I have Eversource, too. And had no option to sign up to CS via Tesla. Tesla takes a maintenance percentage off the top. But I'm OK with that. BTW, Tesla did a poor electrical job at the service panel wiring and FAILED the local inspection. Tesla, to its credit, came out less than a week later and fixed it. Now the wait for Eversouce to replace the meter and finish the job. Been waiting since last August. But optimistic. Missing some of the best sun power days: long days, no leaves on trees. Good luck with yours!
Connect Solutions is a virtual power plant of distributed residential energy storage in New England that pays the battery owner about $1000 for an average Powerwall to supply about 5kw of power over 2-3 hours about 60 times a year.