Energy Saving Solutions

[paul1609]

Stewart,
You claim solar energy is not cost effective. You overlook that the cost of fossil fuels and Nuclear continue to rise due to scarcity vs demand and safety issues respectively.
Meanwhile the cost of renewable energy continues to fall due to increased economies of scale and R&D. a few years ago solar PV was expected to reach grid parity by 2020 (incl in the UK), rapid falls in panel prices means this will now be sooner than 2020.
Therefore countries which are net importers of energy (like the UK) which invest in Renewable energy now, improve their balance of payments and energy security in the long run.

Do you realise most of our oil imports come from Russia, and most of our coal imports from Columbia, neither countries particularly strong on democracy and human rights. Are comfortable to be heavily financing these regimes?

Output for solar is proportional to irradiance so it doesn't have to be bright direct sun for PV to work. Actually the solar resource in the UK isn't as bad as many people think especially in the south west due to the Gulf stream. Irradiance is currently rising year on year in the UK if you look a the met office data.

You are right that dust is persistent and cleaning does improve performance, however the performance loss is never more than 10%. Which in the context of very high irradiances in dusty but extremely sunny equatorial regions is small fry. With regards abrasion, I'm not convinced thats a major problem, a rougher surface might actually reduce cosine reflection losses. (the cells themselves are etched with a pyramidal surface for this very reason).

anyway cant sit on here all day educating you about solar, maybe you should read my book 'Choosing Solar Electricity'...

Fraid I'm with Stewart on this one. The technology as it exists isn't cost effective.
If the Government had been prepared to guarantee the tariff of nuclear power stations in the same way as it did the feed in tariff for solar panels Britain would have been covered by nuclear power stations by now.
Its no coincidence that the solar industry created a huge fuss with court challenges when the government wanted to reduce the tariff to a more reasonable though still very generous one.
Expect the installation of solar panels on your roof in the uk to be a fad of the past within 5 years.

 

[HSTEd]

As for solar power hitting grid parity before 2020, this is normally a figure generated by assigning a ludicrously low, in many cases 0, interest rate to the capital costs neccesary to buy and install the panels.

They then demand fully commercial interest rates be applied to nuclear power, apparently in an attempt to make it appear far less viable.
They also fail to take into account the cost of energy storage as I mentioned earlier with respect to wind.

 

[jon0844]

I believe solar has a place, but will wait until prices come down and I can just buy and install my own panels, for my own use.

The companies acting as middle men are only after Government grant money and will definitely move on, just as they did after doing LPG conversions. Why should the tax payer be made to heavily subsidise these people?

 

[paul1609]

I believe solar has a place, but will wait until prices come down and I can just buy and install my own panels, for my own use.

The companies acting as middle men are only after Government grant money and will definitely move on, just as they did after doing LPG conversions. Why should the tax payer be made to heavily subsidise these people?

It not even the taxpayer its the consumer. The poor who don't have the money to invest are being made to subsidise those who do and companies who are running the free electricity schemes its madness.

 

[DXMachina]

I like the idea of widespread solar PV panels reducing gross electricity usage in daylight hours, thus letting polluting powerplants and those running on imported fuel spin down.

It's good for environment and the economy in theory. But this logic requires people to be willing to make a big investment in their homes, and companies in their premises, in order to cut future running costs, and it also requires that each installation generates enough power to defray its own carbon-cost of installation

 

[PTF62]

I like the idea of widespread solar PV panels reducing gross electricity usage in daylight hours, thus letting polluting powerplants and those running on imported fuel spin down.

So you end up with double the generation capacity, summer/daylight generation and winter/night-time generation, with double the infrastructure costs and environmental overhead, for a saving in summer/daylight fuel use (leaving aside the problems of spinning down a coal or nuclear station).

That might be a sensible approach is specific circumstances (the Nevada solar power plant, where there will me massive use of electricity during the day for aircon), but generally in the UK?

 

[DXMachina]

So you end up with double the generation capacity, summer/daylight generation and winter/night-time generation, with double the infrastructure costs and environmental overhead, for a saving in summer/daylight fuel use (leaving aside the problems of spinning down a coal or nuclear station).

That might be a sensible approach is specific circumstances (the Nevada solar power plant, where there will me massive use of electricity during the day for aircon), but generally in the UK?

erm, yes, as I view this ecologically not economically.

