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Scientific Irrigation Scheduling Update

Scientific Irrigation Scheduling Update. Regional Technical Forum June 17, 2014. Scientific Irrigation Scheduling Measure Overview. Current Category: ( tbd ) Current Status: Under review for compliance w/ RTF Guidelines Current Sunset Date: [none]

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Scientific Irrigation Scheduling Update

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  1. Scientific Irrigation SchedulingUpdate Regional Technical Forum June 17, 2014

  2. Scientific Irrigation SchedulingMeasure Overview • Current Category: (tbd) • Current Status: Under review for compliance w/ RTF Guidelines • Current Sunset Date: [none] • Reason for Update/Review: Need to categorize this measure in compliance with the Guidelines

  3. Overview • RTF Scientific Irrigation Scheduling (SIS) measure has been out of compliance with the Guidelines since the Guidelines were developed three years ago. • Attempts by RTF contractors (2012) and RTF Staff (2013) to update the measure to a Standard Protocol have been unsuccessful. • Challenges in determining both the baseline and efficient cases • Available baseline data insufficient • RTF Staff have discussed possible approaches to updating the measure with regional experts and stakeholders and still don’t have a feasible path forward. • BPA is researching the feasibility of a method to estimate savings, which is based on the statistical methods that they are currently using for custom industrial measures. • Staff is now asking the RTF for guidance on next steps for this measure.

  4. Today’s Objectives • Review the measure and its recent RTF history • Discuss proposed research plans • Discuss RTF options for categorizing this measure • RTF decision on categorization

  5. Review the measure and its recent RTF history • Discuss proposed research plans • Discuss RTF options for categorizing this measure • RTF decision on categorization

  6. What is SIS? See backup slides for • an overview of the measure • why the current measure is out of compliance with the Guidelines

  7. Current Savings Method • The current SIS Calculator estimates water savings as 10% of the Water Requirement (WR) • WR is based on crop type, location, soil type, weather • This “10%” savings estimate is based on research conducted by Quantec from 2003 - 2005 • Quantec, “A Study of Irrigation Scheduling Practices in the Northwest” December 2003, for BPA. • Quantec, “Phase II: Measurement of Water and Electricity Impacts”, June 2005, for BPA, NEEA, Pac. NW Generating Cooperative • These studies estimated that water savings of growers going from inefficient water management practices to efficient water management practices was about 10% of the WR.

  8. Guidelines Issues • The 10% savings number is not statistically significant. • The 10% savings number does not reflect the already efficient irrigation practices of many eligible irrigators • The first phase of this study found that 43% of irrigated acres currently (as of 2003) use efficient water management practices. • The 10% savings estimate does not account for this baseline mix of practices. • However, the current measure is available to all growers, including previous participants and other efficient irrigators.

  9. Recent History of Measure • http://rtf.nwcouncil.org/measures/measure.asp?id=184 • Subcommittee meetings – July 9, 2013 / August 8, 2013 / November 8, 2013 • Reviewed current measure, discussed Guidelines compliance issues, discussed feasibility of research • Meeting minutes and supporting documents: http://rtf.nwcouncil.org/subcommittees/SIS/meetings.htm • RTF Presentation – Provisional Standard Protocol proposal – November 19, 2013 • RTF Decision: refer the entire measure to the SIS Subcommittee to evaluate the baseline conditions and the potential inclusion of a screen based on crop type and contract type. • Subcommittee Survey – retrofit or current practice baseline? – December 2013 • Conclusions: SIS is a current practice measure because every year a grower “shops” for an irrigation strategy, and no SIS equipment is left in place for the next year. • Staff and BPA visit to IRZ Consulting - January 23, 2014 • Discussed technical details of SIS, the RTF’s challenge, and problems with proposed research options

  10. Recent History of Measure (cont’d) • Staff conclusions: • Existing data is not sufficient for a proven Standard Protocol • A feasible research plan to obtain reliable baseline data for a provisional Standard Protocol has not been identified • BPA agrees to look into bringing measure into compliance with the Guidelines – January, 2014 • Subcommittee meeting – June 2, 2014 • BPA discusses their research intentions. Much work to be done in developing model, selecting sample, collecting data. • Subcommittee recommendation to RTF: Provisional Standard Protocol • Subcommittee expressed concern over losing the measure

  11. Review the measure and its recent RTF history • Discuss proposed research plans • Discuss RTF options for categorizing this measure • RTF decision on categorization

  12. Proposed Research Approaches • Staff have proposed several research approaches, but none have been deemed feasible by the Subcommittee and other experts we’ve spoken with. Barriers to research: • Sample size required (100s to 1000s of farms) • Burden on utilities • Unreliability of self-reported water consumption – need for metered water or metered kWh plus pumping system • Cost of metering water • Complexity of systems • Complexity of irrigation decision making • [see backup slides for details] • BPA is looking into the use of a regression-based model similar to what they use for custom industrial projects. • The Subcommittee has not offered any other research plan proposals. • There is interest among regional experts in meeting to discuss this issue and to coordinate ongoing research.

