Water - an under utilised resource?

The UK is blessed, or some might say cursed, with an abundance of water. Rivers, lakes, reservoirs and the sea that surrounds our islands. Not to mention the stuff that falls from the skies on a regular basis. Do we make use of this enough?

Water - an under utilised resource?

Water – an under-utilised resource?

“Water, water everywhere and all the boards did shrink.
Water, water everywhere but not a drop to drink”

As Coleridge wrote in The Rhyme of the Ancient Mariner.

Water is an amazing chemical. Incredibly simple, just 2 molecules of Hydrogen and one of Oxygen, but also incredibly complex in its physical nature. It can coexist in all 3 physical states at the same time under our normal atmospheric conditions meaning life is possible on our humble lump of rock. It reaches its maximum density at 4ºC meaning ice floats in water rather than sinks below the surface. Water is also an amazing solvent, allowing an array of chemicals to dissolve into solution and has the capacity to hold vast quantities of material in solution. It can also hold an enormous quantity to heat.

Life would not be the same without Water.

So what do I mean when I ask “do we make enough use of our water?”

600 years ago during the so called “Dark Ages” industry was powered by water. Rivers were harnessed by water mills of all types and sizes to grind corn, to turn lathes and potting wheels and even to power blast furnaces to make steel. Water wheels were so important that many were fortified and defended by armed guards. On the Isle of Man they even used giant waterwheels to pump water hundreds of feet up out of mine shafts (Lady Isabella at Laxey).

Then James Watt et al developed steam power and the Industrial Revolution happened, we forgot about hydraulic horsepower and moved to steam power. Hydraulic power still exists today in the form of our hydro-electric power stations but for the main part it has become a forgotten resource.

With our knowledge of the impact our activities have had and are having on our planet is it time to look backwards to move forwards? Can we redevelop our hydraulic power and harness new hydraulic resources?

By way of a couple of examples:
1) The city of Albi, on the River Tarn, in France has a water turbine in an old mill building. This building is located by the old bridge and is basically in the centre of town. 15 years ago when I visited I was amazed to discover this single turbine was producing enough power for 10,000 homes in the city and plans were in place to install a second turbine in the same building. 20,000 homes worth of clean, quiet, unobtrusive but most of all reliable power slap bang in the middle of a major city.

2) Scottish Canals have installed a “Water Source Heat Pump” in the mooring buildings at Gairlochy on the Caledonian Canal. This provides clean, reliable heat for the shower and toilet block all year round by extracting a little of the heat energy carried by the water flowing through the canal. It takes 1kw of electricity to obtain 4kw of heat so a net gain of 3kw.

Imagine, if you will, Teddington Lock on the Thames. The weir here has a drop of 2.7m and with a flow rate of 42 cubic meters per second (as observed at Caversham Lock much further upstream (only place I found an official flow meter)) this gives a potential generating capability of 1MW. Plans were put forward recently to harness this with a 500kw system but I am not sure if it ever went ahead (Environmental concerns, notably those raised by anglers about the potential effect on fish populations were the reason behind delays). Additionally at Teddington there is a 2 to 3m tidal range.

So we have the potential to harness the river flow and the tidal range to generate electrical power. Plus there is the heat being carried downstream to be harvested. Is it beyond the realms of imagination to build a combined heat and power station alongside the river? The heat pump being powered by a small % of the electricity generated and providing cheap heating to local schools, care homes, social and community centres and hospitals?

Do this all along the Thames, the Trent, the Mersey and all the other major rivers in the UK and we suddenly have a massive heating resource plus a decent potential electricity generating resource. Add in canals and the numbers go upwards.

Now comes the interesting bit. Thanks to our position on the edge of the Atlantic Ocean we are also blessed with unusually warm waters (doesn't feel like it when you dive in but they are for our latitude). The Gulf Stream keeps our island warmer than it should be for our position as it carries gazillions of kilojoules of heat from the Caribbean across the Atlantic and up into the Norwegian Sea and Arctic Ocean. If we can capture even just a tiny fraction of the heat from this “river” the potential for heating becomes substantial.

Forget about trying to harness wave power it is engineeringly unfeasible. Look at the damage a winter storm can do. Trying to build a structure that can withstand that kind of energy whilst producing electricity is a non starter. There are ways to harness wave power but indirectly (I may discuss these later or in a separate piece) but a water source heat pump just needs a pipe to suck water in and another to expel it again. These can be buried under the seabed to protect them from the worst the storms can throw at us. We could even re-use old sewage outlet pipes!!

Then we have our tides. We have some of the largest tidal ranges on the planet. In the Severn these can be as high as 14.5m. In Fort William where I live we see 1.5m to 4m tides with corresponding tidal streams as the water is squeezed through the Corran Narrows and the Loch Eil Narrows. Sitting in traffic on the Ballachulish Bridge a few days ago at spring tide you could physically see the water rushing through from Loch Linnhe to Loch Levan under the bridge. A 6kt current (7mph or 11kph) presents a significant volume of water. Moving water has power, a tidal stream turbine in these sort of flows would be capable of producing reliable, regular power for hundreds, if not thousands of homes in the area. Do we need to bother with tidal barrages with these sorts of flow rates happening all around our shores? Isn't an 18m tidal turbine sitting on the seabed better than a massive wall across a bay? If the barrage wall also had wind turbines and water source heat pumps to maximise the energy harnessed then maybe not.

I hope this sparks the imagination as to what we could do with all the water around us and perhaps we can start to rebuild our hydraulic power to replace our fossil power and maybe even reduce the dash for wind turbines everywhere.


Topics: Renewables
Tags: | fish | hospitals | hydrogen | surface water | water | wave power | wind turbines
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