The Anonymous Widower

Thoughts On Last Week’s Major Power Outage

This article on the BBC is entitled Major Power Failure Affects Homes And Transport.

This is the first two paragraphs.

Nearly a million people have been affected by a major power cut across large areas of England and Wales, affecting homes and transport networks.

National Grid said it was caused by issues with two power generators but the problem was now resolved.

This second article on the BBC is entitled UK power cut: Why it caused so much disruption, and gives these details.

It started with a routine blip – the gas-fired power station at Little Barford in Bedfordshire shut down at 16:58 BST due to a technical issue.

Then, a second power station, the new Hornsea offshore wind farm, also “lost load” – meaning the turbines were still moving, but power was not reaching the grid.

These are my thoughts on the incident.

Power Stations Do Fail

Any complex electro-mechanical system like Little Barford gas-fired power station or Hornsea offshore wind farm can fail.

  • Little Barford gas-fired power station was built in 1994 and is a 746 MW gas-fired power station.
  • Hornsea offshore wind farm obtained planning permission in 2014 and is being built in phases. It will eventually have a maximum capacity of 8 GW or 8,000 MW.

Compare these figures with the iconic coal-fired Battersea power station, which had a maximum output of 503 MW in 1955.

I will not speculate as to what wet wrong except to say that as the Hornsea wind-farm is relatively new, it could be what engineers call an infant mortality problem. Complex systems or even components seem to fail in the first few months of operation.

Why Do We Have Gas-Fired Stations?

According to this page on Wikipedia, there are around forty natural gas fired power stations in England.

Most gas-fired stations are what are known as CCGT (Combined Cycle Gas Turbine), where a Jumbo-sized gas-turbine engine is paired with a steam turbine powered by the heat of the exhaust from the engine.

This form of power generation does produce some carbon dioxide, but to obtain a given amount of electricity, it produces a lot less than using coal or ioil.

By combining the gas turbine with a steam turbine, the power station becomes more efficient and less carbon dioxide is produced.

Power stations of this type have three various advantages.

  • They have a very fast start-up time, so are ideal power stations to respond to sudden increases in electricity demand.
  • As they are a gas-turbine engine with extra gubbins, they are very controllable, just like their cousins on aircraft.
  • They are relatively quick, easy and affordable to build. The Wikipedia entry for a CCGT says this. “The capital costs of combined cycle power is relatively low, at around $1000/kW, making it one of the cheapest types of generation to install.”
  • They don’t need a complicated and expensive transport infrastructure to bring in coal or nuclear fuel.
  • They can also be powered by biogas from agricultural or forestry waste, although I don’t think that is a comm practice in the UK.

The carbon dioxide produced is the only major problem.

Gas-Fired Power Stations In The Future

If you read the Wikipedia entry for combined cycle power plants, there is a lot of information on CCGTs, much of which is on various ways of improving their efficiency.

I believe that one particular method of increasing efficiency could be very applicable in the UK.

Under Boosting Efficiency in the Wikipedia entry, the following is said.

The efficiency of CCGT and GT can be boosted by pre-cooling combustion air. This is practised in hot climates and also has the effect of increasing power output. This is achieved by evaporative cooling of water using a moist matrix placed in front of the turbine, or by using Ice storage air conditioning. The latter has the advantage of greater improvements due to the lower temperatures available. Furthermore, ice storage can be used as a means of load control or load shifting since ice can be made during periods of low power demand and, potentially in the future the anticipated high availability of other resources such as renewables during certain periods.

The UK is the world’s largest generator of power using offshore wind and as we are surrounded with sea and wind, the UK is only going to produce more of the power it needs in this or other way.

This  method could be used to store the wind energy produced when the demand is low and recover it, when it is needed.

Could The UK Develop A Chain Of Carbon-Neutral Gas-Fired Power Stations?

In parts of the UK, there is a unique mix of resources.

  • A plentiful supply of natural gas, either from offshore fields or interconnectors to Norway.
  • Large amounts of electricity generated by offshore wind, which will only get larger.
  • Worked out gas-fields still connected to the shore, through redundant platforms and pipes.
  • Closeness to agricultural areas.

Technologies under development or already working include.

