UK Power generation 2018-19

Peak electricity demand in the UK occurs between 5-30pm to 6pm each weekday evening. I have been monitoring daily power generation on an hourly basis for several years. During 2018 extra wind capacity has been added to the grid and a new interconnection between Scotland and England has improved deployment. As a result the net average power contribution of wind has increased since last year’s result. Note that my figures also include an estimated increase in metered wind power to include smaller embedded onshore wind farms using the procedure described here.

Figure 1 shows the latest overall result.

Figure 1. Contribution of different fuels to UK daily peak demand

Figure 2 shows the yearly average contributions to daily maximum and minimum demand for different fuels. Note how at night (minimum power) the contribution of both wind and nuclear increase dramatically, although for different reasons. Nuclear is always on producing a fixed output while wind output depends only on weather conditions. The demand balance is always met with dispatchable fuels – gas, imports, coal in winter, or Bio (DRAX – wood burners). Solar output is minimal in winter.

UK electricity generation by fuel for red – peak demand blue – low demand at night.

Wind supplies an average 13% of peak demand and 18% of low demand at night. Our ageing nuclear stations still provide 19% of peak demand and 28% of low demand night-time energy.

We can see how crucial gas generation plays in smoothing out the erratic power generation from wind in the following plot.

Comparison of daily peak power supply from Gas and Wind. Gas is tuned to smooth out the surges and falls in power generation by UK’s fleet of wind turbines.

In 2019 roughly half the electricity supply was from low carbon sources and half from fossil fuels (gas and coal). Further expansion of wind capacity always needs an equivalent amount of gas capacity to offset days with no wind.

About Clive Best

PhD High Energy Physics Worked at CERN, Rutherford Lab, JET, JRC, OSVision
This entry was posted in coal, Energy, nuclear, renewables, wind farms and tagged , . Bookmark the permalink.

14 Responses to UK Power generation 2018-19

  1. Ron Graf says:

    Does anyone know if coal is deemed more desirable than expanding nuclear? It seems to me the steady base that on top of a steady background of nuclear could sit the variable, solar, wind and hydro. Bio could be used as a gap filler. And gas could stand down to being the emergency backup, while coal is eventually dropped. Is that the plan?

    • Clive Best says:

      The UK ‘planned’ to build at least 3 large new nuclear stations. One is in construction (Hinkley C), the others are in limbo for financing reasons. Coal is supposed to be phased out but is still essential in winter to meet demand. Several coal stations lie idle in summer but ramp up ready to meet shortfalls in winter. The answer is a less severe regime for new nuclear, whereby years of planning are fought against continuously by the green lobby. Meanwhile Wind and solar get direct subsidies paid to them from our electricity bills. The original plan was to have at least 33% nuclear. I can’t see renewables ever working without gas backup. Ramping up and down gas stations makes them less efficient and probably shortens their lifetimes. But hey – the carbon emissions figures go down so who cares !

      • Ron Graf says:

        Perhaps the green protest movement could mature to become more proactive and practical force and compromise on nuclear in exchange for wind, bio, solar and storage technology investments. To me that seems like the brightest future prospect. However, currently, at least here in the USA, the green movement is part of the “resist” movement with arms folded except to gain full control.

      • J Martin says:

        Ideally, nuclear should be ramped up to provide all base load in my view.

  2. Ort says:

    “Further expansion of wind capacity always needs an equivalent amount of gas capacity to offset days with no wind”.
    ? Do you have any reference for this claim?

  3. GeoffM says:

    Clive, are you aware that you can get an exact figure for metered wind via this, currently it’s 12051 MW:

    • Clive Best says:

      Yes. I am using the Elexon API to get the values once an hour. However I actually increase the Wind instatntaneous power by about 60% to include all the non-metered wind farms. These are the small ones of 10-20 turbines dotted around the countryside. Likewise Solar is not metered at all. It is simply estimated based on hours of sunshine, angle of the sun by Sheffield University

  4. Dan Pangburn says:

    The fallacy of renewables is revealed with simple arithmetic.

    5 mW wind turbine, avg output 1/3 nameplate, 20 yr life, electricity @ wholesale 3 cents per kwh produces $8.8E6.

