Will fracking and the dash for gas cut UK carbon emissions?

When George Osborne announced his grand plan to build as much as 37GW of gas fired power stations, I decided to set up a spreadsheet to try and calculate the overall CO2 emissions that would result from the scheduled closing down of coal, oil and nuclear powers stations and the added emissions of the 37GW gas fired power stations.

I assumed that only Sizewell B would be kept running and spent hours to check which coal and oil fired power stations would be closed (many are to be closed by 2015 because they opt out of the EU Large Combustion Plants Directive).

It's actually quite difficult to calculate yearly/monthly emissions but not so difficult to calculate hourly carbon emission rates on a like for like basis.

The current total nuclear capacity is about 9.2GW with 8GW to be decommissioned, leaving 1.2GW from Sizewell B remaining (ignoring the recent Hinckley Point announcement). The total CO2 emissions from Sizewell B is about 20247 gCO2/hour and the reduction in emissions is about 136136 gCO2/hr.

The total existing oil/coal power plant is about 18.9GW, of that about 8.4GW is to be decommissioned by 2015, leaving 10.5GW, some of which will be biomass conversions. The approximate reductions in CO2 emissions from that change is about 950400 gCO2/hr.

Adding the two reductions together you get approximately 9524247 gCO2/hr reductions in CO2 emissions.

Now if you calculate the emissions from running the Osborne gas plants (37GW).
You get an additional 14245000 gCO2/hr from those new power stations.

So the resulting net change in emissions per hour would be 14245000 - 9524247 = +4720753 gCO2/hr

The CO2 break even point would be (9524247/14245000)x37 = 24.7GW of gas fired power generation.
Progressively reducing that new 24.7GW of gas fired generation capacity to something less would start reducing the carbon emissions.

Notes:

CO2 emissions accounted for by nuclear power stations is mainly in construction and mining of fuel.

Emissions assumptions:
Nuclear energy = 17 gCO2/KWh
Gas = 385 gCO2/KWh
Coal/Oil = 900 gCO2/KWh
Because there are very few oil fired power stations and they are/were rarely operated, I lumped them in with coal emissions to simplify calculations.

So would using more gas cut UK emissions?

It depends on how it was used and clearly the creation of 37GW of power stations that will be under the political guidance of a changing democratically elected government, would mean it would be difficult to guarentee the new gas fired power stations would be used sensibly.

Building 37GW of gas turbine power stations and then running them as a base load would actually increase carbon emissions. Note though, I have not done any calculations regarding the remaining 10.5GW of fossil fueled power stations. We know that half of Drax is/will be converted to biomass.

Basically if something is waiting there to be used, would you just leave it to idle? Especially if political parties are squabling over votes and using energy prices for ideological purposes. The temptation will be to use the full 37GW of new gas plant.

The probability is that the dash for gas in the UK would not reduce CO2 emissions by any significant amount and the anti-science political types would exploit the power station capacity they have to hand.

At least with wind turbines, solar energy, nuclear energy etc. you don't give politicians a tool that can be made to create unsustainable CO2 emissions.