Experience with Connected Solutions?

[richmke]

I am buying a house and planning to install solar. There is net metering in CT, so that solves most of the sizing issues. I am thinking of batters for backup (and a generator for backup to the backup, but that's not my question).

Anyone with experience with the Connected Solutions Program? How much incentive payment did you get? How large is your battery? How larger is your inverter?

With Active Dispatch, they can give you "up to" a 3 hour window. They don't say how small the window can be. I'm wondering if I need to size the battery and inverter so it can be discharged in one hour. I don't want to loose out on incentive payments if the windows are short.

Seems like with the new program (which is a 10 year program), if only 1/2 the battery capacity is used (on average), then it pays for itself. If it can use the entire 80% of capacity, then I Win! I could even consider a Sol-Ark 3 battery system to power the entire house without having to worry about load shedding.

Thanks in advance.

[peakbagger]

No experience, but in Mass, there are four or five incentives programs each with their own requirements. You really need to get the details on the incentives and design around them. It can be very fast payback with large commercial batteries in Mass.

[richmke]

I have the information. The issue I have is how much of the power of the battery will the Utility take (on average over the year)? Then I can calculate the benefit. I assume there is some relationship between the kWh of the battery and the kW of the inverter.

[soby]

The CT incentive looks very similar to the MA incentive based on what I was able to dig up here: https://www.eversource.com/content/c...emand-response.

The email I receive to warn me of an event usually comes the night before and looks like this:
Email.JPG

Events are usually 2 hours but they are sometimes the full 3 hours. On those days, they basically take over your inverter and you are locked out of making changes to the battery behavior. The inverter will divert all available solar power to the battery until it gets to 100%. Then when the event starts, the battery will start to drain and the full discharge rate until it hits about 15%. This is a chart of the discharge events I've encountered in 2020 and 2021:

CS.JPG

The blue bar over each number represents the number of hours out of 3. I have a single 9.3kWh LG Chem RESU10H hooked up to a 7.6kW StorEdge inverter. Most inverter/battery combinations max out at 5kW so that is the theoretical max you can output for the duration of an event. At the incentive rate, that would translate to $1,125 like the FAQ says but, in reality, that number will be lower and there's a couple of reasons why that would be.

1. Capacity: 85% of my battery capacity is just under 8kWh so at 5kW I can only manage 100min before the battery is drained for the day. That averages out to just under 4kW. You'll notice that the best I've ever done on a 2 hour discharge is 3.91kW early on. It managed to that again in 2021 but it was lower on average. 3 hour discharge events suck for me because the average drops down even further to under 2.6kW. The 3 hour discharges really drag the average down. If I had a second battery, even 3 hour discharges would be closer to the 5kW max.
2. Inverter Output Max & Time of Day: On the earlier discharges that start at 4pm, I am usually still producing a decent amount of power through the solar panels. My inverter can only output 7.8kW AC so, if my panels are producing more than 2.8kW, the battery output has to be reduced. For example, if the panels are producing 4kW, the battery can only discharge 7.8-4=3.8kW. This is an issue on 4pm-6pm discharges when it's sunny out and the battery never actually drains down to 15% after 2 hours.

You can maximize your rate by ensuring that you have at least 15kWh of usable capacity to discharge and an inverter that can extract the full 5kW at all times during that worst case 3 hour window.