Energy efficiency and embodied energy split from "gas&q

[kenneal - lagger]

.............. But building it is just moving earth and rock just like a motor highway.

But a lot less than the highway.

[vtsnowedin]

.............. But building it is just moving earth and rock just like a motor highway.

But a lot less than the highway.

Depends on the terrain. A highway can climb fairly steep grades over mountainous lines where a railroad has to go around or through the mountains with very expensive tunnels. But yes a double tracked rail line will typically have a one hundred foot wide operating Right of way while a four lane (two each way) highway with shoulders and a narrow(30 ft.) level median strip will have 168 feet or more except in urban areas.
Worked with a paving crew last Thursday. They paved a 13 ft. wide passing lane with a bonded wearing course on 38,000 ft (7.2 miles) of Interstate highway with traffic beside them in one twelve hour shift. 1800+ tons of asphalt mix. They had daylight left over but reached the end of the project.

[BritDownUnder]

They’re doing that in Hawaii now, but just tapping into the molten rock pool below. The control system needs a few tweaks though, as the levelling function lacks fine control.

Man-made lava was what I was thinking. Not being an expert on rocks and the different types and how they react to being melted and then cooled could be my downfall on this mad idea of mine. Maybe the lava once cooled is too brittle for heavy road traffic. I understand that the damage to a road is proportional to the axle weight to the power of four or five. In other words a truck of axle load of 8 tonnes will cause 32000 times as much damage passing over a road surface as a car with one tonne axle load.

It was not only the Hawaiian volcano that got me thinking about this. I understand that there are places known as vitrified hill forts in Scotland.

For vtsnowedin. I was thinking of a mirror around 50 metres in diameter not a city sized thing. At that size you could capture around a megawatt of solar energy and achieve temperatures of around 3500 celsius. Check out the Odeillo Solar Furnace for more info.

[vtsnowedin]

For vtsnowedin. I was thinking of a mirror around 50 metres in diameter not a city sized thing. At that size you could capture around a megawatt of solar energy and achieve temperatures of around 3500 celsius. Check out the Odeillo Solar Furnace for more info.

Oh sure no problem!!!. Consider that the roads it has to be transported on are fifteen meters wide and the overhead wires cross at least six meters high.
I hope it folds up into a nice transportable package.

[BritDownUnder]

For vtsnowedin. I was thinking of a mirror around 50 metres in diameter not a city sized thing. At that size you could capture around a megawatt of solar energy and achieve temperatures of around 3500 celsius. Check out the Odeillo Solar Furnace for more info.

Oh sure no problem!!!. Consider that the roads it has to be transported on are fifteen meters wide and the overhead wires cross at least six meters high.
I hope it folds up into a nice transportable package.

The future will not be easy. Maybe something made of Mylar or a Fresnel lens would do the trick. Quite a lot of cranes can reach 50 metres. I was thinking of outback roads in Australia with very few obstacles and not too many wires either and a long way from sources of concrete. Most of the outback roads here are asphalt or just graded gravel and probably for that reason.

[fuzzy]

I think modular focusing mirrors are an untapped resource. It is well known that the UK grows little of it's own food. There are many reasons such as climate, including land ownership, subsidies etc. In an ideal world of widely owned family crofts with organic gardening, we now have greenhouses and polytunnels. Throw in curved mirrors with blinds for summer and we could grow anything anywhere.

[kenneal - lagger]

I think modular focusing mirrors are an untapped resource. It is well known that the UK grows little of it's own food. There are many reasons such as climate, including land ownership, subsidies etc. In an ideal world of widely owned family crofts with organic gardening, we now have greenhouses and polytunnels. Throw in curved mirrors with blinds for summer and we could grow anything anywhere.

Day length and cloud cover are also considerations. Scotland with it's longer day length than the south of England can grow a lot more stuff than would be thought when you only consider temperature, for instance. Cloud cover in Scotland would be more, I would think, than in the east of England so mirrors would be less effective there. Or, perhaps, more needed than in the east of England where a polytunnel or glass would achieve the same result a Scotland with a little extra lighting.

[BritDownUnder]

I think modular focusing mirrors are an untapped resource. It is well known that the UK grows little of it's own food. There are many reasons such as climate, including land ownership, subsidies etc. In an ideal world of widely owned family crofts with organic gardening, we now have greenhouses and polytunnels. Throw in curved mirrors with blinds for summer and we could grow anything anywhere.

Certainly pays to make use of what 'free' solar resource you have. I understand there is a town in Italy in a sheltered valley that has put in mirrors to literally brighten the place up. Treehugger magazine recently gave an example of a house in Northern Norway that was encased in a geodesic dome style greenhouse that made the place a lot more liveable.

With regard to food I think that greenhouses are underused in the UK compared with Netherlands and Spain. Perhaps making use of power station thermal losses may also help if it can be designed or retrofitted. I would have thought that the idle threats made by European politicians regarding Brexit to cut off the UK's food imports would be a good stimulus to start serious construction of commercial greenhouses in the UK.

[Lurkalot]

I have often thought that roads could be built in sunnier climes by melting rock using an enormous curved mirror and forming the molten rock into a pavement as a replacement for at least some concrete. We can get into discussions on how such a road may be surfaced and levelled but the take away point is that the embedded CO2 in a lot of things is mindblowing.

I seem to recall one of those " how the ancients did stuff" type of tv programmes where someone put forward the idea that the Incas used such a system to shape their large building stones with the really tight joints. They built a reflector and tried it out and was , I'm afraid , a dismal failure. While the reflector did produce a pinpoint off high temperature pointing it at a rock weighting over a ton meant that the heat was dissipated pretty much instantly .

