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Every individual needs energy to live
and to make his body work.

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You, I, that refugee in Syria,
each of us needs energy.

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The amount of energy that we need,

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I can express it as a definite
quantity: 25 cl of petrol.

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This is the energy equivalent
that we consume and need daily.

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Our society, our civilisation
has developed a set of technologies

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that enables us to guarantee our comfort
but actually consumes much more energy.

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So, first, we produce waste:

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each of us produces 2 kg of waste daily,
30% of which is organic waste,

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that is, the residue of the food we eat,

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the food that Nature gives us.

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We consume energy: 5 litres of petrol
is the daily average in Switzerland.

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The problem is that we burn it

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and, as a result, it releases CO2:

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14 kg every day.

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Fourteen kilos per day,
imagine if it were solid,

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you'd have to leave home each morning
with two packs of six bottles of water


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and put them on the pavement.

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Fourteen kilos per day ...
Luckily, it is a gas.


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So it dissipates into the atmosphere,
we don't see it.

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Too often we tend to forget

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that it keeps on accumulating
in the atmosphere.

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We ourselves don't feel it,

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but Teddy-x here
is already seeing its effect.

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We thought it was important
to save Teddy-x

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and come up with a solution
to limit our CO2 emissions.

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To do so, we need to study
the energy system.

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So we took Switzerland and looked
where energy was consumed.

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Forty-seven per cent
of Switzerland's energy consumption

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is for keeping ourselves warm
and illuminating our buildings.

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This energy consumption
occurs mainly in winter

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when it's cold and we need to heat,
mainly in the form of heat.

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Only 25% of our energy
consumption is electricity,

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the rest is heat.

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To this 47%, I'll add transport
which uses 36%,

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and our society's driving force, industry,
which needs about 20%.

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Each square here represents
100 litres of petrol per inhabitant,

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and every red square
represents one CO2 emission.

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When we observe cities, we see that
they tend to concentrate the population.

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It is said that, in the future,

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75% of the population will live in cities.

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When it concentrates the population,
it takes up space.

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In Geneva, each square metre of floor area

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equals a square metre of heated area.

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This means that energy is consumed.

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The Swiss average
is 260 million litres per year

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for the population
in Geneva's city centre.

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It means that one million tons 
of CO2 is emitted.

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Cities also produce waste,

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100,000 tons of solid waste
plus 40,000 tons of organic waste,

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and they have opportunities.

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In Geneva there's the lake
on the one hand,

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and on the other hand, we have
the sun that shines on all our roofs.

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If we convert the amount
of energy that we receive daily

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into litres of petrol,

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we can see that there are
620 million litres of petrol

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that come to our roof each year.

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We can see that there is
more energy available

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than the energy that is consumed today.

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So, together with some of my colleagues
and industrial partners,

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we have asked ourselves
if we could make cities

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really energy-autonomous.

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'Energy-autonomous' means
ideally that we would no longer emit CO2,

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we would not need to import energy,

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that we would not have
to knock down all the buildings

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to rebuild them later
but would use the city as it is,

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and we would not bankrupt
ourselves, of course.

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So, how did we do this?

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As engineers, the first thing we do
is to look at the needs.

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We don't need energy, and the best
would be precisely not to need it.

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So we look at the minimum we need.

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We call on science and thermodynamics.

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Carnot, a French scientist
specialised in thermodynamics,

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showed that in order to heat
a building up to 21°C

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when the environment is at 0°C,

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we need to buy one unit of energy
to deliver 10 of it.

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This is an important element
because it can guide and motivate us.

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Where is the motivation?

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If I look at the amount of energy
I spend using a very good boiler

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that has 90% efficiency, uses gas
and so burns and produces CO2,

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I realise that for the same amount
of heat, that is 10 units,

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I must buy 11 units.

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Here emerges a new question:

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why do we consume 10 times more

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than the minimum
indicated by thermodynamics,

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while producing CO2 on top of it?

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The answer is to be found
in the heat pump.

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What is a heat pump?

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You all have a fridge at home.

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This fridge works on the following principle:

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you take electricity,


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you extract heat to cool
the inside of the fridge,

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and in doing that you heat your room.

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The heat pump does exactly the same:
it takes the outside heat

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and with the help of electricity
it increases the temperature


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in order to provide you with heat.

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Thermodynamics tells us two things.

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The first is that

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the lower the temperature
at which you have to heat,

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the less energy you have to spend.

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That's why the recommendation

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is to install low temperature
heating systems

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and not high temperature ones.

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Thermodynamics also tells us


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that the higher the source temperature,
in other words the environment, the better.

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The problem is finding that source.

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Cities are dense ;
there are buildings everywhere,

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so it is very difficult to make
only one heat pump.

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So we thought of splitting
the heat pump into two:

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On one side, we will use a heat pump

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that will find the good heat sources
in the environment.

