I'd like to share a few threads in this blog:
- How my electric bill looks, and what this means to consumer conservation
- What I've done to control my energy use, and thus carbon emissions, and dollars out of my pocket
- How to use the editgrid tool, and why this is important.
Below are a bunch of graphics, most from scanned images of our home electric bill, but the later ones generated live from online data. The oldest bills that I have from BGE included a rolling 13 month chart, generated after our first bill. Starting in 1995, the bar charts switch from solid to outline shape, no doubt to save the cost of ink or toner.
The bill format has changed twice since this earlier one, so the visual feedback of energy use pattern went away on the first revision, in January 1997. The replacement was a 3 line comparison of the prior month, and the same month a year before. This Electric Usage Profile has remained to today. I am used to crunching numbers all day at work, so this is easy for me, but somehow I think most consumers are inclined to look at the number following the dollar sign.
Earlier versions listed temperature separately from the electric use; later versions show kWH and average monthly temperatures on the same line. The intent is to tell you whether you used more because it was colder (or hotter), or if you just weren't paying attention and left the iron on all month.
If you look at the average daily use charts, you might notice that the Y-axis, for maximum use, has been auto-scaled each month. Assuming this chart was still being produced, it would make it hard to see where changes in behavior, or in efficiency of furnaces or air cooling units had altered. That's part of the reason I am transcribing from the bills to online web pages.
Oh, yeah, the last chart below shows our electric rates in Maryland. Instead of our bills climbing with energy costs over the last decade, we had frozen, even reduced charges (no pun intended) from 1999 to 2005. Then, the rate caps came off and away we went. I'm not going to chart the amount of my bills. If you really want to know, you can probably do the math. Or, let editgrid take care of it.
Hopefully the big investment I made in a new heat pump in August 2007 is starting to show returns. It's either that, or pushing the thermostat down to 62 degrees F. for as long as Kathy can stand it.
I haven't been able to fool editgrid into reversing the chronological order on my charts, so as I add each new month's information onto the top row, it is charted on the left side, not the right. Now that I have the bill for February 2008, I can see a lowered peak for this past winter compared to prior years.
Is this lower because of the heat pump, pushing the thermostat, or a warmer winter? I thought I'd be able to tell more graphing average daily use against average temperature, but it is not so clear. I probably need a formula using "degree days", which BGE supplied a long time ago but probably abandoned to obscurity.
I found out about editgrid.com on Twitter. It isn't Google, but it seems to have a viable business model where you pay to share edit rights with others, but publishing single-owner pages is free. The interface works great from IE or Firefox, and there are innumerable great web features possible. As you can see below, I simply add a link to a generated image URL, and live data shows up on my web page.
<img src="http://www.editgrid.com/export/sheetobject/7225386.png" />
Temperatures 1993 - 1996 (November readings, December bills)
Electric use per billing period (1994-1997, 2007)
Electric daily use (1993-1996)
I signed up for an online account at www.bge.com, but I have not found any useful features there, such as digital displays of my energy use, temperature charts, etc. I can get a copy of my bill, but it is in a crippled PDF format that does not allow copying. What good it that. Matthias Z.!?
Energy use by month from 2007 though the present (older data is to the right):
Electric use March (meter period roughly Feb 9 - Mar 11)
Electric use February (meter period roughly Jan 9 - Feb 9)
Recap of electric energy costs from BGE (Constellation Energy utility)
More details on electric use at my house: