4. Environmental and Social Aspects

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Del curso dictado por École Polytechnique

Photovoltaic solar energy

109 calificaciones

École Polytechnique

Photovoltaic solar energy

109 calificaciones

The course is an introduction to the photovoltaic (PV) applications in the general mix energetic context dominated by climate warming mitigation. The various uses of solar energy are firstly presented before a short description of the principle of the direct solar photon conversion into electricity (PV). The various PV technologies are reviewed in the current context dominated by crystalline silicon cells. The perspectives of the various technologies are then analysed in terms of R&D investments. From a more scientific point of view the basis of the solar cell operation is presented from the solar spectrum characteristics. The fundamentals of PV conversion are summarized. In particular the various sources of the conversion efficiency limitations are reviewed. The solar PV systems, from cells to grids, are also addressed, with a particular emphasis on the challenges of grid-integration of PV and the development of storage technologies. The environmental and social impacts of PV are compared to the competing energy sources. Generally PV is at advantage as referred to other fossil or renewable sources. Finally the fast evolution of economics and financing of PV is presented together with the current key players, mostly Asian companies.

De la lección

SOLAR PHOTOVOLTAIC SYSTEMS

Survey of the economics of the Photovoltaic industry. Social impacts, storage and grid integration of the PV energy.

1. R&D Investments in PV Systems4:10

2. Economics & Financing5:10

3. Key Players3:25

4. Environmental and Social Aspects7:57

5. Grid Integration5:13

6. Survey of Electricity Storage Technologies7:19

Conoce a los instructores

Pr. Bernard Drevillon
Professor at Ecole polytechnique
Former Director of the Thin Film Laboratory at Ecole polytechnique (LPICM)
Erik Johnson
CNRS Researcher
Laboratoire de Physique des Interfaces et des Couches Minces (LPICM)

[MUSIC]

In this new series we will look at on environmental aspects of photo.

Let's start by raising a key point of energy sources, the energy payback time.

In the case of a PV system, that represents the production time required

for the compensation of the energy used during manufacture.

The return time is generally very low for PV systems.

Typically less than two years in Europe for technology based on.

Metallurgy is based on item purchase process.

Of course this time significantly affected by the sunlight as seen here.

It is twice as long in Northern Europe than in the Mediterranean areas.

Recovery time depends on the technology used

with relative balance between the contribution of the module and

the BoS for crystalline silicon based technologies.

This time is lower for thin films that use less item processes.

Less than here in Southern Europe vicinity.

The emission of greenhouse gases I compare here.

The technologies based on crystalline silicon are significantly less

emission than fossil sources, typically in order of lower.

However, they are affected by metallurgical positions.

The range of variation is important because the emission of greenhouse gases

considerably depends on energy source used during manufacturer as will be seen later,

either in the case of coal than in the case of nuclear power, for instance.

If we consider only the median values,

PV is close enough to the concentrated solar and wind power.

Let's now return to the payback time, but now in terms of CO2.

CO2 is emitted during the production of the PVC cell.

Then the operation of PV

reduces COD emission by substitution to the fossil fuels.

This payback time is estimated year based on the location of manufacture and

installation for different levels of sunshine in each case.

For China where manufacture most of the PV modules, but dominated by

electricity from coal, the pay back time is very fast, one or two years.

Module production, consumes but allows very quickly to save CO2.

Now, if these Chinese modules are installed in Europe,

whereas the electricity pollution is more balanced the situation is much less

favorable, with return times of more than 10 years.

Initial coal consumption in China become detrimental.

In extreme cases in that of France terminated by nuclear power

characterized by weak CO2 emissions.

This payback time can reach, or even exceed,

the lifetime of the PV modules in black on the table.

Let's deal with now with a significant environmental aspect, that of recycling.

More than 80 percent of crystalline silicon base module may be recycle year.

This is due to the recycling of gas, using the encapsulation of cells,

that takes advantage of recycling techniques.

Silicon manufacturing processes produce waste, as in the semiconductor industry.

Recycling enables a reduction in energy consumption, and

reduces the energy paid by time of one year in the case of crystalline silicon.

The case of thin film recycling is ever more critical

because of the use of rare earth in the soil.

In terms of long footprint, contrary to what is often referred

PV compares quite sources taking into

account the entire chain including storage capacity, coal, gas and so on.

Only the nuclear occupy smaller area for the same production level.

However, biomass requires considerable area for the same energy density.

The onshore wind turbine requires spacing to avoid turbulence failure meter,

however most of the ground floor could be still used for agriculture.

As an order of magnitude, the presence of solar modules on lands that

1% of the territory of France or the US meet the required national power.

It should be noted that, often,

large PV plants are located on arid soils, in the US in particular.

Another major environmental issue is water resources.

Main heat sources require large amounts of water.

For cooling, as seen here,

this is particularly the case of concentrated solar and nuclear.

This is also the case of geothermal energy.

PV's definitely has advantage, considering this aspect.

We will continue to discuss the system aspects in the next seconds

by addressing the integration aspects in the electrical grid.

Thank you.

[MUSIC]

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