Wind Energy And Cherry Point
Two weeks ago the Pamlico County Board of Commissioners and the Pamlico County
Planning Board had a joint meeting at the court house to receive a briefing by
Cherry Point on wind generation systems. Specifically, Cherry Point briefed on
problems for their air operations that are anticipated from wind
turbines.
The briefing acknowledged that it is national policy and the policy of the Department of Defense to encourage alternative energy sources. The briefing did not emphasize, as it might have, that Secretary of the Navy Ray Mabus has been a leading proponent of alternative energy.
The main focus of the briefing was how wind turbines adversely affect Marine radar systems and how important radar is to their air operations. The main challenge was how to mitigate those effects.
Unfortunately, Cherry Point officials offered no hope and no prospects of hope for mitigation. "To date," one presentation slide asserts, "no study data is published indicating technology exists to eliminate wind turbine adverse effects on radar."
Not so. There are studies.
A 2008 study by MITRE Corporation, one of DOD's most experienced electronics contractors observed. "There is no fundamental physical constraint that prohibits the accurate detection of aircraft and weather patterns around wind farms. On the other hand, the nation’s aging long range radar infrastructure significantly increases the challenge of distinguishing wind farm signatures from airplanes or weather.
"Progress forward requires the development of mitigation measures, and
quantitative evaluation tools and metrics to determine when a wind farm
poses a sufficient threat to a radar installation for corrective action to be
taken. Mitigation measures may include modifications to wind farms (such
as methods to reduce radar cross section; and telemetry from wind farms to
radar), as well as modifications to radar (such as improvements in processing;
radar design modifications; radar replacement; and the use of gap fillers in
radar coverage).
"There is great potential for the mitigation procedures, though there
is currently no source of funding to test how proposed mitigations work in
practice. In general, the government and industry should cooperate to find
methods for funding studies of technical mitigations. NOAA has an excellent
research plan, but no adequate funding to carry it out.
"Once the potential for different mitigations are understood, we see no
scientific hurdle for constructing regulations that are technically based and
simple to understand and implement, with a single government entity tak-
ing responsibility for overseeing the process. In individual cases, the best
solution might be to replace the aging radar station with modern and flexi-
ble equipment that is more able to separate wind farm clutter from aircraft."
Mitre's conclusion: "This is a win-win situation for national security, both improving our radar
infrastructure and promoting the growth of sustainable energy."
So the problem isn't technology, it is budgets for what may prove to be fairly minor improvements to radars, new procedures, and possibly coatings for turbine blades to reduce their radar cross-sections. I got the distinct impression that the Marine Corps isn't sufficiently concerned to spend any R&D funds fixing their radars. Why should they, if they can achieve the same end at no cost by intimidating state and local government? The only cost would be to retard economic development in Pamlico County and that doesn't cost the Marine Corps a dime.
In her introductory remarks to the meeting, Commissioner Holton emphasized the potential economic development benefits of wind energy to Pamlico County.
Speaking of mitigation, any measure to replace fossil fuel energy sources with non-carbon alternatives such as wind, solar or nuclear, will delay anticipated sea level rise from global warming. That should matter to every resident of Pamlico County and elsewhere in Eastern North Carolina. In my case, I just raised my house three feet to mitigate the effect of storm surge after Irene. But predictions are that the sea level will rise one meter (39 inches) this century. If so, my house is back in the flood waters.
So I am in favor of wind, solar and nuclear power. No single solution - all of the above.
This discussion has been going on for awhile here and here and here and here and here and here.
3. The problems concern two types of radar: Air Defense systems (AD) and weather radar.
4. My reading of the report to Congress is that there is no problem with Air Traffic Control (ATC) radar. The reason for this is that ATC relies not only on direct radar return ("skin paint") but also on transponder beacon returns like IFF. The briefing did not mention this distinction, but the bulk of the briefing was by Cherry Point's ATC expert. I don't know if Marine ATC controllers have the aircraft turn off their IFF or other beacons while training at high speed and low altitude in this region. Maybe they do, but if so, we should be told. Whether to turn it on or off during training ops is a procedural issue.
5. Distance from the affected radar can itself provide the necessary mitigation. The key factor is distance from the radar to the radar horizon - which is a bit further than the unobstructed visible horizon would be. Bottom line is, that for a normal radar height, and a blade tip height of 300 feet, there would be no interference beyond a distance of 30 miles, even without special mitigation. For a blade tip height of 500 feet, the safe distance would be 35 miles. Trouble is, Pamlico County is within either distance. But that only applies to AD radars. For ATC radars, there should be no problem.
So what kind of radar are they talking about? The briefing did not provide enough information for Pamlico County planners and commissioners to develop suitable regulations for wind farms.
Weather radar is a different matter. Here is a pretty good illustration and discussion of the problem: http://www.crh.noaa.gov/mkx/?n=windfarm There is also some discussion of weather radar in the report to Congress. I did not get the impression from the Cherry Point briefing that they are worried about the weather radar.
I'm not sure what to make of it.
I think the county needs more information.