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For example, if I have water in the lake,
a river or underground,

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I can extract this heat
and carry it where I need it.

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Then I can use a second heat pump

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which gives me exactly
the temperature that I need.

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You have a heating system
at low temperature,

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so you will pay less than someone
who has a high temperature heating system.

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In order to carry the heat,
the idea is to use the CO2.


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What we can do is use two tubes:

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one tube with CO2 in the liquid state, 
one tube with CO2 in the vapour state.

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We can take the steam, condense it,

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and in this way we can deliver heat,

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and we can use a heat pump
to reach the temperature we need.

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Now, if someone wants to be cooled,
I can take the liquid and boil it off.

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I can then cool my buildings
down directly.

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Because they are connected with a pipe,

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I can also cool the building
that needs to be cooled

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with the building that needs to be heated.

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This ultimately allows me
to save a good amount of energy.

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Then, on the way, we can identify
all the good heat sources that we have.

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For example, the waste water
that leaves your house at around 20°C

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can be used to heat the buildings.

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as well as the water in the lake,

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or the water that leaves the water
treatment plant, or geothermal energy.

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So now, I have a system
that enables me

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to exchange energy
between the different users.

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Another important element
is that I use CO2.

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CO2 has a high energy density
which means we don't need large pipes.

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We can insert pipes in the pavement

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and don't have to bury them
because CO2 doesn't freeze.

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We don't have to go very deep.

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Therefore we can manufacture
precast pavement

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that enable us to transport
the energy that you need.

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So, here is a complex system
that, thanks to a heat pump,

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allows us to warm up,
to be directly cooled,

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that also enables refrigeration
in shopping centres, for example,

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where fridges or freezers are needed,

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that also enables us to recycle
the heat of our waste when we burn it,

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and that uses all the opportunities
that the environment has to offer.

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Now the question is:

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is it more efficient
than the traditional system?

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To get the answer, we did a case study:

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an area in Geneva
where there are offices,

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appartments, banks, shops -

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for those who know it,
it is the "Rues Basses" area.

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We calculated the amount of energy

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that is needed and used today
to provide heating and cooling

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and we saw that we need 12 energy units,

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10 in the form of heat and natural gas
and two in the form of electricity.

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We also saw that the natural gas
is mainly used in winter,

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while electricity is used
in summer for cooling.

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The same system with the CO2 network
only needs two units.

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We made a factor of six
in our energy consumption.

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We only need 16% of the energy
that we consume today

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without changing the buildings.

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Obviously, if we insulate the buildings
we will save even more.

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Of course, everybody said,
'Yes, but it's going to be too expensive'.

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And the answer is: 'Yes,
it's very expensive at present.

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But in fact, the system we propose
will cost less and will be profitable,

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while today's system is not profitable'.

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Now. I've almost achieved my goal,

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but I still need to provide
electricity to the system

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so I am not quite self-sufficient yet.

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I have to provide electricity in winter,
so now the question is:

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how do we make electricity in winter?

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We can import electricity from outside

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but then, we will emit a lot of CO2
and so lose many benefits.

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I can also use new technologies
such as the gas combined cycle

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which has a better efficiency

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and emits far less CO2
because it uses natural gas.

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But I can also say,

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'Why not use renewable energies
to make my heat pumps work?'

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The problem is that renewable energies
are mainly available in summer.

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The sun shines a lot in the summer,
far less in the winter.

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We can also use
a different kind of technology.

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The EPFL has patented a new concept

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that combines a fuel cell
and a gas turbine,

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that has 80% electrical efficiency,

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much higher than the best
gas power plant,

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and that separates CO2 for free.

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So now, I have some CO2 in a tube,

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and that's perfect
since I already have a tube.

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I have residual heat because I'm at 80%.

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I still have 20% left which is great

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since I have the means
to carry it towards my users.

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So now, my system enables me
to produce electricity,

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to catch CO2 and to meet my heat needs.

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But I’m still using fossil fuel
because I’m using natural gas.

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So here, we must go back
to look into History

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00:12:05,478 --> 00:12:09,868
and see what gifts
Mother Nature has given us.

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00:12:09,876 --> 00:12:12,208
In fact, Nature has given us two things.

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On the one hand, we have a treasure.

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The treasure is something
that never gets refilled.

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It is there and we can only use it,
and this is what we do:

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we take a part of the treasure
and burn it to produce CO2.

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And Teddy-x is not very happy actually.

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What you can observe
is that the reservoir has run out

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and nobody is refilling it.

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00:12:37,455 --> 00:12:41,804
That means our children will have less
than what we've received from our parents.

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00:12:42,612 --> 00:12:46,921
We can also look at Nature’s
current and savings accounts

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which are renewable energies
that come in different forms.

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00:12:50,284 --> 00:12:56,299
We have the sun, the wind,
the water and the biomass.

