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Topic Title: Arguments AGAINST hydro power ?!
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Created On: 05 December 2012 03:33 PM
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 05 December 2012 03:33 PM
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aroscoe

Posts: 91
Joined: 18 October 2002

Dear all

One of the primary schools near me is taking place in a debating competition next friday. They have been given the (rather short straw) stance of arguing against hydro (and possible barrage) power. Its a P7 class so I guess they are about 11-12 years old. I visited them for a couple of hours and they had some great ideas which I just added to a bit.

So far, we came up with the following points
- Lack of suitable remaining sites (and planning)
- Large capital cost
- CO2 emissions from concrete production
- Flooding of land (animals, habitat, human dislocation e.g. 3 Gorges)
- Distruption of tidal/reed beds etc (Severn Barrage etc)
- Disruption of fertilisation of flood plains (Egypt, etc)
- Silting behind dams (Aswan dam)
- Disruption of fish e.g. Salmon (e.g. Columbia dams)
- Possible fish deaths due to over oxygenated water from large releases
- Costs of dissassmbly at end of life.
- Cross-boundary water disputes/agreements/interaction. E.g. Columbia River (US/Canada), Colorado River, 3 Gorges?
- Power stations owned by foreign companies but within UK system?
- Limit to energy available even in big, high dams is equal only to ~100MW gas station for a couple of days, unless there is significant new rainfall (gravity is a weak force)

Anybody got any other good ideas to throw in? They have about another week to prepare!!!



-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 05 December 2012 03:39 PM
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aroscoe

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I forgot to add:

- Fashionable "run of the river" schemes often provide very low levels of energy compared to modern requirements, especially those on TV shows where they show environmentalists installing such things etc.

- The Siberia Hydro accident, which is an outlier and atypical but of course is spectacular.
http://eandt.theiet.org/magazi...ia-hydro-disaster.cfm




-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 05 December 2012 07:43 PM
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jarathoon

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Some historical context you are onto a loser here...

http://en.wikipedia.org/wiki/L...y_medieval_watermills

"at the time of the compilation of the Domesday Book (1086), there were an estimated 6,500 watermills in England alone"

I doubt there would have been so many of those pesky English around in the following millenium if it wasn't for water power...

Or so many roads and lanes called "(Old) Mill" this or that...

I presume the Romans brought the water wheel to these shores first.

Apparently inefficient Horizontal Mills (Norse Mills) with vertical axis of rotation, were used in the Scottish Highlands.

http://en.wikipedia.org/wiki/Water_wheel

Try doing the same work as even one of these inefficient horizontal water wheels (especially with Scottish rainfall levels) and you will understand why the British peoples fell in love with the technology.

However the original water power technology transfer was via invasion and occupation, which is an obvious disadvantage.

Re: Dams

Building dams is a dangerous business and they have been suseptable to failure in the past during earthquakes etc.

http://en.wikipedia.org/wiki/Dam_failure

James Arathoon

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James Arathoon
 05 December 2012 11:07 PM
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jarathoon

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Then again... There must be ways of hiding 12 kW of water driven power generation better than this. The archimedes screw although efficient needs a big dam to generate sufficient head to drive it.

http://www.youtube.com/watch?v=VmMSKiknNOA

Perhaps the norse invaders were right after all; a momentum driven horizontal wheel is better if all you are after is small amounts of power from lots of rainfall.

Is it possible to fix a horizonal water wheel into a river, with flaps that are held perpendicular to the flow in the forward direction and lie parallel (and with minimal resistance) to the flow in the return direction?

The fastest flow is in the centre of the river so this is where you want to take the momentum from. Might get a few watts to drive a small TV and an LED reading lamp, and dont need to build a dam, or stop the fish from getting past.

James Arathoon



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James Arathoon
 06 December 2012 08:56 AM
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ectophile

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Other possible arguments against:
- In tropical areas, flooding of rainforests causes rotting and release of methane.
- Risk of catastrophic floods if the dam breaks.
- Possibly, increased risk of earthquakes.

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S P Barker BSc PhD MIET
 06 December 2012 11:58 AM
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amillar

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So if they can get over the idea that any engineering solution involves understanding many technical and social problems, then all involved in this debate will have learnt something: there are no easy answers but that doesn't mean you shouldn't do anything! You just need to address the issues one by one.

Could be a fun debate, hope it goes well!

