ENBRIDGE: Federal regulators, citing a “pattern of failures,” will require a safety improvement plan for Enbridge’s entire U.S. system before allowing it to restart a pipeline that ruptured in Wisconsin last week. Meanwhile, Canadian officials will conduct a safety audit of the company’s control room procedures. (Reuters)

ALSO: A dispute between Enbridge and a Colorado company over a connection to a Minnesota terminal is taken to the State Department, covering some of the same legal ground as the Keystone XL debate. (Greenwire)

WIND: A Senate panel yesterday approved a one-year extension of the wind production tax credit after Iowa Sen. Charles Grassley threatened to side with Democrats on the issue. (New York Times)

MEANWHILE: Chicago-based Exelon Corp., one of the largest wind power producers in the U.S., is calling for an end to the production tax credit. (Chicago Tribune)

ETHANOL: Industry backers say E15 will save drivers money. But a closer look at the numbers shows that isn’t necessarily true. (Midwest Energy News)

CLIMATE: A Democratic congressman introduced a bill yesterday that would impose a tax on carbon emissions. (The Hill)

NATURAL GAS: Alliant Energy announces plans for a new $700 million natural gas plant near Marshalltown, Iowa, at a site once under consideration for a new coal generator. The utility will also spend $400 million upgrading two coal plants elsewhere in the state. (Des Moines Register)

NUCLEAR: A new report finds community-wide disaster training in Cedar Rapids,  necessitated by its proximity to a nuclear plant, helped prevent fatalities during the 2008 flooding that devastated the city. (ClimateWire) 

FRACKING: Energy experts say Ohio Gov. John Kasich’s claim that the state has a trillion dollars worth of oil and gas reserves is “way off base” and “probably wrong by a couple of zeroes.” (Associated Press)

LIGHT BULBS: GE announces a fully dimmable CFL bulb, and 3M plans to begin selling a $25 LED bulb with a 25-year lifespan by the end of the month. (Cleveland Plain Dealer, St. Paul Pioneer Press)

WASTE-TO-ENERGY: Methane gas from a Columbus, Ohio landfill will be harnessed to generate electricity and power vehicles under a $25 million deal announced this week. (Columbus Dispatch)

COMMENTARY: In a Huffington Post interview, Michael Liebreich, CEO of Bloomberg New Energy Finance, says “a different and better energy system is not only just possible, it’s inevitable”; and Media Matters outlines a detailed history of how the Wall Street Journal editorial board has for decades been “on the wrong side of science.”