The Lovely Wife brought up an issue with my last post. She asked why if our intent to save energy we were getting a much bigger breaker box. Also, I thought I would clarify a bit how our underground electrical service works. Most houses in the US have their service from wires strung in the air from the power pole to the house.
The reason we have a bigger breaker box is because we are getting at least 4 new circuits in the breaker box which will serve the house. These are three 220V/20 amp circuits for the on demand electric hot water heater, and one 220V/40 amp circuit for the electric car charger. There may be a couple of additional 110V/15 amp circuits for the HRVs and the garage. All our existing electrical circuits will remain unchanged on the existing inside house circuit breaker panel, which has no space for the new circuits. The old panel on the outside of the house, which you saw in the photo on my last post, is much smaller because it contains only one breaker in it, a 100 amp breaker for the whole house. The new one will contain the 200 amp breaker for the whole house, plus the breakers for the new inside circuits.
As for saving energy, our system remodel is designed to save on heating gas through much more effective insulation. When it comes to electricity, though, we are substituting electricity for other sources of energy that are harder to make renewable. The on demand hot water heater will substitute electricity for gas for backup hot water heating (the main hot water heating is solar), and the electric car charger will substitute electricity for petroleum-based gasoline. Then an expansion of our solar PV system will offset all but 2000 kwh/yr of our electricity use with clean, 100% non-fossil carbon based solar electricity. The 2000 kwh/yr (estimated) that we do not offset will be drawn from the grid. Since the State of California has a renewable mandate of 20% by 2020 (with 33% being a stretch goal), the likelihood is that the grid will become much cleaner before transportation fuels or heating gas do (btw: don't let the media story of "clean" natural gas fool you, natural gas produces fossil carbon and thus contributes to global warming too, it just produces much less of it, about half that of coal or oil).
Because our service is underground, the upgrade process has been very complicated. Most people in the US (and many other parts of the world too) have service from an aerial line that runs from the poles on the street where the utility has their lines to the house. Upgrading such an aerial line is much simpler, the lineman comes, removes the old line, installs a thicker new line, and you are done. Of course, you still need to get a new breaker box with a larger breaker for the 200 amp service.
In our case, the utility lines are buried in conduits beneath the streets, along with the phone lines and the cable lines. This makes our neighborhood look much neater, without a lot of poles along the streets with wires draped over them. But it does make upgrading the service much more difficult. Here is a picture of the cement box where the electrical lines enter my and my neighbor's property:
Somewhere beneath that box, two conduits lead out at angles to our houses. My neighbor had his service upgraded to 200 amps in 1985 when he had central air conditioning installed.
When PG&E comes, hopefully on Feb. 23, they will dig a trench from the box to the place where the pipe from the new breaker box is, under the area where our sidewalk used to be (and will be once again when the job is through). Here you can see a clear space to the concrete access box, which is right next to the green sword shaped leaves in the center of the picture (it's a naked lady, native California plant that blooms in August):
There are still a couple of clearing items that need to be done, the small rock wall, and I think we will probably have to repair the irrigation in our neighbor's yard if the trenching damages it. But I think PG&E shouldn't otherwise have a problem with digging the trench.