  13. Review the measure and its recent RTF history • Discuss proposed research plans • Discuss RTF options for categorizing this measure • RTF decision on categorization

  14. RTF Guidance is Needed • We have • A Standard Protocol that has been out of compliance since the Guidelines were developed • No sufficiently reliable best practice baseline • No feasible research plan • No promise of such a plan in the near future • More regional potential and interest than a Small-Saver • A lot of interest in keeping this measure • The RTF needs to categorize this measure. Options: • Proven, • Provisional, or • Deactivated

  15. Options for the RTF - Proven RTF accept the Quantec study results as Best Practice and sufficiently reliable • Use Quantec Phase 2 results – SIS saves 10% relative to inefficient irrigation practices • Use Quantec Phase 1 results - 57% of acreage in the baseline is subject to inefficient irrigation practices • 57% of acres irrigated without water management (10% savings) • 43% of acres irrigated with water management (0% savings) • [Water Savings %] = [10%]x[57%] + [0%]x[43%] = 5.7%

  16. Options for the RTF – Proven (cont’d) Guidelines issues regarding accepting the Quantec study for a proven measure: • Savings Reliability - “…the sampling, data collection and other errors are sufficiently small and unbiased. Sufficiency is determined by the collective opinion of the RTF.” (Guidelines, Roadmap Section 1.3.6) • Best Practice Savings Estimate – Estimate relies on the “best practical and reliable data collection and estimation methods.” • “Practical” = “can be carried out with proven techniques and resources deemed reasonable by the RTF.” (Guidelines, Roadmap Section 1.3.8. )

  17. Options for the RTF – Proven (cont’d) • RTF would need to agree that: • The uncertainty in the Quantec 10% savings estimate is “sufficiently small and unbiased”. • But Staff have shown that this savings estimate is not statistically significant • The Quantec study remains the best practical and reliable data collection and estimation method. • However, if this is true, then repeating the study to obtain a larger sample seems like a feasible option. • The market portion of the study is 12 years old. • Measure identifiers such as crop type and location are not necessary Or • Crops that are commonly subject to efficient practices and areas that are subject to water constraints are ineligible for the measure

  18. Options for the RTF - Provisional • Savings Model 1. [Savings from inefficient to efficient practices] x [prevalence of inefficient practices] [pick A or B] and [pick C or D] • Savings from inefficient to efficient practices • Option A – regression-based pre/post analysis of billing data plus farm data (crops, pumping system details, soil type) • Option B - Accept 10% as best practical. While we do not have statistically significant validation of this, experts have told us that this is a reasonable estimate. • Prevalence of inefficient practices • Option C – Phone survey – similar to Quantec Phase 1 • Option D – Custom query of USDA Farm and Ranch Irrigation Survey 2. Other savings model • ? The Subcommittee recommends the RTF accept SIS as a Provisional Standard Protocol

  19. Options for the RTF – Provisional (cont’d) • Any provisional option will require a provisional savings estimate • Staff recommends using the Quantec-based 5.7% savings derived earlier in this presentation. • Staff have received recommendations for 10% savings so that program willingness-to-pay remains high enough to attract participants. • Staff does not recommend this since it is known that some level of efficient irrigation practices exist in the region, and choosing 10% ignores that fact.

  20. Options for the RTF - Deactivate • Acknowledge that while SIS is a useful service and most likely results in energy savings, it may be too expensive to determine these savings with the level of certainty required by the RTF for a Standard Protocol. • If/when a feasible research plan is developed, RTF could make this a Provisional Standard Protocol. • Guidelines still allow for utilities to use this measure as a Custom Protocol or Other UES - Savings would be determined through impact evaluation • Staff recommends that the RTF deactivate the SIS measure until a Provisional Standard Protocol research plan is developed.

  21. Review the measure and its recent RTF history • Discuss proposed research plans • Discuss RTF options for categorizing this measure • RTF decision on categorization

  22. Proposed Decision – Staff Recommendation “I _______________ move that the RTF deactivate the Scientific Irrigation Scheduling Standard Protocol.”

