Posted: 8 October 2013
Comments (4)
Searching for a solar solution
Searching for a solar solution

National Grid is co-chairing a task force to look at how the increasing supply of solar photovoltaic (PV) power can be managed efficiently to provide a good deal for consumers.

The grid can accommodate up to 10GW of solar PV without changing how it is balanced.

Working alongside the Department of Energy and Climate Change (DECC), distribution network operators and the solar PV industry, National Grid is exploring the technical challenges, opportunities and costs that come with rising levels of solar PV energy, and the impact this is likely to have on ‘balancing the grid’ ie. matching supply and demand in real time.

So far, the team has concluded that the grid can accommodate up to 10GW of solar PV without changing how it is balanced. Findings also revealed that a mix of different solutions could help the grid handle even more solar PV in future as more panels are installed.

One option is designing solar PV installations so they can reduce their output on sunny days when not a lot of electricity is being used across the country. Other solutions include encouraging the use of electricity at times when PV installations are producing more energy, different methods of storing the electricity generated by solar PV, and exporting electricity abroad through interconnectors.

More information:

Click here to read the DECC’s solar roadmap report.
Click here to read National Grid’s latest report on Solar PV.

  • Ian Bottomer

    I don’t agree with reducing the output on sunny days as this would be like asking the wind farms to reduce output on windy days for free. Also when the sun is out in summer Air Con demand is high, in the winter it will be very cold on sunny days (high pressure, clear sky’s). How about having the inverter suppliers having staged reduction when the frequency is high and a tiny battery back that slows the electricity reduction when the sun goes in, so rather than an instantaneous drop off of output it is over 30 seconds. I also have built a device that takes my export PV generation and diverts it into my immersion heater providing me with hot water. You can buy these devices on the general market. These could also be designed in frequency sensitive software so on a falling frequency the demand to the immersion heater could be switched off aiding frequency recovery.

  • Alice Etheridge

    Thank you for your views on this Ian. These are exactly the types of issues that we are considering alongside industry colleagues on the Solar PV Grids Task Force (I’m from National Grid/co-Chair of Solar PV Grid Task Force). If the Government takes the decision that reducing the output on sunny summer days is the most cost effective option, it is anticipated that this would only cut in for very limited amounts of time. We are talking about a handful of days per year, for a few hours – really sunny Sundays when people are still in bed or outside enjoying the sun, businesses are not operating and solar panels are operating at their highest outputs. This would only impose a tiny restriction on output, and would allow many more people to enjoy the benefits of solar power. We’d envisage that this would be the last option to happen, after the market had reduced the output from other generation. The intention would be that the inverter would reduce output gradually as the frequency rose. This would avoid the problems that you identify with an instantaneous reduction.

    Your other options would also work well to reduce the impact on balancing supply and demand on sunny days with low demand and they are being considered by the Task Force. Batteries connected to the PV units have the potential to be very helpful in terms of smoothing their output but this will of course depend on whether PV owners see them as cost effective. As you suggest another approach is to find a demand for the generation locally at times of high output, whether that is to heat water or in future to charge electric vehicles.

  • Thomas Purchase

    I think this is a very interesting debate.
    Could the introduction of Redox flow cells provide the answer to storing excess generation at a much more efficient exchange rate compared to lead acid batteries?
    One of the main advantages of all vanadium flow batteries are their fast response to changing loads. Another advantage is the capacity of the system is determined by the size of the vanadium tanks, meaning large capacities are possible and can be left discharged for long periods of time with no ill effects. It could work on a number of scales: At the transmission level for surges in supply, distribution level or domestic level for homeowners to take advantage of cheap electricity prices when the time is right.

  • Eric Rowley

    I also use a Solar i-Booster to utilize our Solar PV energy to Immersion heater.
    Am now planning to also utilize spare Energy to Filter & Pump Rainwater into storage tanks to use:-
    1 To Replace fresh water in WC.
    2 – In Washing machine.

    To power UV filters for potential use in Hot water system for bath /shower.

    I am convinced that we engineers can find many ways to utilize the electricity generated on-site to use on-site so reducing the ammount we actualy export.

    E.g.Pumping Water is one key area.

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