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Eugene

(61,595 posts)
Wed Nov 25, 2020, 11:51 AM Nov 2020

Boris Johnson's 'jet zero' green flight goal dismissed as a gimmick

Source: The Guardian

Boris Johnson’s 'jet zero' green flight goal dismissed as a gimmick

Experts says technology alone will not get close to solving aviation’s emissions problems

Damian Carrington Environment editor
@dpcarrington
Wed 25 Nov 2020 12.32 GMT

Boris Johnson’s “jet zero” goal of a commercial transatlantic flight producing no carbon emissions by 2025 is a “gimmick”, according to experts, who say technology alone cannot solve the impact of global aviation on the climate crisis.

Such a flight would not be impossible, the experts said, but could only be a one-off and would encourage the view that other measures such as taxing jet fuel and frequent fliers were not needed to tackle aviation’s carbon problem.

The jet zero technology idea was part of Johnson’s 10-point “green industrial revolution” plan launched last week. But experts called jet zero “severely underfunded”, and pointed out that the government would not begin consulting on a strategy to decarbonise aviation until next year.

The UK has also not demanded green action from airlines in return for coronavirus bailouts, unlike France. The pandemic has halved passenger numbers but the industry expects them to recover by 2024. However, the experts also praised the UK for taking some action, given that only a few countries are even beginning to tackle an issue seen as one of the most difficult climate challenges.

The aviation industry says more efficient planes and buying millions of tonnes of carbon offsets can compensate for big future increases in passenger numbers. Independent experts say new taxes to deter flying are vital, and agree with the aviation industry that green jet fuels are needed too. These exist and could power long-haul flights, but are currently expensive. Long-haul electric or hydrogen planes are unlikely before the middle of the century, if ever, by which time emissions should already have been cut to zero.

-snip-

Read more: https://www.theguardian.com/world/2020/nov/25/boris-johnsons-jet-zero-carbon-flight-goal-dismissed-as-a-gimmick-experts-technology-avaiation-emissions

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Boris Johnson's 'jet zero' green flight goal dismissed as a gimmick (Original Post) Eugene Nov 2020 OP
I've oft-wondered if hybrid jets are possible ... where fuel gets you up above the clouds mr_lebowski Nov 2020 #1
Not exactly "a majority" Miguelito Loveless Nov 2020 #2
Yeah .004% is pretty f***ing far from a majority lol ... mr_lebowski Nov 2020 #3
Actually, heavy machinery Miguelito Loveless Nov 2020 #4
I understand the tech exists or is close but these fleets of trucks and construction equipment mr_lebowski Nov 2020 #5
 

mr_lebowski

(33,643 posts)
1. I've oft-wondered if hybrid jets are possible ... where fuel gets you up above the clouds
Wed Nov 25, 2020, 12:02 PM
Nov 2020

And once you're up there, something like solar-powered paint all over the top of the plane could generate at least a decent portion of the power needed for the majority of the flight.

Miguelito Loveless

(4,438 posts)
2. Not exactly "a majority"
Wed Nov 25, 2020, 01:13 PM
Nov 2020

The top solar panels right now can generate about 400w per sq meter. My back of the envelope math says a 747 has about 500 sq meters of surface area, half of which would be under the plane, so can't generate power. So, 250 sq meters of surface visible to the sun when flying during the day at cruising altitude. Even then, not all of the surface will be generating max power because the sunlight will not be at an optimum angle on some areas of the aircraft. Let's be generous and say 200 sq meters are avilable.

That works out to 80kW of power, which is very good when talking about a house, but not so much when powering a jet aircraft. (My home array manages 15kW easy in Spring and Summer on a clear day, about half that in winter. This power my home, and two EVs).

There are a TON of variables about power consumption for the engines on a 747, but again, taking the BEST circumstance we need about 5 MEGAwatts of power, PER engine at cruising speed. Meaning, 20MW for 4 engines at cruising speeds (probably around 90MW for takeoff). So, our solar PV would provide 0.004% of the needed power.

Even assuming massive improvements in PV tech in the coming decades, we are never going to come close to the power needs of a jet aircraft being met with solar power. Also, there is an actual upper limit as to how efficient solar PV can be, which is about 40% (currently we are are at 20%-23%).

Hybrid jets are possible, but would use batteries and perhaps hydrogen fuel cells. Short haul prop aircraft are feasible if we can get energy density in batteries to about double current levels (possible in next decade).

Our best use of solar PV is on the MASSIVE amount of roof space we currently have available on private homes and commercial buildings, especially when paired with battery packs. This tech gets cheaper every year (battery prices have fallen about 90% in the last decade). We could see another huge reduction in solar install costs if we enacted a NATIONAL permitting standard, as a major part of the cost now is the labor needed to comply with the thousands of varying standards imposed across the nation by counties.

 

mr_lebowski

(33,643 posts)
3. Yeah .004% is pretty f***ing far from a majority lol ...
Wed Nov 25, 2020, 02:39 PM
Nov 2020

Thanks for running the numbers. I sensed it was a pipe dream but I had wondered if it was remotely possible.

It's going to be a hugely heavy lift to convert certain devices to renewables ... aircraft, diesel trucks, and heavy construction equipment come to mind ... I'm pretty certain those devices are destined to operate on liquid fuels for the foreseeable future. But maybe we can scale up fuels based on something like algae, where you're at least sequestering the carbon before burning it in the machinery, resulting in a (close-to) net neutral carbon scenario.

Miguelito Loveless

(4,438 posts)
4. Actually, heavy machinery
Wed Nov 25, 2020, 04:06 PM
Nov 2020

like construction equipment will probably go electric as battery energy density improves. We are seeing smaller excavators, trenchers, cranes, and such already. And even in some cases, bigger equipment can work. For example there is a monster electric dump truck at a mine in Switzerland that climbs empty and descends full, and because regen braking almost breaks even on energy use and regeneration. It can pretty much run all day without recharging.

There is a big demand for electric road construction equipment because they are quieter (thus can operate at night) and without the fumes, safer to be around while in operation (on top of lower maintenance/fuel costs).

Long haul trucking will probably be electric, as battery chemistry and design are within maybe 5 years of matching a modern diesel truck. Musk said in a recent interview that the Tesla semi would be able to manage 1000 km on a single charge, which is about 3/4's the current diesel range. These truck will be out next year.

https://electrek.co/2020/11/24/tesla-semi-electric-truck-621-miles-range-elon-musk/

Every passenger EV sold replacing an ICE vehicle means 500-800 gallons of fuel a year will be unburned. Tesla, by itself, is on track to sell half a million cars this year, and 1 million the next. That works out to a minimum reduction of 250 million gallons of gasoline next year, and 500 million the following year. It will not take long for this to start hammer oil company profits. While US automakers procrastinate, ceding the EV market to Tesla, the EU and China are shutting down ICE cars by 2030-2035.

 

mr_lebowski

(33,643 posts)
5. I understand the tech exists or is close but these fleets of trucks and construction equipment
Wed Nov 25, 2020, 07:24 PM
Nov 2020

are both huge, and expensive to replace (sunk costs are very high). Plus it'll take a while to ramp up production.

I anticipate it taking a good while to make a large dent in the ICE engines in these fleets, and those things pollute a lot.

Plus we still burn natural gas and coal to produce a shit load of the electricity needed in the first place. And we'll be burning a shit load of FF's in order to physically create millions of tractors (of both kinds) too.

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