20% has an advantage with respect to thin-film technologies, that have lower efficiencies.
In Chapter 1 we have seen that hydropower is responsible for 16% of the total
worldwide electricity production while 12% of the electricity is generated in nuclear
power plants. How do these numbers compare to solar electricity? This question is
answered in Figure 2.6 (a), where the installed capacity (in GW) of several electricity
generation technologies is shown on a logarithmic scale. The figure only considers
electricity generation technologies that are not dependent on fossil fuels. We see that the
installed nuclear power capacity is hardly growing any more, while the installed
hydropower is still slightly growing with time. Wind is growing at a much faster rate of
20% per year. Solar has by far the largest growth rate with an annual increase of installed
capacity exceeding 40% since 2008.
However, it is not fair to compare the installed power between technologies like this,
because the numbers shown in the graph represent the maximum (peak) power the
different technologies can generate instead of the average power they have delivered in
reality. The relationship between the totally installed power and the power generated on
average is called the capacity factor C F . Of the technologies shown in Figure 2.6 (a)
nuclear has by far the highest capacity factor with C F (nuclear) = 90% followed by
hydropower with C F (hydro) = 40%. For wind electricity we assume C F (wind) = 30% and
for solar electricity C F (solar) = 15%. The low capacity factor for PV systems can be
explained by the fact that for most geographical locations, almost half of the solar day is
devoid of solar radiation at night time.
Figure 2.6 (b) shows the effective installed power corrected with the capacity factors.
Currently solar energy generates about an order of magnitude less electricity than wind
energy and more than two orders of magnitude less than hydro and nuclear electricity.
Seeing the development in recent years, nonetheless we can claim that the trend in the
growth of solar energy will continue in the coming years. If we therefore extrapolate the
trends of the last decade until 2020 we see that the installed power of solar energy will
exceed nuclear, wind and hydropower by then. It is just a matter of time before solar
electricity will be the most important electricity generation technology that is not based on
the combustion of fossil fuels.
In Chapter 1 we have seen that hydropower is responsible for 16% of the total
worldwide electricity production while 12% of the electricity is generated in nuclear
power plants. How do these numbers compare to solar electricity? This question is
answered in Figure 2.6 (a), where the installed capacity (in GW) of several electricity
generation technologies is shown on a logarithmic scale. The figure only considers
electricity generation technologies that are not dependent on fossil fuels. We see that the
installed nuclear power capacity is hardly growing any more, while the installed
hydropower is still slightly growing with time. Wind is growing at a much faster rate of
20% per year. Solar has by far the largest growth rate with an annual increase of installed
capacity exceeding 40% since 2008.
However, it is not fair to compare the installed power between technologies like this,
because the numbers shown in the graph represent the maximum (peak) power the
different technologies can generate instead of the average power they have delivered in
reality. The relationship between the totally installed power and the power generated on
average is called the capacity factor C F . Of the technologies shown in Figure 2.6 (a)
nuclear has by far the highest capacity factor with C F (nuclear) = 90% followed by
hydropower with C F (hydro) = 40%. For wind electricity we assume C F (wind) = 30% and
for solar electricity C F (solar) = 15%. The low capacity factor for PV systems can be
explained by the fact that for most geographical locations, almost half of the solar day is
devoid of solar radiation at night time.
Figure 2.6 (b) shows the effective installed power corrected with the capacity factors.
Currently solar energy generates about an order of magnitude less electricity than wind
energy and more than two orders of magnitude less than hydro and nuclear electricity.
Seeing the development in recent years, nonetheless we can claim that the trend in the
growth of solar energy will continue in the coming years. If we therefore extrapolate the
trends of the last decade until 2020 we see that the installed power of solar energy will
exceed nuclear, wind and hydropower by then. It is just a matter of time before solar
electricity will be the most important electricity generation technology that is not based on
the combustion of fossil fuels.