More Gas Power Stations to be Built

The government have issued a policy statement on security of electricity supply which states :

• the development of new conventional generation (including gas-fired and gasoil/distillate-fired generation) is a national priority and should be permitted and supported in order to ensure security of electricity supply and support the growth of renewable electricity generation

This amounts to an admission that the renewable programme has failed. Imagine if a smoker said I will need to smoke more just to support my attempt at quitting smoking. They would rightly be ridiculed.

 

• it is appropriate that existing conventional electricity generation capacity should be retained until the new conventional electricity generation capacity is developed in order to ensure security of electricity supply

Many years ago on this blog I warned that wind energy would never be capable of replacing a power station. Here we have an admission that Moneypoint coal power station and Tarbert oil power station cannot be replaced by renewables. So what is the point? Henry Ford's model T replaced the horse and cart. The telephone replaced the telegram.

The same government banned gas and oil exploration and of course a coal mine would never be allowed to open again in Ireland. So what will all these fossil fuel power stations run on in the new energy scarce future ? Hot air? Wishful thinking? Empty platitudes? Virtue signalling? Of those, we have plenty. 

Precarious Winter Outlook

According to the Eirgrid Winter Outlook, the Irish electricity system will be operating at twice the level of acceptable risk this winter. The system is expected to enter the Alert State at times of low wind, low interconnector imports and low temperatures. No mention is made of Huntstown or Whitegate power stations. Are they assumed to return as expected? We are not told [update: it appears that Huntstown will be back later this week]. 

There are a number of engineering realities that are laid bare in the report that are a sobering read and at odds with the endless spin that has been published in the past in the media about green energy. 

•  Only 9% of total wind energy capacity is deemed as reliable or can be relied upon. 

•  Forced outage rates (the rate at which power stations are breaking down) have increased by 5 times over the past 5 years. This would appear to indicate that these power stations cannot cope with higher levels of intermittent wind energy.

•  Some CCGT (gas) plant is scheduled to be unavailable for 5-6 weeks of the winter period because of scheduled maintenance. This will be in November and early March. There is no guarantee that wind energy will be available during these weeks and, hence, the highest risk of blackouts will occur during these periods. This proves that wind energy cannot replace, nor is it equivalent to, a power station. 

There is also another factor which does not seem to be included in this report. Wind farms, like power stations, also need maintenance - in particular, the older fleet. Whilst it is unlikely that a significant amount of them would break down at the same time, sourcing replacement parts may take more time than normal in the present supply chain crisis. 

This is the first time that Eirgrid have published a winter outlook that warns of a high risk of blackouts. Last year, they were concerned about a trend of "increasing demand, dispatchable generation exiting the market and increasing generator forced outage rates". 

They were correct, that trend has continued into this year. Did anyone listen or take note ? Of course not. But then Eirgrid's own chief, Mark Foley, dismissed concerns about blackouts, saying  people can sleep soundly in their beds this winter.  

We must trust the plan. 

Lifespan of a Gas Turbine

 According to Siemens a gas turbine is designed to run for 40 years with maintenance every 3 years as this video explains:

https://www.youtube.com/watch?v=bj3a1e901Uk

The gas turbine in Whitegate power station was severely damaged last December when a small piece of metal broke loose and damaged the blades. The turbine was installed in 2010. So it is unusual that the turbine would be so severely damaged after just 10 years. 

Replacing Moneypoint Coal Power Station - Real World Example

By Owen Martin



Moneypoint coal fired power station was built in 1985 and has been operating ever since, making it quite possibly one of the most successful capital projects ever in Ireland. It has three generating units, each with a capacity of 285MW, making it the largest single power station in the country (total output 855MW). All three of the units suffered forced (or unexpected) outages this year. This blog article will look at what happened when the final unit went offline on the 26th September at 11pm. 

Firstly, it is important to point out that Moneypoint is required to be on load (or online) at all times to support the 400kv network from the West to the high demand centre in the East (see graph here).  This means that when Moneypoint is no longer operating, something else must be ready to instantly step in to replace it. 

It is often claimed that renewables can replace Moneypoint. On the 25th September, wind energy was at very high levels at over 2,000MW. But during the 26th, it declined steadily to below 500MW. Prior to the Moneypoint outage, wind began rising again reaching around 700MW at 11pm. So between 70-75% of wind power  had dissipated within twenty four hours. By the 29th, it had fallen to almost zero. Wind energy's intermittency is one of the main reasons why it can never replace a power station. Just when wind energy was needed the most, it was not able to deliver.

There is another more technical reason why wind cannot replace a power station which is explained in more detail here. In short, a certain amount of conventional power stations must be kept running to maintain a stable grid.

We can see in the below graph, that the back up plant that replaced Moneypoint was Tynagh gas powered station (CCGT) in County Galway.

Like any gas powered station, Tynagh can be switched on and off as required i.e dispatchable. An interactive presentation of the gas and steam turbine is available here. Since replacing moneypoint, the plant has itself tripped three times with the latest trip due to "high exhaust temperature". 

Mechanical faults are common to both fossil fuel and renewable plant, the crucial difference is that intermittency only occurs with renewables. The above staggered profile of Tynagh (in red) is very similar to that of another gas plant - Great Island, which you can see in a previous post on this blog. It could be that ramping the generator up and down like this leads to mechanical problems.

A recent report by Dublin City University titled "Is Natural Gas Essential for Ireland's Future Energy Security"  stated :

In contrast, we argue that by far the best way to address both Irish energy security and the pressing need for rapid decarbonisation is to constrain and reduce energy consumption (through efficiency measures and/or absolute reductions in energy services) and to directly exit from the use of all fossil fuels, including natural gas, as quickly as is safely feasible, replacing them by indigenous zero- or (potentially) negative-carbon energy resources to the maximum possible extent.

The recent closure of Moneypoint and it's replacement by Tynagh gas powered station shows that even with large amounts of renewable capacity available (in this case wind), back up gas powered stations are still a necessity for the foreseeable future. 

New Gas Plant Suffers Outage

The Waterford power station will be out of action till the end of the year

Great Island combined cycle gas powered station (CCGT) was commissioned in 2015. The power station is one of the most efficient in the country and replaced the older fuel oil plant on the same site in County Waterford.  On 25th October, it suffered a forced outage, and is expected to be offline till the end of December. Since Moneypoint is also offline at the same time, these are testing times for Eirgrid, the system operator. 

The power station has a capacity of 464MW, which leaves a capacity margin of 1,329MW from now until the week before Christmas when it's expected that two of the coal powered units at Moneypoint will be back online.

This will be the lowest capacity margin in recent years (the capacity margin is the proportion by which the total expected available generation exceeds the maximum expected level of electricity demand, at the time at which that demand occurs).  This blog recently reported that only 10% of our 2,000 or so wind turbines can be relied on over the winter period to deliver reliable power and therefore it will be fossil fuels that will be required to keep the lights on. 

It is difficult to say exactly what may have caused the outage. It can be seen in the graph below that the power station was being cycled a lot in recent times which may have added to the wear and tear on the generator's turbines.