Meeting of the Parliament 11 November 2015
I, too, thank Mike MacKenzie for bringing this important debate to us. I also thank him for the history lesson about Tom Johnston. I have a family connection to that, because my grandfather was one of the civil engineers who did some of the heavy lifting, so to speak, in the work that was done on hydroelectric power stations across Scotland in times past.
We all know that renewable energy is intermittent. It is not just that the wind does not always blow; although tides come and go, there are long slack periods in between. We readily recognise that storage is part of a power system.
I suspect that most MSPs have been to briefings by National Grid, so we know fine well that it is used to the idea of having to buy spare capacity and pay over the odds for it at peak times. National Grid has also bought opportunities to reduce demand, as has been pointed out—Joan McAlpine commented on that.
However, I do not recall National Grid ever talking about storage in any of our briefings. If it did so, storage was very much the Cinderella issue. Storage has obviously been somewhat off National Grid’s radar, too, but it will have to come on to that radar. That is partly for reasons that members have mentioned and which I will not repeat, and partly because of a point that I do not think has been mentioned yet, which is that, although we have all spent our time talking about renewable electricity generation, the biggest part of our energy demand is for heat for domestic and business purposes.
If we are to use renewable energy to meet the heat demand, we will have to generate a great deal more electricity, but we will have to get it to where the heating is required and—this is the crucial bit—make sure that it is available when the heating is required, which might well be in the evenings and overnight rather than during the day, when the electricity might have been generated. Storage is therefore a crucial part of getting the heat balance across Scotland in connection with renewables.
We have always known that standard generating power stations waste heat. We have all seen the enormous cooling towers and wondered why they were there, but the laws of thermodynamics demand that they are there. If those power stations had been built in the middle of our big cities, we would not have needed the cooling towers, because we could have used the waste heat to warm our houses. District heating systems in various places have been known to do that.
That brings me to my next point, which is that we should store energy where it will be useful as heat. Many storage systems generate waste heat and, if we can use that for district heating, that must be far more efficient in overall energy terms.
If we can take energy out of the sky through wind turbines, the cost of that energy will not be terribly great but, given that we have to put enormous amounts of capital into the ground and then into the wires that move the energy around, we want to have efficient systems. That is why it is important that we get our storage in the right place. It needs to be distributed, but that means that compressed air, liquid air and flywheel storage, which are in themselves relatively inefficient, can become more efficient if they are put in the right place. The waste is always heat but, if we can collect that and put it into a district heating system, it ceases to be wasted and becomes useful heat.
That point adds to the complexity of what is already a complex enough problem. I am grateful to Mike MacKenzie for bringing it before us.
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