COP26 has not achieved its objectives. This is very bad news, but it is worth while looking at the situation that prevails in the UK to understand the reasons. The Sixth Carbon Budget UK Path to Net Zero, published by the Climate Change Committee in December 2020, is 448 pages of text, liberally interlarded with glossy charts, tables, and graphs. You can download it here: https://www.theccc.org.uk
There is much in it to absorb. In the previous post, I went to some lengths to convince myself, and others also, I hope, that global warming leading to climate change is real, and that human activity is either wholly, or mainly, to blame. The question now facing us, is what should we, in this country, do?
The CCC document lists the various categories contributing to UK CO2 emissions (based on 2019, i.e. pre-pandemic levels). The four highest are: Surface Transport, 22%; Industry, 20%; Buildings, 17%; and Electricity Generation, 10%. Breaking this down further, 38% of electricity is for domestic use, around 55% of transport is private vehicles, and of buildings, 54% is for domestic heating. Thus around a quarter of CO2 emissions are from each one of us driving our cars, heating our homes, and running our washing machines and dish-washers.
There is a real conundrum over electricity. Over the last thirty years or so we have, quite rightly, virtually phased out coal-fired power generation, an enormous producer of atmospheric CO2 as well as other noxious emissions (although coal continues to be burnt in various industrial processes and is still used as a backstop in electricity generation). The technology that has mostly replaced it is the combined cycle gas turbine generator (CCGT). These high-tech units use a large gas turbine (basically an aviation style turbojet engine), powered by natural gas; the turbine shaft is coupled to the electrical generator, and the hot exhaust gas is used to generate steam to drive a steam turbine, also coupled to an electrical generator. Efficiencies of well over 50% are achieved. CCGT units typically contribute 40% of the National Grid; at various times last year, they satisfied between 50% and 64% of the total load. The problem with that is, that natural gas is a fossil fuel, there are only between 50 and 80 years’ worth left on the planet at current rates of usage (and Russia has the largest share), and burning it emits CO2 and other pollutants. There are other methods in use to generate electricity—eg solar, hydro, biomass, and direct purchases of electricity from our neighbours—but the ‘big three’ are CCGT, wind and nuclear.
If anything, CCGT generation will have to increase in the short term as coal-fired power generation is completely eliminated and demand for electric car charging and heat-pumps (see below) starts to ramp up. More offshore wind turbines are constantly being built and these, together with one or two new nuclear power plants, will eventually reduce the need for CCGT generation, but this is medium to long term; Hinkley Point C is not due to start electricity generation until 2026 at the earliest. Short term, it is difficult to see how gas usage could be reduced, particularly since at times of light winds, CCGT generation has to increase substantially to fill the gap. All of this is in parallel with the recent quadrupling of wholesale gas prices. The announcement that Rolls Royce has received funding for the design stage of ‘mini’ nuclear reactors is no help, since at the very best, if these devices are built, they will not be producing electricity for at least ten years. The problem of electricity generation feeds directly into the question of domestic gas central heating.
Around half of the natural gas used in this country is produced here, with the balance imported. Of this gas, 25% is burned in CCGT installations for electricity generation, and 33% is consumed by domestic central-heating boilers. A recent story in The Guardian reported that twice as much CO2 is emitted from central heating boilers as from gas fired power generation.
All of this places the environmentally conscious person in a real bind. To make a significant difference to his/her CO2 ‘footprint’, the individual needs to use their car less, lower the temperature in their home, and run the washing machine/dishwasher less often (and pay considerably more for gas, electricity, and petrol/diesel). On the question of central heating, grants are being offered to convert from gas to air or ground source heat pumps. The trouble with that is that the grant on offer—£5k—will cover considerably less than 50% of the cost, and heat pumps use lots of electricity—around a kilowatt for every three or four kilowatts of heat.
Translate these uncomfortable home truths into government considerations, add in the cost of ‘greening’ industry, and we can see why there is no great enthusiasm among most governments for agreeing to significant reductions in CO2 emissions.
What should we do? I don’t know; the only practical comment I can make is to observe that for an island surrounded by sea, not to have a massive investment in tidal power is almost bordering on the criminal. Tidal power is purest green and it is completely predictable. Whatever happens, we are going to need a lot more electricity; the greener the better.
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Welcome to the Mirli Books blog written by Peter Maggs