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Solar and Wind Electricity & Net
Metering
On-grid wind and solar systems require Net Metering: a system
that keeps track of the difference between the electricity that
you store in the grid and the one you take from it. If your
system generates more electricity than you use, the electric
meter will spin backward.
Note:
There is no difference between net metering for grid-tied PV
solar and net metering for grid-tied wind generating systems.
The elements presented below are valid for both systems, and for
hybrid ones.
Net
metering & Wind and Solar PV systems size
The size of
your generating system doesn’t interfere with net metering. If
you have a small system and your production is lower than
consumption, you just have to pay the difference. If you have a
large system and your production is higher than consume, you can
store the extra electricity on the grid (and eventually sell
it).
Conditions & Net Metering
All residential users of small solar and wind energy systems
(and hybrid systems) are eligible for Net Metering. Most
residential PV solar and wind systems connected to the grid and
using net metering, range between 2 and 4 kilowatts, but there
isn’t usually a required minimum size. You just need to be
connected to the grid. Law may demand the wind or solar system
to be located on your property and that its capacity doesn’t
exceed a certain limit.
Current electric meters
Most current
residential meters are bi-directional, in other words, capable
of measuring your electric outputs and inputs involving the grid
and your PV solar or wind system. If this is your case, your
meter is suitable for net metering.
But some companies may want demand two meters: one to measure
the electricity that goes to the grid, and other to measure the
inverse fluxes. Just contact your utility for information on
this issue.
Net metering agreements
Net metering
involves an agreement between you and your utility or electric
provider. Typically the meter will be read once a month, and
will show the net amount between the electricity you take from
the grid and the one you store in it. And that’s that difference
that you will have to pay (if positive).
In many states there are electric companies (Electric Service
Providers) and companies that distribute electricity (Local
Distribution Companies), or simply a company that does both
functions. Usually Electric Service Providers handle the Net
Metering billing and accounting, while local distribution
companies handle the technical questions: connection of your PV
or wind system to the grid, safety, inspections... Just contact
these companies, demanding the agreement.
Selling energy to the grid
If your wind or PV solar system produces more electricity than
you use, the utility or electric provider is not required to
purchase the excess, unless otherwise agreed.
Typically, law do not required the utility to pay for possible
excess generation, but some agreements might involve that
payment – just contact possible utilities or electric providers
in your region, to see which buy excess generation.
Advantages of Net Metering
Net Metering has obvious
advantages: it’s a simple system, that allows an automatic way
to store the electricity your system generates and your are not
using, and also a simple way to recover that stored electricity
whenever your needs exceed your electric system production.
Eventually, it also allows you to sell part of your production,
if it exceeds your global needs (and if the agreement and your
utility or electric provider contemplate it).
In some cases, you may also benefit from lower rates. If your
wind or solar system generates most of your electricity needs,
you may be charged with lower rates if your annual net
consumption falls below the utility baseline limit.
Disadvantages of Net Metering
If your PV solar or/and Wind system meets the standards and
typical performance, you will not be charged for fees,
inspections or certifications. You just need to have a
bi-directional meter (a simple and common type of meter that you
probably already have).
However, in some cases, grid
connections can be expensive, namely if you live
in a remote place: running a power line between a remote site
and the utility grid can amount from $15,000 to $50,000 or more
per mile.
And obviously, net metering will make you dependent of external
events and electric companies decisions and politics.
Billing & Net Metering
The type of
agreement between you and the utility may vary. The utility will
read your meter monthly, and you will receive monthly statements
with the amounts of electricity consumed and generated.
Annual billing
is very common, but you may opt by monthly billing. Companies
may or may not buy excess generations, depending on the terms of
the agreements and the current practice of the electric
providers and utilities.
See also:
Basics on Solar Energy Systems
Types of solar
water heating systems
PV Photovoltaic: solar
production of electricity
Solar home space heating systems
Solar home space cooling
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Net Metering and Solar and
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