This is from Brian and is derived from
David JC MacKay's book, available for free on the internet, "Renewable Energy
without hot air" -
www.withouthotair.com Some ball park statistics about energy and Nottingham (I hope someone will
check my maths and logic )
According to David JC MacKay's book a "reasonably affluent individual" uses
195 kWh per day. 1 kWh a day is the equivalent of leaving a 40 watt lifebulb
on all day. According to MacKay's book 1 kWh per person per day converts
into 22 TerraWatt hours per year if you multiply it up to cover not one
person but everyone in the UK for a year. A Terra Watthour is 100,000,000,000
Watt hours (10 to the power 12)
So 195 kWh converts into 22 x 195 = 4290 TWh per year for the whole UK for a
year.
The population of greater Nottingham is about 0.6% of that of the UK
So a ball park figure for the usage of energy by greater Nottingham would be
0.006 x 4290 = 25.74 TWh per year. Let's say 25 TWh per year
I am not absolutely clear however how far this list includes a variety of
goods and services that do not go directly into consumption - for example
there is nothing in MacKay's book for public services like the NHS - MacKay
describes the energy cost per person per day of "defence" and nuclear weapons
- and also of university education - but not of primary and secondary
education, or the NHS, or local authority services....so my guess is that
there is some serious undercounting - but you can't have everything. MacKay
is all about starting the ball rolling with ball park figures.
How much to reduce this figure and by when? One approach is to follow the idea
in the study by Zero Carbon Britain, written and published by the Centre for
Alternative Technology, and say that we want to cut out fossil fuel use in
Nottingham altogether over 20 years. In the CAT study this is done 50% by
what they call "Powerdown" (reducing energy use by energy efficiency and
lifestyle changes) and 50% by "Powerup" - developing an infrastructure of
renewable energy sources (wind, solar, wave, tidal etc).
So, in that spirit, as a first approximation we can apply the idea of Zero
Carbon Britain that over 20 years we want to reduce energy demand in Greater
Nottingham by 50% (Powerdown)
ie. by 12.5 TWh per year
and get the other 12.5 TWh per year from renewables - generated in Nottingham
OR purchased by stuff that Nottingham produces (which will also take energy)
and imported as energy into the city - eg from marine power/wave/tidal power -
in which case our energy descent plan needs to say what we are going to sell
to purchase this energy.....
In MacKay's book there is a study of a typical person's energy consumption in
kWh per day. Thus, for example, a typical person will use 40 kWh per day in
car travel and a further 30 kWh in air travel (not on one day, of course, but
averaged as a daily amount from more occaisional flights), 37 kWh in heating
and cooling, 4 kWh in light, 5 powering gadgets like computers, 15 for food
and farming, 48 + in "stuff" ie making the material objects we use like
cars, computers etc - (of which 40 kWh is probably energy used abroad to make
the stuff we import) and 12 kWh transporting stuff around....and then4 kWh in
defence....
So scaling these figures up for Nottingham means that we currently use this
amount of energy as ball park figures and must reduce the overall total by 50
over 20 years.
Cars (or land transport ) 5.28 TWh per year
Air travel 3.96 TWh per year
Heating/cooling 4.88 TWh/y
Light 0.528 TWh/y
Gadgets 0.66TWh/y
Food, farming, fertilisers 1.98 =TWh/y
Stuff (consumer goods etc) 6.34 TWh/y
Transporting stuff 1.58 TWh
I suggest these are the sorts of figure that we need to start to work with in
our Energy Descent Plan.
I rather think that in practice the potential of Nottingham to generate
renewable energy is rather small - it is a long way from the coasts, it is
not in a windy part of the country, many roofs are not facing south, the
Trent has a microscopic hydro resource but not much drop to go with the flow
- so 50% may not be enough - and we will also need to think from where we buy
in what energy and what we export to pay for it.
Of course one can also argue that some of this list is more essential than the
rest - food for example. I suspect that as the shopping economy falls to bits
there will not be nearly as much buying of stuff (mainly imported embodied
energy) as now. Nottingham will thus have to re-find a role producing most of
its own stuff (essential consumer goods - though other than food there are
not many of them).
But these are the sorts of things we are going to need look at in our energy
descent planning. Of course it will have narratives and interesting stories to
put it into words that others can grasp - bit if we are to get real about the
main issues we need to work with at least ball park figures. We will also
need to start to generate figures about how much doing this is going to cost
(in money and energy) - so that we approach this problem by going for the
renewable energy investments (eg solar panel manufacture and installation
costs) and the energy saving investments (eg insulation material cost and
installation costs) which give most return on expenditure. In this respect I
mean the energy returned on the energy expended AND the financial cost
returned on the financial cost expended.
When I was a development worker we were always told by the funders and the
City Council we had to do things with numbers - specific, measurable,
attainable, realistic and timely. (SMART) OK, I think we have to do this here
now. This is my first iterative approximation to the task in hand.
Brian
