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Distribution Measures: Voltage Reduction and Optimization Regional Technical Forum January 21, 2014.

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Presentation on theme: "Distribution Measures: Voltage Reduction and Optimization Regional Technical Forum January 21, 2014."— Presentation transcript:

1 Distribution Measures: Voltage Reduction and Optimization Regional Technical Forum January 21, 2014

2 Two protocols… (Automated) CVR Standard Protocol #1(Automated) CVR Standard Protocol #1. Energy savings derived from 90 days of day- on/day-off data collection. Early version approved by RTF in 2004 Major revision November, 2011 ( latest draft dated May 15, 2012) – Stalled out in subcommittee – Main sticking point was proposed eligibility requirements (baseline system must meet certain IEEE standards, …) (Simplified) Voltage Optimization(Simplified) Voltage Optimization. KWh savings based on savings factors derived from NEEA’s DEI research (which included a day-on / day-off CVR study). “Canned” factors vary by climate, AC saturation, and ER heat saturation – Only trying to be right-on-average – Only apply to residential feeders (a little light commercial in the mix is okay) Early version approved by RTF May 4, 2010 Revised version brought to RTF in November, 2012 – Sent to back subcommittee for further discussion – Subcommittee took a step back to consider a change of course Both protocols currently in limbo (they’ve been “under review” for a long time). 2 – Introduction Conservation Voltage Reduction

3 Where the effort stalled Subcommittee: Maybe four documents would be better than two… – Automated CVR #1 for existing conditions – Automated CVR #1 for optimized feeders – Guidance on feeder upgrades and optimization (reconductoring, phase balance, voltage drop comp.) – Simplified voltage optimization protocol Others: Maybe zero protocols would be better still. – By late 2012, some stakeholders not sure RTF-approved CVR protocols such a great idea. And lots specific comments and concerns… 3 – Introduction

4 Where the effort stalled Specific comments and concerns… Fixable technical issues – Do we need different ∆V calculations in some cases? – Others Fundamental technical limitations – End-use mix changes so savings factor is a moving target – Hard to know the average ∆V seen by customers on a feeder – Persistence of savings is tricky Familiar non-technical questions in an unfamiliar field – What standards define obsolete / ineligible equipment – Will the presence of an RTF-approved protocol stifle M&V research? – Which DE costs/benefits are for CVR; which are part of something else Less familiar non-technical issues – Distribution engineers’ responsibilities, procedures largely separate from EE – Right-on-average figures not right for capital-improvement decisions – EE target pressure may not weigh enough to alter DE decisions 4 – Introduction

5 About today’s presentation The Big Question: Should the RTF continue to pursue CVR protocols? – If yes, need direction on some issues. – If unsure, need staff/CAT homework assignment. – Plan to discuss this question last. First, discuss protocols under assumption that our goal is proven/active for both – How do they work? – What issues do they face? – What would it take to get them to proven/active? 5 – Introduction

6 Outline for today RTF Scope and Objectives CVR Background CVR Standard Protocol #1 Voltage Optimization Protocol What’s next for RTF CVR? 6 – Introduction

7 RTF Scope and Objectives 7 – Role of the RTF

8 How we interpret our role Charter (see additional slides) describes several technical functions Dedicated forum for resolving scientific questions – What do the experts know about measure savings (kWh)? – Decisions and recommendations based on data, engineering principles, technical judgment RTF decisions and recommendations often have policy dimensions, but policy decisions generally belong to others (PAC, Council, state officials) – Should bundling have a role in cost effectiveness? – How do we pick provisional values when we don’t have data? – Staff/CAT resource allocation—which measures get developed? – Try to get guidance from the PAC; also have some case law. Operative interpretation of the RTF’s Role: – RTF publications and recommendations should reflect our purest technical understanding, with clear statements about the limitations of that understanding. – Entities using RTF work products should weigh program, economic, and other concerns to ensure that these products are used responsibly. 8 – Role of the RTF

