OhmHour calculations incorrect?

Member Posts: 17

I've triple checked this, and want to see if anyone else is seeing mis-calculations during the last 3 OhmHours (haven't gone further beyond this).

10/10/2017 1:00-2:00 PM PDT OhmHour
Award rate: 5 pts per kWh saved
Forecasted use: -2.741 kWh
Actual use: -8.320 kWh
Calculated Points: +50% for a 10 in a row streak, 2X points for Platinum.
-2.741 - (-8.320) = 5.579 kWh
5.579 x 5 x 1.5 x 2 = 83.685 points
Actual Points: 42 awarded points

10/14/2017 2:00-3:00 PM PDT OhmHour
Award rate: 300 pts per kWh saved
Forecasted use: -5.704 kWh
Actual use: -6.900 kWh
Calculated Points: +55% for a 11 in a row streak, 2X points for Platinum.
-5.704 - (-6.90) = 1.196 kWh
1.196 x 300 x 1.55 x 2 = 1112.28 points
Actual Points: 915 awarded points

10/18/2017 5:00-6:00 PM PDT OhmHour
Award rate: 300 pts per kWh saved
Forecasted use: 0.775 kWh
Actual use: -0.500 kWh
Calculated Points: +60% for a 12 in a row streak, 2X points for Platinum.
0.775 - (-0.500) = 1.275 kWh
1.275 x 300 x 1.60 x 2 = 1224 points
Actual Points: 996 awarded points

Is there something logical error I am making so that I do not match up to OhmConnect's calculations.

Thanks.

• San DiegoMember, Moderator Posts: 1,625
I think you have the formula wrong.

Points = Base Points X (Status + Streak/100)

1.275X300X(2+0.6)= 996
• Member Posts: 17

I searched all through the FAQs and could not find the formula. Thanks.

The first example I gave might be inaccurate because it could have been before I hit platinum level.

• San DiegoMember, Moderator Posts: 1,625
There's a couple of mentions in the forum but it's not in the FAQ.

https://forum.ohmconnect.com/discussion/1244/calculating-your-ohmhour-points
• Union CityModerator Posts: 1,017
Would be good to get that formula in the FAQ.
• San DiegoMember, Moderator Posts: 1,625

@[email protected] Just be aware of the risk you take if you are available for OhmHours during the sunshine hours. The risk is that there's an OhmHour on a cloudy day and you go over your forecast because you don't generate enough. You will lose your streak and you'll be starting again from ZERO. Perhaps not a big deal when your bonus is 50% but when it gets to 400% you might be a little annoyed if you lose it for something "out of your control".

• Member Posts: 17

Understood, but I mitigate this risk nearly in full by using up all available solar during daylight hours to charge our two EVs.

Even on a cloudy day, the PV array is large enough that it feeds something back into the grid.

• Member, Moderator Posts: 414

@[email protected].com said:
Understood, but I mitigate this risk nearly in full by using up all available solar during daylight hours to charge our two EVs.

Even on a cloudy day, the PV array is large enough that it feeds something back into the grid.

• Member Posts: 17

I mean in realtime. My solar system has monitoring clamps installed on it, and I literally adjust the charge rate on the cars up and down as the sun passes over the sky (yeah, I work from home and it's a welcome distraction).

I also spread out the charge rate throughout the daylight hours, so that I don't have a constant time of day that I'm not charging.

The only sticking point is if the cars are fully charged, then there is little juice that can be sucked down from the solar (hence what you see on that day you pointed out).

At 2-3PM, i can pump back into the grid 8-9.5 kWh from the PV if nothing else is using power, on a sunny day.

Pool will go in later in the year or early next year, so with the pool pump, the baseline utilization will go up. This should give me some more cushion from "cloud day" streak threats.

Considering some Powerwalls as well, but haven't made that decision yet.

• Member, Moderator Posts: 414

@[email protected].com said:
I mean in realtime. My solar system has monitoring clamps installed on it, and I literally adjust the charge rate on the cars up and down as the sun passes over the sky (yeah, I work from home and it's a welcome distraction).

