Definitely not a poo bus

[whole diary]

[Bmblbzzz]

No, not at all. No poo whatsoever. There'll be no poo-pooing these buses. A year or so after the demise of Bristol's "poo buses", we're to get 100 buses running on... "bio-methane". 

Fleet of 100 biogas buses could be coming to Bristol
Bristol24/7, August 29, 2017 < previous article | next article >
More than 100 Bristol buses, including 30 MetroBus vehicles, could soon be powered by bio-methane.

A new £4.79m fund from the Office for Low Emission Vehicles is designed to help unlock a £28m investment by First West of England to potentially transform a significant part of their fleet into the gas-powered buses.

The new low-emission buses, which could start running by 2019, will operate in locations where the most benefit will be gained in reducing pollution.

The funding will help introduce 110 new gas powered buses, 30 of which will be used on MetroBus services.

Bristol City Council cabinet member for transport, Mhairi Threlfall (pictured above), said: “This is an exciting step forward for everyone living and working around the Bristol area and yet another example of our strong local authority partnerships levering funding for much-needed transport improvements.

“We are looking forward to working with First and our neighbours to unlock the investment needed to operate and manage a new fleet of buses using innovative technology.”

[Red Squirrel]

According to my Googlings, these buses should emit 70% less GHG^▸ (Greenhouse gas) and 'virtually no' PM10s^▸ (Particulate Matter with a size under 10 microns). Not to be sniffed at, I'd say. Wonder how the total cost of ownership compares?

[JayMac]

According to my Googlings,

Is this like palm reading, except consulting a different part of the body?

[Red Squirrel]

According to my Googlings,

Is this like palm reading, except consulting a different part of the body?

Yes.

[trainer]

According to my Googlings,

Is this like palm reading, except consulting a different part of the body?

Yes.

I'm sure we all look forward to the orificial official release concerning the first buses to run.

[Red Squirrel]

This bus gets the runs for those who wait, it does not wait for those who get the runs.

[chuffed]

Remains to be seen whether it runs a sh1t service.....

[Red Squirrel]

...I'm here all week...

[grahame]

Is this the same story from The BBC^» (British Broadcasting Corporation - home page)

Bristol is to get a new fleet of low emission buses in a government drive to cut pollution.

South Gloucestershire Council will be awarded £4.8m to spend on 110 gas buses for services around Bristol.

Go South Coast with Wiltshire County Council will also receive £500,000 for three electric buses to be used on park-and-ride services in Salisbury.

Transport minister Paul Maynard said the move would improve air quality across the UK^▸ (United Kingdom).

The firms are among successful bidders for £11m of available funding for low-emission buses in England and Wales.

A total fleet of 153 electric and gas-powered vehicles will be delivered for services in Bristol, York, Brighton, Surrey, Denbighshire and Wiltshire, as well as the stations to fuel or charge them.

It is part of a £900m programme aimed at propelling the UK to the top of the market for greener cars, vans and buses.

[continues]

[TonyK]

According to my Googlings, these buses should emit 70% less GHG^▸ (Greenhouse gas) and 'virtually no' PM10s^▸ (Particulate Matter with a size under 10 microns). Not to be sniffed at, I'd say. Wonder how the total cost of ownership compares?

The part of the grant aimed at the buses rather than the refuelling plant equates to a little over £27,000 per vehicle. I suppose this is how much more than a standard diesel bus that these cost. An article on the Bristol 24/7 website gives a manufacturing cost of £295,000, compared to £675,000 for the electric buses used on the UWE to Temple Meads route.

Before I pour scorn on some of the hyperbole, I will say that I fully support anything within reasonable cost that could help to clear up the air in Bristol, and the world beyond it. As Red Squirrel has pointed out, greenhouse gases are greatly reduced (with a caveat), and small particles of soot are absent. So far as I can tell, much less nitrogen dioxide (NO₂) is produced by a gas powered engine than by a diesel, because it operates at a lower pressure, so does not initiate the reaction between atmospheric nitrogen and oxygen that has suddenly made diesel engines so unpopular. These buses will certainly emit less unwanted rubbish than even the cleanest diesel. 110 cleaner vehicles in Bristol won't clear the air overnight, but it's a start. The refuelling station will also be open to third parties, which might encourage local delivery firms to invest in the technology.

The caveat is that the engine produces carbon dioxide and water vapour, both greenhouse gases. They are, however, much weaker in effect than the methane the were produced from, were it to be introduced into the atmosphere, as is the case whenever organic waste is buried in landfill.

Now for the hyperbole. Another more cynical headline could be "Government gives First Bus a bung of nearly £5 million to run MetroBust". South Gloucestershire may have signed the letter asking for the cash, but they won't any of the assets. I assume this misleading spin is to avoid the potential embarrassment caused by government giving public money to private companies. I'm not bothered by that when it is for the greater good, but there are some who would be.

