Maryland plans to deploy a new tool in the race to get automakers to sell more electric cars in states outside California: The state plans to install 5,000 electric-car chargers across the tiny state.

Last week, the state's public utilities commission approved a proposal by four of its largest utilities to install the 5,000 chargers in an effort to sell 300,000 electric cars in the state by 2025 and reduce greenhouse gas emissions by 40 percent below 2006 levels by 2030. That's a lot of chargers for the nation's ninth smallest state.

Maryland is one of nine states (soon to be 10) that have joined California in requiring automakers to sell zero-emission cars—plug-in electric and fuel-cell models—in the state.

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So far, most sales of those models have been concentrated in California, though a change in the law last year is expected to require automakers to bring more cars to the other 8 states in the Northeast this year.

In response, the states have banded together to promote electric cars and to build infrastructure. One of consumers' main objections to electric cars is that they can't find a place to charge them, and even electric car owners complain of finding too many public chargers occupied or out of order. More charging infrastructure is a key factor in selling more electric cars.

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Maryland's plan calls for installing Level 3 fast-charging stations along highways where there are currently gaps in charging coverage for electric-car drivers, as well as subsidizing installation of chargers in workplaces, homes, and apartment buildings.

In return for Maryland electric ratepayers covering the cost of installation, the utilities are required to implement time-of-use electric rates to reduce charging costs for electric-car drivers, and give rate-payers a way to cut costs further. The utilities will also offer rebates to customers who install smart chargers that can communicate with the utility to find the most affordable, effective, and cleanest time to charge.

In announcing the decision, Maryland Public Service Commission Chairman Jason Stanek said, "Today’s decision not only ensures that charging infrastructure will support Maryland’s transition to electrified transportation, but also maximizes the benefits of smart charging while minimizing cost impacts to ratepayers."