9 CVR Comments Related to RTF’s Role Protocols savings estimates may only be “right on average.” May not suffice for capital investment decisions. – RTF exists to support use of EE as a resource. Protocols reflect trade-offs between reliability and research expense that are appropriate for that role. – Protocols may not have insufficient rigor for some purposes. Do utilities have to use RTF-approved protocols? What about alternative (custom) methods? – Issue is between utilities and regulators. The RTF does not require that its protocols be used in any context. M&V for distribution efficiency is an active area of research. Shouldn’t the RTF just wait till the dust settles? – Maybe, but this is true for many of our measures. A lot of research has been done at this point, so we do know some things about savings due to CVR. Sometimes a measure can achieve deep savings by including components that would not be cost-effective as stand-alone measures (bundling). – The RTF tries to avoid taking positions that require or ban bundling. 9 – Role of the TRF

10 More RTF background, better slides! Check out Tom’s orientation slides from January, 2013.Tom’s orientation slides 10 – Role of the RTF

11 CVR Background 11 – CVR Background

12 Some common ground 12 – CVR Background Conservation voltage reduction saves energy. The results of this study conclusively show that operating a utility distribution system in the lower half of the acceptable voltage range saves energy… --NEEA DEI Project Report (RW Beck, 2007) How much energy it saves depends on… End-use mix (varies across feeders and over time) Average ΔV that can be achieved on a given feeder

13 Where do CVR savings come from? Customer side of meter: Some end uses consume less energy when operated at lower voltages (within ANSI standards). 13 – CVR Background ΔVΔV

14 Where do CVR savings come from? Utility side of meter: Line- and transformer losses decrease when voltage is lowered. 14 – CVR Background ΔVΔV

15 Where do CVR savings come from? Complication 1: KWh savings per ΔV depends on mix of end uses. Complication 2: 15 – CVR Background ΔVΔV ΔV not as simple as in the graph. Estimating average ΔV requires assumptions about feeder equipment and load.

16 Broader Distribution Efficiency Other potential system improvements include… Reconductoring Increase distribution primary voltage Transformer load management Balancing loads and phases Adding parallel feeders Seasonally unloaded transformers Power factor improvements These carry their own rewards but also enable greater voltage reductions for deeper CVR savings. 16 – CVR Background

17 Some Recent DE Activity NEEA DEI Project Final Report (NEEA, 2008) – Load Research Project ( ) – Pilot Demonstration Project (c ) Distribution Efficiency Guidebook (NEEA, 2008) Long-Term Monitoring and Tracking DE (NEEA, 2014) Energy Smart Utility Efficiency (ESUE) Program (BPA, ongoing) PacifiCorp’s DE Pilot Study Avista CVR Program Impact Evaluation (Avista, 2014) Evaluation of CVR on a National Level (PNNL, 2010) M&V research by PNNL and WSU researchers (2014) Green Circuits DE Case Studies (EPRI, 2011) 17 – CVR Background

18 NORTHWEST ENERGY EFFICIENCY ALLIANCE NEEA Long-Term Monitoring and Tracking Distribution Efficiency (DE) Study RTF – January 21, 2015 Christopher Frye – NEEA; (Jeff Harris - NEEA presenting)

19 (Automated) CVR Standard Protocol #1 19 – CVR Protocol #1

20 (Automated) CVR Standard Protocol #1(Automated) CVR Standard Protocol #1. Earlier version approved by RTF in 2004 (pre- Guidelines) Today’s slides based on latest draft, dated May 15, 2012 – Draft intended to be guidelines-compliant – Was not been approved by the RTF – Stalled out in subcommittee Calculator last modified in 2008 (may need updates) 20 – CVR Protocol #1 Protocol versions

21 Primary electrical systems serving any combination of residential, commercial, and industrial loads, operated radially, primary voltage ≥ kV CVR systems that can be turned on an off on a daily basis (voltage set points can be changed daily) For each affected feeder, must be able to record hourly average… – voltage (source and EOL, by phase), – ambient temperature (source), – KW and Kvar (source) And then we have performance thresholds – Based on load flow simulation models (pre- and post-) informed by historical data and proposed upgrades 21 – CVR Protocol #1 Eligibility Major limitation What’s the right set of requirements?

