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How and Why to Design an Off-Grid Electrical
System
Why Construct Off-Grid Electrical
This
study is organized around a series of logical choices. Many of
those have to do with what is feasible. That is a definition of
what is physically and legislatively possible, as well as the
thorny issue of economic viability. Just because someone can shove
a bent wire into an outlet does not make the action prudent or
useful. It is physically possible, but the reality of the world
is such that a conductive wire, tapping the electricity flowing
through a high voltage circuit, will either blow a circuit breaker
or melt the wire. That might mean replacing an overworked breaker,
especially if the experiment has been conducted too many times,
and the cost of that levity might soon become prohibitive. As
well, it is not exactly feasible to indulge in such behaviour--even
for the social media accolades--and there are legislative implications
if your insurance company uses your deliberate flaunting of safety
standards against you as you stand by the smoking wreckage of
your house.
In
short, each of those factors come into play, and although setting
up a grid-tied or off-grid system is much more complicated than
playing with wires and electricity, it still follows a similar
logic. You must first ask what system is physically possible,
and once that thread is pulled, it will inform much of the feasibility,
financial or otherwise, of the system that you build.
Grid-Tied or Off-Grid
If
you want to build an off-grid system you should first ask whether
the grid can supply your power more safely, consistently, and
cheaply than a system you can build. If your install is close
to local grid service--or the cost is not prohibitive to establish
a connection--then building your own system merely to tout a kind
of independence can be foolish financially. There is much talk
about energy independence, and the term energy security gets passed
around in the political arena, but on the ground where we actually
live, your power bill could be paid for many years in advance
for the price of building your own electrical generating system.
An independent system is many times the cost of most North American
electrical bills--even calculated over many years--and the grid
is relatively stable most of the time, depending on where you
live.
The
cost of a solar panel system powerful enough to power a house,
for instance, can be tens of thousands of dollars and according
to this optimistic estimate from a green innovations company,
the payback period is not short: “solar power systems in Canada
pay themselves off within 8-15 years of installation.”[1] A residential wind turbine works out
to between four and eight thousand a kilowatt: “A system that
would offset most of an average home’s electricity use (10,000
kWh/year) will cost roughly $50,000 before incentives.”[2]
The
Tesla Powerwall has been heavily advertised, but the price tag
is equally prohibitive.[3]
And that is merely the storage arm of the system, although the
latest versions are only sold at the sale price if the customer
buys Tesla’s solar panels as well.[4] A 10 Kilowatt micro hydro system can
cost as much as fifteen thousand dollars,[5] and that does not include the installation
of piping, the building of a dam if that proves to be necessary,
and a protective shed for the inverters and other equipment.
The
purpose of that daunting list is not to frighten those who are
considering an off-grid or grid-tied electrical system, but merely
to point out that basic economics are sometimes the better part
of valour and that unless there is reason to avoid it, the local
power grid is at least an order of magnitude less expensive.
In
other countries, where the price of electricity has risen precipitously,
the lowering cost of off-grid alternatives make it more viable,
especially once government subsidies have been taken into account,
but otherwise the homeowner may be betting on the wrong horse.
The
intermediate option is to build a grid-tied system in which you
provide most of your own power but rely on the grid during peak
hours or days without wind or much direct sunlight.
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