A $2 million donation by Orange-based Avangrid is helping keep a rebate program for zero-emission vehicles on the move.

The Connecticut Hydrogen and Electric Automobile Purchase Rebate program, which was launched in 2015, provides direct financial incentives up to $5,000 for Connecticut residents who buy or lease a new zero-emission vehicle. That includes vehicles that run on batteries or electricity as well as plug-in hybrid-electric along with cars and trucks that operate on hydrogen fuel cells .

Nearly $4.6 million in rebates has been issued or reserved for the purchase or lease of 2,135 electric vehicles in Connecticut, according to state environmental officials, Gov. Dannel P. Malloy said in a statement.

“Connecticut has made tremendous strides over a short period of time in helping to put more electric vehicles on the road and we remain committed to this effort because it represents a triple win of increasing our energy independence by reducing fossil fuel consumption, creating new opportunities for growing our green economy and improving public health,” Malloy said in a statement. “This rebate puts money right back in people’s pockets, providing an added incentive for consumers to embrace new approaches and help lead the way to a more sustainable future.”

The program initially was funded using money made available through the 2012 merger between of what then was known as Northeast Utilities and NStar. State officials agreed not to stand in the way of the merger in return for a series of concessions from the company, which then changed its name to Eversource Energy.

The $2 million the rebate program is receiving also is coming from an energy company merger — the 2015 union between Iberdola and UIL Holdings, which owned The United Illuminating Co. and three natural gas utilities.