The importance of good numbers:
Quantifying your wants
A friend and colleague in the renewable energy industry likes to say that
people don’t want electricity — they want lights, TV, and cold beer. His point
is well taken. When I ask clients how much energy they need, they rarely
answer in electrical units. They may say, “Well, we want lights, a stereo, a
fridge, and a computer for our cabin in the mountains and all the normal
appliances in our house in the city.”
Thinking more specifically about the energy you want is useful. If you tell me
you want “lots of electricity,” I can only tell you it will cost “lots of dollars.”
But when you start listing the actual appliances you want, you’re getting a
good start on energy assessment. The next step is to convert the description
of what you want to power into numbers.
I’m surprised how regularly people make important financial decisions based
on guesswork. For example, what happens when you mail-order clothing
by saying, “Well, I think she wears a size 12” or “My recollection is that his
sneakers are size 9”? You usually won’t get very good results. You want to
confirm important data before wasting your effort and dollars. Confirmation
is even more important when you’re installing an energy system.
You need to know how many kilowatt-hours you want each day. If you can cut
to the chase and get this number with less pain, go for it. But make sure it’s a
good number, not a wild guess. Without a solid energy number, your design —
and therefore your project budget — will be questionable. Trying to pin down
how much energy you want isn’t glamorous work, but without a good energy
estimate, you have three possible outcomes:
✓ You get very lucky and design a system that makes just the amount of
energy you need. (This is extremely unlikely.)
✓ You purchase a system that doesn’t make as much energy as you want,
and upgrading may be very difficult and costly.
✓ You spend more money than necessary to purchase and install a system
that makes more energy than you need.