Monday, 23 January 2012

Heating up the CO2 and back up debates

In December 2011, The Clingendael International Energy Programme (CIEP) published a paper that looked at the potential for CO2 emissions reduction as a result of using wind power to displace normal electricity generating plant. In essence, this paper concluded that CO2 emissions resulting from wind generated electricity are far less than they could, or should be.

The paper concludes that this situation has arisen because the non-renewable plant that is displaced by wind power tends to be that which has the highest variable (ie, fluctuating, operating) costs - and this tends not to be coal fired plant which tends to have the highest CO2 emissions - but gas fired plant - which tends to have lower CO2 emissions. Now admittedly, the paper assumes that the driving force behind massive adoption of wind power is CO2 emissions reduction - but that is not the case in Scotland. The main driver here are our policies of 100% of our electricity coming from renewable resources by 2020, although CO2 emissions reduction arguments are often used as a supporting justification for any wind power scheme.

Irrespective of the driver, if what this paper is saying is true - and I'm the first to admit that I do not believe I am qualified to critique its contents or approach, then a lot of people have a lot of explaining to do. The paper can be downloaded here.

However, leaving the CO2 emissions aide, there are some very interesting pieces of information sprinkled throughout this paper that potentially undermine the renewable energy industries attempts to 'debunk' those who oppose wind farms. For example, opponents have long argued that wind power cannot be the cornerstone of a large scale energy policy because of the need for 'back up' capacity if the wind is not available. The renewables industry tends to try and counter this argument by saying that 'all power sources need back up capacity' - which is true - sort of. The back up problem is one of scale. Currently, the National Grid has at its disposal 1,350MW of electricity to cover unexpected, infrequent outages. These are covered by what is called the Infrequent Infeed Loss Limit (which is due to be increased in 2014 to 1,800MW). 1,350MW is still only really about the output of a single, large conventional power station - and that is essentially it. If we loose more than that amount in terms of generational output at an inconvenient moment - the lights will start to go out (as happened in 2008 when Sizewell B and Longannet both went offline within 5 minutes of each other, creating a supply shortfall of 1,510MW). Ouch.

Now according to the CIEP 2010 paper (page 24 refers), we will need to maintain between 70% and 80% of our wind powered output capacity to account for the unavailability of the wind. This presents a couple of problems. The first problem is: how do we calculate 70-80% of output capacity? The output from wind turbines varies with the wind speed, so this 70-80% is not a static figure. Secondly, holding this much capacity in reserve represents a significant increase in generational capacity that has to be installed and maintained - just in case. What will this plant do whilst it is not needed? Stand idle? Additionally, we see some political slight of hand going on here. If we use conventional generational capacity to 'fill in the gaps', how can we say we are generating 100% of our electricity through renewable resources?

Once again, I cannot comment on the validity of the figures presented in this paper, although they stand up to my (unqualified) scrutiny. However, these sorts of issues are demonstrative of the need for a proper systems driven design for our 2020 electricity generation and supply system. We do not currently have this and it is probably now too late to implement such an approach if we really are going to generate 100% of our electricity by 2020. Instead, we have ever moving goal posts driven by political motivations, underpinned by unsustainable subsidies. The minutia of policy implementation is left to commercial organisations to figure out with no attempt at coordination. And by the way, it is not those same commercial organisations that have to match supply and demand - that is the preserve of the National Grid - they're the ones who have to figure out the mess the generators and politicians give them whilst still keeping the lights on.