This post is concerned with the two main forms of UK Weather Dependent Renewable Energy in the UK, Wind Power, (Onshore and Offshore), and on grid Photovoltaic Solar Power. In the UK these amount to ~75% of all installed Weather Dependent Renewable Energy. The other Renewable energy inputs are traditional Hydro power ~8% and the remainder are other sources such as biomass, waste and landfill gas amounting to ~17%.
The capacity percentage, or load factor, of any power generating installation is calculated as the actual electrical output achieved annually divided by the nominal maximum Nameplate output. This article uses the real measures of capacity reported in up to date time series data of UK Renewable installations. It thus provides reasonably correct comparisons of the efficacy of Weather Dependent Renewables as is reported annually by the Renewable Energy Foundation in the UK.
When announcements are made about Weather Dependent Renewable Energy installations, they are reported as the full Name Plate capacity usually in Megawatts and also often disingenuously as the number of homes that could be supplied at their full level of power output. So such announcements are always over optimistic because the question of Capacity Percentages / Load Factors are not fully explained. So Renewable Energy announcements usually assume erroneously that the wind blows all the time at a productive speed and that the sun shines overhead 24 hours /day.
But because Weather Dependent Renewable Energy output is crucially dependent on the vagaries of the weather, (for wind), and the weather in combination with the season and the time of day, (for solar), the useful electrical output achieved by Weather Dependent Renewables is inevitably substantially less that the maximal Name Plate capacity of the installation. Accordingly in 2017 Weather Dependent Renewable Energy in the UK was operating at about one fifth of nominal name plate capacity overall.
Inevitably power production fromWeather Dependent Renewables is un-coordinated with the timing of the actual demand for electricity. In the UK, peak electricity demand usually occurs on winter evenings when Solar power is non-existent and when weather patterns can on occasions reduce wind speeds widely across the country virtually to nil: anticyclonic conditions often occur widely across the country, particularly in Winter. Add to that, that there can be no functional coordination between the timing to the Weather Dependent Renewable Energy production and a Nation’s demand for electricity.
Traditional methods of electricity generation using Fossil Fuels particularly or Nuclear Power are not subject to the vagaries of the weather and can produce electricity whenever needed to match customer demand. Crucially traditional forms of electricity generation are both non-intermittent and dispatchable to meet demand whenever needed: they thus provide a much more valuable service to electricity users.
When viewed from the needs for the engineering viability of a nation’s electrical supply, without that Government interference, Weather Dependent Renewable Energy generation would never have been used as part of the electrical generating mix. Without the Government mandates and financial subsidies the Weather Dependent Renewable Energy industry is simply not a viable business.
Thus substantial extra costs and the potential for supply failure, although mandated by Government, are in fact serious burdens on both domestic and industrial electricity consumer. As the part played by Weather Dependent Renewable Energy grows in the Electrical grid so those cost burdens and the risks to reliability will also continually increase.
The Renewable Energy industry could not exist without its Government mandated subsidies, consumption mandates and preferential feed-in tariffs.
In summary: Weather Dependent Renewable Energy is both very expensive and at the same time wholly unreliable.
Calculating capacity percentages
Reporting on Weather Dependent Renewable Energy actually generated after installation is commonly presented as annual Gigawatt Hours (GWhrs) generated per year, noting the amount of electrical power actually supplied to the grid by the installation over the whole year.
Annual Gigawatt hours are easily converted to an equivalent rating in Gigawatts by dividing by the number of hours in the year (365*24) = 8760. This output value can be compared with the original Nameplate capacity, to calculate the capacity percentage or load factor of any generating installation for comparison.
Importantly, this percentage factor does not account for the usefulness of the electrical power produced at any particular time to meet electrical demand, because of the inevitable intermittency and non-dispatchability of Weather Dependent Renewable Energy power sources. In 2017 the combined capacity percentage for UK Weather Dependent Renewables (Wind and Solar) in 2017 was ~20%.
Therefore it is a generous measure of performance when comparing the usefulness of the electricity generated from Renewable sources with any dispatchable generation.
The Renewable Energy Foundation time series data for the UK up to 2017
The Renewable Energy Foundation in the UK has provided comprehensive time series data on the progress of Renewable Installations in the UK since 2002. This included Gigawatt Hour estimations of electrical output by type of generation.
The UK progress in the development of Weather Dependent Renewable installations since 2002 is shown below.
Even though the UK, with its adverse weather and Northern situation, is one of the most unfavourable contexts for Solar power, there was been excessive commitment to Solar PV power, trebling the scale of installations in the period 2013 – 2015. This has specifically shown the irrational influence of Ed Davey as the then Secretary of State for Energy.
It is incredible, that as a result of his influence, the scale of Solar installations now match Onshore wind power in the UK. But the capacity / load factors for UK Solar energy is only about 10%, simply due to the adverse UK weather. And Solar energy cannot contribute at all at peak load times on winter evenings.
These commitments to Solar energy were made against strenuous DECC internal advice.
This was clearly stated by the late Prof David Mackay in a final interview before his untimely death in 2016. His eventual view that to try to power a developed country such as the UK with Weather Dependent Renewable energy was:
“an appalling delusion”.
As he also said at the time:
“There’s so much delusion, it’s so dangerous for humanity that people allow themselves to have such delusions, that they are willing to not think carefully about the numbers, and the reality of the laws of physics and the reality of engineering….humanity does need to pay attention to arithmetic and the laws of physics.”
The derisory Solar contribution to UK electrical production is made clear below.
For further comparative purposes the average percentage capacities / load factors achieved since 2002 are taken rather than the recent results. But it is clear that 2015 was a particularly productive year for Wind power in the UK, especially Offshore, whereas 2016 was a poor year for wind power. In 2017 the output from wind power recovered somewhat. Nonetheless as Wind power shows that degree of variability Wind power can never be regarded as consistent and dependable power source.
The order of the differential can be seen in the UK data where there is a very substantial commitment to Offshore Wind Power.
There is an “urban legend” that Offshore wind power has a regular capacity value of ~45%. A level approaching 40% was achieved in the peak year of 2015 but this level has not been attained since. This is entirely contradicted by the lower values measured from overall European data and the direct time series measurements from the UK, a major proponent for Offshore Wind Power.
The capacity values shown for the UK are the combined values since Renewable installations started in 2002 rather than the current values from 2015. 2016 at 17.2% overall was a particularly non-performant year for Weather Dependent Renewables in the UK. At a capacity value of 20.5% 2017 proved to be somewhat more performant.
The following website makes detailed cost comparisons, avoiding the distorting effects of Government policies supporting Renewable Energy.
Cost comparsion figures are derived from US EIA reports on comparative costs for various electrical generation technologies.
The separate results for the UK are shown below:
These figures are summarised in comparison with the use of Natural Gas-firing below:
In comparison with the EU(28) as a whole the costs of UK Renewables are about 25% higher both because of the heavy commitment in the UK to costly Offshore wind power and also because the rapidly developed Solar installations over the past few years.
None of these capacity / load factor or cost comparisons account for the inevitable intermittency and non-dispatchability inherent in the performance of Weather Dependent Renewables.
If the objectives of using Weather Dependent Renewables were not confused with possibly “saving the planet” from the output of Man-made CO2, the actual cost in-effectiveness and inherent unreliability of Weather Dependent Renewables would have always ruled them out of any consideration as means of electricity generation.
Weather Dependent Renewables are approximately 12 – 13 times more expensive in capital and lifetime costs when compared to the use of Gas-fired Generation technologies.
via Tallbloke’s Talkshop
April 5, 2018 at 04:30AM