Archive for August, 2016

Highway Robbery? Vibrating Freakin’ Roadways to Generate Electricity

Sunday, August 7th, 2016

Just when I thought it couldn’t get any more stupid…

Solar Freakin’ Roadways was a bad enough idea…now, the California Energy Commission has agreed to fund several projects to investigate the generation of electrical energy from piezo electric cells placed in road surfaces. The idea is that since a piezo device can convert mechanical vibrations into electricity, they can regain some of the energy lost by cars and trucks that are constantly vibrating the roads.

At first it seems like a reasonable idea…until you think about the tiny amount of energy involved compared to the cost of such devices.

While I’ve seen estimates that assume up to 40% of the energy expended by a vehicle is available for recapture, this amount is not available to produce road vibrations. Most of the energy losses are elsewhere — wind resistance, waste heat generation, friction in the driveline — and only 4% goes into the rolling resistance of the tires.

And most of THAT 4% rolling resistance is lost by generation of heat as the tire flexes….I’ll bet less than 1% goes into vibration of the road surface itself, which is what the piezo devices would be capturing a part of.

Then, what portion of that 1% could be harvested? Maybe a tenth of it? So, now we are talking about retrieving about 0.1% of the energy expended by moving cars and trucks. And that’s if the cells have 100% efficiency, which they don’t.

So, no…not “up to” 40% is available to capture by piezoelectric devices. And considering the cost of the piezoelectric cells, this would be a really bad idea…except for whatever company is getting rich off of manufacturing them.

Plus, there is the additional question of whether the devices are passively harvesting some of the road vibrational energy that would occur anyway…or would they be an active additional source of rolling resistance of the tires? If it’s the latter, then it would be ‘highway robbery‘, because it would be reducing the fuel efficiency of cars, and stealing a small portion of that extra energy required to push against the devices to convert it to electricity.

While a pilot project in the Netherlands found that Generating Electricity from Vibrations in Road Surface Works, reading of that article reveals the amount generated isn’t enough to even power a street light.

And this does not even address the practical issues involved in replacing a portion of road surfaces with piezo strips. Will it be like driving over rumble strips (see the photo above)? That won’t be very popular. What will it do to the integrity of the road surface? What if one breaks free and flies through a windshield and kills someone?

Sounds like just another energy boondoggle to me.

UAH Global Temperature Update for July, 2016: +0.39 deg. C

Monday, August 1st, 2016

July Temperature Recovers Slightly from Previous Free-Fall

NOTE: This is the sixteenth monthly update with our new Version 6.0 dataset. Differences versus the old Version 5.6 dataset are discussed here. Note we are now at “beta5” for Version 6, and the paper describing the methodology is still in peer review.

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for July 2016 is +0.39 deg. C, up a little from the June, 2016 value +0.34 deg. C (click for full size version):


The global, hemispheric, and tropical LT anomalies from the 30-year (1981-2010) average for the last 19 months are:

2015 01 +0.30 +0.44 +0.15 +0.13
2015 02 +0.19 +0.34 +0.04 -0.07
2015 03 +0.18 +0.28 +0.07 +0.04
2015 04 +0.09 +0.19 -0.01 +0.08
2015 05 +0.27 +0.34 +0.20 +0.27
2015 06 +0.31 +0.38 +0.25 +0.46
2015 07 +0.16 +0.29 +0.03 +0.48
2015 08 +0.25 +0.20 +0.30 +0.53
2015 09 +0.23 +0.30 +0.16 +0.55
2015 10 +0.41 +0.63 +0.20 +0.53
2015 11 +0.33 +0.44 +0.22 +0.52
2015 12 +0.45 +0.53 +0.37 +0.61
2016 01 +0.54 +0.69 +0.39 +0.84
2016 02 +0.83 +1.17 +0.50 +0.99
2016 03 +0.73 +0.94 +0.52 +1.09
2016 04 +0.71 +0.85 +0.58 +0.94
2016 05 +0.55 +0.65 +0.44 +0.72
2016 06 +0.34 +0.51 +0.17 +0.38
2016 07 +0.39 +0.48 +0.30 +0.48

The July pause in cooling as La Nina approaches also happened during the 1997-98 El Nino. I’ve examined a daily time series of satellite data for 2016, and this behavior is due to intra-monthly variations in temperature, probably mostly driven by episodic deep convective activity in the tropics. Depending upon how the calendar months line up with the resulting peaks and troughs in temperature, the result is a rather irregular monthly temperature time series. It can be viewed not so much as a variation in radiative cooling to outer space, but a variation in convective heating of the troposphere.

To see how we are now progressing toward a record warm year in the satellite data, the following chart shows the average rate of cooling for the rest of 2016 that would be required to tie 1998 as warmest year in the 38-year satellite record:

Given the behavior of previous El Ninos as they transitioned to La Nina, at this point I would say that it is unlikely that the temperatures will remain above that projection for the rest of the year, and so it is unlikely that 2016 will be a record warm year in the satellite data. Only time will tell.

The “official” UAH global image for July, 2016 should be available in the next several days here.

The new Version 6 files (use the ones labeled “beta5”) should be updated soon, and are located here:

Lower Troposphere:
Lower Stratosphere: