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Net Metering
NorthWestern
Energy Net Metering Documents
Northwestern Energy has issued its net-metering policy documents, officially
called "Interconnection Agreement for Customer-Owned, Grid-Connected Electric
Generating Facilities of 50 Kilowatts or Less Peak Generating Capacity."
The nine-page document also includes
pages spelling out the utility’s net metering requirements for grid connection
of renewable resources. In brief, a net metering system is one that:
-
Uses as its fuel renewable
resources; defined to be solar, wind or hydropower, or other generation system
pre-approved by the utility.
- Has a generating capacity of not
more than 50 (fifty) kilowatts.
- Is located on the customer-generator’s
premises.
- Operates in parallel with the
NWE distribution system.
- Is intended primarily to offset
part or all of the customer-generator’s requirements for electricity at the specific
site where the generation is installed.
NorthWestern Energy Net Metering Procedure
Net metering allows homeowners
to receive the full value for the electricity that their solar energy system
produces. The term, net metering, refers to the method of accounting for the electricity
production of a photovoltaic or wind energy system. Net metering allows homeowners
with such systems to use any excess electricity they produce to offset their electric
bill. As the homeowner's system produces electricity, the kilowatts are first
used for any electric appliances in the home. If more electricity is produced
from the system than is needed by the homeowner, the extra kilowatts are fed into
the utility grid.
Under Federal law, utilities must
allow independent power producers to interconnect with the utility grid and purchase
any excess electricity they generate. Many states, including Montana, have gone
beyond the minimum requirements of the Federal law by allowing net metering for
customers with PV or wind energy systems. Under net metering, the electric meter
of the customer will run backwards when their solar electric system is producing
more energy than they need to operate their home at that time. The excess electricity
produced is fed into the utility grid and sold to the utility at the retail rate.
At the end of the month, if the
customer has generated more electricity than that used, the utility credits the
net kilowatt-hours produced at the wholesale power rate. If the customer uses
more electricity than they generate, they pay the difference. The billing period
for net metering may be either monthly or annually.
Montana has an annual billing period.
On January 1, April 1, July 1, or October 1 of each year, as designated by the
customer-generator as the beginning date of a 12-month billing period, any remaining
unused kilowatt-hour credit accumulated during the previous 12 months must be
granted to the electricity supplier, without any compensation to the customer-generator."
Net metering allows homeowners who are not home when their systems are producing
electricity to still receive the full value of that electricity without having
to install a battery storage system. The power grid acts as the customer's battery
backup, which saves the customer the added expense of purchasing and maintaining
a battery system.
Generally, the preferred method
of accounting for the electricity under net metering is with a single, reversible
meter. An alternative is dual metering, in which customers or their utility purchase
and install two non-reversing meters that measure electrical flow in each direction.
This adds significant expense to installing a PV system. The current trend around
the country is toward a single, reversible meter.
Some utilities are opposed to net
metering because they believe it may have negative financial impacts on them.
However, a number of studies have shown that net metering can benefit utilities.
The benefits include reduced meter hardware and interconnection costs, as well
as reduced meter reading and billing costs. Grid-connected PV systems can also
help them to avoid the need for additional power generation, may increase the
reliability and quality of electricity in the grid, and produce power at peak,
when utility generation costs are higher and they often need the extra power.
Renewable
Northwest Project has published a Net
Metering Q&A with specific information about Montana and answers to commonly
asked questions about how net metering works and how it can help you save money
on your electricity bill.
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