Every individual needs energy to live and to make his body work.
You, I, that refugee in Syria, each of us needs energy.
The amount of energy that we need,
I can express it as a definite quantity: 25 cl of petrol.
This is the energy equivalent that we consume and need daily.
Our society, our civilisation has developed a set of technologies
that enables us to guarantee our comfort but actually consumes much more energy.
So, first, we produce waste:
each of us produces 2 kg of waste daily, 30% of which is organic waste,
that is, the residue of the food we eat,
the food that Nature gives us.
We consume energy: 5 litres of petrol is the daily average in Switzerland.
The problem is that we burn it
and, as a result, it releases CO2:
14 kg every day.
Fourteen kilos per day, imagine if it were solid,
you'd have to leave home each morning with two packs of six bottles of water
and put them on the pavement.
Fourteen kilos per day ... Luckily, it is a gas.
So it dissipates into the atmosphere, we don't see it.
Too often we tend to forget
that it keeps on accumulating in the atmosphere.
We ourselves don't feel it,
but Teddy-x here is already seeing its effect.
We thought it was important to save Teddy-x
and come up with a solution to limit our CO2 emissions.
To do so, we need to study the energy system.
So we took Switzerland and looked where energy was consumed.
Forty-seven per cent of Switzerland's energy consumption
is for keeping ourselves warm and illuminating our buildings.
This energy consumption occurs mainly in winter
when it's cold and we need to heat, mainly in the form of heat.
Only 25% of our energy consumption is electricity,
the rest is heat.
To this 47%, I'll add transport which uses 36%,
and our society's driving force, industry, which needs about 20%.
Each square here represents 100 litres of petrol per inhabitant,
and every red square represents one CO2 emission.
When we observe cities, we see that they tend to concentrate the population.
It is said that, in the future,
75% of the population will live in cities.
When it concentrates the population, it takes up space.
In Geneva, each square metre of floor area
equals a square metre of heated area.
This means that energy is consumed.
The Swiss average is 260 million litres per year
for the population in Geneva's city centre.
It means that one million tons of CO2 is emitted.
Cities also produce waste,
100,000 tons of solid waste plus 40,000 tons of organic waste,
and they have opportunities.
In Geneva there's the lake on the one hand,
and on the other hand, we have the sun that shines on all our roofs.
If we convert the amount of energy that we receive daily
into litres of petrol,
we can see that there are 620 million litres of petrol
that come to our roof each year.
We can see that there is more energy available
than the energy that is consumed today.
So, together with some of my colleagues and industrial partners,
we have asked ourselves if we could make cities
really energy-autonomous.
'Energy-autonomous' means ideally that we would no longer emit CO2,
we would not need to import energy,
that we would not have to knock down all the buildings
to rebuild them later but would use the city as it is,
and we would not bankrupt ourselves, of course.
So, how did we do this?
As engineers, the first thing we do is to look at the needs.
We don't need energy, and the best would be precisely not to need it.
So we look at the minimum we need.
We call on science and thermodynamics.
Carnot, a French scientist specialised in thermodynamics,
showed that in order to heat a building up to 21°C
when the environment is at 0°C,
we need to buy one unit of energy to deliver 10 of it.
This is an important element because it can guide and motivate us.
Where is the motivation?
If I look at the amount of energy I spend using a very good boiler
that has 90% efficiency, uses gas and so burns and produces CO2,
I realise that for the same amount of heat, that is 10 units,
I must buy 11 units.
Here emerges a new question:
why do we consume 10 times more
than the minimum indicated by thermodynamics,
while producing CO2 on top of it?
The answer is to be found in the heat pump.
What is a heat pump?
You all have a fridge at home.
This fridge works on the following principle:
you take electricity,
you extract heat to cool the inside of the fridge,
and in doing that you heat your room.
The heat pump does exactly the same: it takes the outside heat
and with the help of electricity it increases the temperature
in order to provide you with heat.
Thermodynamics tells us two things.
The first is that
the lower the temperature at which you have to heat,
the less energy you have to spend.
That's why the recommendation
is to install low temperature heating systems
and not high temperature ones.
Thermodynamics also tells us
that the higher the source temperature, in other words the environment, the better.
The problem is finding that source.
Cities are dense ; there are buildings everywhere,
so it is very difficult to make only one heat pump.
So we thought of splitting the heat pump into two:
On one side, we will use a heat pump
that will find the good heat sources in the environment.
For example, if I have water in the lake, a river or underground,
I can extract this heat and carry it where I need it.
Then I can use a second heat pump
which gives me exactly the temperature that I need.
You have a heating system at low temperature,
so you will pay less than someone who has a high temperature heating system.
In order to carry the heat, the idea is to use the CO2.
What we can do is use two tubes:
one tube with CO2 in the liquid state, one tube with CO2 in the vapour state.
We can take the steam, condense it,
and in this way we can deliver heat,
and we can use a heat pump to reach the temperature we need.
Now, if someone wants to be cooled, I can take the liquid and boil it off.
I can then cool my buildings down directly.
Because they are connected with a pipe,
I can also cool the building that needs to be cooled
with the building that needs to be heated.
This ultimately allows me to save a good amount of energy.
Then, on the way, we can identify all the good heat sources that we have.
For example, the waste water that leaves your house at around 20°C
can be used to heat the buildings.
as well as the water in the lake,
or the water that leaves the water treatment plant, or geothermal energy.
So now, I have a system that enables me
to exchange energy between the different users.
Another important element is that I use CO2.
CO2 has a high energy density which means we don't need large pipes.
We can insert pipes in the pavement
and don't have to bury them because CO2 doesn't freeze.
We don't have to go very deep.
