The Grid 2025 Challenge

A dataset representing an entire year of high resolution electricity demand and renewable energy production for Great Britain in 2025.

Examples

Here are some examples of potential applications of the data set.

Contents

  1. Calculation of Deficits and Surpluses
  2. Energy Storage
    1. Ideal case: 100% Efficiency
    2. Realistic case: <100% Efficiency
    3. External Energy Supply
  3. Footnotes

Calculation of Deficits and Surpluses

The supply deficit across the year in the data set

The data set's supply deficit across the year. The supply surplus (represented by positive values) is most pronounced in the summer when solar panel power production is at a peak.

The difference between the demand and supply across the year can be calculated by subtracting the demand values from the wind and solar power production values for each row in the data set. This produces a new set of numbers representing the deficit or surplus of power on the grid. Using the equation deficit(x) = (wind production(x) + solar production(x)) - demand(x), where x is a row in the data set, positive values will indicate a supply surplus and negative values will indicate a supply deficit. The sum of wind production and solar production is refered to as total power production.

To guarantee a stable power grid, where no electrical device connected to the grid receives too little or too much power, electricity demand and total power production need to be in balance at any time. Therefore technologies have to be developed to achieve a balance between these two variables.

Energy Storage

One possible solution to mitigate the supply deficit and supply surplus can be given by using an electricity storage technology. Since power cannot be stored, it is first necessary to convert the units from power to energy. For the following investigation the conversion from Mega Watt to Giga Watt Hour will be used: GWh = MW × 0.25h × 10-3. The key idea is that in times of surplus, the storage could be charged and therefore increase the total demand for electricity on the grid. If the charged amount of the storage is equal to the surplus of the grid, a balance between production and demand will be reached. In times of deficit, the storage can compensate for the lack of available electricity by discharging and maintaining the stability of the grid.

Ideal case: 100% Efficiency

Energy storage size for an efficiency of 100%

The size of the energy storage for an efficiency of 100% across the year 2025. A total of 36816 GWh + 9667 GWh = 46486 GWh needs to be stored to mitigate the fluctuations.

An ideal case is assumed in which the storage technology has an efficiency rate of 100%. To avoid any deficit, the storage needs to have an amount of 36819 GWh stored at the beginning of the year 2025. Therefore on Mar. 30th at 7am, the storage will be discharged. Additionally a maximum amount of 9667 GWh needs to be stored on Oct. 11th at 2pm to avoid any surplus in the grid. Therefore a total storage size of 46486 GWh is needed to compensate all fluctuations across the year 2025.

Realistic case: <100% Efficiency

The finding for the ideal case does not represent a realistic scenario, since there is no device which achieves an efficiency of 100%. Pumped Storage Stations (such as the Cruchanan Station) achieve an roundtrip efficiency up to 80%.[2] Assuming, the efficiency of 80% is taken into account for the process of discharging (in times of a deficit), a larger amount of energy needs to be stored to fulfil the energy deficit of the grid in each moment. The equation input(x) = deficit(x)/0.8 represents the input amount. For the charging process (in times of a surplus) an efficiency of 100% is assumed.
In case of an 80% efficiency there is an energy deficit of 23584 GWh at the end of the year. This is due to the energy losses during the charging process and therefore the annual average of production no longer meets the annual demand. The balance between production and demand is broken.
By increasing the renewable energy production by an amount of 7.22%, the balance can be restored. In this case the storage needs to have an amount of 43453 GWh stored at the beginning of the year to compensate the deficit and an additional 9372 GWh to avoid any surplus in the grid. Because of this a total storage size of 52825 GWh is needed to compensate all fluctuations across the year 2025 with an storage technology of 80% efficiency.

  • Energy losses due to an efficiency rate of 80%

    Total energy loss of 23584 GWh due to a storage technology efficiency rate of 80% across the year 2025. The annual average production does not meet the annual demand anymore.

  • Energy storage size for an efficiency of 80%

    The size of the energy storage for an efficiency of 80% across the year 2025. Renewables energy production increased by 7.22% to compensate the efficiency loss of 23584 GWh. A total of 43453GWh + 9372 GWh = 52825 GWh needs to be stored.

External Energy Supply

Energy storage size for an efficiency of 100%

Nedded external power supply in dependency of the efficiency rate.

Many different storage technologies are available and each of them could be a possible solution to guarantee a balance between power production and electricity demand at any moment. An investigation of the needed external power supply in dependency of the efficiency rate of the storage technology has been performed.

Footnotes

  1. D.J.C. MacKay. Sustainable Energy - Without the Hot Air. UIT, 2009. ISBN: 9780954452933. Also available for free online.
  2. H. Ibrahim, A. Ilinca, J. Perron. Energy storage systems—Characteristics and comparisons Renewable and Sustainable Energy Reviews, Volume 12, Issue 5, June 2008, Pages 1221–1250, ISSN 1364-0321, DOI: 10.1016/j.rser.2007.01.023.