Prof Dave Elliot and Renew – Claverton Energy Group's "House Magazine"

Renew, the long-running 34 page bimonthly newsletter on renewable energy developments and policy, is now being offered to subscribers in PDF form.  It’s an invaluable and unique source of news and analysis produced by Prof  Dave Elliott of the Open University. Now in its 30th year, it covers news and issues from the UK, EU […]

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Vision 2020 and beyond – Dr. Gregor Czisch Ex Kassell University discussed the integration of African Power production internally and with Europe to fully exploit the vast hydro power available at the Inga Dam site

” The Grand Inga dam can provide 2/3 of African power needs and some of Europe’s”

While integration – meaning electrical inter – connections of neighbours – on the

one hand may enable cheap electricity, on the other, it can cause dependence.

Therefore, to avoid a single source dependency, it might be seen as a better

solution, to use less favourable resources inside a given country, and accept higher

costs and other disadvantages. Another way out of this dilemma is diversification of

interconnections. Therefore regional integration may be more attractive when the

number of participating countries rises.

In some cases, regional integration is the only reasonable way of using known

resources which are too big for a national approach.

An extreme example is the hydropower potential near Inga, by the Congo River, in

the Democratic Republic of Congo. The African Power Pools have been formed in

order to erect large scale regional integration projects – leading in a structure one

may call an African Supergrid – to be able to handle the tremendous amount of

electricity which could be produced here at very low prices, and which would be

enough to deliver two thirds of the current African consumption. But the huge

capacity makes it difficult to bring the different objectives together.

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Baseload nuclear power not needed in an all-renewable future

What square of land area of wind turbines would be needed in reasonable sites in the UK to in one year generate all UKs power demand?

Data

A 5 MW turbine rotor diameter is 126m ( from the Repower website http://www.repower.de/index.php?id=12&L=1 )

According to Martin Alder, a wind farm owner and developer:

Across wind turbine spacing = 3 x dia (Assume tower to tower)

Down wind turbine spacing = 5 x dia

According to Colin Palmer, of Wind Prospect, a leading wind farm developer, load factors of 30 – 35% onshore, and 40% offshore are readilly achievalbe.

So assume 33%.

Calculation

Take a 70 mile by 70 mile square. This equals 112 km by 112 km

So downwind, turbine spacing (tower to tower) will be 126 x 3 = 378m. Thus in 70 miles / 112 km we can accommodate (112 x 1000 / 378 ) +1 = 297.3 towers (allowing half blade length to protrude out of area at edges).

Similarly, cross wind, we need 5 x 126 = 630 m. Thus in 70 miles / 112 km we can accommodate (112 x 1000 /630) +1 = 178.8 towers (again allowing half blade length to protrude out of area at edges).

Thus a 70 mile by 70 mile square can accommodate 297.3 x 178.8 = 53,157 turbines..

At 5 MW each, these will generate at peak 265.7 GW.

Assuming reasonable sites and a 1/3 , 33% load factor, this will generate on average 79.73 GW.

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Energy and carbon savings with trams – a short paper by Professsor Lewis Lesley

“Getting urban car trips down from 70% to 50% would save about 5% of UK carbon emissions.”

Transport is an energy intensive activity, heavily dependent on oil (99.97%) and a significant emitter of carbon dioxide (30% of UK total). Exhortation and education can reduce car dependency but in the absence of draconian powers to force people to change travel modes, people will freely choosing sustainable alternatives is surely the best way? Market research and behavioural studies demonstrate that for short journeys, under 2 miles (50% UK car trips) walking and cycling are acceptable options, when there are safe and attractive routes. For longer urban journeys ( < 5 miles = 75% of UK car trips) public transport should be the alternative to car ? In the UK most urban public transport is by bus (80% of trips). Car users however are not willing to use buses. Studies by the US Transportation Research Board shows that on a like for like basis of frequency, travel speed, fares etc, buses attract 40% less car users than even old rail services

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Professor Lewis Lesley and other Claverton think tank members discuss rail electrification and carbon savings

Most of the (sub)urban electric trains in UK are multiple units, where most if not all coaches have motors. The reason for this is the need to get high adhesion for rapid acceleration, by distributing the track forces to most if not all wheels. Rapid acceleration (and braking) are needed when stations are close together get a high service speed.
Inter City trains do not need urban rates of acceleration but high top speeds. Electric motor coaches are (much) more expensive than “trailer coaches”, so having one or two locomotives per train is a compromise over costs. THe TGV trains in France climb steeper gradients than most railways (3%) but 6 power bogies on an 18 coach (36 bogie) train is enough to get up the hills

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