Lamplight from tides
Despite its long and fascinating history, Bristol has had a reputation over time of being the graveyard of dreams. Some dreams assume concrete form and it is the lack of concrete – or any other building materials – that are the subject of local author Eugene Byrne’s new book ‘Unbuilt Bristol’, which is published today by Redcliffe Press at a very reasonable £15.00.
Unbuilt Bristol is described as ‘The city that might have been 1750-2050’. As regards the book’s content, Eugene writes:
While all your old favourites are there (all the other proposals for a bridge over the Avon Gorge, the insane 1960s/70s plan to fill in the Floating Harbour and cover it in roads etc.) there are plenty more which you won’t have heard of. Like the Victorian scheme to put Bristol’s main railway station in Queen Square, or a visionary 19th century plan to run the city’s street lighting using power generated by the rise and fall of the river Avon.
And it’s the latter idea – that visionary 19th century plan to run the city’s streetlights on tidal power from the Avon that forms the subject of this post.
The project to generate electricity from the Avon to run Bristol’s streetlights is described in Charles Wells’ A short history of the Port of Bristol’, which was published in 1909 and is available free from the Internet Archive. Regarding the amount of tidal power available and the fate of the project itself, Wells wrote:
…when proposals were first brought before the city for the introduction of electric light (November, 1881), Mr. Smith secured the appointment of a committee to consider an interesting scheme for utilising the great power of the tide in the river Avon for generating the electricity. Mr. Smith said he believed by this method a saving of about £6,000 per annum could be effected compared with the cost of generation in the ordinary way. Prof. Silvanus P. Thompson, who was on the staff of Bristol University College, had made calculations (upon data supplied by Mr. T. Howard, Dock Engineer) showing that the available tidal power at Totterdown was over 6 billions of foot pounds per annum, equal to 279,389 h.p. per tide. At Rownham the power was three times greater, and at Avonmouth over 2,000,000 h.p. per tide. To light by electricity the 4,274 street lamps then in the city would require from 4 billions to 2 billions of foot pounds per annum according to the system adopted. There was, however, no practical result from the appointment of the committee, and in March 1891 the Corporation voted £66,000 for the beginning of the present installation with an ordinary power station on Temple Backs.
Where it meets the Severn estuary at Avonmouth, the Bristol Avon has a tidal range of 15 m (49 ft), the second largest in the world, only being beaten by the Bay of Fundy in eastern Canada.
Given the present concerns about burning fossil fuels and carbon emissions, perhaps it is time to revisit generating electricity from the Bristol Avon, although one factor that could prove a disadvantage is the heavy load of silt sloshing up and down the river with every tide.
Anyone who uses Skype, has agreed that Skype may also read their text messages too. 
On 4th May, Debian made the following