help greatly.
Residents are cleaning up in parts of southern Missouri after violent weather swept across the region, cutting power in scattered communities and causing minor damage.
The Missouri Public Service Commission approved a more than $160 million electric rate increase for Ameren customers in 2009.
The House voted 91-24 Wednesday.
The bill in question provides for an upgrade of the electricity delivery system, but consumer groups say it also makes it much easier for Ameren and Com Ed to raise rates.