Description, Modeling, and Measurement of Utility Noise Les - - PowerPoint PPT Presentation

Description, Modeling, and Measurement of Utility Noise

Les Blomberg Noise Pollution Clearinghouse Box 1137 Montpelier VT 05601

Board’s Order

• A sound "primer" on such topics as how sound

is described, modeled, and measured.

– Metric – Modeling – Monitoring

• Merits of, and approaches to, potential

development of a review of scientific and technical literature regarding sound impacts from energy facilities

The Challenge in Developing a Metric, Criteria, and Monitoring Plan

Metrics and Criteria Used in Scientific Research Metrics and Criteria Usable in Compliance

• r Enforcement

Lden Ldn Lnight Leq(1) Leq(24) Yearly Average Lmax See Presentation

Outline

• Lessons Learned from Previous Utility Cases
• Better Monitoring Options
• When Do Noise Problems Occur
• 21st Century Noise Monitoring
• Not in Presentation

– Low Frequency

Lessons Learned

• 1. Current monitoring is expensive and inconclusive

– “…it is unlikely … that the results obtained in this survey actually quantify the project-only sound” (Vermont Wind, 1St Quarterly Report, Executive Summary) – “A slightly higher level at the exposed primary position than at the shielded position only 75 ft. away could well be just a matter of greater exposure to tree rustle, birds or far off ambient sounds.” (Vermont Wind, 1St Quarterly Report, 19) – “an unequivocal determination of the project-only sound level, exclusive of any background contamination, is not possible “(Vermont Wind, 1St Quarterly Report, 27)

Lessons Learned

• 2. Without turning the turbines off, determining

turbine levels is difficult to impossible.

– 1 hour averages means data has lots of

• pportunities for contamination
• Very little useable data

– Don’t know if the site 2 miles away has the same background as house – Source contamination behind house

Lessons Learned

• 3. Need to take the accuracy of modeling into

account when considering noise predictions

– ISO 9613 (basis for modeling) has a 3 dB error

• Wind turbines exceed the height for the standard

Lessons Learned

• 3. Need to take the accuracy of modeling into

account when considering noise predictions

– Concawe has an even larger error

Concawe, 28

Lessons Learned

• 3. Need to take the accuracy of modeling into

account when considering noise predictions

– CADNA on error

DataKustik Technical Note, 4

Lessons Learned

• 4. Inside turbine noise levels are not much less

than outside when windows are opened

– ASTM E966 – Can’t extrapolate from one house to another

Lessons Learned

• 5. Lack of an Aesthetics (Act 250 Criterion 8)

standard is responsible for much of the noise problem

– People are complaining about hearing the noise in their homes – Need to account for quiet backgrounds in many communities, especially at night – In Act 250, noise is most often addressed under Criterion 8

Lessons Learned

• 6. Needing NRO mode means the turbines are

too big

– Turbines size is the most effective noise control – NRO less effective in ridge top/high wind shear locations – NRO requires constant monitoring to

• Trigger NRO
• To ensure compliance
• Assess the effectiveness of NRO in ridge top settings

Lessons Learned

• 7. Microphone location is critical

– Creeks, vegetation, roads create contamination – Incomplete screening of background location – Partial screening at source site – Need a collaborative process to select microphone locations

Better Monitoring Options

• 1. Shorter time periods

– Lmax – Leq(1 min) – Act 250 uses Lmax

Better Monitoring Options

• 2. Distance is a surrogate for noise

– Not sufficient alone – Cheap and easy – Depends on turbine size

Better Monitoring Options

• 3. ANSI S12 100

– Upward masking – Most human caused noise is < 1,000 Hz – Filters potential contaminating sounds > 1,000 Hz

• Leaf-rustle

– Peaks at 2,000 to 3,150 HZ

• Insects

– 8,000 Hz

Better Monitoring Options

• 3. ANSI S12 100

Better Monitoring Options

• 4. Audibility

– Audibility most popular addition to noise regulations in last 20 years

• Cheap
• Effective

– NYC, Burlington, Montpelier, Woodstock, Morristown, Wallingford, Fair Haven, … – No audible noise in non-participating homes – Correlates well with what people complain about

Better Monitoring Options

• 4. Audibility

– “Plainly audible means any sound that can be detected by a person using his or her unaided hearing

• faculties. As an example, if the sound source under

investigation is a portable or personal vehicular sound amplification or reproduction device, the enforcement

• fficer need not determine the title of a song, specific

words, or the artist performing the song. The detection of the rhythmic base component of the music is sufficient to constitute a plainly audible sound.”

Williston Noise Ord.

21st Century Noise Monitoring

• 1. Real-time web-based data sharing

– Noise monitoring – Power production – Meteorological conditions – Increase trust and openness – Increase compliance

Crafting Usable Metrics and Criteria for Compliance that Approximate those Used in the Scientific Literature

Metrics and Criteria Used in Scientific Research Metrics and Criteria Usable in Enforcement or Compliance Short time periods Distance S12 100 Audibility

Don’t Forget

• Error
• Aesthetics criteria
• NRO noise control limitations
• Inside measurements
• Microphone location