Cohousing-L Mailing List: Solar microgrid, anyone?

[David Mandel (dlmandel]

The great information about EV charging prompts me to ask this question
that I've been starting to explore for my community.

More than a quarter of our households already have EVs and that is sure to
grow. We've installed a couple of shared L2 charging stations using
existing meters (one common, one at a household -- users reimburse for the
cost) and are looking into ways to install more.

But this begs some other urgent questions. EV charging increases our use of
electricity, as does the gradual replacement of gas-powered appliances
(heating, stoves, dryers) with electric that is happening or contemplated
in individual homes and the common house.

And we have been warned that the transformers supplying our electricity,
installed when we built the community 29 years ago, are likely insufficient
to handle the extra demand. To merely find out the degree of the eventual
shortfall would cost thousands of dollars, our utility tells us, let alone
to upgrade/replace them.

Moreover, our units were all wired with only 90 amps of service, low by
today's standards and insufficient, some tell us, to operate the additional
chargers and appliances many of us would like to install unless we take
care not to use too much simultaneously.

This leads to consideration of how else we could both increase supply and
spread out demand. And the obvious answer is rooftop solar.

Two households have already installed panels, but doing it individually
does not really seem the best way. Some of our roofs are a lot more
suitable than others (shade, direction, configuration), and for any that
are highly suitable, the utility doesn't allow you to generate more power
than you already use. (How shortsighted!) This is on top of a major push by
California (and probably other) utilities to drastically lower the rate
they pay for net metering, as well as imposing a high fee for solar users
to maintain "their share" of the grid. (Another shortsighted approach
seemingly driven by the current economics, not the pressing need to
decarbonize.)

A great answer in theory would be to develop a community microgrid, which
would involve:

   - Maximizing the amount of generation by installing panels on the most
   suitable roofs, individual households and common structures.
   - Using batteries to store the power, enabling its accumulation and use
   at the most appropriate times of day.
   - Finding a not-too-complicated way to distribute the energy and share
   the costs and benefits among households.

I'm engaged in early conversations with some solar designers/installers who
are interested in the idea, and with a board member at our (publicly owned)
utility about getting its cooperation and assistance.

So my question is whether any of you have accomplished or are contemplating
such a project. If so, let's compare notes and ideas.

One more thing: It's clear that accomplishing this would be very expensive,
probably beyond our community's ability to finance fully even with a
long-term, low-interest loan -- which would make sense for part of it. What
other possible sources of funding might be available?

Thanks for any ideas,
David Mandel
Southside Park Cohousing, Sacramento