Thursday, November 17, 2011

Further Proposed Hydroelectric Power on River Thames.

The Berkshire village of Streatley is about 8 miles (13 km) from Reading and 16 miles (26 km) from Oxford. It is located in the Goring Gap on the River Thames and is directly across the river from the village of Goring on Thames, in Oxfordshire. The two villages are connected by the Goring and Streatley Bridge with its adjacent lock and weir. The Goring Gap was cut through the chalk at the end of the last ice age by the large amounts of melt water entering the Thames. The newly formed route flows through Berkshire and London before finally egressing into the North Sea.

It is proposed to generate hydroelectric power from the River Thames at Goring and Streatley by the installation of 3 reverse Archimedes screws with a combined generating capacity of 246 kW. Some five million tonnes of water flows through the Goring Gap daily. There is nothing in the river as yet, since it has taken six years so far for the completion of all necessary feasibility studies, and to get various permissions from the Environment Agency. It was originally intended that the Swan Hotel would receive electricity from the installation but now the plan is to connect to a much closer sub-station on the Goring side of the river.

It is expected that the average annual power output will be 1000 Megawatt-hours, which is sufficient for the electricity needs of 350 homes. On the basis of four estimates for the construction phase and a firm price from Spaans-Babcock for the three 3.6 m diameter 4-flight screws, it appears that the project will cost at least £2 million.

The projected income is £165,000/annum for electricity sold onto the grid, according to an average annual rain-fall, mindful that this can vary by a factor of two between a "dry" year (1996) and a "wet" year (2007). It is intended that the commissioning and operation will take place from Autumn 2012 and beyond, and that the installation should generate clean renewable electricity for at least 50 years.

Another hydropower scheme of similar power-output is being mooted, this time at Abingdon, 5.5 miles south of Oxford.

As noted in a previous posting (, there are two other hydropower installations already generating electricity on the Thames, one at Mapledurham and a smaller one at Sonning.

Related Reading. ...and thanks to Dave Holt for providing some updated details which I have used here.

Monday, November 14, 2011

"What Happens When The Oil Runs Out?"

This is a link to the Question and Answer session after a talk I gave with the above title to the Isle of Wight Cafe' Scientifique on September 26th:

The talk itself can be found at:

I am available to give talks and quite often asked to speak on this topic in general.

Wednesday, November 09, 2011

100 kW Hydroelectric Turbine at Mapledurham.

The village of Mapledurham is adjacent to that of Caversham where I live, near Reading in the English south east, and is a pleasant 4 mile walk from here tracing the banks of the River Thames. Mapledurham House is a beautiful Grade 1 listed manor house, set on the Mapledurham Estate which holds the last commercial working water mill on the river. The estate has belonged to the Blount family since 1492. Later, the Blount sisters Teresa and Martha became friends of the poet Alexander Pope to whom he sent one of his most famous poems, "The Rape of the Lock".

There has been a turbine at Mapledurham since the 1920s which provided electricity to the manor house for many years but is no longer operational. This, however, has been replaced by a brand new turbine based on an Archimedes screw design and at full-power generates almost 100 kW. Of this, some 3 kW are drawn-off to run and control the installation. The output is not constant of course and the device is automatically turned-off when the lock is used and the water level falls, then it ramps back up to 85 - 95% of full capacity. Over a year it is thought that some 500,000 kWh of electricity will be produced at a value of £100,000 which will be sold-on to the energy company Npower.

I have been told that over a 20 year period, the project should generate around £1 million profit, which will be used to restore the listed mill buildings, and thus it appears as a sound business investment. The installation capital, provided by the Mapledurham estate is around £650,000, including interest. The electricity will be bought by the chain Marks and Spencer, who are keen to increase their use of green energy. The Mapledurham Estate is also investigating the use of cow manure to generate biogas, since they have a dairy herd, which also supplies Marks and Spencer.

The turbine itself weighs 24.7 tonnes and has a diameter of 3.5 metres. Its dimensions are such that an eight foot railway sleeper should be able to pass through it without causing damage, and obviously anything up to that size coming from further upstream. The length of the turbine has been truncated so that it fits within the limited space available to it at the mill, which has marginally reduced its maximum power output from around 120 kW.

