DHP Supplemental Fuel Screen Subcommittee Meeting

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DHP Supplemental Fuel Screen Subcommittee Meeting Regional Technical Forum December 10, 2013

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DHP Supplemental Fuel Screen Subcommittee Meeting. Regional Technical Forum December 10, 2013. Today’s Agenda. Subcommittee duties Motivation for screen Discuss candidate screens that have been proposed Site visit screen Bill screens (VBDD, “simple” monthly) Wrap up and next steps. - PowerPoint PPT Presentation

Transcript of DHP Supplemental Fuel Screen Subcommittee Meeting

Page 1: DHP Supplemental Fuel Screen Subcommittee Meeting

DHP Supplemental Fuel ScreenSubcommittee Meeting

Regional Technical ForumDecember 10, 2013

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Today’s Agenda

• Subcommittee duties• Motivation for screen• Discuss candidate screens that have been

proposed– Site visit screen– Bill screens (VBDD, “simple” monthly)

• Wrap up and next steps

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Subcommittee Duties• At its November meeting, the RTF voted to establish DHP

Supplemental Fuel Screening Subcommittee• Proposed duties for DHP Screening Subcommittee:

1. Identify workable screen(s) for all zones2. Evaluate their implementation characteristics3. Determine reliability of companion UES(s) for each screen4. Make a recommendation to the full RTF

• Subcommittee should have at least (5) voting RTF members with expertise in programs, Zone 3, and DHP savings calibration

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Motivation for Screen

VBDD screen results from previous analyses shown as an example.

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Motivation for Screen

VBDD screen results from previous analyses shown as an example.

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Site Visit Screen• Description:

– The home is either inspected by the utility or a contractor

– If there is no heat source other than electric the home would qualify

– If there is any other heat source, even if the owner says they don’t use it, the home would fail the screen

– If home does not have a wood stove but still has a flue:• Home would fail screen

• If homeowner chooses to remove the flue they would be considered full electric

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Site Visit Screen (continued)

• Companion UES’s: – “Pass” screen (no supp. fuel) savings could be

based on the self-reported “does not have supplemental fuel” survey group

– “Fail” screen (has supp. fuel) savings could be based on the “does have supplemental fuel” group

– Question: should these UES’s be Provisional and require further study? (see “Cons” on slide 24)

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Site Visit Screen (continued)

• Pros:– Provides greatest potential for screened savings– Relatively easy to implement with contractor help. The

contractor should be going to the home to provide a bid and therefore can provide the verification of heating systems (can also combine this with random inspections)

– New homeowners can qualify with no previous usage history.

– Rentals can be upgraded by the owner without having to have continuous renters with consistent usage numbers.

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Site Visit Screen (continued)

• Cons:– Screen does not eliminate seasonally-occupied homes – We will miss homes that utilize secondary heat

sources but still use enough electric heat to see successful savings of over ~3000 kWh/year

– This program design may encourage some people to stop burning wood. If people know by removing their wood stove and flue, they qualify for the incentive, they will do so. We don't know what percentage of participants this will be, so we should study it.

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Bill Screen 1 – VBDD• Description:

– The screen requires 12 months of utility bills prior to the DHP retrofit. There can be no change in occupancy within the 12-month billing history used for the screen. A variable-base degree day (VBDD) method is then used to assess the fit between outdoor air temperature and heating energy use, which is used to determine the existence of supplemental fuels. The following output values are required to pass the screen:

• R2 ≥0.6

• Normalized, Annual Space Heating Estimate (SH) in kWh/yr

– Heating Zone 1: SH ≥ 3,750 kWh/yr

– Heating Zone 2: SH ≥ 7,500 kWh/yr

– Heating Zone 3: SH ≥ 7,500 kWh/yr

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Bill Screen 1 – VBDD (continued)• Pros:

– No site visit required– Minimal data required for screen (e.g. square

footage or other home characteristics not needed)• Cons:

– 12-months of prior bills with no change in occupancy eliminates some potential program participants

– Uncertainty in the screen’s ability to correctly identify supplemental fuel use requires some guesswork for NEBs

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Bill Screen 1 – VBDD (continued)• Companion UES’s:

– The table below compares electric savings for those who pass the VBDD billing screen versus those who reported “no supplemental fuel use” in the occupant questionnaire

 PASS Side

Screened by Occupant Questionnaire

Screened by VBDD Billing Analysis, R2 and min space

heat% Difference

  Savings SavingsHeat Zone (kWh/yr) (kWh/yr)

1 2,780 2,735 2%2 1,911 1,942 -2%3 1,811 1,907 -5%

ALL 2,702 2,666 1%

Note: The occupant questionaire was part of the DHP pilot study and VBDD screen relies only on billing history

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Bill Screen 1 – VBDD (continued)• Companion UES’s (continued):

– This table compares electric savings for those who fail the VBDD billing screen versus those who reported “supplemental fuel use” in the occupant questionnaire

FAIL Side 

Screened by Occupant Questionnaire

Screened by VBDD Billing Analysis, R2 and min space heat % Difference

  Savings SavingsHeat Zone (kWh/yr) (kWh/yr)

1 (111) 625 -118%2 (305) (238) 28%3 (1,422) (959) 48%

ALL (242) 423 -157%

Note: The occupant questionaire was part of the DHP pilot study and VBDD screen relies only on billing history

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Bill Screen 1 – VBDD (continued)

  Match Rate Between Occupant Questionnaire and VBDD Screen

  Occupant No Supp Occupant Yes Supp Match RateHeat Zone VBDD No VBDD Yes VBDD No VBDD Yes No Supp Yes Supp

1 1807 490 585 540 79% 48%2 97 70 34 87 58% 72%3 54 32 40 66 63% 62%

ALL 1958 592 659 693 77% 51%

This table shows how frequently the VBDD screen and occupant questionnaire agreed or disagreed on the presence of supplemental fuel.