    Installed cost @ $1.61E6/mW = $8.05E6.
    Operation & maintenance @ $210,000/yr = $4.2E6
    Total cost = $12.2E6

    Add the cost of energy storage facility and energy availability loss during storage/retrieval, or initial and maintenance cost of standby CCGT for low wind periods.
    Solar voltaic and solar thermal are even worse with special concern for disposal and/or recycling at end-of-life (about 15 yr for PV).

    The dollar relation is a proxy for energy relation. Bottom line, the energy consumed to design, manufacture, install, maintain and administer renewables exceeds the energy they produce in their lifetime.

    Without the energy provided by other sources renewables could not exist.

    Combined cycle gas turbine $614/kw ($0.6E6/mW) installed cost.

    • Marcus Pun says:

      Solar PV has a much longer EOL. Panels are warrantied for 80% of power at 25 years. Panels made today can achieve degradation rates as low as 0.3. For the latitude of Great Britain it is quite likely the degradation rate is much slower so having panels last 50 years and having more than 80% operational capacity is not a problem when properly maintained. Even so, a set of panels at let’s say 60%-80% is still effective. The EROI of solar panels is now about 4 years or less with multicrystaline cells. In the last 40 years, the price of a solar panel per watt has plummeted from $101.05 to $0.61, a 99.4% reduction in price. It is expected to fall at least another 25%. This is why Australia and other coutries are starting to realize that solar plus battery or wind plus battery are cheaper than coal and even gas. Cost of storage is also plummeting. Also the initial installation of storage in a grid generates huge savings. The Tesla 100MW / 129MWh storage facility in Australia saved $40 million in cost savings for the utility by replacing gas and other sources for grid stability management. That was 2/3 the cost of the initial installation which took only 3 months. It is why PG&E in California is going to close a few gas plants while having over 1GWh of storage installed within 18 months.

  5. Ben says:

    Hi Clive, not sure if you have seen this Australian electricity market operator report on wind power here. They talk about a similar measurement but express it in percentiles. Enjoy.

    “On average, for 85% of summer peak demand periods, wind generation contributed at least 9.4% of its registered capacity (and for winter, 6.7%). The wind contribution factor is generally higher in summer than in winter.”

    • Clive Best says:

      Presumably 15% of the time wind contributed less than 9.4% of registered capacity and sometimes essentially zero, as in the UK. So something else (coal or gas) must be held in reserve to avoid blackouts.

      These are poor figures as normally one expects load factors >20% for on-shore wind farms. I have visited Adelaide and Port Augusta in summer and winter, and there is often no wind inland.

      • Peter Farley says:

        No it doesn’t because at least in Australia wind is usually lowest during the middle of the day when solar is maximum. There are low wind nights but they are also low demand, so peak fossil fuel output now is about 80% of system peak demand. At times of low wind and solar, fossil fuels still supply 90% of demand but that is 90% of 60% of peak demand.

        If Australia had a 90% renewable grid it will have 5-6 times as much wind and 4 times as much solar as it does now so minimum wind will be at least 35% of demand at night so the balancing generation will need to be about 65% of low demand which is roughly equal to 35% of peak demand. In the eastern Australian case at least half of that can be supplied with hydro.

        In the past most power systems were designed with nameplate generation to be at least 30% over annual peak and around 200% of average demand, this allowed for outages, maintenance, transmission constraints and fuel/water shortages. If one designed a wind and solar system with sufficient overcapacity at expected Capacity Factors to provide 200% of annual requirements the Australian system would have about 70 GW each of wind and solar. That would mean that while a lot of energy was curtailed, minimum wind + solar would be at least 60% of demand. Existing hydro, demand response and storage + despatchable generation = to about 25% of current peak demand would be sufficient to fill the gaps. That would be a yet to be determined combination of existing gas plants fired with bio-fuels and hydrogen, battery and gravity storage and smart charging of EVs

  6. Hello Clive
    Also related to this is of course the question of pumped storage. I realise that UK pumped storage capacity is nowhere near enough to smooth out swings of 10GW, but I recently heard that we don’t even fully utilise the pumped storage capacity we have at the moment. Is that possible ? I was at a public consultation meeting for a new pumped storage scheme on Loch Ness called Red John, and a person there was going to object to it on the grounds that we do not fully utilise the present capacity. He seemed like someone who had done his research. Is there a way to check this with the data you have ?

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