Green Mountain Power has joined the ranks of utilities like Xcel Energy that are working toward 100 percent carbon-free electricity. The Vermont-based utility will target 100 percent carbon-free by 2025 and 100 percent renewables by 2030.

In December, the company said its power sources are already 90 percent carbon-free, so the 2025 deadline won’t be a huge reach. At the same time, Green Mountain said its mix was over 60 percent renewables, coming from mostly hydropower. 

To build up to its 2030 renewables target, the utility plans to increase its purchases of wind and hydropower and add local distributed resources and energy storage.

Currently, most of Green Mountain's electricity supply comes from power-purchase agreements. According to its latest integrated resource plan (IRP), filed in 2018, GMP gets just 20 percent of its supply from utility-owned sources that include hydro, solar, oil-fired and wind projects.

The utility also buys and sells renewable energy credits, but Josh Castonguay, Green Mountain's vice president and chief innovation officer, said in an email that only 18 percent of GMP's power supply is associated with the trade of those credits.  

Green Mountain's service territory covers more than 75 percent of the Northeastern state.

Renewables and storage

Looking to 2030, Castonguay, who also leads Green Mountain's power supply team, said the utility is "focused on dramatically ramping up in-state renewable generation," which it defines as including solar, hydropower, wind, biomass and cow manure digestion. The utility will also focus on regional resources from Canada, New York and New England to build its supply.

In its IRP, Green Mountain specifically pointed to the addition of distributed renewables, hydropower and regional offshore wind. In that document the utility said it assumes the deployment of 50 and 100 megawatts of “additional storage and flexible load resources” will take place in its territory in the next decade. Castonguay affirmed that "storage will be critical" in its plans. 

Green Mountain has already partnered with Tesla on a residential battery program for about 2,000 customers. In addition to two existing solar-plus-storage installations, it’s working on three new projects, totaling 14.4 megawatts of solar and 6 megawatts of storage. The utility said the latter projects will provide an array of benefits including frequency regulation and money-saving during peak pricing.  

Building up Green Mountain's renewable power supply will help Vermont meet the state's requirement that electricity sales reach 75 percent renewable energy by 2032.

According to a report released last year from Environment America, Vermont has significant work to do on in-state renewable generation. The state also plans to reduce greenhouse gas emissions 50 percent below 1990 levels by 2028.

But Green Mountain has framed its thinking beyond state-level benefits. In announcing the targets, President and CEO Mary Powell cited a report released this fall by the United Nations' Intergovernmental Panel on Climate Change that laid bare the short timeline left to fight the impacts from climate change. 

“The report issued in October of 2018 shows we have just 12 years to bend back the curve on carbon,” she said in a statement on the carbon-free and renewable announcement. “Green Mountain Power is determined that through innovation, collaboration and grit, we can make remarkable strides and be the example of the change we want to see.”