Time of Use Rates

So I'm currently investigating moving my electricity rate structure from my current (RE) which is pretty much set at $0.086/kWh  ( http://www.duke-energy.com/pdfs/NCScheduleRE.pdf ) to a time of use rate structure ( http://www.duke-energy.com/pdfs/NCScheduleRT.pdf ).  Yeah, there is a small tier when you use over 350 kWh where it goes down to 0.078 in the summer...but that isn't significant.  Well, thanks to my TED 5000, I analyzed my historial data to see if it was worthwhile. 

First the rates...the time of use rates (TOU)  as shown below have a higher facility charge and lower overall rates.  However, there's this "On-peak demand" charge.  Well, that charge is defined as "the maximum integrated thirty-minute demand measured for the On-Peak period during the month".  So that means if I use 10 kW for 30 minutes in the Winter, then I'll get:  10 KW x $3.33 = $33.30 demand charge.   Sounds expensive right?  Well, let's see if it really works out... 

Below is the my historical hourly energy usage from January 18, 2011 to April 18, 2011. 

As you can see, in the winter I had some pretty high 1-hr usages (Note:  I did 1 hr usage to get more historical data - 90 days - vs the minute data which would have only stretched 48 hrs).

But how does this fall during peak times?  See the graph below which segregates out only the data during peak times:

Generally speaking, the vast majority of the elecrical usage is below 2 KW.  But...there were some pretty noticable peaks.  The extremely large peaks (8-16 KWH) were from that old crappy heat pump using the emergency heat (i.e. electric) because it couldn't keep up.  Those in the 4-6 kWH range are most likely either the dryer or the hot water being generated.  Those between 2-4 KWH could be a bunch of things...and most likely it was one heat pump on (~3.5 KW).  Not to mention this is a 1-hr average. 

So...if I take this hourly data and apply the on and off peak rates, then determine the max 1-hr power usage and apply the on-peak demand charge, what does that get me?  See the table below:

	Ex Cost	Peak TOU	Off TOU	TOU Total	Fac Charge	Max 1 hr KWH	OnPeak Chrg	Total
Jan-11	$153.36	$12.75	$67.23	$79.98	$13.88	15.49	$51.59	$145.45
Feb-11	$104.82	$9.19	$45.26	$54.44	$13.88	5.52	$18.36	$86.69
Mar-11	$99.41	$9.15	$42.04	$51.19	$13.88	6.55	$21.82	$86.89
Apr-11	$43.02	$3.75	$19.06	$22.81	$13.88	3.97	$13.23	$49.92
Total	$400.61	$34.83	$173.58	$208.42	$55.52			$368.95
						savings	$31.66

The "Ex Cost" column is the TED estimated cost for the month.  Overall, it's pretty close.  "Peak TOU" and "Off TOU" are the costs at the "on-peak" and "off-peak" rates.  Then I add in the Facility charge (a constant montly value).  Finally, I determine the Max 1-hr demand and multiply it by the winter charge ($3.33/KW).  Note that April-11 is currently an anomaly because its less than 1/2 the month so the facility+on-demand charge make up 1/2 the cost.
Overall, it shows that I could have saves ~$32 over 4 months with the TOU rates.  It doesn't seem like a lot right?  Well, one thing to remember is that I wasn't even trying to curb my electricity usage.  When I look back at the raw data...the vast majority of the peak usages occured between 7 - 8am (see below):

Sum of Winter Peak Elec
hour	Total KWH
0.00	0.000
1.00	0.000
2.00	0.000
3.00	0.000
4.00	0.000
5.00	0.000
6.00	0.000
7.00	238.660
8.00	75.460
9.00	61.612
10.00	57.602
11.00	62.269
12.00	66.023
13.00	0.000
14.00	0.000
15.00	0.000
16.00	0.000
17.00	0.000
18.00	0.000
19.00	0.000
20.00	0.000
21.00	0.000
22.00	0.000
23.00	0.000

Well...that's due to how I have my programmable thermostate setup and when we take showers for work.  If we get the house heated up 1 hrs earlier and we finish our showers 30 min earlier those peaks are off-demand.  Now there still is some demand (see below), but its significantly less.  Not to mention I now have a significantly higher efficiency HVAC system.  So I would expect these peaks to be much lower.  The worst load would be when the hot water heater runs (4.8 KWH) and that typically lasts only about 10-15 minutes. 

