Off Grid Electricity keeps Lights On

Significant amounts of Diesel generation keeping the lights on at times 

 "With regard to demand side units, even at the start of September we saw a significantly tight period. At that point, wind was giving us very low electricity. Demand side units were asked to become active and they did. They can respond and they can make a material difference there " - Energy Regulator, October 2021

Demand side units are off Grid forms of generation that allow large users of electricity to switch off from the grid and generate their own.

According to eirgrid, most of this form of generation is diesel generators :

Industrial generation refers to generation, usually powered by diesel engines, located on industrial or commercial premises, which acts as on-site supply during peak demand and emergency periods [Eirgrid Report]

The energy regulator, in an Oireachtas Committee debate in October stated that these generators made a material difference in September when wind speeds were low.

What this means is that at times a significant proportion of electricity produced in this country is not counted in the official figures. So when you read that gas has produced 57 % and wind 35 %, these figures refer only to the on grid proportion only. We do not have figures for off Grid which is mainly diesel. 

The Rise in Diesel Generation Units

Diesel Generated Demand Side Unit Capacity Will Equal Two Moneypoint Units by 2022

A Demand Side Unit (DSU) consists of one or more individual demand sites that we can dispatch as if it was a generator. An individual demand site is typically a medium to large industrial premises.  In Ireland, 540 MW of DSU capacity cleared the 2019/2020 T-1 Capacity Market auction held in December 2018 and 620MW successfully cleared the 2022/2023 T-4 Capacity Auction held in March 2019.  Industrial generation refers to generation, usually powered by diesel engines, located on industrial or commercial premises, which acts as on-site supply during peak demand and emergency periods [Eirgrid Report]

 It is a remarkable fact that as more intermittent renewables are integrated into the grid, more industrial sites are relying on diesel generators for their electricity requirements. By 2022,  there will be 620MW, equivalent to two of the three Moneypoint coal powered units. There has been a lot of negative commentary written about Moneypoint and the evils of coal power in recent years , but where has been the outrage written about the rise of diesel generation? Because such demand side generation is off the grid, it is not reflected in the official fuel mix reports, so the media and the "experts" are none the wiser. Hence, why I started this blog six years ago.

Only Ten Percent of Wind Capacity can be Relied Upon Over Winter

Eirgrid, the grid operator, have assessed that only 10% of the entire wind generation fleet in Ireland can be relied upon during the high electricity demand winter period. Solar power fares even worse as zero solar capacity can be relied on as the dark cold evenings draw in.

Conventional gas and coal generators are considered to be around 90% reliable as they can be switched on and off when called upon, once sufficient notice has been given. However, wind is unreliable in nature and is therefore given a "capacity credit" to take account of this unreliability :

 Given the variable nature of wind power, the wind capacity credit expresses how much conventional power generation can be avoided or replaced by a certain level of wind power. 

Only 476MW out of a total of 4,617MW or about 10% can be relied upon in the event that a conventional generator fails :

When it comes to keeping the lights on there is no room for the hyperbole and feel good talk that permeates much of the debate around renewables in the media and in the chambers of the Irish parliament.

The spare generating capacity above electricity demand is called the capacity margin. It has halved from 3,199MW in 2016 to 1,793MW in 2018. Two gas powered generators have closed down in 2018 and Moneypoint coal power station has suffered an outage. 

Generators shut down	Output MW
Aghada AD1 (gas fired steam turbine)	258MW
Marina (open cycle gas turbine)	95MW
Moneypoint (coal)	855MW
	1,208MW

In recent days, it was gas power, the UK interconnector and "other" generators (presumably peat and oil) that ensured the lights stayed on in the absence of Moneypoint and the above units. Renewables (mostly wind energy) varied between 7% and 27% so could not be depended on. Back up power stations are still essential in a grid with large amounts of renewables.

You can also see the importance of the interconnector with the UK (EWIC). Can the UK guarantee they will have spare capacity to export electricity to Ireland ? The black line below shows the profile for coal power in the UK in recent days. As you can see, they too were having problems with their coal units.

Scotland too is in a precarious position and will likely be reliant on imports from the UK over the winter period :

At the time of writing the Torness 2 and Hunterston 3 and 4 reactors were down, leaving Scotland with only 612 MW of nuclear capacity and only 3,900 MW of dispatchable capacity to service over 4,000 MW of demand. However, all three reactors are scheduled to restart by mid-December, and any shortfalls that might occur in the meantime could probably be covered by imports from England [Euan Mearns]

If we get a very cold winter, and there are indications that a cold one is coming, the already strained grid could come under a lot of pressure as demand increases. Couple this with more generator outages, and we could be in for some big problems. This is where the demand side of the equation would become crucial - essentially disconnecting large energy users from the grid who would have to rely on their own generation i.e. diesel generators or combined heat and power. 

Essentially, a return to the pre grid times of the early 1900s, when there was a large and inefficient diesel generator in most big towns in Ireland. 

Demand Side Units Now Reach 540MW

by Owen Martin

A total of 544MW of demand side units (DSU) was contracted for in the recent All Island I-SEM capacity auction. Each DSU will qualify for capacity payments of € 41,800 per MW. So that's a total of €22 million that will be paid each year to encourage off grid generation, including "dirty" diesel generation, in my opinion, a consequence of the mad rush for wind energy.  Since wind cannot always be depended on to meet demand, the obvious solution is to reduce demand.

A Demand Side Unit (DSU) is a demand site that can be instructed by EirGrid to reduce electricity demand. Instructions to reduce electricity demand are called dispatch instructions. Where a DSU consists of more than one individual demand site it is called an aggregated DSU. A DSU uses a combination of on-site generation and/or plant shutdown to deliver a demand reduction in response to an instruction from EirGrid [Eirgrid].

However such industrial sites can offer demand reduction services through a combination of load reduction, running standby diesel generators, or running inactive Combined Heat and Power (CHP) plant [Rationale for DSU].  

Many data centres have installed diesel generators, so presumably they can also qualify as a Demand Side Unit, which will greatly reduce the load on the now wind dominated grid. In fact, we may soon see the entire industry of Ireland registering to become Demand Side Units which would greatly reduce electricity demand and thereby make it easier to meet our renewable targets. Although, in reality, it would be a fudge and would make a mockery of our "green" credentials as we would still be as dependent on fossil fuels as ever. 

It is ironic that the mad rush for clean wind involves moving away from very efficient gas generation to inefficient fast acting forms of generation such as diesel. In fact, the capacity auctions saw DSU's take precedence over the very recently built modern and efficient CCGT in Huntstown, Dublin. So we have one policy which seems to prefer higher emitting generation in direct conflict with the other policies that encourage lower emitting generation.  

It was no surprise then that recently it was announced that Ireland's carbon emissions were rising. This is because central planning is about box ticking and meeting targets rather than a sensible all round plan that can adapt and respond logically to feedback.