Netmetering and Buy-All / Sell-All

The utilities operating in Northwest lower Michigan have very different policies for solar.

Consumers Energy: Passage of SB 437 and 438 has created uncertainty for Consumers Energy customers. The current true net metering program is in place for at least two years and customers will be "grandfathered" for at least 10 years.

When rules for the new laws are issued in 2019, the new "Distributed Generation" system will be in play. The 2009 MPSC ruling on identical wording in PA295 was that systems under 20kW are entitled to true net metering, even though the law says otherwise. In 2018 and 2019 this issue will be argued between the regulated utilities (Consumers and DTE) and the Public Service Commission.

The optimistic outcome is that true net metering will be preserved. The pessimistic view is that the letter of the law will be upheld and true net metering will be ended. The law, as passed, reduces the credits for excess generation from retail (15c/kWh) to "Locational Marginal Price" (3c/kWh). This, of course, will dramatically change the equation for solar in Michigan.

Cherryland has gutted their net metering program by cutting the excess generation credit in half. This makes Cherryland net metering a very long term investment.

However, they created a new program sponsored by their power supplier Wolverine Power. The Buy-All / Sell-All program pays 10 cents per kWh for 20 years and should be financially attractive for most customers, especially small and medium agricultural sites.

Great Lakes Energy is a Wolverine coop and will soon follow Cherryland.

Traverse City Light and Power has a traditional true net metering program.

True Netmetering

True netmetering is the process by which you deliver renewable energy to the grid.

There are two "states" that the system can be in:

Your renewable energy property is producing more energy than you are using. In this state, you are returning excess generation to the grid.
Your energy system is producing less energy than you are using. In this case, you draw energy from the grid.

Your bill is credited at full retail price when you are overproducing.

At the end of the billing period, your usage and production are "netted out". If you overproduced, you are credited with either kw-hours or dollars. Credits are carried forever - they do not reset.

You still must pay any fixed charges such as access fees.

A sample netmetering bill is here. In this case, there were 230 kwh delivered ($28.04) and the customer returned (Net Excess Generation) 413 kwh ($50.34). Note that the customer is carrying a credit of $62.96 and that the rate paid for excess generation is $0.1219 per kwh (12.2 cents). The credit will get used during the winter months and then build up again in the summer.

System Size

There is a limit to the size of a system that can be connected to each meter. MPSC and the utilities limit the size of the "generator" to 20 kw AC for true netmetering (Category 1). For solar PV, the total inverter size must be 20 kw or less.

PV inverters can support about 120% of their AC rating in DC panels. So you can drive 24 kw of panels with a 20 kw inverter system.

Those 24 kw of panels produce 110 - 133% of their DC rating in kw hours of energy per year. So you'll get 26,400 to 32,000 kw hours of energy from a 20 kw AC rated system.

One Meter per 20 kw

If you are planning to generate large quantities of renewable energy, it becomes a challenge to assign one meter to each 20 kw system. It's one meter per 20 kw, no negotiation! Some resourceful folks have split sites into multiple services to get around this issue.