  23. Proposed Decision – Subcommittee Recommendation “I _______________ move that the RTF approve the Scientific Irrigation Scheduling measure as a Provisional Standard Protocol • with a research plan developed by BPA to estimate inefficient-to-efficient savings based on regression-based pre/post analysis; or • accepting the estimate inefficient-to-efficient savings of 10% as best practical and reliable; a research plan to estimate the baseline prevalence of efficient irrigation practices by • a regional phone-survey; • or • a custom query of USDA Farm and Ranch Irrigation Survey; a provisional savings estimate of 5.7% of Water Requirement; and a deadline for the development this research plan of October 1, 2014”

  24. Back-up Slides

  25. Extra material: An overview of Scientific Irrigation Scheduling

  26. Overview of Measure • “Scientific irrigation scheduling is a process growers of agricultural products can use to improve irrigation water management. When used properly, scientific irrigation scheduling provides information on when to irrigate, how much water to apply, and how to apply water to satisfy crop water requirements and avoid plant moisture stress. When used appropriately, irrigation scheduling saves water, energy, labor, and fertilizer, and in many cases improves crop yields and crop quality.” • http://www.bpa.gov/energy/n/agriculture.cfm (emphasis added) • Uses soil moisture monitors, and modeling specific to crop type, soil type, and local meteorology to determine when/how much to water. • Traditional methods rely more on look/feel of soil and crops, predetermined watering calendars, and water availability.

  27. Water Balance Precipitation: water from atmosphere to soil Transpiration: passage of water through plant, from soil to atmosphere Irrigation: water applied to field by grower Evaporation: liquid in soil becomes vapor in atmosphere

  28. Water Balance - Evapotranspiration Evapotranspiration = Evaporation + Transpiration • Combined transfer of water from soil to atmosphere from evaporation and transpiration. • The rate of evapotranspiration depends on: • Weather (temp, humidity, insolation, wind) • Soil type • Crop type Transpiration: passage of water through plant, from soil to atmosphere Evaporation: liquid in soil becomes vapor in atmosphere

  29. Water Balance – Water Requirement Water Required = Evapotranspiration - Precipitation Ideally, the Irrigation water applied is exactly the amount of water required. Precipitation: water from atmosphere to soil Transpiration: passage of water through plant, from soil to atmosphere Irrigation: Water applied to field by grower Evaporation: liquid in soil becomes vapor in atmosphere

  30. What is Scientific Irrigation Scheduling (SIS)? • Precise determination of the timing and amount of irrigation required in a field using three techniques in coordination: • Evapotranspiration and precipitation monitoring • Soil moisture monitoring • Water application monitoring

  31. What is the SISmeasure? • Application of SIS in irrigation decision-making • Can be applied by either a consultant or by the grower • Service is provided for a single growing season • Soil moisture meters are removed at end of season • Crops may rotate from season to season • Climatic data will vary from year to year

  32. How do non-participants make irrigation decisions?

  33. Does not using SIS imply inefficient irrigation? Quantec Study, Phase 1. Baseline Practices • Survey of 776 farms across the PNW • Characterized irrigation practices • Compared reported water use to estimated water requirement • Findings • Practice Group II used 10% less water than Practice Group III • Practice Group I used 12% less water than Practice Group III

  34. What is the Quantec “10%” number? Phase 2 of the Quantec examined the impact of SIS • 19 treatment group sites received SIS • 19 control group sites did not receive SIS • The control group was farms known not to use water management practices. • I.e., the control group was not a random sample of the population, it was only the least efficient irrigators. • Findings: on average, • The treatment group used the “ideal water” amount. • The control group used 10% more water than the “ideal water” amount. • Conclusion: “SIS saves 10% of the ideal water amount”

  35. Overview of Measure: Energy Savings • 1) Ex post estimate water savings (acre-ft) at end of season • SIS service provider reports how much water was used for irrigation • [Water savings] = [Water consumption] x [10%] • 2) Estimate energy intensity (kWh/acre-ft), as a function of pump system at site: • Total Dynamic Head (a function of Lift and Discharge Pressure) • Pump System Efficiency estimates (a function of Pump Type, Pumping Plant Size, and Lift) • 3) Estimate energy savings (kWh) • [Energy Savings] = [Water Savings] x [Energy Intensity] = [Water Consumption] x [10%] x [Energy Intensity]

  36. Details of the Quantec Study

  37. Quantec Study – Phase 1. Baseline Practices 43% of irrigated acres are irrigated efficiently • Survey of 776 farms across the PNW • Quanteccategorized farms according to irrigation decision-making practices • “Examination of reported water use and their deviations from known irrigation requirements indicated that, by and large, farms in practice level I tend to use less water than farms that use less sophisticated practices. Comparison of mean water use derived from a regression model of water use showed that application of the combination of methods used in practice levels I and II are likely to result in water savings of approximately 12% and 10%, respectively.”

  38. Quantec Study – Phase 2. Impact Study The impact study compared growers known to use outside SIS services to growers known not to practice water management. I.e. – compare the best to the worst. “It was therefore decided to select the treatment group from among growers who received water management services through GWMA or IRZ Consulting, and to select the control group from farms in close proximity to the treatment farms. The main advantage of this approach was that it offered a more consistent basis for defining water management practices among the treatment group and significantly helped the recruitment and data collection processes. “To ensure comparability with the treatment group, each treatment field was matched with a local control field with the same crop grown by a farmer known not to practice water management.”

