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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthorJonti
    • CommentTimeOct 31st 2021
    Just read that JCB has signed a multi billion pound contract to be supplied with hydrogen. Though it might be considered a little of topic for here it does obviously have implications for construction machinery. In the rush push electric vehicles has hydrogen been overlooked?

    • CommentTimeOct 31st 2021
    Posted By: JontiThough it might be considered a little of topic for here

    Well, less so than some other topics. It does have to do with building after all :bigsmile:

    In the rush push electric vehicles has hydrogen been overlooked?

    Not that I've noticed; in fact hydrogen seems to have been getting more than its fair share of attention. Green hydrogen might be very useful in several industries (cement, steel et al) and may be of some value for some transport applications, so I'm happy to see JCB sign up for green hydrogen distribution. There are also many examples of electrically-powered construction vehicles of course, some being battery-powered. It's all a question of use cases.
    Volvo have gone for battery powered machinery and hydrogen fuel cell HGVs, but JCB seem to be heavily invested in IC engines and are modifying their engine design to burn hydrogen instead of diesel.

    Same pros/cons as with cars: hydrogen is more expensive and difficult to get hold of, but doesn't require long stoppages to refuel/recharge.

    Be interesting to see which wins out in a construction site environment, and also in forestry, agriculture, quarrying where there aren't many electric sockets on hand.

    There are (were?) some companies trying to develop hydrogen road cars but it looks like car buyers have made their minds up that they prefer battery electric.

    Hydrogen buses been running in Aberdeen for quite a few years now.
    • CommentAuthorJonti
    • CommentTimeNov 1st 2021

    I knew that Aberdeen had hydrogen buses but have not heard of anywhere else so far. I haven't seen very much about hydrogen cars as an alternative which I find somewhat puzzling as from the little I have heard it could be a replacement for petrol/diesel using existing road vehicles and infrastructure. There was a discussion program on Radio Scotland last week where one contributor even suggested that with an adaptation vehicles could tank water which would be changed to hydrogen on demand.

    The case for electric vehicles has been very strongly pushed but I do wonder how green they really are when batteries, decommissioning the existing road stock, how all the extra electricity is produced and installation of all the extra infrastructure is taken into account.
    <blockquote><cite>Posted By: Jonti</cite>
    The case for electric vehicles has been very strongly pushed but I do wonder how green they really are when batteries, decommissioning the existing road stock, how all the extra electricity is produced and installation of all the extra infrastructure is taken into account.</blockquote>

    Most people live in situations where home charging is not feasible - flats, terrace houses etc, and park in the street.
    Either every single street will have to have charging points sufficient for all the cars normally parked there overnight, or there will have to be large car parks set aside for charging millions of cars.

    Unless cars are normally parked at the charging point even when not charging, they will have to be shuffled around somewhere else to free up the charging points. I can foresee massive queues to use charging points, problems with people tripping over unlawful extension leads across pavements, and arguments with neighbours overstaying time at charging points or parking at someone else's charging point.

    Then the moment someone devises a cheap way of using hydrogen in IC engines electric charging will become obsolete.
    • CommentAuthorJeff B
    • CommentTimeNov 1st 2021
    What is needed for cars is the development of a smallish rechargeable battery which could be exchanged at existing filling stations when the battery is down to say 10% of capacity, so no need to hang about recharging. It needn't be particularly small or lightweight - lift the bonnet, bring up a portable A-frame to do the lifting, whip out the battery and drop in a freshly charged one. Job done.
    • CommentAuthorrevor
    • CommentTimeNov 1st 2021
    There is another driver for the construction industry to move off diesel most of the equipment running on diesel is allowed to use duty rebated red diesel as from April next year duty relief on diesel will only be allowed in certain industries associated in the main with agriculture horticulture forestry etc.
    Extract from the gov policy document. Was surprised how much construction vehicles contributed to London pollution. JCB could get a head start here they already do a battery powered digger I believe.


