70 comments on Kyoto, Canadians, Energy and the Environment
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Bunyonhead, thanks for the links - they fill a wee gap in my ken.
As for compressed air in oil and gas pipelines. It sounds a great idea - I don't think I've heard about that before!
So lets assume 100 windmills of 5 MW each, a load capacity factor of 30%, and a further 30% loss of energy compressing air and reconverting that to electricity on-shore (that's a wild guess).
100*5*0.3*0.3 = 45 MW, 24 hours / day = 1080 MW hrs per day
1 MWh = 1.834 bbls of oil (approximatlely)
So that would give a nominal energy production of 1,980 BOE pd.
If I've done my sums right (and there's less than 50% chance of that) I'd say this is too small to fund refurbishment and maintenance of large off shore facilities - but it could be worth looking into further.
The main problem with a lot of offshore infrastrucure is its age - but funding refurbishment may be preferable to decomissioning. I'm pretty sure that deferment of decomissioning lies behind Tallisman's wind farm on the Beatrice Field - and there in lies the TOD Canada link.
I have to wonder how air tight oil pipelines are likely to be. This problem is especially significant if the pipelines are old and have been immersed in salt water for long periods of time.
No idea on the compression and reconversion loss, although intuitively 30% seems high.
I would assume a higher load factor than 30% for far offshore wind. Near-shore wind sites in the UK (North Hoyle, Scrobie Sands, London Array, et al) are assumed to have average load factor of, I think, 38%. Further offshore I think the factor would be higher. I have made a few visits offshore and even on the most pleasant summer day there's still a stiff breeze 300 feet above sea level even just 20 miles out in the North Sea. The same is true of ocean swells for wave generation (bigger and more consistent offshore than nearshore). I'd guess a 30% average load factor is very conservative.
Remember that wind farms are not sited that far out due to the water depth (ditto wave farms where the problem is to anchor them) and the consequent negative economic effects of "planting" them - using an exisiting platform would resolve this.
Each offshore jacket would be unlikely to be able to accomodate more than one or two wind turbines, though the potential for wave farm anchoring is significantly higher in my opinion. I'd be more inclined to go with point absorbers (eg AquaEnergy or Ocean Power Technology) than the Pelamis which needs to face into oncomming waves to "ride" them (difficult to predict wave direction offshore). Out of the two, I'd be inclined to go with the OPT Power Buoy, as it has discrete centralised generation, whereas the Aqua Buoy has a Pelton Turbine within the buoy itself. Obviously an offshore platform can be used to house a central generator which otherwise OPT envisage placing either on the ocean floor or onshore.
Another thought that strikes me is the with lateral mooring to an offshore platform, as opposed to vertical mooring to the seabed, there is further opportunity to generate electricity from lateral movements in the same way as the technology is designed to benefit from vertical movements.
As to air compression within existing pipelines, I agree that there is a question of infrastructure age and the question of leaking. I assume that both oil and gas pipelines are designed to operate at relatively high pressure (presumably considerably higher for gas than for oil) which would be accomodative to the concept. The upside being, clearly, that an air-leak is not going to be at all environmentally damaging.
I came up with the idea of air compression within the pipelines to overcome what I saw as a potential issue of power transmission loss from far offshore platforms. The ability to store power as compressed air and generate at peak times was an additional benefit. However, if the energy loss through compression and reconversion were significantly higher than the simple transmisison loss, it would probably not be worth it.
Your last point is the most significant - decomissioning costs sit as a huge liability on E&P balance sheets. The present value of even simply deferring these costs for 10 years is of significant value to these companies. I am pretty sure that these companies would accept a breakeven on wind/wave projects just for the benefit of the deferred costs, so the question simply becomes one of how much wind/wave you can load on to each platform, and what is the most efficient way of transferrring that energy to shore.
As a side issue, I imagine that companies like http://www.excelerateenergy.com/ will also bein the frame for deferment of decomissiong costs in the future for similar reasons.
That's a great idea, Bunion.
But I've thought of a potential problem : Transmission of gas (whether NG or air) has an energy cost too, because of friction with the pipe.
This needs to be carefully modelled to see if compressed air is viable... The techniques of compression, transport and storage are mature, because they are applied to NG. Whether they remain viable with compressed air, which has a much lower energy content, is the question. Or would you need much greater pressure in order to obtain a viable energy medium? In which case, new types of infrastructure would be required.
I am not at all technically minded and wouldn't even know how to start modelling this.
Why would the energy content of compressed air be lower than the energy content of compressed NG? I would have thought that compressed air would have a higher energy content than compressed NG (at the same pressure) simply by virtue of being a heavier gas.
This site (http://www.doc.ic.ac.uk/~matti/ise2grp/energystorage_report/node7.html#S...) suggests that air is pressurised to about 75 bar. I know that the National Transmission System (onshore) in the UK operates at up to 85 bar, and a rudimentary Google search suggests that offshore NG pipelines operate at higher pressures, so I don't see any direct issues there.
It seems that there is already a company planning to work in this direction in Canada(http://www.energybulletin.net/11252.html) - interesting to note a direct reference to in-pipe storage.
I also know of a company in the UK that plans to install mini-turbines within the onshore system to decompress gas from the high pressure system to allow it to flow into lower pressure networks and indutrial facilities. Frustratingly I cannot remember the name of the company and am having difficulty finding it by Google search. Off the top of my head, they were suggesting something like 2000 MW of generation potential just in the onshore system alone, simply by using turbines to decompress the gas through deceleration, rather than decompressors which consume energy.
If anyone has the technical ability I would be very interested to see if this idea warrants further investigation.
Oil pipelines are usually not pressurized. There is no point because it is a liquid and is pretty well incompressible.
The gas pipelines probsbly date back to the 1980's with an expected life of 30 years ...
I was right - I got some bad news and some good news:
My 30% energy loss should of course lead to a factor of 0.7 (not 0.3)
I've also had some debate with Luis (which is on-going) about converting MWh to BOE
http://zfacts.com/metaPage/lib/zFacts-e-calculator.php
This link says 1MWh = 0.58833 boe, which is in line with what Luis says - different to the figure I used above which came from Heading Out.
I'm also happy to incorporate a higher laod factor of 0.35
So the new sum goes like this:
100 turbines * 5 MW * 0.35 load factor * 0.7 conversion efficiency * 24 hours * 0.58833 boe = 1729 BOE pd
It still seems a big number to me, and despite a myriad of potential difficulties (leaking pipes etc) is IMO worth exploring a bit further. Compressed air always sounded off the wall to me, but it seems to make more sense compressing it in a long steel pipe than in a cavern.
WRT to wave power, there was a big splash on the front of yesterday's Press and Journal with the go ahead for a wave farm in Orkney - 3MW - this will be the world's biggest.
That was Pelamis I guess? OPD based in Edinburgh (sort of your neck of the woods, I believe)
Pelamis is one of several companies to receive funding from the Scottish government for innovative ocean power development work described here.
A new 500 MW wind farm in the outer Thames estuary was approved on Monday as part of the second round of proposals for offshore wind power in England. The first round of approvals should produce 1,100 MW and the second round an additional 5,000-7,000 MW. More information here.
I don't see any mention in these two news articles of using abandoned O&G platforms, which does seem like a good idea. I have this recollection that undersea power transmission lines are pretty expensive to install, but no idea how much of a consideration that might be.