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 06 December 2012 12:11 PM
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drhirst

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You should also see: http://wwf.panda.org/what_we_d..._initiative/dams/wcd/. The work as also funded by the World Bank.
Large dams that bury biomass can become a significant source of methane. Sometimes it is even argued that the global warming potential of the methane is greater than that of fossil fuel generation, because methane is such a potent greeenhouse gas.
David

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David Hirst
 06 December 2012 06:54 PM
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aroscoe

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Nice comments, keep them coming.

That one about methane is quite interesting. The pupils said something about that but I didn't believe it at the time - since my visualisation of something emitting methane was a stagnant pond not a deep cold reservoir like I am used to seeing in the UK.

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Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 06 December 2012 09:47 PM
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jarathoon

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Harder to argue against pelton wheel microgeneration in upland areas which can generate the necessary water head. They are small and compact and only need a relatively small bore pipe to the top of a nearby hill.

http://www.youtube.com/channel/HCB1-5W1zTp04

However pelton wheel generation systems need a small resevoir as well if you want on demand power from them; but they can be the same size as normal agricultural reservoirs, when the electricity is for a single farm house.

There is interesting fluid dynamics associated with the pelton wheel. You double up on the forward momentum from the water jet, by effectively bouncing the water back on itself. They are really noisy but very efficient.

The main disadvantage is that they cannot be used in low lying flat terrains, unless they are illegally attached to the household water supply. However the water companies go around with steel listening rods to detect such "leaks".

Actually the water companies use a lot of energy simply to pump water around.

The Romans used constant gradient Aqueducts to transport water over large distances without pumps. So is it better to have sometimes big imposing structures to help transport water around or use lots of energy to pump it?

One Victorian example of a gravity fed aqueduct system is the Elan Valley Reservoirs supplying the Frankley Reservoir outside Birmingham.

http://en.wikipedia.org/wiki/Elan_Valley_Reservoirs

"Pumping was not required because the network drops 52 metres (171 ft) along its 73 miles (117 km) length from its source to Frankley. A gradient of 1:2300 maintains a flow of less than 2 miles per hour (3.2 km/h); water takes one-and-a-half days to reach Birmingham.[3] The aqueduct, which was started in 1896 and opened in 1906, crosses several valleys and features numerous brick tunnels, pipelines, and valve houses.[4]"

Here reservoirs are needed for drinking water storage not energy generation. You can't completely do down dams and reservoirs without telling the people of Birmingham, for example, were they should get their drinking water from without using their late Victorian engineered system of water supply. Or you have to tell the people of the Netherlands that they can no longer use dykes and must surrender their lowest lying areas back to the sea.

And oh dear oh dear doesn't Glasgow have a gravity fed water system, with a Dam on Loch Katrine?

http://www.scottishwater.co.uk...sgow-by-george-wyllie

You really are going to struggle if the other school bring that up!

Then their is the Dinorwig pump storage system, which also uses a reservoir

http://en.wikipedia.org/wiki/Dinorwig_Power_Station

"The original purpose of the scheme, it is claimed, was to deal with the difficulty that National Grid would have had if the large numbers of nuclear power stations then planned had been built."

Quick response electricity generation. Is this really worth having?

At Culham where they have the Jet Fusion reactor, they have a horizontally mounted (vertical axis) flywheel energy storage system, so they reduce their peak power requirement from the grid. What size of flywheel would you need to replace Dinorwig?

What about using the Norwegian Fjords or Scottish Lochs for energy storage? Apparently it is theoretically better to use lots of smaller energy storage systems nearer the end user, which rules out water systems unless we build lots of water towers in our towns and cities.

Gas, Coal and Nuclear electricity generation stations all rely on water as the thermodynamic fluid. When power stations use rivers or the sea as cooling water sources fish deaths can result if water temperatures rise too much. Should we try to banish water from the energy generation system totally?

James Arathoon


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James Arathoon
 07 December 2012 08:29 AM
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JohnRRussell

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Some small run of river hydro schemes in Scotland have attracted planning objections from white water canoeists because they can't pass the weir.
 07 December 2012 09:15 AM
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jarathoon

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The maximum power output of some of the hydro schemes being given planning permission are up to the size of a big wind turbine 6MW

http://www.scotland.gov.uk/New...ases/2010/04/20104605

Found this link on the Scottish Natural Heritage Site

http://www.snh.gov.uk/planning...newable-energy/hydro/

The Scottish Renewables site has a Hydro Contruction Guide to Good Practice

http://www.scottishrenewables....-guide-good-practice/

There seems to be no upper limit to the amount of energy that can be abstracted from a river, and limited consideration made to recreational use being made of the river.

Blocking a river that is used by canoeists etc seems a disproportionate change to the environmental landscape when one potential alternative is a single large wind turbine (approx); but then again a lot more people hate the look of wind turbines than go canoeing.