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00:12:56,299 --> 00:13:02,435
The biomass is much like the savings
account because it is stored.

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I can therefore take the biomass
and convert it into gas.

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00:13:07,217 --> 00:13:10,536
Organic and chemical processes exist

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that enable us to convert
the biomass into gas.

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When the process is not efficient,
it generates heat

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and I have a tube to use that heat
so it's great when I need heat.

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As for the gas, I can use it
in fuel cells.

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I’m also trying to learn from Nature.

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If I think carefully, I need energy,
where do I find it?

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I find it in food which is stored energy.

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I don’t feel variations
like I do with the sun

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that changes from hour to hour
and from season to season.

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How did Nature do that?
By photosynthesis.

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It took CO2 from the atmosphere,

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used the photons coming
from the sun, used water,

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and created carbohydrates
that make up my food

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and the trees as well.

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We can do the same
with a technical system.

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I can take the sun,

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transform it into electricity
with photovoltaic cells,

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00:14:04,833 --> 00:14:09,846
then I can take these, CO2
and water, and create methane.

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00:14:10,036 --> 00:14:13,707
And what I'm going to do
is to take the CO2 I stored

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and create methane in the
liquid state to store as well.

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It's going to become
quite a complex system

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because, in the summer,
I'll take liquid CO2

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00:14:22,058 --> 00:14:27,394
to make liquid methane
by means of the shining sun,

239
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and in the winter, I'll take
the liquid methane

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and feed it into the fuel cell

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00:14:31,686 --> 00:14:35,746
to produce the electricity that I need
for heating and lighting,

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then, I'll capture the CO2,

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bring it back into my tube
and convert it into liquid CO2.

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By doing so, I’ll have a system
that seems very complicated,

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but don’t forget that you have many tubes
coming into your houses every day.

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You have the electrical cable,
the Internet cable,

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and also the drinking water
and the waste water leaving your home.

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So adding a new tube is not necessarily
as difficult as it seems.

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It's a system that enables us
to warm up, to cool down, to refrigerate,

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00:15:08,768 --> 00:15:10,504
to add value to all of our waste,

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00:15:10,504 --> 00:15:15,600
and to store the solar energy produced
during the summer on our roofs

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00:15:15,600 --> 00:15:19,013
to make it available during the winter.

253
00:15:19,747 --> 00:15:25,368
If I can do that, I'll have a system
entirely autonomous in energy.

254
00:15:25,941 --> 00:15:27,292
The system I had before

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00:15:27,292 --> 00:15:31,782
burnt a large quantity of energy
to meet my needs,

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00:15:31,782 --> 00:15:35,417
emitted a lot of CO2,
and emptied my treasure.

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00:15:35,545 --> 00:15:40,780
Today, with an investment -
the installation of new infrastructure

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00:15:40,780 --> 00:15:46,822
with heat pumps, fuel cells and storage -

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00:15:46,822 --> 00:15:51,047
I will be able to fulfil the same needs.

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00:15:51,357 --> 00:15:54,630
I don't need to change the buildings
or to change your comfort,

261
00:15:54,630 --> 00:15:57,460
you will still have the same
temperature in all your rooms.

262
00:15:57,630 --> 00:16:00,715
You will simply have
solar panels on your roof,

263
00:16:00,985 --> 00:16:03,296
You will have fuel cells

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00:16:03,296 --> 00:16:09,965
that generate electricity from the methane
produced during the summer.

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00:16:10,480 --> 00:16:14,852
You will recycle the heat from the hot
water poured in the sewer

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because you will be able to use it
in your heat pumps.

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You will recycle energy from your waste,

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00:16:19,967 --> 00:16:25,001
and in the end, in fact,
you're going to export electricity,

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00:16:25,001 --> 00:16:28,331
an electricity available on request.

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00:16:28,341 --> 00:16:31,200
That means that you'll be able
to decide when to export it

271
00:16:31,200 --> 00:16:34,500
when you have too much,
and it'll be stored as methane.

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00:16:34,783 --> 00:16:35,979
As a point of interest,

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00:16:35,979 --> 00:16:39,429
the storage space required for this
is 10 times smaller

274
00:16:39,429 --> 00:16:45,510
than the amount of tanks 
we would need in all the buildings

275
00:16:45,510 --> 00:16:49,511
if we heated everything with fuel oil.

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00:16:51,000 --> 00:16:52,924
And that's my conclusion.

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00:16:53,070 --> 00:16:54,960
Anyway, Teddy-x can thank us,

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00:16:54,960 --> 00:17:00,413
because if you are able
to transform cities

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00:17:00,413 --> 00:17:04,423
into independent electricity producers
without CO2 emissions,

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00:17:04,423 --> 00:17:09,371
he may have the opportunity
to find a more secure block of ice.

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00:17:09,746 --> 00:17:11,069
Thank you very much.

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(Applause)