  • Offshore creation of hydrogen using electricity generated by offshore wind and then using the redundant gas pipes to bring the hydrogen to the shore.
  • Using a hydrogen-fired CCGT power station without producing any carbon-dioxide.
  • Feeding carbon dioxide to plants like salad and fruit to make them grow better.
  • Using excess electricity from renewable sources to cool the air and improve the efficiency of CCGT power stations.

I can see all these technologies and development coming together in the next few years and a chain of carbon-neutral gas-fired power stations will be created

  • Hydrogen produced offshore on redundant gas platforms, using electricity from nearby wind farms, will be turned back into electricity, where it is needed by onshore hydrogen-fired power stations.
  • Redundant gas platforms will be refurbished and reused, rather than demolished at great expense.
  • Some natural gas will still be used for power generation
  • I’m not quite sure, but I think there could be dual-furled CCGTs, that could run on either hydrogen or natural gas.
  • Any carbon dioxide generated will be stored in the worked out gas fields or fed to the crops.
  • Gas storage onshore will ensure that the gas-fired power station can respond quickly.

I also believe that there is no technological and engineering challenges, that are too difficult to solve.

This strategy would have the following advantages.

  • It should be carbon-neutral.
  • Because there could have as many as two hundred individual power stations, the system would be very reliable and responsive to the loss of say a cluster of five stations, due to a tsunami, a volcanic eruption or a major eathquake.
  • If power from renewable sources like offshore wind is low, extra stations can be quickly switched in.
  • It is not dependent on fuel from dodgy dictators!
  • It would probably be more affordable than developing nuclear power stations.

There is also the possibility of bringing more hydrogen onshore to be used in the decarbonisation of the gas-grid.

Conclusion

A chain of carbon-neutral gas-fired power stations, linked to hydrogen created offshore by wind farms is very feasible.

Last week, after the double failure, extra stations would have immediately been switched in.

Energy Storage

The fastest response system is energy storage, where a giant battery holds several gigawatt-hours of eklectricity.

Electric Mountain

The biggest energy storage facility in the UK is Dinorwig Power Station.

This is the introduction to its Wikipedia entry.

The Dinorwig Power Station , known locally as Electric Mountain, is a pumped-storage hydroelectric scheme, near Dinorwig, Llanberisin Snowdonia national park in Gwynedd, northern Wales. The scheme can supply a maximum power of 1,728-megawatt (2,317,000 hp) and has a storage capacity of around 9.1-gigawatt-hour (33 TJ)

It is large and has a rapid response, when more electricity is needed.

We probably need another three or four Electric Mountains, but our geography means we have few suitable sites for pumped-storage, especially in areas, where large quantities of electricity are needed.

There are one other pumped-storage system in Wales and two in Scotland, all of which are around 350 MW or a fifth the size of Electric Mountain.

In the Wikipedia entry entitled List Of Power Stations In Scotland, this is said.

SSE have proposed building two new pumped storage schemes in the Great Glen; 600 MW at Balmacaan above Loch Ness, and 600 MW at Coire Glas above Loch Lochy, at £800m. Scotland has a potential for around 500 GWh of pumped storage

I’m sure the Scots will find some way to fill this storage.

If all else fails, there’s always Icelink. This is the description from Wikipedia.

Icelink is a proposed electricity interconnector between Iceland and Great Britain. As of 2017, the project is still at the feasibility stage. According to current plans, IceLink may become operational in 2027.

At 1000–1200 km, the 1000 MW HVDC link would be the longest sub-sea power interconnector in the world.

The project partners are National Grid plc in the UK, and Landsvirkjun, the state-owned generator in Iceland, and Landsnet, the Icelandic Transmission System Operator (TSO)

Plugging it in to Scotland, rather than London, probably saves a bit of money!

Conclusion

Increasing our pumped-storage energy capacity is feasible and would help us to survive major power failures.

Batteries In Buildings

Tesla have a product called a Powerwall, which puts energy storage into a home or other building.

This was the first product of its kind and there will be many imitators.

The Powerwall 2 has a capacity of 13.5 kWh, which is puny compared to the 9.1 GWh or 9,100,000 kWh of Electric Mountain.

But only 674,074 batteries would need to be fitted in the UK to be able to store the same amount of electricity as Electric Mountain.

The big benefit of batteries in buildings is that they shift usage from the Peak times to overnight

So they will reduce domestic demand in the Peak.