  39. Quantec Study – Impact Study • Analysis • Meter irrigation water use - indirect measurement: log line pressure at point of delivery, multiply by sprinkler design flow rate • Estimate “ideal” water use – use water balance model specific to county-level weather, field soil type, crop type (evapotranspiration rates) • Ideal water use is the normalizing factor for all fields (control and treatment) • Findings • Control group used 12% more water than ideal • Treatment group used 2% more water than ideal • Based on this, a 10% water savings for SIS is proposed

  40. Quantec Study – Impact Data • Note: • Small sample size • Limited crop type • High variance

  41. Quantec Study – Impact Data Impact appears to be on the least efficient irrigators. Variance = ( [actual] – [ideal] ) / [ideal]

  42. Quantec Study – Limitations of Analysis • Small sample size – 19 treatment, 19 control • Results not statistically significant • But SIS subcommittee and regional experts have said that 10% is a reasonable estimate of savings for growers who weren’t using efficient methods before. • Others have suggested that savings are as high as 20%. • If we only know that our Best Practice savings are between 0 and 20%, we can’t say if our 10% Simplest Reliable estimate is within 10% of the Best Practice estimate. • Limited geography and crop type • Dated – study conducted 2003 – 2005 • Baseline only represents a subset of the population (non-SIS users) • Does not examine take-back – (i.e., use of saved water elsewhere on farm)

  43. References • Quantec, “A Study of Irrigation Scheduling Practices in the Northwest” December 2003, for BPA. [link] • Quantec, “Phase II: Measurement of Water and Electricity Impacts”, June 2005, for BPA, NEEA, Pac. NW Generating Cooperative [link]

  44. Extra material: Why is the current measure out of compliance with the RTF Guidelines?

  45. Guidelines Compliance Issues A Proven Standard Protocol requires • Best Practice method of estimating savings • Best practice method would require direct (water) or indirect (kWh) metering of treatment and control sites • We have some of this data from the Quantec study, but it is neither current or statistically significant. • Simplest Reliable method that is sufficiently reliable (Guidelines, Savings, Section 3.4.2) • With +/- 20% of Best Practice per site, or +/-10% overall • The 10% of Water Requirement is a candidate Simplest Reliable method. • Because we don’t have a Best Practice savings estimate, we can’t say if our 10% estimate meets this criteria.

  46. Guidelines Compliance Issues A Proven Standard Protocol requires (cont’d) • Current Practice or Pre-conditions baseline • Current Practice: • SIS subcommittee indicated that SIS is best described as a current practice measure: each year growers are in the market for an irrigation strategy. There is no SIS infrastructure left in place at the site. • Savings for a current practice SIS measure could be claimed repeatedly. • A current practice baseline “is defined by the recent typical choices of eligible end users in purchasing new equipment and services” (Roadmap, Section 3.2.1) • This would include both inefficient and efficient irrigation practices. • The 10% savings estimate only includes inefficient irrigation practices in the baseline

  47. Guidelines Compliance Issues A Proven Standard Protocol requires (cont’d) • Current Practice or Pre-conditions baseline (cont’d) • Pre-Conditions: • If SIS were seen as a behavioral change, with impacts lasting more than one growing season, then a pre-conditions baseline would be appropriate. • For the pre-conditions baseline, the 10% savings estimate (if it were sufficiently reliable), would be appropriate. • However, savings could not be claimed repeatedly, because once SIS was implemented at a site, the pre-condition at that site in future years would be SIS. • Effectively, the program would be limited to sites that had not previously used SIS or similar efficient irrigation practices.

  48. Guidelines Compliance Issues A Proven Standard Protocol requires (cont’d) • Measure identifiers (Roadmap, Section 3.1) • Measure identifiers should be used to uniquely identify measure applications where there are large differences in savings • The current measure applies the same savings 10% in all cases. • However, we have heard from the Subcommittee that savings depend on • Crop type – Current practice varies by crop type • Water availability and rights – savings primarily occur where water consumption is not constrained. The frequency of water constraint varies by area (e.g. some areas have more water scarce years than others). • Prevalence of SIS in territory – Infrastructure and local adoption drive additional adoption.

  49. Guidelines Compliance Issues A Provisional Standard Protocol requires • “… a research plan is required that describes how data and analyses will be conducted in order to prove reliability of a simplified method and achieve approval for the Proven category.” Guidelines, Roadmap Section 7.1 • Despite the efforts of the RTF Staff and RTF contractors, no such research plan has been deemed feasible by the SIS community.

  50. Extra material: Proposed research approaches

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