# Category Archives: energy-efficiency

## we must also embrace clean coal

“…coal produces more than 40 percent of the world’s electricity, a foundation of modern life. And that percentage is going up.”

http://www.wired.com/2014/03/clean-coal

Filed under energy, energy-efficiency, erik-green, future, green

## Our oil problem

“Our oil problem is not that “we’re running out.” Our oil problem is that we’re producing so much of the stuff that we are changing the planet’s climate.”
— David Frum, ‘Peak oil’ doomsayers proved wrong

True on climate, but the commenters at the article have it right:

“[W]e are extraordinarily blessed with a moment of respite to temporarily postpone the extremely difficult economic environment brought on by the decline of abundant oil….but it is only temporary, and we would be wise to use this moment to prepare ourselves.”

My comments: Keep bringing on the bikes, insulation, and solar. ðŸ™‚

Filed under energy, energy-efficiency, erik-green, green, solar

## To figure out how much electricity/energy we use each month…

Like many/most people who have grid-tied PV solar panels…. to figure out how much electricity/energy we use each month I have to do some math. Â That’s because the smart meter doesn’t know how much electricity we use directly from the panels. Â Some electrons never even hits the electric co’s meter, which can only show numbers for 2 things: (1) the extra KWh flowing out and (2) the extra KWh we need that is coming in (at nights, clouds and cold cold weather)

That’s not enough. Â I also have to read (3) the total produced by our PV solar panels. Â And then do some math. Â The pain in this is that since one’s electricity bill is usually not calendar month, and our smart meter isn’t being read automatically by any device, I have to remember to “read the meter” near the beginning/end of the month. Â I can’t use numbers on my electricity bill.

Algebra:

The basic idea: Â IN KWh = OUT KWh

(2) ELECTRIC CO METER IN (FROM GRID) + Â (3) PV PRODUCED = (1) ELECTRIC CO METER OUT (TO GRID) + X (USED BY HOUSE)

Solve for X and I’ve got it.

Additionally I think it makes sense to divide by the number of occupants in your house before comparing with your friends. Â And maybe adjust by things like HDD and CDD (heating degree days and cooling degree days) if they live in a different part of the Earth.

So that’s KWh used per person per month. Â  We have averaged under 800 KWh per month year round on average for 28 months. Â And we have 4 people here. Â With 8 living with us for 10(?) months in 2011.

So under 200 KWh per person per month. Â For everything, including heating and AC, cooking, lawn mowing and 2 home offices.

It’s hard to compare to most people in the northeast because most people don’t know their grand total since almost no one heats their house with electricity (geothermal or air-source heat pumps) like we do. Â So they’d need to add up their gas/propane/wood/oil BTUs used and convert to KWhs.

Filed under energy, energy-efficiency, erik-green, solar, zero energy home

## “Even the hard core in the green movement use washing machine”

Hans Rosling: The magic washing machine — one of the best TED talks I’ve seen (or via youtube) He divides the world into 4 groups. Below the poverty line. (fire people) Below wash line (bulb people). Below air line (wash people). And the rest (the air people) And it’s a zero-sum sustainability game so the dots need to be distributed somehow. Are you going to deny a washing machine to the rest of the world?

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## 2011/12: The year in heating

We have an emonitor gizmo that tracks our home energy use by circuit. One circuit is the air-source minisplit heat pump (the heat and cool in the house).

For the YEAR ending April 2012, the heatpump circuit shows:

3,009 KWh (total for year, heating and cooling and some hot water)
2,598 KWh (Oct-Apr — 7 mostly heating months)

Remember that we also heat our water with an air-to-water heat pump in the conditioned basement, so during the heating months, it is stealing heat from the house. So the 2598 includes some of that. Let’s pretend it is 10% of our total load (no idea) so that would be

2338 KWh (Oct-Apr — mostly heating months. HOME HEATING ONLY)

If we pretend the price we pay for electricity is \$0.15/KWh (it’s more complicated than just a simple number like that with this and that charges) but close… then that is:

\$350.70 (our estimated heating bill for winter 2011/2012)

Nice.

(Well, and actually… minus some significant fraction of that which is covered by our PVs (electric solar panels). We don’t have net metering, so our electric bill is rarely \$0 even in the summer. I just don’t unclude the PVs cause I generally think of them as an offset. Not an important part of the house.)

SMALL IMPROVEMENTS “FOR SOMEDAY”:
– The silly 20KWh/month our minisplit uses whether it is on or not. Nothing to do about that at least in the winter. But I could flip the dip-switch for 5 months of the year.
– Someday I will add a submeter for the minisplits since the emonitor is probably 10% off in some direction. (I believe that’s the spec I’ve seen.)
– More PVs, perhaps this string with a central inverter and small battery for:     – night-time (since no net metering) and
– power outages (we have a well so it would at LEAST be nice to have running water when the power goes out.)

## We’d be net zero but…

Our house would be net zero source energy but…

– well filters: we avg 54 KWh / month
– well pump: 10 Kwh / month
– radon fan: 40 KWh / month
– 2 home offices: 60 KWh / month
– Mitsubishi minisplit: 20 Kwh / month (EVEN WHEN OFF DUE TO A COIL HEATER THINGY!)
– electric lawn mower: (not much, but just sayin’)

What else did I forget?

TOTAL:
So that’s 54+10+40+60+20 = 184 KWh / month
= 2208 / KWh per year

… that we can’t help that some other net-zero types of house don’t have since our house has a well and 2 home offices and a mitsubishi mr slim air-source heat pump with what I would consider a design flaw!

We use approximately 10,000 KWh per year for everything (heat, hot water, lighting, cooking, etc.) And our 6.9 KW PV panels make about 8,400 KWh so if we didn’t have the extra 2200 KWh, we’d be easily net zero.

BUT… then there is driving. Someone who lives in a city in and walks everywhere is blowing us away. We drive maybe 15000 miles per year at 20 MPG (minivan). There goes net-zero.

## More interesting Steve Jobs quotes

I will collect them here as I find them.

“I read a study that measured the efficiency of locomotion for various species on the planet. The condor used the least energy to move a kilometer. Humans came in with a rather unimpressive showing about a third of the way down the list. … That didnâ€™t look so good, but then someone at Scientific American had the insight to test the efficiency of locomotion for a man on a bicycle and a man on a bicycle blew the condor away. Thatâ€™s what a computer is to me: The computer is the most remarkable tool that weâ€™ve ever come up with. Itâ€™s the equivalent of a bicycle for our minds.”

“When you grow up, you tend to get told that the world is the way it is, and your life is just to live your life inside the world. Try not to bash into the walls too much. Try to have a nice family life. Have fun, save a little money. Thatâ€™s a very limited life. Life can be much broader, once you discover one simple fact. And that is: everything around that you call life was made up by people that were no smarter than you. And you can change it. You can influence it. You can build your own things that other people can use. Once you learn that, youâ€™ll never be the same again.” (at 3:30 in the PBS program)