Hydro on the Kennet, Could a 'Big Society' approach deliver a low head electricity Options

[On the edge]

In the 1900's much of Newbury's electricity supply came from a hydro generator at Greenham Mill. Today's demand for renewable energy might make this a useful source again. Moving water can also make an attractive display - so if properly designed, a hydro station could be an attractive feature. Of course, there would be many hurdles to jump - but the end result would be satisfying and useful. Something of lasting value to the town. Could this be managed as a community programme - we do it ourselves? Real big society stuff - with a difference! So, if there is any interest - I'm willing to try and call a public meeting to see if we can kick things off. What do you think?

[user23]

Sounds like a good idea, at least to see if you can get people with the necessary skill sets and enthusiasm to do it.

Great to see a positive thread too.

[Richard Garvie]

Sounds like a good idea, at least to see if you can get people with the necessary skill sets and enthusiasm to do it.

Great to see a positive thread too.

What he said. I'm happy to come along, even if it's to provide refreshments and get stuck in.

[Lee]

I'm in

[Simon Kirby]

Yes, I'm in.

[Ron]

Like dealing with waste to energy, there are many forms of plant for generating power from water. Some are very simple and quite crude, whilst others are very sophisticated. As a mech eng with some fluid experience I would also be interested.

[Cognosco]

In the 1900's much of Newbury's electricity supply came from a hydro generator at Greenham Mill. Today's demand for renewable energy might make this a useful source again. Moving water can also make an attractive display - so if properly designed, a hydro station could be an attractive feature. Of course, there would be many hurdles to jump - but the end result would be satisfying and useful. Something of lasting value to the town. Could this be managed as a community programme - we do it ourselves? Real big society stuff - with a difference! So, if there is any interest - I'm willing to try and call a public meeting to see if we can kick things off. What do you think?

Count me in I will do whatever I can to assist.

[blackdog]

In the 1900's much of Newbury's electricity supply came from a hydro generator at Greenham Mill.

Was this a special generator or just something attached to the old mill wheel?

There must be several places where water powered generators could be installed - all the old mill sites for a start (West Mills, Town Mills, Greenham Mills, Hollands Mill, Ham Mill), the sluice by the library and the one in Northcroft. But a dry summer would see them grind to a halt in order to ensure there was enough water in the canal.

[Richard Garvie]

Was this a special generator or just something attached to the old mill wheel?

There must be several places where water powered generators could be installed - all the old mill sites for a start (West Mills, Town Mills, Greenham Mills, Hollands Mill, Ham Mill), the sluice by the library and the one in Northcroft. But a dry summer would see them grind to a halt in order to ensure there was enough water in the canal.

I think a community project like the one by the NWN could be done as a pilot, and could potentially be funded through local community pots of money. If it was successfull, there would be no reason not to attempt more. But I do agree, summer could reduce the amount of capacity produced.

[On the edge]

As there has been some positive response, I've spoken to the Newbury Sustainability Group as they have an outline scheme and said we'd hold a public meeting. Just as soon as I get a response, I'll publish and then get a date and venue.

[Biker1]

You'll have to get the Environment Agency involved.
They control all the rivers in the UK.

[Simon Kirby]

In dry autumns flows can drop below a tenth of peak winter flows. The various turbines at Greenham have suffered from low flows at times, and there was in fact a mill pond at one time.

If the scheme is designed to use a modest amount of the site's potential, like just 1 cumec of flow (enough for around 5kW of power) then it has minimal impact on the site and is only affected in the dryest years. Of course it then generates less revenue, but I don't see it as primarily commercial venture, more a social one.

The scheme will need an abstraction license from the Environment Agency if the chosen site doesn't already have one, it'll need planning permission, will need permission from British Waterways if it's on the canal, and the support of the K&A trust too, and it'll need the cooperation of the landowner. If the scheme affects the local marinas and mill owners then they'll also need to be happy with the design.