To read the various news articles at face value, you would be forgiven for thinking that First will be taking hourly deliveries of food waste, and shovelling it into a giant machine, producing a special gas that is quite different from normal natural gas. Not so - biomethane is chemically identical to the fossil fuel version. First's refuelling plant will be connected to the gas national grid in much the same way as mu=y gas boiler is. The biomethane will be produced elsewhere, possibly in Avonmouth by someone such as New Earth Solutions, although I am not sure if they are still going. Viridor are currently building a much bigger plant in Avonmouth. The gas from such plants is "bought" by First, then pumped into the national gas supply. First then turn on the tap and draw an equal amount from the same national supply, making this an accounting device, because the plant would be producing gas anyway. Again, I have no issue with the process, which solves more than one problem. Waste is used rather than buried, energy is produced, and greenhouse gases fall. It's the somewhat dishonest gloss put on the story that I object to. On the plus side, if we get too many gas buses to be able to fuel them all from biogas, we will be able to use the methane producedd by hydraulic fracturing of deep rocks.

An analogy. Some years ago, a French bottler of naturally sparkling water was found to have been removing the carbon dioxide from the spring water before transporting it to its distant bottling plant. Its explanation was that it expelled the gas into the atmosphere to make the water easier to transport to much closer to its customers. It then removed the same gas from the air and injected it back into the water - voila! It didn't go down well.

So I welcome the introduction of gas-powered buses, but would like to see more honesty. GHG and PM10 are now listed in the Abbeviations and Acronyms page.

[Red Squirrel]

The caveat is that the engine produces carbon dioxide and water vapour, both greenhouse gases. They are, however, much weaker in effect than the methane the were produced from, were it to be introduced into the atmosphere, as is the case whenever organic waste is buried in landfill.

Except that:

...the greatest advantage of biomethane over fossil fuels is the fact that it does not contribute to carbon dioxide emissions despite the fact that biomethane combustion produces this greenhouse gas as well. This is due to the fact that the utilization of biomethane is basically only utilization of energy which is released during the natural decomposition of organic matter. Carbon dioxide which is released into the atmosphere during biomethane combustion equals the amount of carbon dioxide that is emitted during natural decomposition of manure for instance.

Source: biomethane.org.uk

[Tim]

The caveat is that the engine produces carbon dioxide and water vapour, both greenhouse gases.

AIUI^▸ (as I understand it), Both CO2 and H2O are greenhouse gases but only in the upper atmosphere.  CO2 released at ground level will find its way to the upper atmosphere and be a greenhouse gas.  But water vapour released at ground level will not result in more water vapour in the upper atmosphere because water vapour as we know condenses onto surfaces and in clouds and often falls out the atmosphere as rain.

Methane - CH4 is itself a greenhouse gas and a potent one at that so care must be taken to avoid leaks of the fuel in production and distribution. 

But the combustion products are CH4, per unit energy produced are much better for the environment than the combustion products of say petrol or diesel and better still than coal.

CH4 + 2O2 -> CO2 + 2H2O, ie two molecules of (harmless) water are produced for every molecule of CO2 when methane is burnt.  For diesel the proportion of CO2 in the exhaust is much higher.  I appreciate that this is a simplification because the energy produced when making a molecule of CO2 will depend on where the Carbon is bonded in the fuel and will be different from the energy produced when making a molecule of H2O, but simply it is enough to know that oxidising the C atoms in a fuel produces energy as does oxidising the H atoms, the former is harmful to the climate and the later is not so a fuel with a greater proportion of oxidisable  H atoms to C atoms will be better for the climate. 

[stuving]

Hold on - there's two things going on here, and getting mixed up: "bio" and "methane".

Being bio means this is not fossil carbon at all, it's already out in the atmosphere and the biosphere (and the sea) that communicates with it. Hence grabbing it at a point in its cycle where it's got energy that can be release by burning has no long-term effect on the climate.

Being methane does alter the amount of CO₂ produced per energy released, compared with longer hydrocarbons or coal. That affects its rating as a fossil fuel, if you have the choice of what you dig up and what you leave in the ground. Hence gas-fired electricity generation is still being built while coal-fired is being shut down, though that is also because gas plant is easier to fire up quickly when the sun goes in (or is eclipsed).

But being methane has nothing to with the status of  biomethane as "zero emission". It's not what you emit that counts, it where you got it from (if you're a bus, that is). If there was a shortage of truly bio methane, and mineral methane is used instead, it still has low to lowish emissions.

[Bmblbzzz]

I was simply thinking "A poo by any other name would smell as rosy." Surely this is a poo bus, but with funding (and different accounting)?

[Bmblbzzz]

Thank you, FTN, for the clear but extensive explanation of the process in both chemical and financial terms. One little thing I'd quibble with though: "110 cleaner vehicles in Bristol won't clear the air overnight, but it's a start." Yes, but they will only do their little bit to clear the air to the extent that they replace rather than supplement dirtier vehicles. Though even if they are supplementary they still set an example and make available the refuelling station, as you point out.