Green, ethical, energy issues in the news

Martyn1981 wrote: »

Hiya Z. I can't tell if you are positive or not about the direction the UK may move in.

Clearly I'm pessimistic, but do you see more promise? I'm concerned at the removal of support for PV and on-shore wind, and the failure to move forward on tidal (particularly the Swansea scheme as a test case almost). But knowing that new off-shore wind is currently supplying about 5% of our leccy, and should increase to 10% by 2020 is promising.

Mart.

Hi

Fully positive, but taking a wider viewpoint and certainly not even contemplating an 'at any cost' career legacy approach for some politician or civil servant.

Depending on which figures you believe, the simple act of cancelling just three 'H' projects (Heathrow, HS2 & Hinckley) would release vast resources which can be reallocated to projects which could achieve a great deal more good in both the environmental and economic fronts ....

We in this country tend to expend little more than time & money in allowing expensive bodies to vastly over-think, over-plan and over-egg the benefits of major projects, but when it comes down to delivering to promise, totally shirk the responsibility to hold departments & contractors to account .... there's absolutely no excuse for it other than poor management processes and incompetence.

Regarding the Swansea scheme, considering the cost and it's relative insignificance, I'd cancel that too and reallocate the funding to a number of strategically placed permanent tidal flow schemes which could ultimately be incorporated into a full-scale Severn-Barrage ... it's a by-product of joined-up-thinking called modular phased development which, by utilising the well proved manufacturing concept of concurrent engineering could actually start delivering renewable energy to the grid before those supporting the current 'Whitehall approach' have even finished sharpening their pencils ..... forget the idea of a tidal £305/MWh(ish) cfd ... if the government can't find a contractor to quickly deliver a decent scale test-bed solution for well below half the latest cost of off-shore wind using existing technologies & engineering practices then they're simply no good at their jobs and should be advised to retrain elsewhere at someone else's expense ...

I see far more promise in positive decisions than allowing continual drift without consequence, so reviewing and/or cancelling anything which doesn't have a directly quantifiable positive economic impact combined with a real ROI would be a good thing in my book. Prioritisation is key, the country can build the fancy 'nice to have' pretty things, vanity projects or more costly alternatives when there's piles of surplus money in HMTreasury and nothing important left on the 'to do' list to spend it on, but until then we should concentrate on what delivers immediate quantifiable cash benefits to UKplc .... if that means Gas, Gatwick & Great Western in the meantime then, unless you're one of the very few people directly linked to the formerly mentioned three H's, what's the issue ??

HTH
Z

Martyn1981 wrote: »

Hiya Z. I'm aware of the £305 figure but it is the bidding limit, here's the list the government produced (page 7):-

Investing in renewable technologies – CfD contract terms and strike prices

But these are not the amounts the technologies will get, they are simply the highest figure that can be submitted for consideration, or part of a bidding process.

As mentioned, Swansea was asking for £168/MWh, and the government has not given approval (yet?) despite it being nearly half the CfD bid max.

You'll see that the figure for PV in 2014 was £120, but the bids came in at £80. As did the on-shore wind bids, though the CfD max was £95.

I'm not trying to be difficult, but it's an important point as I often see people quoting the CfD max to show that PV costs more than HPC, rather than the actual auction results.

On a personal note, I don't understand why the government doesn't release a revised document, as it is 3years old, highly misleading, and most RE has fallen considerably in cost since then.


Here's some recent tidal flow news:

Nova hails 'world first' tidal array

[Edit: The CfD pricing document caused some consternation when it was produced, as the government set a £120 figure for PV, when the STA (Solar Trade Association) had suggested £100. The suspicion was that HMG didn't want PV to appear too cheap following the HPC CfD. M.]

Mart.

Hi

I understand what you're saying .. however, in the absence of actual bids for a large scale strategic tidal stream development in the Severn estuary then whatever figure we debate will be pure guesswork. The fact remains that the £305 figure is current and therefore will be seen as a potential target for any developers to aim for, but that's not the point at hand ...

In simple terms, because water has a higher density than air it has a higher mass which results in a proportionally greater energy potential for any given volume at any given flow rate - moreover, unlike airflow, the three dimensional flow disruption of water is severely hindered in the vertical plane by gravity and mass which suits flow concentration and significantly reduces the spill rate ...

Spill rate now becomes important, with the relative densities of air (1.225kg/m3) and water (1000kg/m3) being so great not only is the energy available within any given swept area over 800 times greater (1000/1.225) but engineering flow concentration also multiplies velocity whilst confining spill (resistance induced flow around the swept area) .... this means that for a given swept area a far greater proportion of energy can be harvested ...

A well engineered flow concentration system should easily quadruple the flow velocity thus multiplying the potential energy harvest for a given swept area by a factor of 64 as well as effectively eliminating spill .... so somewhere between 64x and 100x more energy becomes possible just by building a concrete/stone structure .... but it doesn't end there! ....

Because the flow is concentrated through a swept area the turbine diameter of that swept area can be significantly reduced ... this is pretty useful when looking to reduce build costs .... shallow(er) water systems suddenly become feasible which has significant impacts on material, transport, labour, design, access and ongoing running costs ....

So what's the potential for concentrated tidal flow vs wind ? .... well if we consider 800x more from mass combined somewhere in the range of 64x to 100x from flow concentration ... shall we say that for a given swept area at a given flow velocity, it's possible to extract a conservative 50,000x (800x64) more energy from water .... then there's the load/capacity factor wind at 25% vs tidal at 60% which would raise the ratio to somewhere in the region of 100,000:1 .... that represents a 1.2m diameter concentrated flow turbine delivering the equivalent annual energy of about 4.5 of the largest offshore wind units (8MW nameplate/220m) costing around £25million each, so something for around the size & cost of the Plymouth breakwater with just one 1.2m diameter concentrated flow turbine would deliver more energy for less investment than the best performing wind turbines currently available ....

So, if we can build offshore wind farms which are financially viable at the latest strike prices, why on earth can't we engineer tidal flow or barrage solutions which cost less, deliver more energy and do so with considerably lower subsidy ? .... perhaps we should simply train new generations of engineers to the level attained a couple of hundred years ago ... :D

All theoretical of course and open to significant performance constraints, but it could be engineered to be modular and repeatable & certainly puts the estimated costs and benefits of such schemes to shame! ....

HTH
Z