And the UK climate is highly suitable for solar power generation

 

[LE Greys]

<SNIP> Obviously, express trains (does anyone still call them that?) . . . <SNIP>

I do!
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So you end up with double the generation capacity, summer/daylight generation and winter/night-time generation, with double the infrastructure costs and environmental overhead, for a saving in summer/daylight fuel use (leaving aside the problems of spinning down a coal or nuclear station).

That might be a sensible approach is specific circumstances (the Nevada solar power plant, where there will me massive use of electricity during the day for aircon), but generally in the UK?

I'm rather surprised the Severn Barrage hasn't come up. I personally don't support it, since it will screw up the Severn from a wildlife point of view, but a smaller version of it, perhaps using tidal turbines that don't impact the flow too much, is a possibility. Currently (and I've had lectures on this) the things are simply too complicated and too expensive to install ever to make any money, but cost is going down and down. If there's one thing we have ing this country that we can rely on, it's the tides.

Incidentally, I also thought that PWRs were self-regulating to some extent. Something to do with neutrons going too fast to react if the temperature in the reactor gets too high, so at times of low power demand, the reactor heats up, then cools down to something stable that produces less power, until you crack the throttles open again and the process reverses. That's why they can be used in ships, with power demand that varies from "generators in idle" to "we need everything you've got".

 

[paul1609]

erm, yes, as I view this ecologically not economically.

And the UK climate is highly suitable for solar power generation

Sadly the ecological cost of production and maintening a duplicate generation system almost certainly wipes out any ecological gain from solar or wind power.

 

[HSTEd]

I do!
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Incidentally, I also thought that PWRs were self-regulating to some extent. Something to do with neutrons going too fast to react if the temperature in the reactor gets too high, so at times of low power demand, the reactor heats up, then cools down to something stable that produces less power, until you crack the throttles open again and the process reverses. That's why they can be used in ships, with power demand that varies from "generators in idle" to "we need everything you've got".

You can throttle nuclear reactors quite easily, but most of the time throttling them down rapidly involves just dumping steam direclty to the condensor rather than running it through the turbine.

It increases maintenance and remember that operating costs for a nuclear power plant are roughly 1-2 US cents per kWh. You have to pay capital costs no matter what so once you have the station it should be running flat out if at all possible.

 

[TGV]

Does anyone know the cost of generating a kWh through a wind turbine? Or Solar arrays?

We can work out what would be needed, and at what cost, to run a single train.

The average energy required to run a typical 25kV powered express train is around 22kWh/mile (including net effects from regenerative braking). So for a 200 mile journey, that's 4400kWh (or 4.4MWh). A high speed train (>200km/h) would be more obviously, but based on something like a Pendolino, it's a good place to start.

 

[Yew]

Alternatively, what about using HHO gas to save fuel? I'm a scientist and can confirm that this is definitely legit.

Thats quite interesting, although it would do nothing to increase gas mileage, it could possibly reduce emissions. In old gas turbines sometimes water was injected into the combustion can to turn nox into Nitric acid. Reducing Nox emmisions. I'm not sure how it affected pressure though.

 

[DaveNewcastle]

You have to pay capital costs no matter what so once you have the station it should be running flat out if at all possible.

Which was exactly the reasoning behind the unmetered supply of electriity to light Belgium's motorways. There would be no additional cost at the point of supply.

As far as I can remember from my work for the industry (with AGRs), most UK reactors do not lend themselves to responsiveness to demand - the thermal inertia is so great that once they're running then any attempt to inhibit the fission (other than an emergency dump) takes a long time to reduce steam pressure. As HSTEd has noted, any further regulation is realatively crude and is done further down the line, either diverting pressure from the turbines or taking a turbine off-line.

Returning to the references to hydroelectric generation, I will comment that I am very dissapointed in recent development. There are 2 well established hydro power stations at Cruachan and Foyers which, during periods of low demand, will run "in reverse" and actually use surplus power in the grid to pump water back up the hill to the lochs above.
My disapointment is that the latest hydro power station constructed recently on Loch Ness at Glendoe does not have that capability. The reason is entirely attributable to the terms of the agreement which only required the developer to provide power; not to store energy.

But Glendoe hasn't been of much use in generating power either, as its high pressure water-supply tunnel has collapsed after just months of operation.

