Monday, 25 December 2017

Technical Problems with High Levels of Wind on Christmas Eve

New Report Describes Total Decarbonisation Dream as Wishful Thinking





On Christmas Eve, wind was providing just over 60% of electricity demand. This is new territory for the Irish grid (or indeed any grid). Eirgrid began trials of allowing a maximum of 65% for wind energy (wind penetration) in November. Wind generation was also exceeding the wind forecast. 

Jolly good I hear you say. However, it can be troublesome balancing this level of wind as other plant are forced to run below their optimum efficiency. The additional unforeseen wind also creates more problems as scheduled plant are constrained off.  Variances in the frequency are a good indicator of just how much trouble these high wind conditions can cause. A stable frequency is required for a stable grid and a certain amount of conventional plant is required to maintain the frequency within a tiny range. 




As the wind level rises, the frequency falls below 50Hz. At around 15:40, some of the wind energy is shut off and the frequency returns again to 50 Hz.


These technical problems have been highlighted in a new report on the German electricity grid (Hidden Consequences of Intermittent Electricity Production).




Another important difficulty caused by intermittency is the increased vulnerability of the electricity grid to instabilities. This is particularly visible in countries that are not so well interconnected like Ireland. An example of a threatening oscillation occurring at a 400MW power generator (24/4/2014 between 21:40:40 and 21:41:00) is shown in Fig. 3 (adapted from M.Zarifakis et al.,  “Models for the transient stability of conventional power generations stations connected to low inertia systems”, Eur. Phys. J. Plus 132, No.6, 289 (2017), op. cit.).

Grid stability is now a major issue around Europe :
Further, if one keeps the current Alternative Current grid technology, a certain minimum amount (~ 20-25%) of “rotating mass” has to be present to guarantee stability.  If this cannot be sufficiently provided using biomass, and if fossil and nuclear based power stations are not allowed, problems will arise. Instabilities caused by large contributions of intermittent power e.g. from wind or solar PV pose a major threat to the stability of the electrical network of a country and to the safe operation of conventional generator systems, as exemplified in Ireland. If no economical solution can be found for such difficulties, conventional backup power based on fossil fuels or nuclear power will necessarily have to remain part of the electricity system.
Their conclusion is in agreement with the work carried out on this blog :

A last point is the economic feasibility of such a system. Germany, with currently an installed capacity of about 90GW in solar PV and wind, has one of the largest renewable systems installed in the world. The cost (including feed-in tariffs, subsidies, extra costs because of court cases due to unfulfilled promises etc…) is estimated between 250 and 300 billion Euros, integrated over the last 10 years. The CO2 reduction on world scale realized by this system is less than 1‰. As discussed above, a 100% iRES without backup or storage systems makes not much economical sense and will lead to a doubling or tripling of the total costs, compared to the conventional system in use now. It is to be expected that not many countries are able to pay for such a costly and inefficient system. The question can thus be raised if the current EU plans for the electricity sector are bound to fail? 

Finally, the electricity sector is only a minor part of the problem. If one wants to completely decarbonise our economy then one should also include other private and economic sectors. Given already the challenge of a 100% renewable electricity system and the complexity of replacing the present primary energy supply based mainly on chemical energy by renewables, this total decarbonisation looks to be wishful thinking, at least at the present stage of technology. Would it not be more useful to invest in research and development of conventional and new energy systems rather than blindly investing in an existing “green” technology which seems bound to miss its goal? The other question is whether decarbonisation should be our primary concern. Is this really the best investment for a better future for mankind, as discussed in B.Lomborg, “Cool It”?A critical assessment of the EU plans is also voiced in countries outside the EU, in particular the United States under the presidency of Obama. Does transforming the present primary electricity supply (based presently mainly on fossil and nuclear sources) into a 100 % intermittent Renewable Energy System, as imposed by the EU, need to be the challenge and moral quest of the 21stcentury? This will for sure affect our society and standard of living if current EU plans are not corrected for the problems that are emerging from the grand renewable experiment in Germany of the recent years.


