Renewable energy, many think, is the answer to all our energy issues. There is no fault in wanting to minimise our reliance on carbon-based fuels borne out of a concern for the environment, but the thinking is currently flawed due to irrational fears and he reality is that when countries close nuclear plants in favour of solar and wind farms, they are invariably replaced by gas or coal.

There must be caution against advocating for renewable energy as a sole solution to our global warming predicament.  Firstly, wind turbines and solar panels are land-intensive; and material intensive for the energy they produce. In addition, hydro-power, solar and wind are relatively destructive with a high ecological impact due to the low amount of energy they deliver, from mining to waste disposal.  Unpredictability and intermittency of a weather dependent supply cannot be solved by batteries, which store energy for no more than hours.  Plus, intermittent sources are backed by methane-intensive gas power, which is expensively managed to fit with peak demand times.

But even in adopting ‘a bit of everything in the mix’, are wind, solar and tidal power really any kind of substitute for affordable and plentiful low carbon electricity?  Why are these technologies not successful, when, despite many years of Government initiatives, energy prices and greenhouse gas emissions continue to rise?

Anti-Nuclear Bias

Misinformation about nuclear energy stems from cold war political propaganda and also the persistent use of the Linear No Threshold (LNT) model which was unreliably adopted in the 1950s on the assumption that no dose of radiation is the only safe level.  Significant flaws of evidence in this model are that it ignores the facts that:

• we have been exposed to radiation since life first evolved on earth.  High-sensitivity radiation detectors show that it’s impossible to completely escape it, and
• plenty of evidence determines that cells can and do repair following low-level radiation exposure

What if renewable energy is actually keeping us dependent on gas? Bear in mind, that gas transmission has the unavoidable problem of leaking methane, which is 80 x more damaging as a greenhouse gas than carbon dioxide and so we should be trying to eliminate as much of this as possible. However, it is the only current fuel source which can respond quickly to changing patterns of weather upon which variable renewable energy technologies depend. See Gridwatch’s Fuel type power generation production.

Take wind for example: the peaks and troughs are extreme. Note also that the power combined output of onshore and offshore installed is at 304 GW, theoretically to match the demand. However, output is somewhere between 10 and 15%. The difference between supply and demand is filled with gas, which have to work around the fluctuations. This excess ramping of gas turbines is inefficient and can generate higher emissions due to start-stop idling as opposed to running at a steady rate. 

Renewable power generation is heavily resource dependent. Let’s take into account materials such as concrete, glass and steel needed for a lifetime’s supply.  Nuclear has a high energy density which is is 10 billion times better than for renewable energy sources considered (due to the tiny Planck length of the atomic nucleus).

* If the UK covered every roof with solar panels, and all accessible coastline with wind turbines, we’d still only have a fraction of the electricity supply necessary to meet demand.

* Variable weather-dependent power is intermittent so that when the wind drops (or the sun goes down), the power stops and this is backed by a significant amount of gas.

* We need 50GW carbon free electricity. At present we cannot even use the renewable capacity to offset retiring coal-fired and nuclear power stations and import a significant amount of electricity, from the continent.

* Renewable installations require significantly larger land footprints to deliver equivalent volumes of power. The new solar farm proposed by EDF in Cambridgeshire will deliver only 0.01% of the UK’s electricity needs, despite being nearly the same size as Cambridge itself. 

* As renewable energy cannot be stored and is difficult to manage, despite heavy investment in battery power and smart grids.

* There are now over 1600 wind farms in the UK, which can produce large quantities of energy, which can be wasteful when it is deemed superfluous to requirement.

* The “quality” of our electricity is very important, since microprocessors and electric motors rely on the stable voltage and frequency of the supply to work properly. It was an important achievement of the 1926 Electricity Act to unify the voltage and frequency throughout the UK by joining up selected large power stations, working in unison through the “Grid”, to give us our present reliable high quality electricity. A multitude of turbines is reversing this process, and if continued to any great extent, would endanger the quality of our electricity and possibly cause power cuts.

* Until recently, heavy subsidies were available in the way of Renewable Obligations Certificates (ROCs).

Biomass – burning wood for energy
Burning wood instead of fossil fuels has its own problems. To plant enough willow to keep a single 1,000 MW (e) power station operating would cover an area bigger than Kent. As wood is cellulose, a carbohydrate, less than half of its weight (the carbon part) burns to produce heat, the rest evaporates as water; it is thus half as productive per tonne as coal and is actually very poor in energy content.  To keep up with our renewables obligations, the UK burn wood chip in combination with coal in conventional power stations at Drax and Ironbridge.

Wind

Wind power is the largest renewable energy provision in the UK according to figures presented by the suppliers in 2019.  If the wind farm supplies more than the grid requires, the windfarm suppliers are asked to switch off and then require compensation.  This payment makes up a large percentage of the Balancing Use of System (BSoUS) section you can find on your electricity bill [Ref].

Back Up Power 

In general, the national grid relies on a steady controlled generation of power from generators and turbines.  This can be supplemented by occasional “chaotic” power generation such as that provided by wind and solar, but cannot depend upon it. To avoid black out and “crashing” the grid, wind power and other renewables must be supplemented at all times by a back up generation capability equal to 80-90% of the installed renewable energy capacity, so that when the wind drops, the tide turns or day turns to night there is reserve to avoid failure.

Land requirements

Wind turbines and solar farms require vast areas of land or sea to generate the same output as a single conventional power station.  To produce 1,000MW of electrical energy – the size of an average power station – nuclear requires the equivalent of 10 football pitches. Wind (when it is blowing) requires an area the size of Dartmoor, and solar would need half as much again. Biomass (wood) needs a forest the size of Wales. Britain currently needs at least 55 of these 1,000MW(e) power stations to meet peak demand and renewables come nowhere near to meeting the requirement.

An equivalent wind farm is estimated to require in the region of 400-1000 times more land than a nuclear powered facility.

Without government subsidies, many of the existing and proposed wind farms we currently see would be uneconomic.  Some have estimated that wind power is roughly twice as expensive as that of conventional fossil fuel based power, [see ‘cost’], as defined by the ‘strike price’ – i.e. that which is agreed by the electricity seller, based on predicted market demand.

On the one hand, it is thought that the potential for wind and other renewable power could be improved by the use of batteries to viably store energy, but others  believe such technologies blight the landscape and or cause noise pollution, have a relatively short lifespan, and damage eco-systems due to such as bird strike.

Solar
The issues with Solar energy are much the same as wind. It can only be collected 50% of the time ie during daylight, and only then when there is no heavy cloud cover. The fixed solar panels vary in output throughout the day, as sun rises to a maximum and then declines. Therefore efficiency is low until improved photo voltaic technology is developed. Heat collectors on the roof to warm up water for domestic or industrial use are useful, however they aren’t a recipe for self sufficiency. Even in perfect conditions, the amount of energy available has a modest upper limit.

Wave power – tidal streams
For tidal streams to generate a reasonable amount of energy ie 1000 MW, 1000 turbines are needed. The capital cost is quite high, the carbon emissions are low, but as the generation of tidal power is not constant and electricity can only be generated when the tide is running, it too has to be supported by 80% of the installed renewable energy capacity, to avoid black outs.

Conclusion

So what to do? We shouldn’t completely discount renewable energies. Solar panels can make sense on traffic road signs and calculators for example.  But to deal with the energy crisis facing us in terms of the growing gap between capacity and demand we have to refocus the debate and look at a balanced power generation solution for the UK, embracing a mixture of technologies which above all includes Nuclear.

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