The awesome power of water

It was a beautiful summer morning, Saturday 28th July. Soon after getting up, I left the house, walked to the canal and helped a struggling beginner narrow-boat user with a lock gate. He and his friend offered me a trip down the canal, so I joined them for a peaceful mile or so of the Rochdale canal.

Needless to say, I wasn't in Norwich!  I had stayed the night with friends in Hebden Bridge, a place reminded of the power of nature recently when it experienced flash floods just a couple of weeks earlier.  Reservoirs further up the rivers were reportedly still full from previous rainfall, and the quick inch and a half of rain that fell within a matter of hours could go nowhere but the streets, devastating businesses and homes.

Flood damage in
Hebden Bridge

Later in the day, I would see how the awesome power of nature can be harnessed for good, when I visited National Trust property Gibson Mill, which forms part of the Hardcastle Crags estate, not far North of Hebden Bridge - definitely worth a visit if you're in the area! Gibson Mill prides itself on being entirely off-grid, with 100% of its electricity, heating and water sourced on site. Electrical power is from water turbines and a 4kW solar photovoltaic array, water comes from a spring on the estate and heating is provided by a biomass (wood) boiler, using wood exclusively sourced on site.

The most fascinating part of this, to me, is the water turbines.  There are two, one that was originally installed in the 1920s but has since been refurbished and given a new generator.  When running, it can produce up to 9kW, but due to the flow-rate required, they only usually run it in the winter.  The other was installed during refurbishment works in 2005, and is rated at 1.5kW.  This turbine runs almost constantly, keeping the batteries topped up, which then provide the power to the mill.  Usage is also kept to a minimum, with energy efficient appliances in the café kitchen, and low energy lighting (which was consuming only 600W for the entire building whilst I was there!).  The only thing which struck me was that there is the potential to over-produce energy (since the batteries were full all the time I was there, but energy was still being produced), and therefore that energy was simply dumped as heat.  I wonder what possibility there is for something which only uses power when power is available, but that does something productive with that waste energy.  Anyone got any ideas? Bear in mind that exporting back to the grid is made impossible by the remoteness of the mill.

The awesome power of water - lock in Todmorden.

If you want to read more about the refurbishment of the mill (which was a lot more extensive than the installation of the electrical system), have a look at the article at http://www.buildingforafuture.co.uk/summer06/gibson_mill.pdf.

Images: Canal near Todmorden; water damage in Hebden Bridge; Lock near Todmorden. All photos by the author.