If you’ve read the footnotes in our individuals’ sustainabilty stories, you will have seen that we say that the carbon intensity of grid electricity is (or at least was in 2023 data) 0.333g CO2 per kilowatt hour (kWh).

A kWh is what we call on our bills a ‘unit’ of electricity. It’s what costs us €0.30 on average at present. It would be about as much electricity as it would take to boil a litre of tap-water in a kettle 9 times.

So on average each unit of mains electricity you use in Ireland emits a third of a kilogramme of CO2.

This is because, at the moment, our electricity comes from natural gas, coal, and oil powered generators as well as wind and photovoltaics (solar). As we get more renewable energy onto the grid, that 333g CO2/kWh will reduce – especially if it replaces coal. This is indeed what is happening as in 2000 the carbon intensity of electricity in Ireland used to be about 650g CO2/kWh.

In 2030 when there will hopefully be much more solar and offshore wind electrcity installed in Ireland the CO2 emitted in electrcity production here will become much less – there’ll still be some because there will be a need for back up generation for when there’s not enough wind and/or sun.

As for today, is it possible to reduce the carbon intensity of the energy you use in your home?

Yes indeed there is:

Each of these need a bit of teasing out, but for today, we’ll look at the first two points.

Green tarrifs can be very helpful in promoting sustainability. Choosing a green tarrif indicates to utilities the degree of committment you have (and others like you) to sustainable energy. Depending on your provider, there may be a direct benefit from those who pledge to re-invest green tariff profits into increased green generation. Ask your provider if they do this.

Unfortunately there may be problems with how the green tariff is defined by some providers. If they simply try to ‘offset’ the carbon intensity of the back-up fossil fuel generation they need when they don’t have wind and solar capacity, then this is not really sustainable.

Key to achieving true sustainability through choosing a green tariff is to ask your electricity provider by email whether they re-invest in green or offset in credits.

The other action you could take is to make a decision to switch to using your washing machine and dishwasher at night. This is because, in general, in Ireland it’s windier at night and at present, night-time is an off peak time and both these facts benefit renewable energy production.

The early hours of the morning are when demand is low (few businesses operate then and most people are asleep) and wind energy is higher. It tends to be windier as that’s when the difference between sea temperatures and land temperatures is greatest. You can track energy demand and energy generation on this Eirgrid dashboard. This is also when (and indeed why) those with smart meters are charged the least for their electricity, and it’s why we have a night-rate of electricity. Since clothes and dish washing is usually not time-sensitive, and these machines can be programmed to start at 3am, it’s when these should be used.

Also if you have to use the immersion to heat your water, get a timer and have it come on during those hours.

We’ll discuss PV in another post. But it’s worth looking into now.

The Irish Electricity Demand and Renewables Energy Generation Dashboard

Eirgrid’s System Demand & Wind Generation Dashboard