    "Red diesel is diesel used mainly for off-road purposes, such as to power bulldozers and cranes used in the construction industry, or to power drills for oil extraction. It accounts for around 15% of all the diesel used in the UK and is responsible for the production of nearly 14 million tonnes of carbon dioxide a year. Red diesel used in the construction and infrastructure building sectors was also estimated to have caused 7% of nitrogen oxide emissions and 8% of PM10 emissions (a type of particulate matter) in London in 2018."
    • CommentAuthorRobL
    • CommentTimeNov 1st 2021
    The batteries are all pretty heavy - typically around 5kg per kWh. Our 30kWh leaf can go 100miles at a pinch, and I think weighs around 160kg. It's placed low down under the cabin floor for good weight distribution and better handling. The newer, more aspirational battery cars on offer likely have heavier batteries giving more range and acceleration, so even more reason to place them low. You could still swap them out if need be, but after owning the leaf nearly 2 years I've only fast-charged twice, so I wouldn't be interested as it's only a 20min wait to fast charge.
    More of a personal bug-bear of mine is that most fast chargers require an app on your phone, personal details, login, membership etc. I refuse all that nonsense, and only use pay-as-you go chargers and generally slow charge at home.
    All very true, but as far as I can see the big car manufacturers experimented with all the options for a decade or more, and it seems they've all arrived at the same answer (plugin battery electric). They all seem to have quietly ditched their hydrogen development concepts for cars, although pushing ahead for HGVs and large vehicles.

    Possibly Toyota are still dabbling with hydrogen cars, I saw a couple of Mirais in Aberdeen a while ago, they have to go to the bus depot to get refuelled.

    It's easy to use hydrogen in an IC engine, only the cylinder head is different, but it's not very efficient so would use a lot of fuel, which will be made from a lot of fossil gas or electricity. The other wasteful/expensive bit is turning the gas or electricity into hydrogen and storing it and delivering it to the user, so the refueling costs are always going to be expensive, compared to just using the electricity directly. Possibly makes sense for heavy commercial vehicles that can't afford to wait around while recharging, and can't carry enough weight of batteries to keep going all day.

    Maybe if there are more hydrogen bus depots in future, the cost of doing all this will come down, JCB's deal to import solar hydrogen from Australia is aiming for this. Then, hydrogen cars might become competitive again, but that's sometime/maybe in the future, I hear that we haven't got time to wait and see!

    Edit: AIUI, hydrogen burns hotter in an IC engine than petrol/diesel so is worse for NOx pollution. As with petrol/diesel there are design tricks to reduce NOx but they add cost and/or inefficiency.
    • CommentTimeNov 1st 2021
    I can't see hydrogen IC engines gaining any market at all. They need vast quantities of fuel. They use it inefficiently (Carnot limit etc) and they produce NOx like any combustion engine. So they'll be banned in London, for example.

    Hydrogen fuel cells offer better efficiency and less emissions so they will dominate I think. The fuel still costs a lot though, and of course making it is an inefficient use of electricity.

    Toyota are pushing fuel cell vehicles fairly hard but they have limited success here because of the lack of fuel stations. We'd need a lot more than a few pumps in bus stations if fuel cell vehicles ever take off.

    I can see the need for some fuel-based propulsion in large forests, but generally both farms and quarries are localised enough and are equipped with electric power for other machinery and lights etc so I don't think they will have any great problems providing power for batteries. Of course another possibility for forests is flow-battery powered motors.

    According to wikipedia a hydrogen IC engine has quite a lot of components that need changing, so is more expensive than a petrol or diesel equivalent. And you can't simply reuse an existing engine in the same vehicle.
    • CommentAuthorphiledge
    • CommentTimeNov 1st 2021
    Id be suprised if you see much in the way of agricultural or forestry EVs. When its harvest time tractors and harvesters work dawn til dusk for days in a row. Unless the fleet return to base a couple of times a day to swap out batteries, I dont see it as feasible, but even then massively expensive having banks of spare batteries.

