On Fri, 14 May 2010 17:59:29 +0100, Roger Chapman
wrote:
On 14/05/2010 17:52, Bruce wrote:
How many off-shore wind turbines do you get for £14M

On current estimates, the likely cost of a Severn Barrage is between
£23 billion and £30 billion.

Where are you getting your figures from?

The lowest projected cost per kWh of electricity generated is 27p.
Some options would give a cost exceeding 40p per kWh. Compare that
with gas at 4p and wind at 17p to 21p per kWh.

So not only would it cost up to £30 billion to build, it would never
produce a return on capital because every kWh generated would require
am extremely heavy subsidy.

and often would
they need replacing over the next 200 years?

A tidal barrage in the Severn would silt up after three or four
decades. What would you do then?

On what do you base that opinion?


One of my research contractors, who is also a personal friend, is a
sedimentologist has worked on every single Severn Barrage study since
the 1970s. There have been quite a few studies.

All hydro-electric dams suffer from siltation. For example, the Aswan
High Dam in Egypt is now almost useless for power generation because
the silting has significantly reduced its capacity. To varying
degrees, the same is true of the dams on the Colorado River in the
USA. These are among the largest hydro-electric dams in the world.

But they are all sites on rivers that have a fairly low silt content.
In contrast, the Severn Barrage will be located on an estuary with an
extremely high silt content. Siltation is unavoidable. Even a design
that minimises the problem will last only a few decades.