"...and probably hideously inefficient. You'd probably be better throwing the pasta straight into a furnace..."
Incinerating food lacks the valuable exercise aspect offered by hauling a big rock up on a wire.
CityCyclingEdinburgh Forum » Debate!
Electricity
(47 posts)-
Posted 9 years ago #
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Hmmm. If people are going to go to all the trouble of building wind turbines on huge tall stalks they could start putting big rocks on wires down the middle of them and adapting the blade-turbine mechanisms to be able to switch to winding the big rock up during times when any electrical power generated would be superfluous.
Posted 9 years ago # -
Incinerating food lacks the valuable exercise aspect offered by hauling a big rock up on a wire.
Whats that saying, chopping wood heats twice, once in the work and once in the burning.
Posted 9 years ago # -
Probably make more sense (still not much) for the turbine to spin up a flywheel in the base rather than hoisting heavy things up it.
Posted 9 years ago # -
The heavy thing need not be so heavy as to require vastly stronger construction. A spinning flywheel is all very well but it still loses energy at a greater rate than a big rock dangling from wire.
I assume gigantic Coriolis dynamos were thoroughly discounted as a feasible means of safely harvesting the earth's rotation sometime in the late 1800s?
Posted 9 years ago # -
While PV is still stuck in the realm of niche off-grid stuff, isn't solar water heating really quite viable even here in the UK?
I think that's what the installation at the commie is, there's a little readout of energy harvested at the top of the changing room stairs.
Posted 9 years ago # -
big rocks on wires down the middle of them and adapting the blade-turbine mechanisms to be able to switch to winding the big rock up
I think it would have to be a pretty enormous mass to store any meaningful amount of the turbines time. 1t @30m is still only about 80wh which would be a few moments of time for a large turbine.
isn't solar water heating really quite viable even here in the UK?
I think so, mainly because you can have an enormous panel to soak up the fairly low amount of solar energy for very little cost. I suspect the biggest inhibitor is the push for the combi boiler, adding another water tank as a preheater feeder for the combi is an expense and effort that most folk don't want. I suspect that if most people still had hot water tanks then these things would be more common.
Having said that, it looks stupidly expensive to have one installed. £3-5k and realistically you'll still need to use some gas in the winter so the saving quoted are pretty grim, payback in the decades. Whilst the PV pay back is quicker thanks to various subsidies.
Posted 9 years ago # -
We have a perfect south-facing roof for panels so I have done a little research. I gather that people get the best results here by using PV to drive an immersion heater, strange as it may seem.
I have considered trying DIY water heating (or preheat) as we already have a tank, but life has been too short so far.
Posted 9 years ago # -
I gather that people get the best results here by using PV to drive an immersion heater,
Very odd, I guess that is instead of selling any excess back to the grid. Looking at the relative costs of a PV or solar thermal I can see why one would chose a PV set up.
Posted 9 years ago # -
Solar heated water very popular a bit further south in Europe, where the sun is HOT.
Makes sense on a new build, or if you're redoing the roof/converting the loft space. Otherwise maybe a bit dear still.
Posted 9 years ago # -
We looked at Solar Panels very recently (Dec), trying to get them installed before Mr Osborne made them 83% less attractive.
You can by a diverter for as little as £300 which will divert any unused PV electricity to water heating during the day.
The benefit comes as you still get the FIT, as well as the free hot water. The FIT is assumed based on the size of system / location / amount you generate, NOT the amount you actually use. It's not actually measured in any way...
Until SMART meters are installed you get the double benefit.
Posted 9 years ago # -
edd1e_h
No need to apologise. Books are for dismantling. I just happened to be reading that one and thought it apposite.
I like the guy's approach to getting orders of magnitude correct. That's how I approach problems myself. I'm not sure he's likely to drop too many techno-clangers given that he was chief scientific adviser to the Department of Energy and Climate Change and professor of engineering at Cambridge.
Posted 9 years ago # -
We have a 4kw PV set up.
In the depth of winter we get some days we get barely 0.5kWh - today was 2.6kWh.
Come the summer though we get days of up to 30kWh.
Overall it is delivering as expected and is paying back well.
I totally recognise that it only made financial sense for us because we got the lucrative FIT rates before they were cut. Not sure it's still the case.
Posted 9 years ago # -
@Bbaldycyclist, the cuts were reduced to "just" 67% rather than the full 83%. It doesn't sound like much but based on my back of an inner tube packet calculations might mean that if you have a perfect roof a solar PV setup can still pay itself back. Of course it also means that Solar is now vastly less subsidised than Nuclear and IIRC coal/gas.
Payback now depends on being able to efficiently use most of the generated power and even then is now in the 16-20 year range rather than 5-10 as it was before the cuts. The efficient use part is tricky as it requires you to have an existing load which as Hankchief says that can be a lot of energy in the middle of summer, possible for a commercial installation but unlikely in a domestic one.
Diverting the power to heat hot water, or indeed anything else which can be heated with gas does save money. However assuming your alternative is to heat with gas it can only be considered a saving against the KwH cost of gas which might be around a third of the cost of Electricity.
If you don't worry about the time for the capital to pay itself back then you should be able to get an actual cash return somewhere in the region of 3-4% and if you were to have space for a larger array (up to 10Kw) you might be lucky enough to get more as the FIT now doesn't change below that.
We installed 3.99Kw of panels on a sub optimal roof in December so don't know how much we will generate in the summer yet, although based on today's production I assume Hankchief's roof is also not perfectly shaped so perhaps somewhere similar to his. We decided to add an immersion heater which cost despite only costing £150 may take several years to pay itself back.
Posted 9 years ago # -
@ac you have to be slightly careful about comparing readings between systems.
I know someone local who had an identical system to our installed and on any given day we would get different results depending on it being a sunny morning or sunny evening due to alignment of our systems being different. Over the year it evened itself out though.
Posted 9 years ago # -
@HankChief, Yes you are right of course the sun profile can lead to very different daily outputs from different systems. Our friends who have a lovely south facing roof generates about double what our eastish/westish/southish one does but on a cloudy day we can generate more than them due to having panel optimisers in our system.
When I looked last November Edinburgh appears to get more hours of sunlight before the solar Noon than after it due to a combination of factors. However the average home is likely to use more power in the afternoon which again makes it very hard to compare actual savings from systems.
One thing I forgot to mention in my earlier email is that if you are replacing a roof then Solar can still have an early payback. The company who installed ours are now specialising in building solar panels into a roofs. This saves on the cost of labour and reduces the materials needed thereby saving in the initial cost and reducing the payback time.
Posted 9 years ago # -
"
EDF has confirmed that its finance director has quit ahead of an expected final investment decision on the £18bn Hinkley Point nuclear power plant.
Thomas Piquemal stepped down because he feared the project could jeopardise EDF's financial position, according to reports.
"
Posted 9 years ago #
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