22 Step 1. (Data collection) Metering at feeder source: – Hourly average kW, kvar, voltage (each phase), temperature Metering at “EOL” locations: – Select low-voltage points based on load flow simulation – Collect voltage (hour-level averages for each phase and low-voltage point) Select 90 days for on/off CVR operation with data collection – Don’ have to be consecutive but get a range of conditions 22 – CVR Protocol #1 Steps to estimating savings

23 Step 2. (Regression) Estimate CVRf (%ΔkWh / %ΔV) via regression model fit with hour-level data. Dependent variable is: kWh Explanatory variables are: CDD, HDD, “zone-average” V CVRf estimate is the coefficient of voltage variable. Step 3. (Estimate Energy Savings) ΔkWh (savings) = kWh ANNUAL * CVRf * %ΔV kWh ANNUAL based on historical data ΔV is difference between estimated control-zone-average voltage levels in CVR-on and CVR-off cases 23 – CVR Protocol #1 Steps to estimating savings

24 Technical Comments on Steps 2-3. ΔV estimate assumes a kind of linearity that doesn’t always hold. – Assumption is consistent with definition of ΔV used in the regression, so this isn’t much threat to kWh savings estimate. Particular regression model specified in the protocol but lots of variants are reasonable. – Protocol’s model is probably the simplest reasonable – Additional variables/features could be added – Other fancy set-up options, too (multilevel regression, etc.) – RTF protocol seeks to describe simplest reliable method. – Protocol can be updated if clear improvements are proved out. – Alternative methods always available for custom evaluation. 24 – CVR Protocol #1 Steps to estimating savings

25 CVR factors vary over time. This issue is common to a lot of RTF protocols. We only seek to be (about) right on average. This is largely an operational measure. How do we know operation won’t change? Current protocol draft requires annual validation for three years. Need to discuss in subcommittee. This is a pre-condition measure. Obsolete equipment is a common threat to long-term savings, but RTF often leaves eligibility specs to programs. For RTF, “obsolete” usually means major near-term updates inevitable. RTF usually leaves lost opportunity issues (doing this measure now changes conservation options later) up to programs. Eligibility / performance thresholds. Is there a technical reason for having eligibility requirements in CVR 1? I.e., would first-year savings estimates be wrong if you applied the protocol to a system that’s not up to snuff? No, because protocol directly measures energy consumption with CVR on / CVR off. 25 – CVR Protocol #1 Other known CVR #1 issues

26 (Simplified) Voltage Optimization Protocol 26 – Simplified VO Protocol

27 Protocol version (Simplified) Voltage Optimization(Simplified) Voltage Optimization. Early version approved by RTF May 4, 2010 Today’s slides based on latest draft, dated Nov. 14, 2012 Revised version brought to RTF in November, 2012 – Draft intended to be guidelines-compliant – RTF sent to back subcommittee (no decision) Calculator needs review (but it’s pretty simple) 27 – Simplified VO Protocol

28 Primary electrical systems serving mostly residential and light commercial loads For each affected feeder, must be able to record hourly average… – voltage (source and EOL, by phase), – ambient temperature (source), – KW and Kvar (source) Minimum performance thresholds – Based on 7-days of hour-level data for reflecting normal operation pre and post-VO 28 – Simplified VO Protocol Eligibility What’s the right requirement? Major limitation

29 Step 1. (Identify Savings Factor) Look up VOf (%ΔkWh / %ΔV) in table Table based on NEEA Load Research Project Values vary by climate, saturation of ER heat, and AC saturation VOf only counts end-user energy savings (distribution losses calculated separately ) Step 2. (Estimate Energy Savings) ΔkWh (savings) = kWh ANNUAL * VOf * %ΔV kWh ANNUAL based on historical data ΔV is difference between estimated average voltage in CVR-on and CVR-off cases 29 – Simplified VO Protocol Steps to estimating savings

30 Technical Comment. ΔV estimate assumes a kind of linearity that doesn’t always hold. VOf figures are based the customer-level meter data, so they relate actual customer-level ΔV to changes in kWh. Need good estimates of actual zone-average ΔV. In present draft, system performance standards help support the linearity assumption. Additional (mid-line) metering may support ΔV estimates if performance standards are weakened. 30 – Simplified VO Protocol Steps to estimating savings

