The Texas Public Utility Commission’s February 2021 emergency rules allowing an increase in electric rates to $9,000 per megawatt hour in response to Winter Storm Uri were “invalid and ineffective” and “wreaked havoc” on the state’s power system, lawyers representing several large energy companies told a Texas appeals court Wednesday. A decision by the Austin Court of Appeals could impact the efforts by more than a dozen electric providers challenging billions of dollars in ERCOT invoices.