The briefing acknowledged that it is national policy and the policy of the Department of Defense to encourage alternative energy sources. The briefing did not emphasize, as it might have, that Secretary of the Navy Ray Mabus has been a leading proponent of alternative energy.
The main focus of the briefing was how wind turbines adversely affect Marine radar systems and how important radar is to their air operations. The main challenge was how to mitigate those effects.
Unfortunately, Cherry Point officials offered no hope and no prospects of hope for mitigation. "To date," one presentation slide asserts, "no study data is published indicating technology exists to eliminate wind turbine adverse effects on radar."
Not so. There are studies.
A 2008 study by MITRE Corporation, one of DOD's most experienced electronics contractors observed. "There is no fundamental physical constraint that prohibits the accurate detection of aircraft and weather patterns around wind farms. On the other hand, the nation’s aging long range radar infrastructure significantly increases the challenge of distinguishing wind farm signatures from airplanes or weather.
"Progress forward requires the development of mitigation measures, and
quantitative evaluation tools and metrics to determine when a wind farm
poses a sufficient threat to a radar installation for corrective action to be
taken. Mitigation measures may include modifications to wind farms (such
as methods to reduce radar cross section; and telemetry from wind farms to
radar), as well as modifications to radar (such as improvements in processing;
radar design modifications; radar replacement; and the use of gap fillers in
radar coverage).
"There is great potential for the mitigation procedures, though there
is currently no source of funding to test how proposed mitigations work in
practice. In general, the government and industry should cooperate to find
methods for funding studies of technical mitigations. NOAA has an excellent
research plan, but no adequate funding to carry it out.
"Once the potential for different mitigations are understood, we see no
scientific hurdle for constructing regulations that are technically based and
simple to understand and implement, with a single government entity tak-
ing responsibility for overseeing the process. In individual cases, the best
solution might be to replace the aging radar station with modern and flexi-
ble equipment that is more able to separate wind farm clutter from aircraft."
Mitre's conclusion: "This is a win-win situation for national security, both improving our radar
infrastructure and promoting the growth of sustainable energy."
So the problem isn't technology, it is budgets for what may prove to be fairly minor improvements to radars, new procedures, and possibly coatings for turbine blades to reduce their radar cross-sections. I got the distinct impression that the Marine Corps isn't sufficiently concerned to spend any R&D funds fixing their radars. Why should they, if they can achieve the same end at no cost by intimidating state and local government? The only cost would be to retard economic development in Pamlico County and that doesn't cost the Marine Corps a dime.
In her introductory remarks to the meeting, Commissioner Holton emphasized the potential economic development benefits of wind energy to Pamlico County.
Speaking of mitigation, any measure to replace fossil fuel energy sources with non-carbon alternatives such as wind, solar or nuclear, will delay anticipated sea level rise from global warming. That should matter to every resident of Pamlico County and elsewhere in Eastern North Carolina. In my case, I just raised my house three feet to mitigate the effect of storm surge after Irene. But predictions are that the sea level will rise one meter (39 inches) this century. If so, my house is back in the flood waters.
So I am in favor of wind, solar and nuclear power. No single solution - all of the above.
This discussion has been going on for awhile here and here and here and here and here and here.
Not certain I have the whole story, I did more research on the wind farm/radar issues. What I have found is:
1. There is data. Some was reported to the Congress in 2006: www.defense.gov/pubs/pdfs/WindFarmReport.pdf
2. There is information on what mitigation works.1. There is data. Some was reported to the Congress in 2006: www.defense.gov/pubs/pdfs/WindFarmReport.pdf
3. The problems concern two types of radar: Air Defense systems (AD) and weather radar.
4. My reading of the report to Congress is that there is no problem with Air Traffic Control (ATC) radar. The reason for this is that ATC relies not only on direct radar return ("skin paint") but also on transponder beacon returns like IFF. The briefing did not mention this distinction, but the bulk of the briefing was by Cherry Point's ATC expert. I don't know if Marine ATC controllers have the aircraft turn off their IFF or other beacons while training at high speed and low altitude in this region. Maybe they do, but if so, we should be told. Whether to turn it on or off during training ops is a procedural issue.
5. Distance from the affected radar can itself provide the necessary mitigation. The key factor is distance from the radar to the radar horizon - which is a bit further than the unobstructed visible horizon would be. Bottom line is, that for a normal radar height, and a blade tip height of 300 feet, there would be no interference beyond a distance of 30 miles, even without special mitigation. For a blade tip height of 500 feet, the safe distance would be 35 miles. Trouble is, Pamlico County is within either distance. But that only applies to AD radars. For ATC radars, there should be no problem.
So what kind of radar are they talking about? The briefing did not provide enough information for Pamlico County planners and commissioners to develop suitable regulations for wind farms.
Weather radar is a different matter. Here is a pretty good illustration and discussion of the problem: http://www.crh.noaa.gov/mkx/?n=windfarm There is also some discussion of weather radar in the report to Congress. I did not get the impression from the Cherry Point briefing that they are worried about the weather radar.
I'm not sure what to make of it.
I think the county needs more information.
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