Posted By: jamesingramhttp://www.sciencealert.com/how-graphene-could-help-solar-panels-produce-energy-when-it-s-raining" >http://www.sciencealert.com/how-graphene-could-help-solar-panels-produce-energy-when-it-s-raining
Well that's an idea

A short while ago, it seemed (to me) that PV economies-of-scale had been largely reached and set-up costs had reduced to a plateau where they were likely to stay.

Far from it, apparently - non-silicon (e.g. thin film/organic) PV panels on the way, new non-bright-sun sources being harnessed, economy-of-scale hardly begun. PV will shortly resume its up-front cost-downward trajectory, becoming as ubiquitous and affordable as mobile phones - and thereafter the marginal 'per kWh' cost of electicity production wil become (well, is already) near-zero.

Centralised electicity producers won't begin to compete; the grid will still be needed for a while more; near-PH buildings will cost nothing to power; the non-PH existing buildings will become prohibitive if not impossible to power.

Then there's thermoelectric production from temperature difference e.g. waste heat - good enough for arctic explorers to power a glimmer from their cooking stove apparently. PV as presently understood was in that microvolt bracket to begin with. All worth intensive development.

.

"And when we have nuclear power, it'll all be too cheap to meter!" Said someone sometime...

That's a good one

Posted By: fostertom

Posted By: jamesingramhttp://www.sciencealert.com/how-graphene-could-help-solar-panels-produce-energy-when-it-s-raining" >http://www.sciencealert.com/how-graphene-could-help-solar-panels-produce-energy-when-it-s-raining
Well that's an idea

Centralised electicity producers won't begin to compete; the grid will still be needed for a while more; near-PH buildings will cost nothing to power; the non-PH existing buildings will become prohibitive if not impossible to power.

mmm-kay

Remind me what the replacement rate for buildings in the UK is?
And the %age of new buildings that are to passive standard?
And the payback time for a rebuild of a house (or retrofit to passive standard) based on average UK household energy costs of £1,264 p.a. (you can add a loading factor of c10 to that if you want - make it £10k p.a. for simplicity).

Then explain how self generation with individual household solar panels and batteries is going to work in areas of high population density. Such as:
https://upload.wikimedia.org/wikipedia/commons/1/18/Hong_Kong_Night_Skyline.jpg
or even just
https://www.thebureauinvestigates.com/wp-content/uploads/2013/05/shutterstock_772862.jpg

UK population (http://www.tradingeconomics.com/united-kingdom/rural-population-wb-data.html) is
- 88.7% Urban
- 26% in agglomerations of >1m

Can you define "a while"?

and I think you're in the realms of fantasy and that it's dangerous to make these claims without actually providing the maths to back them up. Just waving your hands in the air saying "will eventually reverse", "exponential", "improve vastly" doesn't do it.


Demand side - the big wins are already banked as far as i can see.
- improvements in lighting are now marginal. The big gain was incandescent to LED
- TV's have got bigger, offsetting nearly all of the gains from Tube to flat panel
- cooking is resistive - no efficiency gains to be had (other that better insulation)
- Fridges/Washing. Gains are now marginal

You're in the same space as the futurists often unchallenged 'electric cars will solve congestion and pollution'. A road full of electric cars is just as congested as if they're diesel. Current power generation isn't clean so they just move the pollution elsewhere. Power currently 'generated' by fossil fuels in motor vehicles is roughly equivalent to our national electricity generation capacity so we either need to double the capacity or move all current demand.

ie to actually eliminate the grid and current generation you need local generation at double current demand. More if you're adding water heating to it as well (assuming that's largely gas at present).

I don't have time to do all the research to prove or disprove (but I'm not the one claiming any problems have been solved) but my instinct is that the numbers don't add up and that it's a *long* way off.

Posted By: Simon Stilland I think you're in the realms of fantasy and that it's dangerous to make these claims without actually providing the maths to back them up. Just waving your hands in the air saying "will eventually reverse", "exponential", "improve vastly" doesn't do it.

Quite right.

PV collector efficiency is about 20% at the moment, theoretically 50% is possible, but even if you get to 100% collection is ultimately limited by the insolation and collector area. Small area, small power collected.

kWhr harvested is directly linked to kWpk of the collector; to try to separate them is either disingenuous or demonstrates lack of knowledge.

You don't need PH standards of insulation to dramatically reduce heating energy demand, just go back to 1950s levels of heating. People wore thick clothes and didn't heat most of the house at all.

