Status and prospects of PV Technology – Sustainable Energy – TU Delft


What is the current status of Solar energy? To gain some insight into the current status,
I would like to discuss the production of solar modules. We will consider different aspects of the
production, starting off with the annual installation of PV technology. This figure shows the global annually installed
peak power, in GWp, as a function of time. The solar cell production shows an exponential
increase over the last 14 years. Between 2000 and 2011 the overall production
increases annually by more than 40%, which is an unprecedented growth. The figure also shows the relative contribution
of various PV technologies. The green and yellow colours represent the
mono c-Si and multi c-Si PV technologies respectively. As you can see, these wafer based modules
are the dominant technology and contribute to around 90% of the total module production
and installations. The inorganic thin film PV technologies, like,
Cadmium-Telluride, CIGS, and amorphous silicon are responsible for the remaining 10%. This figure shows the contribution of various
nations to the world-wide solar module production. The vertical axis represents the percentage
of the total annual production. The horizontal axis represents time, going
back 20 years. We can see that the location of the production
has strongly shifted over the last decade. Up to 2006, Japan and the US, denoted by yellow
and pink, had a combined market share of roughly 60%. The European market share, denoted by grey,
was increasing slowly up to a decade ago. From 2006 onwards, we see a big growth of
production in China and Taiwan, denoted by orange. This growth was made possible by huge investments
of the Chinese government in to scaling up PV module manufacturing in China. In 2015, around 75% of all PV modules were
produced in China and Taiwan. We are now looking at the world-wide cumulative
installed PV power, which was up to 2012 exponentially increasing in time.. The different colours reflect the different
regions in the world. The green area corresponds to Europe, which
shows that historically the majority of PV systems are installed in Europe. A large fraction of the PV capacity in Europe
is installed in Germany. The Asia Pacific region, shown in orange,
has recently caught up with Europe. Most of the PV power in Asia is installed
in Japan and in China. China is the fastest growing market at the
moment. This is demonstrated by the unprecedented
increase in the installed PV capacity from 2010 to 2015. The light blue area reflects the PV capacity
installed in North and South America. Yellow corresponds to the Middle East and
Africa. It is important to note that the total installed
solar power has passed the 100 GWp mark in 2012. At the end of 2016 we are expected to pass
the 300 GWp boarder. Another aspect that controls demand is the
cost-price of PV technology. How does the cost-price of electricity generated
by a PV system compare to the electricity delivered by your energy company? To answer this, we have to look towards the
learning curves. The learning curve is the graph which shows
how the cost-price, or in this case the sales price, is dropping in time. In time the industry gets more experience. Progress in technology provides for better
PV modules with higher efficiencies. This experience results in better and faster
processing, leading to higher production yields. Up-scaling of production leads to lower cost
of the source materials. Learning curves usually show an exponentially
decreasing cost-price in time, until the technology or product is fully developed. In this graph we have the averaged global
sales prices of a PV module, in inflation adjusted euro per Wp. The sales price is plotted against the cumulative
production in GWp. Important to note is that the sales prices,
discounting some fluctuations, follow a largely exponential decay. Currently, the average retail price of PV
modules is below 50 cents per Wp. Now we will see how the cost-price of a PV
system is not only determined by the module. The red dots show the decrease in the cost-price
of a complete PV system. As you can see, in the early days of the PV
technology, the system price was dominated by the module price. In the current situation however, the contribution
of the non-modular components start to play the most dominant role. By non-modular components, we consider components
like the racking, wiring, invertor, battery for stand-alone-systems, or even maintenance
costs. The difference between the red and blue line
corresponds to the non-modular costs. The green curve represents the learning curve
of the non-modular components. His learning curve is not dropping as fast
as the module price. This means that nowadays, the reduction in
the cost-price of a PV system will be mainly limited by the cost-price of the non-modular
components. This shows the advantage of c-Si PV technology,
with respect to thin film technologies. C-Si modules efficiencies range from 14% up
to 20%. Higher conversion efficiencies means higher
yields per area. While the non-modular cost per area are the
same, the cost-price per Wp of the non-modular costs will consequently be lower for modules
with higher conversion efficiencies. In block 2.1 we have discussed that in 2015,
hydro-power is estimated to be responsible for 16.6% of the total world-wide electricity
production. Nuclear power is responsible for around 16%. The question now is, how do these numbers
compare to solar? For that, I have constructed the following
Figure. On the vertical axis you see the cumulative
installed capacity, expressed in Gigawatts of power. Note that this is a logarithmic scale. Here we only consider the energy sources which
are not based on fossil fuels. Light blue represents hydroelectricity, dark
green represents nuclear, red represents wind and dark blue represents solar. The installed nuclear power is hardly growing
anymore, whereas the installed hydro-power is still slightly growing in time. Wind is growing at a relative rate of 20%
per year. As you can see from 2008 solar is the fastest
growing energy technology with a rate far above 40%. However, it is not fair to compare the installed
power between technologies like this. The numbers given here represent the maximum
power the energy source can produce, but it is not the averaged power the electricity
source has delivered in reality. The relation between these two is called the
capacity factor, which is basically a measure of how often an electric generator runs for
a specific period of time. Nuclear has with 90% the highest capacity
factor, followed by hydro-power with an averaged capacity factor of around 40%. For wind energy I have assumed an averaged
capacity factor of 30%. For solar I have assumed a capacity factor
of 15%. The low capacity factor for PV systems can
be explained by the fact that for most geographical locations, almost half of the day is devoid
of solar radiation, at night time. If we use these capacity factors, we can look
at the effective installed power for these electricity sources. Currently solar energy generates an order
of magnitude less electricity than hydro and nuclear. However, I claim that the trend in the growth
of solar energy will continue the coming years. If we extrapolate the trend of the last 15
years, we see that the installed power of solar energy will exceed nuclear, wind and
hydro-power in another decade. It is just a matter of time, before solar
becomes the most important energy source, not based on burning fossil fuels. But why can solar guarantee a much faster
capacity growth that the other technologies? First solar energy is everywhere and available
in great abundance. Realize that the total amount of energy in
solar light incident on our planet is 10000 times larger than our total energy consumption. By evaporation of water due to solar heat,
Hydro-electricity is a secondary form of solar energy. By solar induced temperature differences,
wind is a secondary form of solar energy. Consequently, solar energy is the biggest
renewable energy source around. Secondly, hydro-, nuclear and wind are centralized
electricity generation concepts. It means that you need a big dam, big nuclear
plant, or a wind park to generate electricity. Building these large systems requires governmental
involvements and big investors. PV systems can be installed centralized in
large solar farms too. However, the unique advantage here is that
PV systems can be installed decentralized as well. Many consumers of electricity can put their
own PV system on their home. They become their own energy producer, independent
of the market. Another important factor is that in most parts
of the world, the cost-price of a PV system have met or dropped below grid-parity. This means that having your own PV system
is cheaper than buying the electricity from the grid. The installation of the decentralized PV systems
will be the big force behind the solar revolution of the coming years. It will change the energy landscape much faster
than most people think, as is evident from this graph. As more and more people become aware of this,
it is more likely that the growth will be further enhanced, than that it will be slowed
down. Over the course of the next couple of videos,
I will introduce you to the technology behind this revolution.

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