Government incentives continue to play an important role in electric-car adoption, encouraging drivers to plug in by sending them checks or giving them solo access to carpool lanes.

However, despite higher purchase costs, electric cars are attractive due to another major financial factor: home recharging.

Minnesota has now become the first state in the nation to mandate lower off-peak electricity rates for electric-car charging, Transport Evolved reports.

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While a number of public-utility commissions permit such rates--and many states also encourage the installation of public charging stations for plug-in cars--so far Minnesota is the only one to pass legislation requiring such an incentive for home charging at optimal times.

Power lines by Flickr user achouro

Power lines by Flickr user achouro

Signed into law by Governor Mark Drayton, the mandate (PDF) requires utilities to develop an electric-car charging tariff that includes a cheaper off-peak rate. It's set to take effect in early 2015.

This will not only guarantee a lower rate for Minnesota drivers who charge during off-peak hours (usually in the wee hours of the night), it will also encourage more of them to do so.

That, in turn, should help ease the anxiety of those concerned that electric-car charging will overload the power grid (although studies almost uniformly show that it won't).

The law is the result of lobbying by Connexus and Dakota Electric--two utility companies operating in Minnesota.

Dakota Electric already runs a pilot program that allows plug-in hybrid owners to charge at a reduced rate from 11 pm to 7 am.

In addition to mandating lower off-peak charging rates, the new Minnesota law requires investor-owned utilities to provide the option of electricity generated from renewable sources.

In practice, that mandate will take the form of an agreement between a green-minded customer and the utility.

For every kilowatt-hour consumed by that customer, the utility would either have to generate or import an equivalent amount of electricity from a renewable source.

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