If we go back to the 50s in other respects (no electronic devices except for a wireless, no internet, no domestic freezers etc) we could cut electricity demand significantly. Good luck, trying to do that without draconian interventions.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/449134/ECUK_Chapter_3_-_Domestic_factsheet.pdf


Domestic electricity consumption, appliance efficiency etc etc.

Interesting charts - freezers/fridges have got a lot better. Add insulation, better heat exchangers etc and you can make quite dramatic improvements. Levelling off now though.

Wet appliances the savings aren't so great - washing machines use less water, more agitation, more soaking but you can only go so low and you still need to heat the water. Which of course explains the exhortations to wash at lower temperatures - behaviour will trump tech on washing.

it rains at night as well ;-)

Posted By: bot de pailleas for electric cars, when they run on petrol they can only run on ... petrol.

Not true even today. Most cars can be converted easily to use LPG or compressed gas. There are also car engines available that run either on petrol or on stored compressed air. Production of methane and methanol from electricity is also practical although not yet economically sensible. The most pernicious downside of combustion engines is their emissions. That is where an electric motor scores, IF the electricity is clean.

But wont most cars be charged during the night when power stations are at idle?

Also, electric car development will boost battery technology development. Energy storage is key both for generators and consumers. Night and day tariffs will become obsolete.

<blockquote><cite>Posted By: fostertom</cite>Cars and buses - not just going electric,
also super-lightweighting via carbon fibre etc, which has square-law effect on energy required.
Indeed - power-of-perhaps-two-and-a-half effect, because with lower power, 4WD motor-in-wheel + regen braking becomes feasible, eliminating engine bay, gearbox/diff, driveshafts, the volume and weight of all those hence lighter body .</blockquote>

I do admire your enthusiasm and actually don't like being negative. I know that's hard to believe.

I've sat in a Tesla (they've a 'showroom' in the Westfield shopping mall in West London). The Tesla model S is built on a lightweight aluminium space frame, has lightweight aluminium body panels and has all the space saving benefits you list. Inside feels huge with a completely flat floor. It's just as you describe with all that heavy mechanical stuff removed.

However, batteries to give a 200km range, and the under armour to stop the batteries turning into a high speed bomb (https://www.youtube.com/watch?v=pYPr_z6BxA0 ) add a little weight. In fact it ends up weighing in at c2000kg, the same as a BMW 5 series. http://www.teslarati.com/tesla-model-s-weight/

Yes, for most journeys the equivalent of an electric golf caddy would be sufficient. 85% of UK commuter car journeys are single occupancy so could be done in something smaller than a Smart car with people renting something bigger to transport stuff, or multiple kids. For longer journeys there are these fantastic, fast, self driving comfortable things called trains.The answer for in-city personal transport is the bicycle - it doesn't need technology, just a reallocation of road space.

These aren't technological problems - the solutions already exist to get 80% there without any extra tech - but the barriers are political and emotional. Just look at the backlash against a small scheme that proposes to remove a nasty multi lane gyratory and prevent rat running through one of London's parks at peak times (but still allow it the rest of the day and still allow cars in the park all the time). This is at a location in Zone 1 London that's a 2 stop tube journey from Oxford Street. http://www.cs11.london/

There's some wonderful technology in the pipeline but it alone doesn't solve the worlds problems - those challlenges are largely human.

<blockquote><cite>Posted By: bot de paille</cite>But wont most cars be charged during the night when power stations are at idle?

Also, electric car development will boost battery technology development. Energy storage is key both for generators and consumers. Night and day tariffs will become obsolete.</blockquote>

Biogas is being pushed in Germany with support from companies like Audi.

Initially from farm production with injection into the national grid

http://marcogaz.org/downloads/EFG2010/2_Dr_Harald_von_Canstein.pdf

But longer term companies like Sunfire are already injecting gas derived from excess green energy into the grid.

Posted By: billt

If we go back to the 50s in other respects (no electronic devices except for a wireless, no internet, no domestic freezers etc) we could cut electricity demand significantly. Good luck, trying to do that without draconian interventions.

This is something I've been musing about for a couple of years. I'd love to have a crack at going back to 1950s level of electricity and gas usage for an average family of 4 (does anyone know where I can find the figures from?)

Rather than actually live as though I'm in the 50s, I'd be looking at using modern technologies. With LED lighting instead of incandescent bulbs, with low energy televisions instead of CRT tubes (or even wireless radios), with an efficient gas boiler and IWI/Double glazing/air tightness instead of a gas fire and 'geyser' for hot water, etc. etc.

It must be doable. Perhaps in stages, I'll got back in time thorugh the decades until I get to 1950s. I'd imagine I'm already in the 90s as I think national energy usage is already lower today than the 1990s?