 

[brianthegiant]

Sadly the ecological cost of production and maintening a duplicate generation system almost certainly wipes out any ecological gain from solar or wind power.

could you refer us to peer reviewed evidence of this?

when you say 'duplicate' you imply (as do the anti wind websites & the tory press) that wind and solar power must be backed up at a ratio 1:1 of power rating. Which is a bit like saying fire stations must have 1 tender for fires, 1 for road accidents 1 for floods and 1 for cats up trees. Which of course they don't, they analyse the risk of each event & share resources accordingly. It's the same with generating capacity. You need contingency for a range of risks in the electricity network:
faults in generators, faults on power lines; surge in demand (kettles on in ad break cliche / eurostar starting up on HS1 etc); and falls in renewable output.
probability says that these things rarely happen at once. so you dont provide backup for all risks independently of one another.

Also because there is a degree of correlation between renewables and demand. max wind output occurs in winter when demand is highest. Likewise peak solar output correlates with peak of commercial / industrial demand esp in urban areas. So again you dont need to provide backup 1:1.

Finally we are installing more DC links to other countries (incl 1 in Chunnel) which have different patterns of weather and demand, esp mainland europe being in different time zone. so these interconnects reduce need for spinning reserve.

 

[Rhydgaled]

Does anyone know the cost of generating a kWh through a wind turbine? Or Solar arrays?

I think my father said that wind turbines generally work out at around £1 per watt (although that varies according to the size of turbine) I've no idea how (or if) you convert watts to watt hours though.

Returning to the references to hydroelectric generation, I will comment that I am very dissapointed in recent development. There are 2 well established hydro power stations at Cruachan and Foyers which, during periods of low demand, will run "in reverse" and actually use surplus power in the grid to pump water back up the hill to the lochs above.

There's also a station called something like Dinorwig (open to the public as 'electric mountain') in Snowdonia which is known as a pumped-storage power station and I believe is used only at times of peak demand. As you described, it pumps water up to the top at times of low energy demand.

I wonder if this could be done (on a much smaller scale) in tall buildings if and when new ones are constructed. Being fully enlosed, you wouldn't permenantly lose any water through evaporation, but the very small scale it would work on probably makes it a daft idea.

 

[GadgetMan]

Network Rail (signallers) could make more of an effort to avoid unnecessary train braking and accelerating. All too often a train slows to a crawl or stop because the signaller is slow or has forgotten to set the route for an express train.

Some efficiency savings like this are easier and less costly to implement with immediate results.

Unnecessary empty stock movements are also a massive waste of fuel and could easily be avoided.

I know of at least 3 units which travel empty from Station A-B at night, then back to Station A in the morning, a round trip of around 50 miles per train. Station A has unit storage facilities, as well as a maintenance depot. Only TOC politics stop the units from being stored there overnight.

I know of another 2 units that are diagrammed to come out from Tyesley, go into passenger service for around 90miles, then return to Tyseley. Madness.

 

[jopsuk]

I think my father said that wind turbines generally work out at around £1 per watt (although that varies according to the size of turbine) I've no idea how (or if) you convert watts to watt hours though.

There's no direct Watt to Watt-hour conversion; the former is a unit of Power, Whilst the latter is an (non-SI) unit of Energy. Power is Energy per unit Time. A Watt is a Joule Per Second. A kilowatt hour is 3.6 megajoules (3600000 J) and is a more conveniantly sized unit for power consumption measurement.

As for the cost per Watt of a turbine, people such as myself are helping to bring that down

 

[ainsworth74]

Network Rail (signallers) could make more of an effort to avoid unnecessary train braking and accelerating. All too often a train slows to a crawl or stop because the signaller is slow or has forgotten to set the route for an express train.

Are you sure it's that and not that they're regulating the traffic (just in a way that doesn't benefit you )?

 

[LexyBoy]

I think my father said that wind turbines generally work out at around £1 per watt (although that varies according to the size of turbine) I've no idea how (or if) you convert watts to watt hours though.

To add to what jopsuk said, a simplistic way of calculating the "conversion" would be based on the lifetime of the turbine.

So if a turbine had a life expectancy of 20 years (175000 hours) the price would be £1 / 175000h * 1000 W/kW = 0.57p per kWh. In practice it will be higher as this assumes the turbine will be operating at 100% of rated capacity all the time and omits the cost of maintenance, transmission losses etc. This report puts it at 3.2p/kWh for onshore wind and 5.5p/kWh for offshore.
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Thats quite interesting, although it would do nothing to increase gas mileage, it could possibly reduce emissions. In old gas turbines sometimes water was injected into the combustion can to turn nox into Nitric acid. Reducing Nox emmisions. I'm not sure how it affected pressure though.

