Sunday, 13 November 2011

The future is err, gas

One of the things about our current government's energy policy that I have harboured a concern about for some time is base load. Eh? Base load is the continual, minimum level of demand for electrical supply. This varies, but in a more predictable manner than peak demand, which can see huge instantaneous demands for power and which is therefore a lot more tricky to predict. Base load supply traditionally comes from specific sources, such as nuclear or coal fired power stations whose output cannot be varied quickly. Gas fired power stations can also be used to help meet base load demand.

OK, so how do we do it in Scotland at the moment? well, we have the following plant at our disposal, all of which could be used to meet base load demand:

  • Hunterston B (820MW - nuclear)
  • Torness (1230MW - nuclear)
  • Peterhead (1540MW - gas)
  • Cockenzie (1152MW - coal)
  • Longannet (2304MW - coal)
source

The combined maximum output from these five plants is 7046MW. Unfortunately, Hunterston B and Cockenzie are both due to close in the next few years, which will only leave a base load capacity of 5074MW. Torness is also currently due to close in 2023.

Longannet, because of its emissions is a big concern (well, it is coal fired). In March 2010, the Scottish Government consented a life extension to this facility; it was to be a flagship Carbon Capture and Store (CCS) project. Unfortunately, whilst the project was deemed possible from an engineering perspective, the UK government funding for the scheme collapsed - so the future of Longannet is, well - rather uncertain.

There is a planning application under consideration by Central Consents for replacing the existing Cockenzie plant with a Combines Gas Cycle plant (nominal output of 1,000MW). There are no plans as fas as I am aware to do anything to replace Hunterston B. Peterhead on the other hand, can actually output 2400MW. However, the local transmission system currently limits its output to just 1540MW. So, where would all these changes leave us? Assuming a way cannot be found to continue operating Longannet, we would have:

  • Torness (1230MW nuclear)
  • Peterhead (1540MW - gas)
  • Cockenzie (1000MW - gas)

and once Torness closes in 2023, we will be down to just 2540MW of traditional base load plant - and totally dependent on gas at just two locations. If Peterhead can be bought up to 100% of its output, we will have 4770MW of base load capacity, but once again, Scotland's dependence on gas will not have changed and its base load will still come from just two sites. How, in any way is this a realistic plan? Well, it's not.

Rather perversely, the Scottish Government has signalled that it is fundamentally opposed to new nuclear power stations, but it is not opposed to extending the life of existing nuclear plant. So, rather than taking a really bold step - perhaps into the world of thorium reactors, it seems that our base load capacity in 10 years time will be met by gas - and very old nuclear reactors. So much for 100% renewables and security of supply. I will do a follow-up post to this one in a few days time so we can see how renewables may, or may not change this rather ridiculous situation.