I'm confident that a sensitive design, mindful of the wildlife in and on the Kennet, would be acceptable to the EA. They're sure to limit abstraction in low flows, but unless the scheme is designed to extract the maximum from the site I don't see that as a big problem. A water wheel is more benign to wildlife than a turbine, and it also makes much more of an attraction so I see this as a likely design choice.

If the weir is on the canal it will need carefully designing because it's likely boats will moor alongside, and that can't affect the flow over the weir, and it can't suck the boat onto the weir either. This isn't so difficult to achieve.

Preventing trash from fouling the wheel is likely one of the biggest technical issues. The Kennet picks up a lot of debris through Newbury, and like a stick in the spokes of a bicycle wheel an obstruction in a water wheel at full tilt would do a lot of damage. It's also no acceptable to pull a water bird through the wheel so the water will need careful screening, and the screens will need frequent scraping - like every few hours, 24 hours-a-day! I expect it'll need to be automated.

For me Victoria Park is the best site, with a weir on the canal between the bridges and the tail race discharging below the hatches. It's a good site because of the number of people who would come and see it, and there's no residential neighbours in case the wheel generates some infrasound. The tail race will be difficult to construct, but it could also be designed to be a terrific feature of the park with the races snaking their way round to the wheel. However, Victoria Park is also problematic because of the confused and contentious vision and refurb plans, and to succeed the wheel would have to be integrated with those plans and quite probably incorporated into any development.

I think there are also a couple of sites above Newbury Lock. John Gould's walled garden on the off-side of the lock could work well, though access is not perfect if it's to be a feature, and it would obviously need to be sensitive to the site. It could also be sited by the granite bowl where the access is very much better. The races would be very short for both sites which makes construction much easier.

There are other sites, but I don't think they lend themselves to it being a public attraction as well as the park and lock sites.

[JeffG]

Not being up with the jargon, I'm guessing here: a cumec is one cubic metre/second?

[Simon Kirby]

Yes Jeff. The power in kW generated by the site is the flow in cumecs times the head in metres (head is the difference in water level above and below the wheel) times 10 (acceleration due to gravity) times the efficiency (guestimate 50%, though it varies quite a lot). So if we're allowed 1 cumec of flow and there's 2.0m of head at the wheel we might hope to generate 10kW of electricity.

Historical flow data for Newbury show that there's a flow of 1.87 cumecs 95% of the time, and at least 3.85 cumecs 50% of the time, so it's not unreasonable to think about designing the wheel to use 1 cumec, and even on those 5% days we'll probably be allowed some flow and we'll just generate less electricity. Efficiency falls off as the flow reduces, but it shouldn't be necessary to turn it off altogether.

And to give an idea of the ecconomics, the feed-in tariff pays 18p per kWh, plus it might be possible to sell the electricity for as much as 10p per unit, so if we generate at 10kW 24/7 that's 87,600 units per year, or a possible revenue of £24.5k.

[NWNREADER]

There are schemes on the www already, but they do not look to be achieving the output Simon talks about. I cannot imagine an 'amateur' build being permitted on a public waterway, and some of the costs mentioned look steep......
Not anti, not at all, just don't get carried away on the tide just yet.

[dannyboy]

Maybe if a local architect could draw up some plans.........

[Simon Kirby]

There are schemes on the www already, but they do not look to be achieving the output Simon talks about. I cannot imagine an 'amateur' build being permitted on a public waterway, and some of the costs mentioned look steep......
Not anti, not at all, just don't get carried away on the tide just yet.

Don't forget that the K&A was renovated by "amateurs". Take a trip to the Claverton or Crofton pumping stations to see what the K&A Trust continue to achieve. Just because someone isn't being paid doesn't make the result any less "professional". The design and construction of the scheme would have to be every bit as well engineered and executed as any professional scheme.

Can you give some details please about the real schemes you mention, and can you say what costs you mean please?

[Cognosco]

Maybe if a local architect could draw up some plans.........

Nah don't want a dodgy wheel?

[dannyboy]

Nah don't want a dodgy wheel?

A wheel - how passe.

[Simon Kirby]

A wheel - how passe.

Ah, but come the revolution...