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Bill Screen 1 – VBDD (continued)

  Match Rate Between Occupant Questionnaire and VBDD Screen

  Occupant No Supp Occupant Yes Supp Match RateHeat Zone VBDD No VBDD Yes VBDD No VBDD Yes No Supp Yes Supp

1 1807 490 585 540 79% 48%2 97 70 34 87 58% 72%3 54 32 40 66 63% 62%

ALL 1958 592 659 693 77% 51%

This table shows how frequently the VBDD screen and occupant questionnaire agreed or disagreed on the presence of supplemental fuel.

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Bill Screen 1 – VBDD (continued)

Can we design a “better” VBDD screen that gets electric savings right for both the pass and fail sides, and the supplemental fuel match correct?

  Match Rate Between Occupant Questionnaire and VBDD Screen

  Occupant No Supp Occupant Yes Supp Match RateHeat Zone VBDD No VBDD Yes VBDD No VBDD Yes No Supp Yes Supp

1 1807 490 585 540 79% 48%2 97 70 34 87 58% 72%3 54 32 40 66 63% 62%

ALL 1958 592 659 693 77% 51%

This table shows how frequently the VBDD screen and occupant questionnaire agreed or disagreed on the presence of supplemental fuel.

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Bill Screen 1 – VBDD (continued)A sensitivity analysis of the screen parameters suggests No

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Bill Screen 1 – VBDD (continued)A sensitivity analysis of the screen parameters suggests No

As we increase the match rate for “yes, has supplemental fuel,” we decrease the match rate for “no supplemental fuel.”

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Bill Screen 1 – VBDD (continued)A sensitivity analysis of the screen parameters suggests No

And vice versa.

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Bill Screen 1 – VBDD (continued)Similar results for Heating Zones 2 and 3 (HZ3 shown below)

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Bill Screen 1 – VBDD (continued)• Proposed option for this screen:

– Set the “pass” and “fail” screen electric savings equal to their corresponding VBDD groups

– Calculate total wood savings and distribute between the “pass” and “fail” groups based on match rate

Heating Zone VBDD Results

Survey Results

Total Sample Electric

Savings (kWh)

Total Sample Wood Savings

(kWh)

Electric Savings per Site (kWh)

Wood Savings per Site (kWh)

pass survey - fail survey 1,234,182 pass survey 0fail survey 1,006,333 pass survey - fail survey 74,123 pass survey 0fail survey 163,507 pass survey - fail survey 114,639 pass survey 0fail survey 180,556

pass vbdd

fail vbdd

pass vbdd

fail vbdd

1,811 1,220

(1,422) 2,099

HZ1

HZ2

HZ3

pass vbdd

fail vbdd

170,251

1,911 566

(305) 1,572

(122,266)

516

1,220

2,780

(111)

6,649,989

(91,720)

250,382

(31,671)

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Bill Screen 2 – Monthly Consumption

• Description: – This would require 12 months of continuous usage by

the same occupant. – Determine baseline electric usage in the home (find

2nd lowest monthly usage for the year and multiply by 12).

– Add up the 12 months of usage and subtract the baseline. This would provide the kWh used for heating.

– If this number is greater than 7500 kWh (for example), they would pass.

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Bill Screen 2 – Monthly Consumption (continued)

• Pros:– Easy to implement for a utility and does not necessarily require a

site visit – This would find all homes that have enough electric heat to save

~3000 kWh/year regardless of various heating sources. This can be very useful since there are many homes with old fuel oil systems that haven’t been used for years due to cost of oil but are still present since it costs to remove them. There are also many homes with fireplaces that are unused or minimally used that would offer excellent electric energy savings for DHP installs.

– Offers black and white explanation to customers of why they qualify: you either have enough kWh to save or you don’t.

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Bill Screen 2 – Monthly Consumption (continued)

• Cons:– New homeowners and rentals would not qualify. In addition,

owners of second homes that have been seasonal would not qualify until they had lived here for one year rather than qualifying them as soon as they made the home their primary residence

– Those wishing to “go off wood” would need to add usage to the grid for one year to prove their eligibility to save energy.

– How do we eliminate or count out usage items like: water trough heaters, snow melt cable, water pipe heat tape, snow melt in drives and walks, space heat in barns/garages/well houses, which are not necessarily tied to space heat usage?

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Bill Screen 2 – Monthly Consumption (continued)

• Cons (continued):– Some homes have electric resistance zonal heat in their

bedrooms but not in the living area. They may pass this screen but upon install of the DHP may not see electrical energy savings due to configuration of the house. The DHP may only save on the wood use in the living/dining/kitchen area.

– Program could provide positive reinforcement to the members who are most wasteful or have the most inefficient homes and penalizes smaller homes, weatherized homes, and homeowners who have an electrically conservative lifestyle.

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Bill Screen 2 – Monthly Consumption (continued)

• Companion UES’s:– Would need to be calculated using a dataset similar

to the annual dataset used for the VBDD screen.– We currently do not have the monthly data in hand

to calculate the UES’s, though we could generate the dataset with a few full days of work (Ecotope estimate)

– Staff would need clear direction from the subcommittee if we wanted to spend the time required to go down this path

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Next Steps

• Is the group in favor of one or more of these screens?

• Would utilities want multiple screens? (e.g., site visit screen and bill screen)

• What about a hybrid screen? (e.g. site visit plus minimum consumption screen)