A solar farm upstate, a discount on a Queens bill

I · How a subscription actually works

When you subscribe, you are buying the rights to a slice of one specific solar project's output, usually enough to roughly match your own yearly electricity use. Each month that project sends power to the grid, and the state's compensation formula, called the Value Stack under a policy known as VDER (Value of Distributed Energy Resources, the rule that sets what a project earns for the power and grid benefits it provides), turns that output into a dollar credit assigned to your account.

In New York City this usually runs through consolidated billing, which means a single Con Edison bill carries both your normal charges and the solar credit. You then pay the subscription company for the credit you received, but at a discount, so the credit is worth more than what you pay for it. The gap between the two is your savings. Nothing gets installed at your home, and there is nothing to maintain.

II · The honest math on savings

Savings run smaller than the flyers suggest. At last public report, most New York community solar subscriptions advertise a discount on the order of 5 to 10 percent of the value of the credits, which for a typical city apartment lands somewhere between a few dollars and maybe fifteen dollars a month. It is a discount, not a windfall, and it moves with your usage, since a hot August with the air conditioner running earns more credits than a mild May.

Read what the discount is measured against. A reputable offer discounts the value of the solar credits you actually receive, so you can never pay more than you saved. Be wary of any pitch that promises a flat guaranteed dollar amount every month, or that bills you in a way that makes the credit and the charge hard to line up. If you cannot match the credit on your Con Edison bill against the charge from the subscription company, you cannot check whether you are ahead.

III · The fine print, and the scams

Community solar itself is legitimate and regulated by the New York Public Service Commission, but the companies selling subscriptions vary widely in quality. The warning signs are consistent: an up-front fee to join, when a real subscription should cost nothing to start; a long lock-in with a steep cancellation penalty; or a salesperson who wants your full Con Edison account number and a signature before leaving you anything in writing.

Anyone can read your account number off a bill, so treat it the way you would a credit card number. Legitimate subscriptions in New York are meant to let you cancel with limited notice and no large exit fee, and they should hand you the contract terms to read on your own time. If a door-to-door pitch pressures you to sign on the spot, that pressure is the tell, so close the door and look the company up first.

IV · Worth watching this week

1. NYSERDA's NY-Sun pages list active community solar projects, so check that any project you are offered actually appears there before you sign anything.

2. The state Department of Public Service continues to review community distributed generation and the Value Stack, and any change could shift future credit values, though nothing is set to hit your bill this week.

3. Con Edison's community solar page shows which subscription providers can bill through your utility account, a routine but useful check before you hand over information.

4. Your own Con Edison bill is the real audit, so watch for the solar credit line to appear within the first two or three billing cycles after you enroll and call if it does not.

5. Because heating and cooling swing your credits, compare a summer bill against a winter bill before deciding whether the subscription is worth keeping.