31 Actual VO factors vary over time and across end users. Are the VO factors in the table really representative of regional averages? Only trying to be right on average. Factors are probably reliable enough for RTF purposes but may need to be updated from time to time. How hard would it be to obtain reasonable VO factors for other customer mixes? Bob? Others? Operational measure issue. Same direction as with CVR #1. (And same need to discuss in subcommittee.) This is a pre-condition measure. Obsolete equipment issue. (Same as before.) Eligibility / performance thresholds. Is there a technical reason why the calculations only apply for systems that meet the performance thresholds? Yes, see ΔV discussion on previous page. Need to discuss alternatives in subcommittee. 31 – Simplified VO Protocol Simplified VO Protocol Discussion

32 Next steps 32 – Next steps

33 Should the RTF continue to pursue guidelines- compliant CVR protocols? We have put a lot of effort into these protocols, and they have an important role to play in capturing a lot of cost-effective energy savings (some of it quite low-hanging fruit). We shouldn’t abandon them without a very good reason. 33 – Next steps What comes next?

34 Additional Slides 34 – Additional slides

35 From the November, 2012, meeting minutes RTF discussion of the NEEA study: Concerns about the variability in the results, whether the results are representative., the lack of a linear relationship between energy savings and change in voltage, and whether it is feasible to get to reliable VO factor values for a standard protocol. Hadley: So you are saying you can’t have a protocol. Wyatt Pierce: It is not cost-effective to prove it out for the energy savings involved; it would take a lot of ongoing effort. I would rather work toward VO deemed savings as a small saver measure. Podell-Eberhardt: Would the deemed route would be acceptable if there is a wide range of variability? T The RTF discussed how the dynamics of the distribution system give unpredictable results for a VO calculation and whether VO works for a standard protocol. Members discussed research that has been conducted on VO and whether the PacifiCorp system is representative for purposes of considering a VO protocol. Baylon: I think the study RW Beck performed for NEEA was representative of the region. Hope: There is a set of system improvements to go through before a utility takes VO measures, and this is followed by years of monitoring. The RTF discussed the monitoring period required for a VO calculation. Grist: We don’t know enough now to make a decision, and we probably should send this to a subcommittee. I don’t think this is a small saver; based on the NEEA work, the Council estimated there are 400 aMW of potential savings. Jones: Even if there are big potential savings, it may not lend itself to a protocol. 35 – Additional slides

36 RTF Charter: Scope and Function …RTF shall advise the Council during the development and implementation of its power plan by: Developing and maintaining a readily accessible list of eligible conservation resources, the estimated lifetime costs and savings associated with those resources, and the estimated regional power system value associated with those savings; Establishing a process for updating the list of eligible conservation resources as technology and standard practices change, and an appeals process through which utilities, trade allies, and customers can demonstrate that different savings and value estimates should apply; Developing a set of protocols by which the savings and system value of conservation resources should be estimated with a process for applying the protocols to existing or new measures; Assisting the Council in assessing: 1) the current performance, cost and availability of new conservation technologies and measures; 2) technology development trends; and 3) the effect of these trends on the future performance, cost and availability of new conservation resources; Tracking regional progress toward the achievement of the region's conservation targets by collecting and reporting on regional research findings and energy savings annually. In carrying out the above responsibilities, the RTF shall develop annual work plans and multiyear business plans… 36 – Additional slides

37 Separate analysis for each “voltage control zone” Performance Assessment (Prior to CVR Installation) Collect historical data – Load shape, total energy, kvar data, customer mix, ER heat and AC kWh estimates Set up load flow simulation model for Pre- and Post- CVR cases – Simulation based on physical configuration, historical data, and proposed upgrades. Use simulation model to test whether Pre- and Post- CVR systems meet performance thresholds. 37 – Additional slides CVR#1 Performance Assessment

38 Protocol specifies “post-period re-verification trigger” Annual persistence review for three years after installation. Check for changes in standard operation – Source voltage (min, max, average), – Weather-adjusted annual energy – Average primary voltage – kW, kvar demand Any change ≥ 15% triggers full protocol do-over Is this how we want to treat persistence? 38 – Additional slides Additional Slide: CVR #1 Persistence


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