OK. Welcome back to the lesson on
a critical appraisal of existing narrative on alternative energy sources.
This is Session C, in which we will discuss
or illustrate the problem experienced by intermittent giving,
an explanation based on metabolic thinking.
In particular we would use the Germany's Energiewende as a case study.
To start the discussion we can have,
this is a provocative figure generated by a Morgan Private Bank report.
And the propagation is that you know,
we have a lot of forecasts about
the quick takeover of alternative electricity in the United States,
but as a matter of fact,
after all these years,
the electricity produced with alternative sources is still below 10%.
And what is really scary is that these 10% include hydropower,
which is the most important source of electricity or alternative electricity.
If you're looking at the situation in Germany,
things are not getting better in the sense
that after the big investment in the Energiewende,
it is true that there is an increase in the amount of electricity
from alternative energy but it's also true that this didn't cut
the emission and this is generating major troubles for
the economic viability of conventional power plant.
So what is the problem?
Again, what I would like to illustrate here is how a thinking
based on the concept of metabolism could help in having a better framing of the problem.
So the major problem is that in reality we are not talking about electricity.
It is not about producing an amount of electricity per year.
It is about matching the supply and demand
at a much smaller scale over hours or even minutes.
So if you are looking at the amount of energy produced and consumed,
this is something which can be of
selection process 73 to 150 gigawatt and is changing quite rapidly during the day.
This is during a week and you can see even during the day there are big changes.
So what is the problem?
Getting back to flow fund relation,
we have two types of flows
and two type of fund element that are needed to generate these flows.
So there is no electricity.
There are two types of electricity and there are two types of power plants.
Lets look at a hypothetical,
I made it up,
the curve of consumption or demand of electricity has to be matched.
We can have a plant.
They are not very flexible in changing their outs,
the supply but they are very efficient so we can use them as
a base loader to go over the majority of the demand and then you have other plants.
They are quicker in starting and producing electricity and adjusting and maybe they are
used less during the years
so in a way you are not taking full advantage of the investment of capital.
So you need two types of power capacity for these things.
You would have nuclear,
coal, brown coal plants that you can use a lot.
I asked base loader, you see these are the one covering these base load.
These are huge plants.
You can now switch on and off nuclear plants these days to get
these big plants in production.
On the other hand, you have other power plants then natural gas turbines,
you can push the button and it's immediately online
or either you just open the water going
through the dam and you can produce with very small time of regulation.
So what happened here,
that if you're looking at intermittent,
the intermittent need the biggest loaders.
They are not producing what is needed and they produce not necessary when [inaudible].
To visualize this, that this is the Peakers here are used
very little during the year and this is not because they are the best plant but
simply because they are performing a different function.
They are capable of adjusting at a very small time.
So, let's imagine now that we are trying to use intermittent into the grid,
in spite of the fact they are neither peaker or loader.
So how can we do it?
Either we are not giving priority so
they are producing when this is useful you are using it,
otherwise you don't or you can see that
intermittent are given priority in
the grid and this is more or less what happened at Energiewende.
So you are forcing the system to use the energy produced by intermittent.
In the case that the intermittents are not given priority,
you have the base load on the bottom,
then you have intermittent on the top and you can
see that you still need peakers because the peaks are not
covered and the large fraction of electricity
produced by intermittent is not used because it's produced when there is no demand.
Of course you cannot use it here because
the baseloaders are covering already the energy required.
So most of the electricity produced is wasted.
What happens if we increase
the power capacity of these intermittent and we put more intermittent.
So if we put more intermittents they keep
producing what is not needed so basically is not solving the problem.
The second possible option is that to add intermittent given priority so
basically the peakers remain there
and we have the intermittent used as loader on the bottom.
And this is much better because we can use all the electricity produced by intermittent.
But we leave some hole here and there and that we still
need backup of coal fired or nuclear or whatever to avoid blackouts.
So what is the problem here?
That's basically the solar and wind capacity goes up.
You are building more panels -- photovoltaic panels,
more windmills -- but you still need all the thermal capacity that was before.
And this is what is generating the problem of CO2 emissions.
In Germany, what happened is that they switched to
a smaller plant called brown plan to reduce the cost,
and of course the big power plants have to remain on even when they are not used.
So their emissions remain even though we are using the electricity from renewable.
So what is the problem is that in the modern electric sector
cannot afford cheap and reliable electricity.
So the real issue here is to have reliable production of wind.
I mean we have to find a way of backing up intermittents.
One way that we are considering is the 12 batteries.
This is where a lot of research is going on.
And then all matching with the more natural gas that
may be able to have a better complementation between
the intermittents and the required peak capacity.
It would be important in the future discussion about this,
is that we have to keep in mind there is not electricity and there are not power plants.
They are baseload power plants and peakers,
and if we do not change that situation,
intermittent per se are not functional because
they either produce electricity that is not
needed or when they are used as a main given priority,
then they still require back-ups.
So they are not solving the problem.
Mario GiampietroICREA Research Professor
Andrea SaltelliGuest researcher
Tarik SerranoPost-Doc Researcher