Conclusion

Government should give incentives for people to add batteries to their houses and other buildings.

Could Hydrogen Work As Energy Storage?

Suppose you had a hydrogen-fired 500 MW hydrogen-fired CCGT with a hydrogen tank that was large enough to run it at full power for an hour.

That would be a 0.5 GWh storage battery with a discharge rate of 500 MW.

In an hour it would supply 500MWh or 500,000 kWh of electricity at full power.

In Hydrogen Economy on Wikipedia, this is said, about producing hydrogen by electroysis of water.

However, current best processes for water electrolysis have an effective electrical efficiency of 70-80%, so that producing 1 kg of hydrogen (which has a specific energy of 143 MJ/kg or about 40 kWh/kg) requires 50–55 kWh of electricity.

If I take the 40 KWh/Kg figure that means that to provide maximum power for an hour needs 12,500 Kg or 12.5 tonnes of hydrogen.

Under a pressure of 700 bar, hydrogen has a density of 42 Kg/cu. m., so 12.5 tonnes of hydrogen will occupy just under 300 cubic metres.

If I’ve got the figures right that could be a manageable amount of hydrogen.

Remember, I used to work in a hydrogen factory and I had the detailed guided tour. Technology may change in fifty years, but the properties of hydrogen haven’t!

Gas-Fired Versus Coal-Fired Power Stations

Consider.

  • The problem of the carbon dioxide is easier with a gas-fired power station, than a coal-fired power station of the same generating capacity, as it will generate only about forty percent of carbon dioxide.
  • Gas-fired power stations can be started up very quickly, whereas starting a coal-fired power station probably takes all day.
  • Coal is much more difficult to handle than gas.

Using hydrogen is even better than using natural gas, as it’s zero-carbpn.

Conclusion

I believe we can use our unique geographic position and proven technology to increase the resilience of our power networks.

We need both more power stations and energy storage.

 

 

August 12, 2019 - Posted by | World | , , , , , , , ,

5 Comments »

  1. Great blog you have here but I was wondering if you knew of any user discussion forums that cover the same topics
    talked about here? I’d really like to be a part of online community where I can get responses
    from other knowledgeable people that share the same interest.
    If you have any suggestions, please let me know.

    Kudos!

    Comment by automonkey.co | August 13, 2019 | Reply

    • Put your interests in a contact form and I’ll see what I can do!

      Comment by AnonW | August 13, 2019 | Reply

  2. We still have the basic questions as to why what sounds like relatively small outages caused so much disruption especially as its summertime when demand for electricity for lighting and heating is at its lowest point compared to mid winter!

    As for why we have so many gas fired power stations? The answer is political and tied up with the Miners Strikes in the 1970s and a decision by former Prime Minister to adopt a ” dash for gas!” Policy to reduce the power of coal miners even though using gas to produce electricity is a waste of gas as is using electricity to produce hydrogen to run cars!

    It’s worth remembering their is a cable under the English Channel that allows electricity generated in France to be exported to the U.K. so what’s going to happen in a no deal Brexit to this back up supply?

    Comment by Melvyn | August 13, 2019 | Reply

    • I trained as an engineer at Liverpool University in the 1960s. Everybody from that era knew coal had only one use. To be painted white by those on National Service. Coal was finished as a fuel. Some in my circle of friends at Liverpool were the children of miners and they knew the industry was dead, like many of the people who worked in it. Mrs. Thatcher was a scientist from the previous generation to me and her generation taught me at University. Not one of my fellow engineers went into coal, as the future wasn’t there. I remember an article in the Guardian in the 1980s, which advocated retraining miners to do jobs like insulating houses, after the inevitable closure of the mines.

      Unfortunately, no-one had the vision to think about closing the mines in an optimal fashion.

      It was an open goal for Arthur Scargill and he took advantage.

      We should use the electricity created offshore to make hydrogen close to the wind farm. The gas can then be transported to shore using the existing pipes. The Dutch are going this route and it is cheaper to get the energy ashore as hydrogen. It also means the same pipes can be used to bury carbon dioxide in the exhausted offshore gas fields.

      Comment by AnonW | August 13, 2019 | Reply

  3. Only 100MW but ingenious: https://www.quarrybattery.com/

    Comment by Brian Armitage | August 14, 2019 | Reply


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