James Arathoon

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James Arathoon
 07 December 2012 10:11 AM
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aroscoe

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There is a problem of energy density, and as you point out 1 6MW wind turbine can go a long way compared to even a quite big hydro scheme.

Here's the calculation I did for the P7 pupils.

You have 1 reservoir, 1kmx1km, 10m deep. Thats 1e7 m^3 of water.

That has a mass of 10e7 m^3 x 1000 kg/m^3 = 1e10 kg (10 million tonnes).

The total energy which could be extracted from that through a head fall of 100m is, with G~10 N/kg is given my mGh

so E = 1e10x100x10 = 1e13 J

This can be expressed in MWh by dividing by (1e6 x 3600), giving

E ~ 2800 MWh

Now, you could build that whole dam to provide rapid response energy or storage. You need to find the site for it, get the planning through public inquiry, prepare the whole site, build the infrastructure, etc. etc. Or, you could simply spash out on a 100MW gas turbine in a containerised turnkey solution, find a bit of brownfield industrial site for it somewhere handy, plug it into the gas and local MV substation, and switch on!

Note that the dam only holds the same amount of energy as that 100MW gas turbine produces in 28 hours. So, while the gas turbine could keep on going, just taking gas when you want it, your dam is empty and you need to refill it or wait for more rain, which could take a long time!

Now, much as I am pro-renewables, the appeal of the latter solution in a market where the future is uncertain is clear! This is what the renewables and storage folks need to compete with.

Fundamentally, gravity is the weakest force by many orders of magnitude. And Einstein showed us that inertia and gravity are one and the same. So, while hydro has terrible energy densities (J/m^3 or J/kg), and flywheels can be a bit better if you really get the rotation speed up, you really need to get to chemical bond breaking/making (the electromagnetic force) to get any decent energy density. This means better batteries or hydrogen storage systems. An of course this is why hydrocarbons are so good (at storing energy!). Of course, storing or retreiving energy from the strong nuclear force has the best density... but thats another debate!





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Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 07 December 2012 10:59 AM
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jarathoon

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So I suppose you want to compare the cost benefit of Hydro schemes with rolling out more biomethane collection on farms etc.

What are the costs of collecting biomethane from diverse locations and stuffing it into the gas grid for use in peoples homes, vs generating hydro electricity for the grid? People are quoting 10% biomethane in the grid as a realistic target, but I am not sure this is correct.

Whatever the exact percentage, it is a potential added source of income for farmers, who need to find new ways to diversify their income streams.

We definitely should be starting the process of finding new ways of continuing to use our existing gas infrstructure, into a future world with limited fossil fuel supplies. 10% would be a good start if that can be achieved. Shutting down the gas grid and putting all energy flows via the electricity grid would be hugely expensive in terms of new electricity infrastructure and extremely wasteful in terms of existing gas infrastructure.

Thinking ahead to a possible world desperate for water and energy:
If you can stimulate a reservoir to produce lots of methane I suppose you could ultimately collect the methane by putting a enden project style dome over it. This would help prevent evaporation losses in summer, but will alter the local micro-climate. Actually probably better to put an enden project style hood over a sewage farm; lots of methane to collect there, but probably will create a much too combustable atmosphere to be a sensible and safe proposition.

There are so many hybrid possibilities when you think about it, most of them are ridiculously uneconomic or have some other basic engineering flaw; but one in a thousand might just work out. Good to get the youngsters thinking about these things from an early age.

James Arathoon

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James Arathoon
 07 December 2012 12:13 PM
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jarathoon

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Sorry I spelt Eden project wrong

http://www.edenproject.com/

If I edit the post the system seems to miss out all the carriage returns and messes up the formating. So I've given up trying to make corrections that way.

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James Arathoon
 07 December 2012 12:22 PM
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amillar

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By the way, for anyone interested in hydro power I'd strongly recommend a visit to the Mary Tavy station on Dartmoor if they have any more open days, we've also run a number of very successul IET LN visits there. Fantastic place, originating from the 1930s http://www.southwestwater.co.u...ry_Tavy_A5_leaflet.pdf

Karl, who runs the place, must have one of the best jobs of any IET member. It's in a beautiful spot, and as he put it to me once "on any day I could be programming a PLC, handstitching a leather belt, or helping to get a sheep out of a leat!"

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 07 December 2012 09:10 PM
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cookers

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If you want a counter to the scary problematic environmental impacts of a large barrier project then the Zuiderzee in the Netherlands is a good example.