It's a complete scam, promoted by those who make "conversion kits" and the naive who believe they can see an improvement. It's true that old engines (including piston engines) could be made to run more efficiently with a controlled water injection, modern engines have management systems which will be confused by the interference and which will result in increased emissions, possibly engine damage and almost certainly invalidation of any warranty.

NOx is much better eliminated using catalytic converters - nitric acid isn't much better than NO2. Not really an option for turbines but fine for piston engines (diesels are more difficult, but catalytic converters are available).

 

[HSTEd]

Water injection in gas turbines is more often used to allow increased power rating by reducing the amount of air that has to bypass the combustor (since if all the air compressed by the compressor was used to burn fuel under normal condiitions the blades in the turbine downstream of it would melt).

It also keeps the air cooler when its going through the compressor, improving engine efficiency.

 

[LexyBoy]

That makes sense - water will be vapourised generating increased thrust and absorbing some heat. Only applies to gas turbines though as you say - and I don't imagine they are used in many scenarios where it's worthwhile carting a tank of water with you!

 

[brianthegiant]

As for solar power hitting grid parity before 2020, this is normally a figure generated by assigning a ludicrously low, in many cases 0, interest rate to the capital costs neccesary to buy and install the panels.

They then demand fully commercial interest rates be applied to nuclear power, apparently in an attempt to make it appear far less viable.
They also fail to take into account the cost of energy storage as I mentioned earlier with respect to wind.

this one could run and run ...
I'm all in favour of comparing technologies on the basis of levelised cost of energy (LCOE). Actually solar grid parity by 2020 does include commercial discount rates.
The problem with comparing anything with fairly with nuclear on a financial basis though is insurance....
There's not a single insurance company which will undewrite all the safety risks with nuclear. So it's down to governments to underwrite nuclear and pick up the tab if theres an accident. As the cost of this underwriting is impossible to quantify it is not therefore included in the LCOE....

Anyway, improvements in renewable energy are being made by R&D and industry growth all the time, hence LOCE for solar continues to fall, because 1) Solar cell efficiency has been improving constantly for the last 30 years, (google image search for NREL solar cell efficiency). 2) production costs continue to fall and will continue to do so for some time. These 2 factors are surely beyond dispute?
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It's a complete scam, promoted by those who make "conversion kits" and the naive who believe they can see an improvement.

In these times of high fuel costs there are sadly quite a few of these sort of 'energy saving' scams, an old friend of mine has made a hobby of exposing & documenting some of them, here: www.eco-scams.com/

 

[HSTEd]

this one could run and run ...
I'm all in favour of comparing technologies on the basis of levelised cost of energy (LCOE). Actually solar grid parity by 2020 does include commercial discount rates.
The problem with comparing anything with fairly with nuclear on a financial basis though is insurance....
There's not a single insurance company which will undewrite all the safety risks with nuclear. So it's down to governments to underwrite nuclear and pick up the tab if theres an accident. As the cost of this underwriting is impossible to quantify it is not therefore included in the LCOE....

This is largely due to the sensationalist treatment of nuclear accidents by large sections of the press which lead to election sensitive governments assigning insanely high damage figures to such accidents.
Such as the Fukushima accident which the press claims will render huge swathes of land uninhabitable forever, conveniently ignoring that 15-30% of the land in the "exclusion zone" has already been reopened for permenant habitation.

Anyway, improvements in renewable energy are being made by R&D and industry growth all the time, hence LOCE for solar continues to fall, because 1) Solar cell efficiency has been improving constantly for the last 30 years, (google image search for NREL solar cell efficiency). 2) production costs continue to fall and will continue to do so for some time. These 2 factors are surely beyond dispute?

Yes, but production costs are now approaching the hard limits imposed by the raw materials in use, this exponential reduction in production costs cannot continue much longer really.
This is like those claims that assume exponential growth to generate sensationalist results.
Likewise the "low hanging fruit" of increasing efficiency of existing solar cell designs have already been taken, which will drastically slow down further gains in efficiency.

LOCE calculations for solar power also conveniently assign zero cost to grid energy storage which is a highly dodgy statement.