Therefore we can manufacture precast pavement
that enable us to transport the energy that you need.
So, here is a complex system that, thanks to a heat pump,
allows us to warm up, to be directly cooled,
that also enables refrigeration in shopping centres, for example,
where fridges or freezers are needed,
that also enables us to recycle the heat of our waste when we burn it,
and that uses all the opportunities that the environment has to offer.
Now the question is:
is it more efficient than the traditional system?
To get the answer, we did a case study:
an area in Geneva where there are offices,
appartments, banks, shops -
for those who know it, it is the "Rues Basses" area.
We calculated the amount of energy
that is needed and used today to provide heating and cooling
and we saw that we need 12 energy units,
10 in the form of heat and natural gas and two in the form of electricity.
We also saw that the natural gas is mainly used in winter,
while electricity is used in summer for cooling.
The same system with the CO2 network only needs two units.
We made a factor of six in our energy consumption.
We only need 16% of the energy that we consume today
without changing the buildings.
Obviously, if we insulate the buildings we will save even more.
Of course, everybody said, 'Yes, but it's going to be too expensive'.
And the answer is: 'Yes, it's very expensive at present.
But in fact, the system we propose will cost less and will be profitable,
while today's system is not profitable'.
Now. I've almost achieved my goal,
but I still need to provide electricity to the system
so I am not quite self-sufficient yet.
I have to provide electricity in winter, so now the question is:
how do we make electricity in winter?
We can import electricity from outside
but then, we will emit a lot of CO2 and so lose many benefits.
I can also use new technologies such as the gas combined cycle
which has a better efficiency
and emits far less CO2 because it uses natural gas.
But I can also say,
'Why not use renewable energies to make my heat pumps work?'
The problem is that renewable energies are mainly available in summer.
The sun shines a lot in the summer, far less in the winter.
We can also use a different kind of technology.
The EPFL has patented a new concept
that combines a fuel cell and a gas turbine,
that has 80% electrical efficiency,
much higher than the best gas power plant,
and that separates CO2 for free.
So now, I have some CO2 in a tube,
and that's perfect since I already have a tube.
I have residual heat because I'm at 80%.
I still have 20% left which is great
since I have the means to carry it towards my users.
So now, my system enables me to produce electricity,
to catch CO2 and to meet my heat needs.
But I’m still using fossil fuel because I’m using natural gas.
So here, we must go back to look into History
and see what gifts Mother Nature has given us.
In fact, Nature has given us two things.
On the one hand, we have a treasure.
The treasure is something that never gets refilled.
It is there and we can only use it, and this is what we do:
we take a part of the treasure and burn it to produce CO2.
And Teddy-x is not very happy actually.
What you can observe is that the reservoir has run out
and nobody is refilling it.
That means our children will have less than what we've received from our parents.
We can also look at Nature’s current and savings accounts
which are renewable energies that come in different forms.
We have the sun, the wind, the water and the biomass.
The biomass is much like the savings account because it is stored.
I can therefore take the biomass and convert it into gas.
Organic and chemical processes exist
that enable us to convert the biomass into gas.
When the process is not efficient, it generates heat
and I have a tube to use that heat so it's great when I need heat.
As for the gas, I can use it in fuel cells.
I’m also trying to learn from Nature.
If I think carefully, I need energy, where do I find it?
I find it in food which is stored energy.
I don’t feel variations like I do with the sun
that changes from hour to hour and from season to season.
How did Nature do that? By photosynthesis.
It took CO2 from the atmosphere,
used the photons coming from the sun, used water,
and created carbohydrates that make up my food
and the trees as well.
We can do the same with a technical system.
I can take the sun,
transform it into electricity with photovoltaic cells,
then I can take these, CO2 and water, and create methane.
And what I'm going to do is to take the CO2 I stored
and create methane in the liquid state to store as well.
It's going to become quite a complex system
because, in the summer, I'll take liquid CO2
to make liquid methane by means of the shining sun,
and in the winter, I'll take the liquid methane
and feed it into the fuel cell
to produce the electricity that I need for heating and lighting,
then, I'll capture the CO2,
bring it back into my tube and convert it into liquid CO2.
By doing so, I’ll have a system that seems very complicated,
but don’t forget that you have many tubes coming into your houses every day.
You have the electrical cable, the Internet cable,
and also the drinking water and the waste water leaving your home.
So adding a new tube is not necessarily as difficult as it seems.
It's a system that enables us to warm up, to cool down, to refrigerate,
to add value to all of our waste,
and to store the solar energy produced during the summer on our roofs
to make it available during the winter.
If I can do that, I'll have a system entirely autonomous in energy.
The system I had before
burnt a large quantity of energy to meet my needs,
emitted a lot of CO2, and emptied my treasure.
Today, with an investment - the installation of new infrastructure
with heat pumps, fuel cells and storage -
I will be able to fulfil the same needs.
I don't need to change the buildings or to change your comfort,
you will still have the same temperature in all your rooms.
You will simply have solar panels on your roof,
You will have fuel cells
that generate electricity from the methane produced during the summer.
You will recycle the heat from the hot water poured in the sewer
because you will be able to use it in your heat pumps.
You will recycle energy from your waste,
and in the end, in fact, you're going to export electricity,
an electricity available on request.
That means that you'll be able to decide when to export it
when you have too much, and it'll be stored as methane.
As a point of interest,
the storage space required for this is 10 times smaller
than the amount of tanks we would need in all the buildings
if we heated everything with fuel oil.
And that's my conclusion.
Anyway, Teddy-x can thank us,
because if you are able to transform cities
into independent electricity producers without CO2 emissions,
he may have the opportunity to find a more secure block of ice.
Thank you very much.
(Applause)