From an ecological perspective, the choice of the design means that fish too will be able to swim through the turbine without coming to harm. Further down river on the weir at Caversham Lock is a fish-ladder to allow fish similar safe passage. The banks of the "pond" into which the water flows through the turbine will need to be reinforced, because of the phenomenon of resonance. When the turbine is operating at high capacity there is little problem, but when that drops below about 30%, and particularly down to around 10%, a wake is created that washes-away the banks of the pond. These are being reinforced with a steel barrier, and it is intended to place boulders into the pond partly for aesthetic reasons and I imagine that also the wake will be broken-up by flowing around them.

There are two turbines to be installed below Windsor Castle, when they are brought over from The Netherlands, and there is a smaller 18.5 kW hydroelectric generator which provides power for the Mill Theatre at Sonning, some four miles further down river from Caversham, with any excess electricity going onto the national grid.

It seems sensible to extract far more power from the rivers in this way, appearing as a "green" source. However, the installation of such turbines will in many locations necessitate considerable engineering and the adaptation, e.g. of weirs to place them. Effects on river-flow and local ecology must also be considered, but this is a good example of using a local advantage, e.g. a river to provide energy at the local level. In order for Transition Towns to emerge fully as resilient local communities that generate much of their own energy, such developments should be encouraged.

That noted, the turbine at Mapledurham is expected to run for 10 years before maintenance is required, but then the "black box" that is the generator needs to be serviced or replaced. The mechanical parts of the turbine, e.g. bearings, are expected to last for 20 years, but keeping the installation running will probably still depend on parts brought in from elsewhere and by some means of transportation, which currently would be powered by liquid fuel. It is debatable what forms of transport will be available to us in the decades to come and hence the viability of technology that cannot be produced and serviced by local hands.

A video of the turbine in operation may be viewed on Vimeo

Wednesday, November 02, 2011

Transition Town Reading.

The Transition Town movement has spread across the United Kingdom and there is one based in Reading, in the south east of England. In the face of peak oil, global economic failure and climate change, TT aims to provide resilient local communities that can weather such assailing forces and provide ultimately a more satisfying and humanly balanced way of living, setting apart from the delusion that "happiness" can be found in the unbridled acquisition of consumer wealth.

I attended a meeting of "Transition Town Reading" last night. Reading is the town in which I live, or specifically it is the Borough which incorporates the village of Caversham, which is where I actually do live. I met a few members of TTR after a talk I gave to Cafe' Scientifique in Reading back in March, but this is the first actual meeting of the group I have attended.

We were asked to express our "personal vision" for TTR and when the guy chairing the meeting said that at the outset, my instinct was to make it for the door! However, there were some interesting ideas and emotions raised and I explained that my interest began with some research I was doing back in 2005, to try and understand the origins of petroleum. Then I read about Peak Oil, was both transfixed and horrified by the whole scenario, and began writing this blog, which lead to my being invited to write columns on and on Forbes, and some reviews that were published in the scientific literature. As the writing took-off more and a wider audience of people read what I had written, some of them invited me to give various talks on the subject, both to the general public and in universities, which I still do.

Following the TTR meeting, I am left with a sense that there is a body of people in this town, as undoubtedly in many others, with pretty much the same values and concerns: what to do about peak oil, climate change, the out-of-kilter Capitalist system based on unlimited growth that we are desperately and unhappily clinging to, trying not to drown in the global torrent, in the perceived absence of any other craft to keep us afloat.

Of course this one sinking rapidly and it would be better to start swimming to the shore as soon as possible!

Why was I attracted to the "Transition Town" movement rather than say to Greenpeace or Friends of the Earth? The answer is simple: that while I can obliquely envisage some future horizon where we are all living in smaller communities using less energy and not driving and generally travelling less, because it is the loss of cheap liquid fuels for transportation that will go first of all fossil energy resources, the "transition" from here to there is not obvious and if we don't plan it and get it right we will descend into anarchy tearing each other apart to grab what resources are left.

So that's why I am attracted to "Transition Towns" and that I am interested in my local region. I have volunteered to help devise an energy descent plan, i.e. how to put together a set of actions that steadily use less oil say by 5% per year until in 20 years we don't need it any more. Now this is naive mathematics, and actually doing it another story altogether.