The Dutch did this and last time I was there the Environment in the Netherlands was still doing OK!

http://en.wikipedia.org/wiki/Zuiderzee_Works
 08 December 2012 08:58 PM
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jarathoon

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Compared with Hydro biomethane injection into the grid has hardly got going in the UK...Centrica (British Gas) has decided to throw its lot in with EDF and place a very big bet on the Hinkley Point C EPR, so it will be up to the small and medium size business sector to do the heavy lifting on biomethane I think.

Although I have found this
http://www.centrica.com/index....geid=1041&newsid=2080

"The average person produces 30kg (dried-out sewage sludge) of sewage per year that could be used for producing gas. That means that the UK's 62.5m people could in theory (see note below) generate enough renewable gas to meet the annual demand of 200,000 homes, up to 1% of the UK's population."

Then we can add farm methane production, breweries, landfill etc. + better insulated houses and the percentage will gradually climb.

The question is how long will it take and how much will it cost to inject an average rate of 6.4 GW of biomethane energy into the gas grid (a combined cycle gas burn at 50 efficiency, equivalent to a twin EPR unit output).

According to wikipedia methane has 39 megajoules per cubic meter energy content.

So to produce an average of 6.4 GW of biomethane energy involves generating 164 cubic metres per second (approx 600,000 cubic metres per hour).

If we look at this site
http://www.nationalgrid.com/uk...bleGasGroup/Projects/

The Adnams Brewery project aims to inject 60 m3/h. Therefore we need 10,000 projects the size of this one generate the same electricity as an EPR. As long as we can build each injection project for less than £1.4 million we are capital cost competitive with the EPR. For each cubic metre per hour the EPR equivalent capital cost is approx £23,500

Surely entrepreneurs can get the capital costs of biomethane production for injection into the grid to well below £23,500 per cubic metre/hour.

(I am ignoring the fact that most gas is burned at a far higher efficiency than the 50% level in combined cycle gas fired power stations, so I can complare it directly with electricity generation asset investment. I am also ignoring the fact that gas can be stored easily unlike electricity)

See
http://www.biogas-info.co.uk/i...nto-the-gas-grid.html

Also I found a PDF slides discussing possibilities for biomethane injection in California here

http://www.epa.gov/lmop/docume...15th/21Tiangco%20.pdf

Not sure what the kWh costs of biomethane are though.

UK gas fracking which is likely to lead to a great deal of public opposition. Population densities are much higher than in the USA states where fracking is happening, and many more people will be affected if things go wrong.

Perhaps it will be better to buy gas from the US when they start exporting it (they will always be able to produce gas cheaper than us anyway) and within the uk concentrate on building up a sustainable biomethane production network for grid injection instead.

James Arathoon

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James Arathoon
 08 December 2012 09:12 PM
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cookers

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James,

With my tongue firmly implanted in my cheek!

You confirm my long held belief that "bullsh*t" (or any close alternative) is often marketed as the answer to all the worlds problems.

There is a lot of it about, both figuratively and real.
 09 December 2012 02:09 AM
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jarathoon

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Dear cookers,

Some specialist energy experts, marketing their bespoke solutions, seem to charge the same cost per hour, no matter what rate of hot air they produce. So I humbly suggest that your figurative association is only applicable to those energy technologies for which there is no measurable way of determining the material value of the output per unit cost.

As far as I am aware the waste generated by cows (or bulls, or indeed bull elephants) can indeed be used to produce biomethane, and there definitely exist ways of determining the material value of the output, no matter how small that may be.

When at Imperial College at the beginning of 2011, I went to two events that had been marketed wrongly as "debates".

Inviting a panel of guests to speak, that all end up defending the same basic viewpoint concerning a particular issue or technology cannot ever be called a debate in my book.

Learning from Andrew that there will, at last, be a proper debate on energy issues involving UK educational institutions has filled me with great delight. I am sorry if I got a bit carried away in the process of contributing ideas. I was only trying to write in the cost comparison spirit of David MacKay's now long forgotten book "Sustainable Energy: without the hot air".

However, having got involved in this worthwhile discussion it now seems entirely reasonable to me that the debate should compare the potential benefit of having biomethane feed-in-tariffs set to encourage investment in small scale gas grid injection, with those feed-in-tariffs already being offered to investors in Hydro electricity generation assets, or indeed solar etc. The relative environmental impacts and regulatory regimes controllling such investments also need to be compared.

James Arathoon


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James Arathoon
 09 December 2012 10:39 AM
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TeesdaleSpark

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It's generally generated a long way from where it's needed.
IET » Energy » Arguments AGAINST hydro power ?!

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