The Zero-Emissions Challenge, Part 2: Electric Use Audit
The most obvious first step in examining our carbon emmissions is our electical usage. Our monthly utility bill says we average 12 Kwh per day.* Plus, we generate an average of 6 Kwh per day with our solar panels, inverted to AC at 85% efficiency, adding 5 Kwh per day more than what the utility reports. That's a lot of power. Where does it all go?
To find out, we created a spreadsheet listing each appliance, its wattage, and on average how much we used it. In some areas, we had to guess. For example, who knows how long our water pump runs each day? But eventually, we came up with what we think is a fair representation of where the power goes.
The answers were instructional. Our biggest use is for lighting, at 4.3 Kwh per day. This was followed by refrigeration (3.4 Kwh), computers (2.7), cooling/air circulation (1.9), and water pump (0.9). Everything else, including washer, dryer, dishwasher, TV/DVD, cell phones, clocks, etc. added another 3.9 Kwh.
Now, what to do with that information? Obviously the goal was to reduce, but how? The most disturbing realization is that we've already taken a lot of small steps to reduce our usage, and we still use a lot. That means we've got to cut deeper, a lot deeper, if we're to make an impact, much less achieve zero emissions.
We perceived three possible levels of reduction: what we could do with little capital investment, what we could do if we had the money, and what we could do if we were forced to zero our emmissions regardless of the impact on our lives. These I'll refer to as the "easy method," the "planned method," and the "hard method."
The "easy method" inlcudes things we can buy and habits we can adopt that won't cost a lot of money or seriously impact our lifestyle. For example, we leave our computer equipment on all day, turning it off only when we go to bed. But by setting it to standy, hibernate, or (in the case of printers and peripherals) just turning it off unless we need it, we found that we could cut power usage from 2.7 to 1.1 Kwh per day. Similarly, by replacing our remaining incandescent lightbulbs with compact fluorescent bulbs (CFLs), we could cut power used for lighting by 72%, dropping the daily usage to 1.2 Kwh. By replacing halogen and sodium fixtures with CFLs, we could cut even more.
Refrigeration remains our greatest challenge. We use it not only for storage of meat, vegetables, dairy, and condiments, but for medicines, seeds, and other perishables. Our deep freeze holds vegetables, flour, and meat stored for the long winter— necessary not only for economy, but because we need to have supplies in case of serious inclement weather, which is always a possibility where we live. Plus, we have an entire fridge set at 55 degrees for aging homemade cheese and making pickles. Under the "easy method," the best we could do would be to eliminate the small fridge we currently use for seeds and livestock medication, consolidating those items into our kitchen fridge. That would only cut .3 Kwh from our usage.
The bottom line for the "easy method" is an estimated reduction from 17 Kwh per day to 12. That's a 30% reduction— but it's still not close to zero.
There is another alternative for refrigeration, which brings us to the "planned method." If we built a root cellar, we could keep in it much of what now needs refrigeration 9including fresh vegetables, cheese, and pickles), easily cutting our usage from 3.4 to 1.4 Kwh. Since we don't have a basement, the cost of building a root cellar would run several thousand dollars. But it's feasible.
The "planned method" would also include increasing our renewable energy production by doubling our solar cells, adding a tracker, and incorporating a wind generator into our system. Even taking into account the 85% loss for the inverter, logical additions would include a wind generator and additional solar panels to increase our usable generating capacity to an average of 17 Kwh per day. Estimated cost: about $20,000, on top of the $16,000 we've already spent. Ouch. But it would cover our estimated usage. With extra storage batteries, it is even possible we could at that point go off grid.*
The combined cost of electricity production and underground storage would be in the neighborhood of $40,000. Looking at the original question: could the average American family achieve this? Clearly the answer is, no.
* These calculations include summer cooling but not winter heating (including electric heat), which I'll discuss in another post.
This post was updated September 19, 2007 to account for errors detected in the original calculation.
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9/22/2007 10:43 AM
www.AsymptoticLife.com wrote:
/images/24708-23496/Gas_can_wasteland.jpg" width=420 border=0>In considering methods of reducing our carbon emissions, I alluded to three methods of reduction: the "easy" method, the "planned" method, and the "hard" method. So far, I haven't said much about the "hard" method. But it's pretty straightforward: assume that emissions must fall to nearly zero immediately. The CO2 outcome is already known: near zero. What's less clear is what such a requirement would do to our lives.First, we'd essentially be limited to the electricity we produce ourselves. At present that's 5 Kwh per day. Timing is not an issue, because ...
Also in search of reducing our refrigeration costs, I came across Sunfrost refrigerators and freezers.
In dimension they are similar to a Subzero -- less depth more width. This makes it easier to find things, with fewer biology experiments in the back of the fridge.
The energy savings are significant, and I believe they build to suit.
Exploring their website at an earlier date, I found a photo of a solar-powered vaccine refrigerator mounted on the back of a donkey, for use in remote areas. Worth considering, I think.
~sunfrost.com/Sunfrost_refrigerators.pdf
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When it comes to carbon emissions and electric usage I think electric appliances play a major role . Renewing old appliances and searching alternatives for electric energy are some important starting steps.
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I would be in favor of electric appliances if the elecricity were generated from renewable sources. As it stands now, though, an electric oven, hot water heater, heater, or dryer generates far more CO2 than its propane- or natural gas-powered counterpart.
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