Max of Winter Peak Elec
hour	max 1-hr KWH
0.00	0.000
1.00	0.000
2.00	0.000
3.00	0.000
4.00	0.000
5.00	0.000
6.00	0.000
7.00	15.492
8.00	3.785
9.00	6.554
10.00	3.214
11.00	3.977
12.00	5.078
13.00	0.000
14.00	0.000
15.00	0.000
16.00	0.000
17.00	0.000
18.00	0.000
19.00	0.000
20.00	0.000
21.00	0.000
22.00	0.000
23.00	0.000

So overall...if we can keep our peak demand to below, say 4 KW, during those peak times (that would be both the upstairs and downstairs geothermal systems running for 30 minutes), then I could increase those historical savings from $32 to $107. 

Moving forward...I think with all the energy effiicency stuff I've done (insulation, geothermal, etc), I think I can reap some great benefits. During the summer, the hot water running won't be an issue thanks to the desuperheater.  It'll just be the A/C...which I can mitigate by setting the thermostat high during that short period of time.  Plus, I'll probably only have the upstairs system run and will have the downstairs system essentially off.

It'll be interesting to try out...I'll try to post something up after this summer to show the results...

Rain barrel

We bought and installed this 48 gal rain barrel yesterday.  $70 from home dept.  My original plan was to could one myself using a 44 gal trash can.  However, once you added up all the pieces, it was about the same price. 

I will say i was disappointed that I couldn't build it myself...plus this unit didn't have a screen nor does it appear to capture all the rain water.  We'll see how it works...

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dook Energy Audit

Well for fun, I decided to sign up for my free dook (yes, I went to UNC) Energy home audit.  They initially called and asked about May13th, which I had to decline as I'll be out of town, but yesterday I got a call that there was a cancellation and they could come out around Noon.  So, I jumped at the opportunity.  Below is an explanation from their website about what you get:

(from:  http://www.duke-energy.com/north-carolina/savings/home-energy-house-call.asp)

How it Works

One homeowner must be present at the time of the audit. A trained energy specialist will visit your home, at your convenience, to conduct a thorough in-home analysis. The energy specialist will:

• Analyze your total home energy usage
• Check your home for air leaks
• Examine your insulation levels
• Review your appliances and heating/cooling system

From the information collected, a custom-tailored report detailing steps you can take to increase efficiency and reduce your energy bill is prepared and given to you before your energy specialist leaves your home.
As part of our commitment to saving you money on your energy bill, we will also provide you with a free Energy Efficiency Starter Kit that includes Compact Fluorescent Light (CFL) bulbs. The energy specialist can install the items at the time of your Home Energy House Call, so you can begin saving your energy dollars right away.
Begin saving on your energy bill today!
To schedule your appointment for a free energy analysis, complete the request form or call 1-877-388-7676 to find out when auditors will be in your area.
The Home Energy House Call is a free program available to the customers of Duke Energy for a limited time on a first come, first served basis. Duke Energy may terminate the program at any time without notice.

My goal of this audit was to see if I could find anything else that I needed to do and possibly get some direction of what to do next. 

Anyhow, Mark (a dook Energy subcontractor) showed up and did my audit.  It lasted about 1.5 hrs and definitely was not as intensive as the home energy audit I did previously using ProEnergy consultants.  There was no thermal camera and no blower door test....which is kind of what I was hoping for, but I guess the audit was free...so what do you expect? 

Well, we walked around, I showed him all the work that I've done, and he asked a bunch of questions...most of which were on a form that he filled out.

Overall, this was the first house Mark has given the highest marks too.  But then again...this is my second audit, so I've already covered most of the stuff not to mention I've gone a little above and beyond. 

I got this simple dook Energy 'energy efficiency kit' which includes 3 CFL light bulbs, some outlet insulation, some weatherstripping, a low flow shower head, and two low flow sink aerators (one for kitchen and one for a bathroom sink). 
Not bad loot...

The most interesting advice I got was:

1)  Install some ridge vents in my attic (mine is currently mechanically ventilated).  In his experience the mechanical ventilation benefit in the attic does not offset the energy usage.

2) When I have a choice of encapsulating my crawl space vs the siding on my house, he suggested doing the siding first.  The installation of the house wrap (mine has none) will significantly reduce air infiltration and will make the house more energy efficient.  Not to mention the new siding will make the house look good.

3)  He mentioned monitoring my crawl space as I'm doing using a weather monitor and if the humidity doesn't move above 60%, then there's really no reason to encapsulate my crawl space.

4)  Finally, he suggested taking a break.   I've gone above and beyond what most folks have done and its time to sit back and relax for a bit...or knock some of the other stuff off the 'honey do' list.  I guess this suggestion is good for my wallet...

PS.  I did go to my hot water heater and turn down the thermostat.  It was set at its factor default of 120F.  I reduced it to what I think is 110F.  I'm not sure because it's a simple thermostat without tick marks.  So, I guessed.  Either way, right now I can't tell a difference in the hot water temperature....and it should save me some energy...

