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Saturday, June 12, 2021

Portland Virtual Power Plant

Portland General Electric is starting a virtual power plant pilot program and we've signed up for it. 

 A Virtual Power Plant is like Energy in the Cloud ☺

What is a Virtual Power Plant (VPP)? 

A VPP allows your electric utility to utilize residential energy storage systems to balance the grid energy needs. You may also see this referred to as utilizing "behind the meter assets." 

If you have a Tesla Powerwall (or another home battery system), normally, that battery in your garage or on the side of your home is only going to respond to your home's demands. Unlike solar, home batteries are usually not allowed to feed energy into the grid. A VPP frees your battery from this restriction and allows it to respond to the grid's needs too. A VPP can be used to reduce or eliminate spinning reserves or peaker plants. 

VPP Example

Say it's a hot day in August at 6PM. People arrive home and turn on their air conditioners (AC), fans, and start cooking diner. This places a big demand on the grid. Let's say that you have solar and home batteries. For round numbers, let's say your solar is generating 4kW, your home is using 2kW, and your batteries are full. The extra 2kW that your solar is generating helps the grid by effectively carrying the load of one additional home in your neighborhood. This is good, but not great since the Powerwalls are not being used in this first example.

Now, let's say it is peak price time and you are on a time-of-use plan. In this situation, your home battery would be discharging to carry your home's load. This allows the full 4kW from the solar panels to feed into the grid. This would mean that your solar would be carrying the load of 2 of your neighbors. This is better than the first example, but we can do even better. 

A VPP allows the utility to dispatch your batteries for more than just your home's needs. So on this hot day, when the grid is burdened, rather than firing up a peaker plant, the utility sends a dispatch message to your batteries (and hundreds of others) to ask them to start discharging near their sustainable rate. Let's say you have 2 Powerwalls and they can continuously discharge at a rate of 10kW. Now along with the solar, you are sending 12kW of power into the grid. This is enough to run 6 homes on your block.

Scenario Solar Production Powerwall  Output Grid Feed-In Homes Supported
Solar Only 
(or Powerwall in Backup Only mode)
4kW 0 2kW 1
Powerwall with TOU 4kW 2kW 4kW 2
Powerwall with VPP 4kW 10kW 12kW 6

This example is for just one home. A virtual power plant could have hundreds or thousands of homes participating and if each of them can ease the grid of the burden of 4 to 10 other homes, then you start to see why the utilities are interested in this idea. 

How Much Of The Battery Capacity Can They Use?

You get to define the 'Power Outage Reserve.' This means you can keep whatever percentage of the battery you'd like for your own peace of mind. In the winter (when outages are more likely here), I keep the reserve at 60%. In the summer, I lower it down to 30%. Even if we have an outage during the summer, we have more energy coming from the solar panels, so I'm not worried about keeping the batteries too full. 

What's In It For Me?

Okay, this helps the grid, but it will cause extra cycling wear and tear on my battery and if there is a power outage, my battery might be lower than it would have otherwise been. Utilities don't expect you to do this out of kindness, there are incentives for participation.

VPP programs have various incentives and payments for the people that participate. Some give you several thousands of dollars of incentives to install home batteries, others even give you the batteries for free. Some pay you for every month that you are in the program, others pay you per event or per kWh.

The PGE program that I'm enrolling in will pay participants $20 per month if they have solar. Ironically, if you DON'T have solar, you get paid $40 per month. You are paid more because the utility can also charge your battery at their discretion when they have surplus power available. When you have solar, the rules are generally written such that you can only charge home energy batteries with solar. 

If you are participating in the Energy Trust of Oregon's Solar Within Reach program, you may be eligible for an instant $5,000 rebate in addition to the above monthly $20. 

If you are within one of PGE's 3 Smart Grid Test Bed areas and you are one of the first 200 to sign up, you may be eligible for an instant rebate of up to $3,000 in addition to the above monthly participation funds.

How Big Is The PGE VPP?

This is a 5-year pilot program with up to 525 homes and up to 4 megawatts of dispatchable power. That's an average of ~7.6kW from each home. Our 3 Powerwalls can provide about twice that much. I guess they expect the average participant to only have 1 or 2 Powerwalls or (more likely) they will not be using the system's full potential. 

Which Home Energy Storage Battery Brands Are Supported? 

The PGE VPP currently supports home battery systems from Generac, SolarEdge, Sonnen, Sunverge, and Tesla.

If you want Tesla Powerwalls and/or Solar, you can use my referral link.

If you want to sign up for PGE's VPP pilot, here's the link

I'm Long Tesla

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