The full report can be found here : 
http://revue-arguments.com/articles/index.php?id=76

5 comments:

  1. This level of frequency variation is highly irresponsible. As wind penetration closes in on the very occasional 75% grid penetration frequency variation will increase significantly exposing the grid to the risk of total collapse. As wind output will became increasingly erratic. That is the difference between output peaks and valleys in wind production will increase significantly. The ability of Eirgrid to compensate for sudden drops in wind output by increasing synchronous production will become increasingly difficult. One mistake or error will collapse the grid. This can happen by underestimating wind speed that will cause significant output drops as significant wind capacity shuts down. Due to wind speeds exceeding the wind turbines cutout speed, with no back up from synchronous plant because of plant failure due to increasing cycling damaging synchronous plant, or the frequency dropping below the design parameters of the various electronic components used to operate the grid. It is known that Irish wind turbines have in the past supplied wind generated electricity to the grid at 48 Hertz. A bag of candles with a box of matches and an appropriate number of candle holders, stored away, will come in handy. When we experience a night time grid collapse. Which is only a matter of when not if. They are still going to fail to get the annualised 37% wind penetration target anyway.

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  2. "Further, if one keeps the current Alternative Current grid technology, a certain minimum amount (~ 20-25%) of “rotating mass” has to be present to guarantee stability."?

    Batteries 'sold' for storage capability, but in reality having a primary function of near-instantaneous stabilisation capability.

    Check out list of (mainland) 'Service1' & 'Service2' euphemisms beginning p16 here:

    https://www.r-e-a.net/upload/rea_uk_energy_storage_report_november_2015_-_final.pdf

    Also, read between the lines of fawning bullshit here:

    https://www.businessinsider.com.au/elon-musks-tesla-battery-south-australia-responded-in-record-time-2017-12

    https://www.younicos.com/case-studies/schwerin/

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  3. In his study of the surplus from and storage of electricity generated by intermittent sources (Eur. Phys. J. Plus 131: 445 (2016), op. cit.), Friedrich Wagner of the Max-Planck-Institut für Plasmaphysik concludes:
    1. A complete (national) supply requires an installed iRES power which is about four times the peak load.
    2. The electricity sources of the iRES system are characterised by a low integral capacity factor of about 18%.
    3. A wind and PV power based iRES system without storage has to be supplemented by a back-up system of about 89% of peak load.
    4. Demand side management (smart meters) will require integration of weekends into normal economic activities.

    Realisation of the above will have wide-ranging economic and sociological ramifications - zero hour working contracts with short notice work scheduling concurrent with peak surplus generation (think going to work on sunny days and time off when it rains).

    If we are really serious about tackling CO2 emissions, we might be better served by actively debating and managing the inevitable economic and societal changes rather than waiting for the unplanned effects of the rapidly rising energy demands that are a consequence of our consumption driven life styles.

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  4. The abstract of the report referenced in this blog in concluding that 100% renewable system is not feasible with current technologies is a clarion call to everybody to wake up. It points out that:
    - Battery storage is totally insufficient and will need a substantial technological breakthrough.
    - Power-to-gas(methane)-to-power has a low overall efficiency (~15%) due to the various transformations involved and thus wastes essentially most of the carbon-free excess power.
    - Hydropower systems require huge volumes of water with a height difference of a few 100 meters, and options for such storage locations are nearly exhausted throughout Europe.

    Trying to reduce storage using cogeneration of power and heat plants has the drawback that such systems often produce heat when only power is needed or power when only heat is needed. It is clear that there is an urgent need for a critical assessment of the practical feasibility of a 100% renewable power system with due consideration of the required backup/storage system.

    If the outcome of these studies is that the required huge storage systems are unfeasible and that at the same time fossil and nuclear options are rejected, the only solution is to adapt the activity of the society to the availability of electricity and to restrict power availability to part of the population/activities during periods of darkness or absence of wind.

    If badly planned, we risk entering a new era where daily life could depend again on the variability of the weather, as it was centuries ago. Get ready to bring out your winter woollies and candles . . . .

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  5. There is direct correlation between excess production and the capacity of installed iRES power, leading to negative prices and thus to additional costs for the taxpayer as capacity increases. If the REFIT floor price is €70/MWh and the wholesale price dips to -€30/MWh, that is €100/MWh of skin in the game . . .

    https://www.nytimes.com/2017/12/25/business/energy-environment/germany-electricity-negative-prices.html

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