Guest essay by Ed Hoskins | Data for the USA, Germany and the UK since the year 2000.
These notes quantify the progress and achievement of the massive movement to install renewable energy solutions for electricity generation in Western Nations. They only concern the two most significant new renewable energy sources ie. Solar and Wind-power. They progressively gauge and quantify the nominal rated energy output for these sources and their capacity factors for the three major Western investors in renewable electricity generation, the USA, Germany and in fact to a lesser extent the UK.
The following data sources were reviewed.
United States of America: data available 2000 – 2012
Germany: data available from 1990 to 2013
United Kingdom: data available 2008 – 2013
These data provide installed “nameplate” capacity measured in Megawatts (MW) and energy output measured across the year in total Gigawatt hours, (GWh). Thus they do not provide directly comparable values as Megawatt nameplate capacity and the consequential actual energy outputs achieved. For this exercise the annual Gigawatt hours values were revised back to equivalent Megawatts for comparative purposes, accounting for the 8,760 hours in the year. This measure eliminates the effect of intermittency and non-dispatchability characterising renewable Energy power sources. It does make direct comparisons possible.
For comparative purposes a normal fossil fuelled power station is rated with a nameplate capacity of about 1000 Megawatts or 1 Gigawatt. Overall the cumulative outcomes show the scale of the differential between nations and the discrepancy between installed nameplate capacity and the actual energy output achieved so far as, as follows:
The three graphs below summarise the available comparative data for each country:
In the USA the contribution from wind-power now nominally amounts to about 16 normal power stations, (1GW) and only about 1 1/2 of a normal power station is provided by US solar power. In 2013 the solar output capacity only reached 18.5% of installed nameplate capacity but the averaged over the whole data set it was as much as 21.6%. The solar capacity value has declined significantly. This relatively high capacity figure is because most solar installations are in Southern, desert states, namely California, Arizona, Nevada and Colorado.
In 2013 the wind-power capacity reached the satisfactory output capacity factor of 26.7% of installed nameplate capacity but the averaged over the whole data set was only 24.3%.
The renewable energy investment in the USA nominally now contributes about 3.8% of electricity generation.
The 25 year investment in Germany’s the renewable energy has nominally contributed about the equivalent of about 6 normal power stations, (1 GW) from wind-power. Solar power nominally contributes about 3 more normal power stations. In 2013 the solar output capacity reached 10.8% of installed nameplate capacity but the averaged over the whole data set was only 7.6%.
In 2013 the wind-power capacity reached the relatively low output capacity factor of 19.1% of installed nameplate capacity but the averaged over the whole data set was only 17.0%.
The vast renewable investment in Germany now contributes to some 15.8% of nominal electricicity generation.
In the UK the nominal contribution from wind-power is now equivalent to about 3 normal power stations, (1GW) and only about ¼ of a normal power station is provided by solar power. In 2013 the solar output capacity reached 6.8% of installed nameplate capacity but the averaged over the whole data set it was rather higher at 7.6%.
In 2013 the wind-power capacity reached the satisfactory output capacity factor of 28.5% of installed nameplate capacity but the averaged over the whole data set it only amounted to 22.5%.
The renewable investment in the UK nominally now amounts to 7.9% of electrical generation.
However there is a major problem with these renewable energy sources. Their electrical output is not dispatchable. Their output is entirely unable respond to electricity demand as and when needed. Energy is contributed to the grid in a haphazard manner dependent on the weather, and certainly not necessarily when it is required.
For example solar power inevitably varies according to the time of day, the state of the weather and also of course radically with the seasons. Essentially solar power might only work effectively in Southern latitudes and it certainly does not do well in Northern Europe. In Germany the massive commitment to solar energy might well provide up to ~20% of country wide demand for a few hours on some fine summer days either side of noon, but at the time of maximum power demand on winter evenings solar energy input is necessarily nil.
Electricity generation from wind turbines is equally fickle, as for example in a week in July this year shown above. Similarly an established high pressure zone with little wind over the whole of Northern Europe is a common occurrence in winter months, that is when electricity demand is likely to be at its highest.
Conversely on occasions renewable energy output may be in excess of demand and this has to dumped unproductively. There is still no solution to electrical energy storage on a sufficiently large industrial scale. That is the reason that the word “nominally” is used here in relation to the measured outputs from renewable energy sources.
Overall the renewable energy output from these three major nations that have committed to massive investments in Renewable Energy amounts to a nominal ~31Gigawatts out of a total installed generating capacity of ~570Gigawatts or only ~5.5%.
But even that amount of energy production is not really as useful as one would wish, because of its intermittency and non-dispatchability.