PETCOKE: Michigan regulators deny a permit to store petroleum coke on the River Rouge near Detroit. (Detroit News)

EFFICIENCY: A federal loan program to promote vehicle fuel efficiency trickles down from the big automakers to the supply chain. (Midwest Energy News)

***SPONSORED LINK: Tour beautiful and sustainable homes in the Twin Cities area  May 31 on the EcoMetro Sustainable Living Tour. Homes feature innovative technology that tackle the challenging combination of cold winters & hot summers with smart design choices, cutting edge building techniques, and on-site renewable energy systems.***

OHIO: TV ads prelude a House vote on a bill to freeze Ohio’s renewable energy and efficiency standards, which could come as early as today; and religious groups rally against the bill. (Columbus Dispatch)

GRID: Duke Energy is seeking nearly $10 million in compensation from the PJM Interconnection, which it says ordered it to activate generating facilities that weren’t needed. (EnergyWire)

EPA: Environmental groups threaten to sue the EPA over a new cooling water rule, calling it “largely worthless.” (Bloomberg Businessweek)

FRACKING: A federal worker safety agency will investigate drilling practices following four oilfield deaths from chemical exposure. (Bloomberg)

OIL: Minnesota’s governor signs a bill requiring railroad and pipeline companies to help fund emergency response training, and a North Dakota refinery is $50 million over budget but still expected to begin operations in December. (Associated Press, Forum News Service)

TRANSMISSION: South Dakota landowners raise concerns over a proposed transmission project. (Aberdeen News)

CLIMATE: A forum at Northwestern University discusses the challenges of storing carbon. (Medill Reports)

***SPONSORED LINK: Only 2 days left to RSVP for Energy, Climate and Rural Minnesota’s Future, hosted by the Center for Rural Affairs, Thursday in St. Peter. We’ll discuss the impacts of climate change and solutions that will bring new opportunities to rural Minnesota.***

SOLAR: How cutting “soft costs” can drive down the price of solar power. (Greentech Media)

COMMENTARY: Ohio will “advertise its regression to employers and investors across the country and around the world” if legislators pass a bill freezing the state’s renewable and efficiency standards. (Toledo Blade)