[Lurkalot]

Seeing as we are talking about energy efficiency I've been wondering recently about batteries and specifically cordless battery tools.
A little while ago I went to a tool show , I'm a woodworker so not as weird as it might sound. To be honest hand tools were pretty scarce and even corded tools were less in evidence . Manufacturers were pushing cordless tools above all else. There is virtually a cordless tool available for every corded equiilevent , not only drills , saws ,planers, routers , sanders but also new battery powered tools that had not previously been around such as a 36v wheel barrow. I will admit wanting to look at a battery lawnmower as an alternative to a petrol powered one . Dewalt had one that took two 18v batteries and would evidently cut 1/5 of an acre on those batteries. On that basis I would probably need four batteries for a days work. It was also very noisy at 96db the same as a petrol .
To get back to my ponderings on energy efficiency I have wondered how much more energy is used by switching to battery tools. There have got to be loses somewhere in the whole charging cycle , although I don't know just how much , and that's without considering that there must also be more embodied energy in all those batteries. Add in the lifespan of cordless tools which seems to be around five years at best and there seems to be an increase in energy consumption to efffectively stand still.
There's very little on the internet about this question although I did find this,
https://www.popularwoodworking.com/wood ... more-green

[Little John]

Cordless tools don't do it for me. They are much more expensive for the same power rating, the batteries eventually die and must be replaced and they are not cheap and it seems to me that the materials used in them are very dependent on relatively rare materials that will only become more scarce as time goes on.

Having said that, I can see why someone might want them for commercial reasons because they are more portable. But, I only use such tools for my own personal purposes and so that kind of portability is not something I need. Or, to the extent I do, I have a petrol generator that can power all of my electric tools.

Additionally, I am, bit, by bit, kitting myself out with a full array of hand tools for when electricity become too expensive and/or I become too poor to spend it on powering electric tools.

[clv101]

I find modern cordless power tools simply amazing. I've built our house more than 90% using cordless rather than corded tools (only actually had power on site for the 2nd half of the build).

Some tools are better than others though. Drills, impact drivers, random orbital sanders, jigsaws, multitools... modern 18V tools are great. Circular saws are pretty much at the limit of cordless, I have a good, brushless 165mm 18v circular saw (with a thin, more efficient blade) which is used pretty much daily even though I also have a more powerful corded plunge saw. For sheet material and 2" timbers the cordless is the better choice.

The only (common) tools I've noticed the cordless is significantly inferior is the planers (cordless can typically only take off ~2mm whereas my corded model can take 4mm), routers, in fact...

Rule of thumb I've found is that if the corded version of a tool takes >750W, then the cordless equivalent will feel gutless, if the corded version is >1.5kW don't bother. Things like chainsaws, brushcutters, lawnmowers are all going to be pretty rubbish in cordless setups.

[Lurkalot]

They had the cordless brrushcutterrs and chainsaws at the show too but I didn't really feel they were up to the job. I was interested in the lawnmower after a discussion on another forum where noise and petrol storage were an issue . I was really surprised just how noisy it was though.
Little john's points are something I agree with. There does seem a much shorter lifespan to cordless tools compared to their corded counterparts. I have a couple of old wolf drills that wouldn't look out off place in a Flash Gordon movie and they are still going strong whereas on the other forum I mentioned there are a number of posts about cordless tools lasting a few years at best. Probably not helping the whole efficiency that once the batteries die it's cheaper to buy a whole new package , tool , charger and batteries than simply replace them.. I'm often a lone voice as well in suggesting using hand tools . When a question is posed " what tool to use" it's normally taken as what power tool to use

[adam2]

Cordless tools don't do it for me. They are much more expensive for the same power rating, the batteries eventually die and must be replaced and they are not cheap and it seems to me that the materials used in them are very dependent on relatively rare materials that will only become more scarce as time goes on.

Having said that, I can see why someone might want them for commercial reasons because they are more portable. But, I only use such tools for my own personal purposes and so that kind of portability is not something I need. Or, to the extent I do, I have a petrol generator that can power all of my electric tools.

Additionally, I am, bit, by bit, kitting myself out with a full array of hand tools for when electricity become too expensive and/or I become too poor to spend it on powering electric tools.

You make good points regarding the short life of batteries for cordless tools, and the often high price of replacements.
I agree that it is well to prepare for an uncertain future by having hand tools.

However I very much doubt that mains electricity will EVER get too expensive to use for power tools.
Consider as an example a powerful electric drill with a 1,000 watt motor. It wont use that much continually, and an hours typical use might average about 100 watts.
So that hour of use has consumed 0.1KWH at a cost of about 1.5 pence.
At ten times todays price it would only be about 15 pence an hour.

I doubt that grid electricity will ever exceed ten times todays price, it would become unavailable first because at ten times todays price so much demand would be destroyed, that it would not be worth running a grid system.

Grid supplied electricity is "the cheapest hired hand that the world has ever known"
Electric hand tools often enable one man to do the work of two men, can you engage a good servant or labourer for a few pence an hour ?

Can you get a laundry maid to do your washing by hand, at a lower cost than doing it yourself in electric washing machine ?

[clv101]

Indeed, thanks to their intermittent use, handheld power tools use very little actual energy. That's why a mere 90 Wh battery can do so much whilst costing virtually nothing to charge. Not only have I built a house with cordless power tools, they've all been charged by a modest PV system.

I think the key to using cordless tools is to treat the tools and the batteries separately. Stick with one manufacture (I chose Mikita), I always buy my cordless tools 'bare', that's with no box, no battery etc. Look for sales, offers, typically well under £100. Then buy batteries separately, again looking for sales, offers.

Any single cordless tool, in a box, with battery and charger is going to look eye-wateringly expensive but that's not how most tools are bought.