Microsoft’s announcement yesterday that it had signed a 20-year agreement to buy all of the 110 megawatt Keechi wind farm’s electricity production marks a big step for the company in going “carbon neutral” through the purchase of wind and solar power. Its rival Google is way ahead, having invested more than $1 billion in wind and solar with contracts to purchase 570 MW of wind energy. But Microsoft “has been innovative in the way it funds its renewable energy purchases. Last year it began levying an internal carbon tax on its various divisions to encourage them to reduce their greenhouse gas spew.” [Quartz]

Prominent climate scientists from institutions like NASA and MIT are calling for acceptance of nuclear power as a necessary and scalable means of reducing emissions in a letter to environmental groups and politicians. The belief that new renewables will provide enough energy to satisfy global demand within the next few decades “isn’t realistic”, the letter says. [AP]

Burning wood pellets can be an effective means for coal plants to reduce emissions, and in some cases wood pellets are even cheaper than coal. But material quantity and quality can be unpredictable, and a pound of wood generates just two-thirds the energy of a pound of coal. [NYT]