Energy/Cost Savings...What to do next?

Ok...I Friday and yesterday I spent countless hours trying to get my HTPC to shutdown and wakeup automatically.  When I manually told it to turn on in 5 minutes and shut it down manually, it worked fine, turning on automatically.  When I let it automatically turn off, it did just fine, but then it wouldn't turn back on.  It appears that I just can't get the system to pass the correct date/time in there.  Not sure why...Long story short...I'm fed up with it.  I'm no linux computer expert and I spent most of my time on Google trying to figure out commands.  I know enough to get by, but that's it.

So, I thought the next most logical step was to finally start looking at an upgrade to reduce power usage since this is on 24/7.  Well...a question arose...are there better investments?  Let's take a look...

I measured all my HTPC components with a Killawatt meter and the total usage is 120W when idle.  The computer itself uses 92W.  Reading online, a nice Intel Core i3 system (with all the accessories) uses around 40W when idle.  So that would save me 52W.  On a daily basis thats 1.2kWh which would save me $0.106/day = $3.23/mo = $38.72/yr.  Generally I would invest about $300 into this which gives me a simple return on investment (ROI) of 7.75 years.  Not all that great, right?

Well...looking at my TED, it's pretty obvious the one thing that is using the most power in my home is the hot water heater (see large single spikes).  The graph above shows last weeks worth of hourly energy usage.  The block on the first day (Sunday) is from doing laundry so that's a mix of hot water and dryer usage.  Overall, It's that time of the year when I don't need heating or cooling, so my geothermal is turned off (House stays between 67 and 75...comfy!).  With the system off, my desuperheater isn't heating my hot water.  So...does it make sense to upgrade my hot water heater?

Well, one of those GE hybrid hot water systems costs about $1400 from Lowe's (I'm not including the tax credit because I can't buy it this year).  If my current hot water heater (4.8kW) is on, say for 2 hrs/day (only 1 hr shown above, but let's factor in winter), then that I'd use 9.6kWh/d which is $0.82/day = $24.8/mo = $298/yr.  A hybrid hot water heater (according to the website) would save me 62%.  So, without factoring in the desuperheater, my ROI is 7.6 years.  With the desuperheater reducing hot water by 40% (a conservative value) then the ROI rises to 12.64 years.  Overall, I'd say this fix isn't worth it unless my hot water heater decides to break.

Out of curiosity, how about solar hot water?  Well...first, I'm not sure if my desuperheater and solar hot water can work together...but let's assume they can.  A solar hot water system (which is not a do-it-yourself job for me given my roof is so steep) would probably cost about $5000 installed.  This is just a guess looking online for similar systems.  What's the ROI?  16.8 years...so yeah, that's out of the question.

Out of these 3, upgrading the computer has the best ROI, albeit the overall savings are small.

However, I think my best bet is going to be contacting my geothermal MFR to see if there's a way for my desuperheater system to heat my hot water.  All the parts are there...there just needs to be some way for the hot water tank to contact the geothermal system to turn on.  And in hot water only mode, then the geothermal system would not turn on the fan.

Always on Electrical Usage

Hmmm...I think its time to tackle the always on Electrical usage. Above is a screenshot from my Google Powermeter.  Notice that my average "always on" power usage is roughly a third of my total power usage.  On some days, that power usage is over a half of my daily power usage!

Really, if you look at my power usage in my previous blog (Phantom Power Usage), by far most of my always on power usage is from my HTPC.  Looking at my schedules, my HTPC really only needs to run for at most 4-5 hrs/day.  So, why is it running 24 hrs/day?

So this weekend, I'm going to look into this.  I've played with this concept before...which works setting it manually, now I just need to get it to work automatically.

I'll keep you posted.

Compost bin

Here's a pic of the compost bin we made

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Veggie Garden and Compost bin

I know...it's not very energy efficient, but I do enjoy some fresh veggies.  So we built ourselves a nice veggie garden using 4"x4"x8' pressure treated wood last weekend.  It's 16' L x 4' wide.  We broken up the ground and mixed in 10 ft3 (~2") of Miracle Grow garden soil.  We'll start planting in a couple weeks (April 18th) for the next new moon.  It'll be fun...we'll get tomatoes, cukes, green beans, peas, carrots, spinach, green peppers, and lettuce.  Cool stuff!

And today I bought myself a cheap trash can, drilled some holes in it to create our compost bin.  Kudos to my boy, Napo, who gave me the idea.  Tomorrow we'll add in some sticks, newspapers, grass, and leaves to get things 'posting.  Good times...