This month I ask: What role do renewables, such as wind and solar, have to play in the future of the UK energy mix?

Renewable energy sources are increasing their presence within the UK energy mix. To be exact, in 2014 a grand total of 19% of electricity generated in the UK, came from renewables and future government plans want to see this percentage rise further. Safeguards against climate change, environmental group pressures and carbon emission targets all lobby in favour of a more renewables- heavy energy mix, but their downfall is their ever questioned economic viability. A classic example of this was in 2013, when the UK wide press detailed articles stating alarming consumer subsidy figures of over £1 billion to wind turbine owners. With current economic austerity measures looming left, right and Tory, it has become increasingly difficult to advocate the expansion of renewable energy sources, such as wind power, which appear to be completely cost inefficient.

solar-roadways_test_01

Credit: solar roadways

However, wind power, together with solar power, actually constitutes a very small portion of renewable energy sources, with biomass currently providing the majority (> 60%) of “high [output] renewables”. As such it does not seem correct to tarnish all renewable energy sources with the same waste-of-tax-money brush currently squandering over UK wind turbines. According to MoneySavingExpert.com, simply owning a solar panel on a family property in Manchester is expected to reduce your bills by over £600 per year, so at a local scale at least the money behind using renewables impresses a bit more sense. Perhaps therefore it is not a question of what role renewables will play in the future of the UK’s energy mix, especially as they are clearly here to stay and to develop, but rather which renewable energy sources should continue to have a place in this future? Perhaps we will all be walking on “Solar Freakin’ Roadways” before we know it…

Helena S Davies is a Ph.D. student at The University Of Manchester

 

 

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    I also question the wisdom if “biomass renewables”. Is not that the same as burning wood? Or is it heavily fertilised ethanol and biodiesel that uses only part of the mingy amount of photosynthetic carbon that the plants provide.
    It is true that trees can be harvested renewably. Willow coppice withes have been grown renewably for centuries, I believe. Short Rotation Coppicing obtains wood fuel for power in the same fashion as the early old Wild West railroad locomotives. The recommended rotation period is three years. That’s when you harvest one third of the coppice. It doesn’t need lots of nitrate fertiliser for some reason, but it does need adequate water. The roots are left for the stumps to sprout again next year.

    But to match the output power of one nuclear reactor in Dungeness, you’d have to coppice the entire county of Kent.

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    Renewable Nuclear
    Fission a uranium 233 or 235 nucleus with a neutron. You will get lots of energy and two or three neutrons. Use one of those for the next fission in the chain. Let a thorium 232 nucleus capture a second neutron. It will become almost immediately Pa-233 (protactinium 233) which decays with a half life of 30 days, to uranium 233, which is fissile.
    These reactions will run very nicely with neutrons moderated by graphite at a temperature of about 500°C, at which a fair number of alkali fluoride salts melt. Hexafluorides or tetrafluorides of thorium, protactinium, and uranium dissolve in this very nicely. This was Alvin Weinberg’s solution to the slight weaknesses of the water moderated, ceramic fueled reactors he first designed.
    Note that its working fluid does NOT require vast pressure to stay liquid, and it was easy to provide a fuse that intrinsically operates if the fuel gets too hot. It’s a hole at the bottom, plugged by solvent that a fan keeps below 350°C or 400°C. If the pumps fail, so does that fan. Any other gross excursion of temperature will have the same effect, which melts the plug and dumps the entire fluid out into a basin where the reaction stops and it solidifies.

    You will note that whereas the fissile material is a rare isotope, it is a brilliantly renewable resource.
    The energy density of such materials is such that less than 0.25% of the annual 25 thousand tons of uranium fed to the US civilian nuclear industry, as about 3.6% of the uranium in 25 hundred tons of fuel rods, has been supplying 20% of the USA’s electric power consumption for decades,
    Also note that the industry has been meltdown-free in the USA since 1980, and that a working reactor emits far less radioactivity than a normally working coal burner, although the radioactive content of coal waste is negligible compared with its chemical toxicity.

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    Theis Beckers analyses the materials costs and resource availability for a 100% solar-base (wind, PV concentrator, biomass) “renewables” in “The Non Solutions Project”, but basically biomass was a failure in Britain when they switched from wood to coal ’cause they’d burnt so much of the woods already. Using sunshine in Britain is patently silly, and read the Rime of the Ancient Mariner to get some idea of the dependability of wind.
    The real alternative to fossil carbon is the energy that has kept the Earth’s core molten for billions of years, and we discovered how to use it for civilian power in about the 1960s. One kilo of fissile nuclei contains as much energy as thousands of tons of chemical.
    Note that when 12 tons of carbon burn, they produce 44 tons of CO2. Hydroelectric power in Scotland or Norway has a catchment area of a great stretch of the Atlantic, and Norway gets the North Sea too. Solar power is very dilute.
    Take a look at the troughs of power delivery from wind, for a week or a month or a year, calculate the area in megawatts x days, multiply by 24,and you have MWh of energy that you have to deliver, at an efficiency of about 75%.
    I think that you will find it is far too big for battery storage, and only about an order of magnitude better for pumped hydro.

    I do not think that the Silent Valley in the Mourne Mountains, which is presently the fresh water reservoir for Belfast, would have sufficed to back up the 600 MW wind armada proposal that was to be built just offshore of Annalong and Kilkeel in the Irish Sea.
    Note that these are places of quite outstanding natural beauty.
    In spite of that, the proposal failed.

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    A lot of renewable technologies see exponential growth, not linear, which means they will take off and will do so quickly (http://bigthink.com/think-tank/ray-kurzweil-solar-will-power-the-world-in-16-years). The bigger issue is that if we don’t develop the energy storage and grid management technologies to deal with them, there will be a bottleneck in development. We’ll end up causing more natural gas to come in to take up the slack, because it’s easy to vary the energy output of gas turbines.

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