    Certainly most of the forestry work Ive seen in Wales is miles from any charging facility and for every worksite youd need a dedicated HGV ferrying batteries between machinery and charging base.

    BEIS forecasts show no reduction in agricultural use of petroleum products as far as the forecasts go up to 2040.

    Seems to me our 5am 200hp+ wake up call during harvest is here for the forseeable!!

    Some info how JCB converted their diesel engine to run on hydrogen.

    Check out the pic of the electric tractor trailing a huge extension cable behind itself!

    >>>>By Phil: "200hp+"
    If the farm had an EV charger that could recharge that overnight, their mains supply would melt off its poles!
    • CommentTimeNov 1st 2021
    From that article

    State of development: "We saw the first prototype running at 1,500rpm"

    Hydrogen as a combustion fuel:

    “Hydrogen combustion is only 20-25% efficient from well to wheel [from the point of harvesting the energy to using
    it as a means of propulsion] versus with 25-30% for hydrogen fuel cells and 80-85% for electricity,” says Simon
    Buckley, knowledge transfer manager for zero emissions mobility at KTN.

    Comparatively, the figure for diesel is roughly 20%.

    “In theory, that means you could run four electric HGVs using the same amount of energy as one hydrogen
    combustion engine.”

    The added processes involved in producing hydrogen also make it expensive.

    It's a good review of the various possibilities though.

    I suppose pair ploughing steam engines looked a bit weird when they arrived, and the whole idea of the Pony Express looks a bit strange.
    • CommentTimeNov 1st 2021
    Incidentally, given the current labour shortages in the agricultural industry and the likelihood of them continuing, I think we'll see a lot more automation introduced soon. And a lot of them can be designed from the start to be suitable for battery power.
    • CommentAuthorrevor
    • CommentTimeNov 1st 2021
    Posted By: djhIncidentally, given the current labour shortages in the agricultural industry and the likelihood of them continuing, I think we'll see a lot more automation introduced soon. And a lot of them can be designed from the start to be suitable for battery power.

    That is happening quicker than you may think. I often listen to the farming today programme on R4 in the mornings and often featured are visits to establishments (e.g.Harper Adams college )and farms developing and trialling such systems. They lend themselves to v large flat field farms. Recent example was a battery powered GPS controlled vehicle that could be adapted to different purposes and when battery was low would return too base for self docking charging. Expected to be in commercial use next year. Many large farms produce large amounts of power via solar pv and by anaerobic digestion of slurry and high sugar crops to make methane to use in a generators so have own power station on site.
    • CommentTimeNov 1st 2021
    Posted By: revorThat is happening quicker than you may think.

    Agreed, that was my point.
    • CommentTimeNov 1st 2021
    There's a short piece about Daimler building hydrogen fuel cell trucks using liquid hydrogen storage, and a venture with BP to distribute hydrogen at https://www.theengineer.co.uk/daimler-truck-bp-hydrogen/

    What's most interesting IMHO is the comment at the end shooting the whole idea down.
    And then there is Tesla's truck with a 300 mile range and apparently charging times designed around drivers required rest periods scheduled for 2022 launch but of course like hydrogen charging points might be an issue.
    • CommentTimeNov 2nd 2021
    I find the notion of Tesla and charging points being an issue being in the same sentence as somewhat amusing. One of Tesla's strongest selling points is their charging network. I can't imagine it will be any different for the trucks when they eventually launch.
    • CommentTimeNov 15th 2021
    • CommentAuthorJonti
    • CommentTimeNov 15th 2021
    Certainly a rant in the last link. I would also question the notion that electric cars could be introduce 'en-masse' today as wishful thinking. There is neither the raw materials nor production capacity, nor the infrastructure to do that. To me the article seemed big on rant and small on facts.

    What is needed is a change in how we as a society travel. Less private and more public transport but for that to happen public transport needs a major overhaul.
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