Reaction to January`s Wind Figures
Another record month for wind but one with a couple of holes in it. The real achievement of wind power in supplying a new record share of our electrical energy needs in January was of course played down by opponents of renewables pointing to intermittency in the output. If you look at the monthly data from the Grid http://www.gridwatch.templar.co.uk/ you do indeed see a couple of days (c. 19th and 21st Jan) that were especially quiet and a couple more that weren’t great. However the striking thing about the graph is actually how steady at between 3 and 5 GW the wind output was for at least 20 of the days in January. If you now look at the data for the other technologies you will see that the slack at the low wind output times was taken up by CCGT or Combined Cycle Gas Turbine generation. This isn’t the inefficient Open Cycle Gas Turbines as is sometimes claimed by those that try to suggest that wind turbines don’t save carbon emissions as these days OCGT are used very rarely and then mostly to deal with the massive spikes in the demand curve or massive fall outs caused by a big failures in centralised coal or nuclear generation or grid problems. Modern CCGT generators are much more flexible than older kit and can deal with pretty much anything the intermittency of wind will throw at them.
So the next issue is whether CCGT necessarily means fossil fuel natural gas. Well no. If we were ever to be lucky enough to get to the point where our wind and other renewables capacity was so high that we had to curtail output because there wasn’t the immediate demand to use the power we could use surplus renewable energy to produce hydrogen and synthetic gaseous fuels. These could be mixed with the normal gas in the gas main to a percentage of in excess of 10% (which I understand would be the maximum percentage for pure hydrogen addition before there were technical issues with burners and other infrastructure). Furthermore stand-alone combinations of wind, solar, hydrogen, syngas and AD/biomass sourced gas feeding to some storage capacity and CCGT dispatchable generation could very conceivably be designed to cope with a much wider range of gas compositions making the use of pure natural gas a thing only of the most urgent crisis in supply.
Currently we are earmarking massive capital investment in Hinkley Point and look set to repeat this several times over in new generation nuclear reactors. If this sort of capital is available it could be being spent on a small number of massive pumped storage facilities on the scale of Dinorwig and a more significant number of small plants such as Glyn Rhonwy http://www.renewableenergyworld.com/rea/news/article/2013/09/the-time-is-right-for-small-pumped-storage-in-the-uk-developer-says . We do not need to wait for yet to be developed battery storage or smart grid solutions (which do seem set to materialise pretty soon nonetheless) to be increasing our ability to tackle intermittency with storage.
Next is the assumption that Renewables means wind. Wind has to be a major player in any current significant renewable portfolio but, by mixing in a number of smaller players we both increase capacity and reduce overall intermittency. Solar, hydro (not pumped storage), wave and tidal are either already available to deploy in larger amounts or are requiring only limited further development to make them economically viable. Such technological diversity reduces the chances of total renewables unavailability to practically zero even without storage solutions and certainly will reduce the periods of very limited supply to such short timescales that our technological fixes can cope with it.
Next is the Question of better grid links to the Continent. Weather systems track across the continent often West to East so if it is calm here one day it is still windy in Germany and will be calm in Germany tomorrow when it will be windy here. Better and more efficient long distance grid connections such as those based on new generation High Voltage Direct Current technology (HVDC) can make the swapping of surplus renewable energy between countries much easier. The best way forward on this is not entirely clear but “technically there is no big obstacle left to prevent the building of a supergrid. So when could it take place? Actually it is probably already happening. Several of the exisitng HVDC schemes could feasibly form part of a future European supergrid.” http://www.powerengineeringint.com/articles/print/volume-21/issue-6/special-focus-hvdc/how-close-are-we-to-realising-a-european-supergrid.html
Finally there is the question of what we have to do to make using fossil fuels OK to plug the gaps. Although fossil fuels are finite and will run out eventually it is clear that the pressing issue is Green House Gas Emissions so the answer is simple ie Carbon Capture and Storage http://www.ccsassociation.org/what-is-ccs/ . This has been talked about for generations now (ie more than 25 years) but development has been painfully slow because there has been no incentive on those making big money from fossil fuels to invest in it. If those people are made to see that they have to compete with renewables not only in terms of immediate financial cost but also on environmental standards I am pretty confident that they can make it work albeit at a cost and perhaps with limits on the rate of usage of fossil fuels to keep pace with the rate at which we can stuff the CO2 underground or elsewhere. This is fine if fossil fuels are part of a varied portfolio of energy sources including large amounts of renewables instead of being the monster supplier they are now.
Finally finally I must stress that although all these solutions to the intermittency problem are to some degree in the future so is the problem itself except in the minds of the renewables opponents. The variation in demand produced by us all wanting to drink tea during the same commercial break in our favourite soap or the fact that it is cold in winter and warm in summer means that the system will have to cope with intermittent demand whatever our generation strategy and even with a new record being set for wind generation for Jan 2015 we can add plenty more renewables capacity before a calm day will put the lights out!