Green Building – The foundations

Over the past 19 months we have been remodeling our home in Tiburon. You can find it on Google maps by entering the address 1 Reserva Ln, Tiburon, CA. Here is the satellite photo pretty close up.

It is hard to see from this perspective but the home is nearly “on the water” of San Francisco Bay. It is located on a very steep hill so the home sits on a number of deep anchors and steel beams. To get a better idea of its location in the Bay area here is a wider picture –

For the past 3 years, I have been involved with the California Clean Tech Open. This is a business plan competition for clean tech or green business plans. And for the past 2 years, I have been the chair of the Green Building category.

So I felt it was incumbent on me to do something myself. So this would not be like my daughter’s soccer team years ago … where I was the coach but had never played the game.

Today this home in Tiburon makes all of the energy it needs to operate year round on a sustainable basis. In the summer, like now, we make more energy than we need and send it back to PG&E for them to use it elsewhere. But in the winter, we expect to pull that power back.

This home has solar photovoltiac panels that generate substantial amounts of power every day the sun shines (which is most days in Tiburon). It also has solar hot water panels for taking more efficient care of that need. It also will shortly have water collecting cisterns that save the rain water we have in some abundance in the winter so that we can water our garden with that in the summer months where we never have rain.

The Small World Group website will soon have a new branch where how this house works and its daily, weekly, monthly and annual performance can be easily seen and tracked. SWG is engaged in additional projects in the green space and we will be telling you about this more in the future as well.

For now, here is a small taste of what is happening! Below is teh energy usage and energy production curves for the home over the past 24 hours. Note that energy usage is show as positive numbers and energy production is shown as negative numbers.

The home has 2 areas that we keep separate for energy accounting purposes – the main house and the apartment. For the apartment you can see that we use an average of 500 watts but that the solar produces an average of 800 watts so we make an average of 300 watt-hrs x 24 hours per day or an excess of 7.2 KW-hrs daily.

The main house similarly uses about 1400 watts per hour but produces about 2000 watts per hour for an excess of 600 watt-hrs x 24 or 14.4 KW-hrs excess daily.

This is actually even better because we are on “net metering” and this means that since we make most of our power from 10 am to about 6 pm, we sell that to the power company at about $0.30 per KW-hr but when we buy more at night we buy at $0.10 per KW-hr. So our leverage is even greater.

But this is summer and we also removed most of our gas appliances and switched to electric heat pumps and so in the winter we would expect to be serious users.

Stay tuned for much more on this subject.

Posted in Essays, Green Perspectives, Personal Stories

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