I also spread out the charge rate throughout the daylight hours, so that I don't have a constant time of day that I'm not charging.

The only sticking point is if the cars are fully charged, then there is little juice that can be sucked down from the solar (hence what you see on that day you pointed out).

At 2-3PM, i can pump back into the grid 8-9.5 kWh from the PV if nothing else is using power, on a sunny day.

Pool will go in later in the year or early next year, so with the pool pump, the baseline utilization will go up. This should give me some more cushion from "cloud day" streak threats.

Considering some Powerwalls as well, but haven't made that decision yet.

Wow, that's a ton of excess capacity! You're in a whole different category from me. Thanks for the clarification--it sounds like with the pool pump you'll potentially pull in some large OC payments, especially if you get more of those 300 points/kWh events!

• Member Posts: 17

My streak was broken this week because of an OhmHour during very cloudy weather, but I am perfectly fine with that, to be honest. It gives me incentive to further tweak my usage.

I've got 3 Tesla powerwalls on order now. Tesla says a future firmware update will allow you to "force discharge" them into the grid. If this does materialize, it will help recoup the cost of the powerwalls (over years, yes).

• San DiegoMember, Moderator Posts: 1,625

@[email protected].com said:
My streak was broken this week because of an OhmHour during very cloudy weather, but I am perfectly fine with that, to be honest. It gives me incentive to further tweak my usage.

I've got 3 Tesla powerwalls on order now. Tesla says a future firmware update will allow you to "force discharge" them into the grid. If this does materialize, it will help recoup the cost of the powerwalls (over years, yes).

As for the future firmware update ....there's obvious safety issues for people working on the grid if a homeowner can "force discharge" back into the grid. I would doubt that the utility would allow battery capacity to be "grid tied" and pumped back in. If they do, there will be surely be a plethora of rules around it and no doubt a different pricing structure is likely to apply making it difficult to "game" the system

• Member Posts: 17

@UkiwiS said:

@[email protected].com said:
My streak was broken this week because of an OhmHour during very cloudy weather, but I am perfectly fine with that, to be honest. It gives me incentive to further tweak my usage.

I've got 3 Tesla powerwalls on order now. Tesla says a future firmware update will allow you to "force discharge" them into the grid. If this does materialize, it will help recoup the cost of the powerwalls (over years, yes).

As for the future firmware update ....there's obvious safety issues for people working on the grid if a homeowner can "force discharge" back into the grid. I would doubt that the utility would allow battery capacity to be "grid tied" and pumped back in. If they do, there will be surely be a plethora of rules around it and no doubt a different pricing structure is likely to apply making it difficult to "game" the system

No, it doesn't work like you are presuming. If the grid goes down, the loadbox/gateway prevents ANY export to the grid (both by the solar and by the powerwalls). It's an inherent safety feature you have to agree to in order to get powerwalls.

If the grid is up, however, all is "fair game" in terms of force discharge to the grid.

• San DiegoMember, Moderator Posts: 1,625
So what price applies to the energy exported and doo you need a separate meter?
• Member Posts: 17

You do not need a separate meter, and the export price still falls under Net Metering for your residence. So if you are on a tiered plan, you get at that rate. If you are on a TOU plan, you get that rate.

The only general stipulation is if over the course of your net metering year, you are a net producer, then you get reimbursed at the "wholesale" rate. Which is a miserly 3-4c/kWh.

Because utilities are allowed to charge you "non-bypassable charges (NBCs)" under Net Metering 2.0, in theory you can be charged a nominal rate for energy you put into and pull from the grid. The NBCs are relatively small at 0.5 to 3c/kWh, but if you are say charging your car at night, those big utilizations can add up. The utilities say it is fair use charges for their infrastructure, but in reality it is just a revenue grab. Powerwalls allow you to circumvent NBCs by using your solar power stored from the daytime at night. Tesla and battery producers term this "Time of Use (TOU) shifting". Being able to force discharge back to the grid during OhmHours (or other peak demand situations) is just icing on the cake to help recoup the cost of the powerwalls.