What is a Smart Grid?

The traditional Electrical Grids that we have in the UK are arrangements of wires that allow electricity to travel in one direction from the generator to the user. The voltage leaving the generating plant whether it is a power station or turbine array is stepped up to a very high voltage that is somewhere between 275,000 and 400,000 volts. This is necessary to transfer electricity long distances across the country as efficiently as possible but still results in losses of about 8% due to cable resistances.

As the electricity is prepared for use in factories and homes, it goes through a series of step-down transformers to feed firstly into the intermediate 132kV distribution grid and then to 32kV and 11kV for the local HV (High Voltage) grid and then finally down to the 230V LV (Low Voltage) grid we use in our homes.

As the number of electrical devices needing power increases with electric cars, heat pumps and server systems for AI, there will be increasing pressure to pump more electricity down the high voltage grid as it arrives from the increasing number of wind and solar farms. This will require a huge investment in new wiring, transformers, and pylons, and there is already a long waiting list for upgraded and new electrical connections that is preventing the building of new homes and investment in businesses.

This approach, however, ignores the fact that there is a growing amount of electricity generated within local communities with photovoltaic systems on house owners roofs, on factories and warehouses, and small wind turbines in rural areas. We are also seeing increased use of battery storage systems locally that can help provide electricity when the wind isn’t blowing or the sun shining as they can store electricity in times of surplus wind and sun. Electric vehicles themselves have the capability to act as large storage batteries and could be used to power homes at times when demand is high and the grid is struggling to provide sufficient power.

With local generation, the electrical energy needs to travel in both directions on the grid and until now the capacity to do that has been restricted by the District Network Operators that own the local grids and who need to match supply and demand at any one time.

How a Smart Grid Works and why it is relevant to the Meadows.

A Smart Grid brings in intelligent devices to optimise the use of the energy available. It does this to ensure most of the local generation is used locally and as little as possible is spilled back to the major grid. It also can help reduce the draw of electricity from the major grid into the local area so that less resources need to be spent on upgrading major grid wiring and can postpone certain types of consumption that are not time critical until there is spare energy available. In this way it can relieve some of the stresses on the grid to supply at busy times and reduce the requirements to invest heavily to upgrade the grid. It therefore has big advantages not just to consumers but also to the National Grid and DNO’s as well.

A smart grid has three components, the infrastructure system of local generation and distribution assets, a management system that controls the flows and billing for electricity use, and the protection system that ensures that voltage levels and flows are maintained at safe levels. The illustration below shows how this might operate in the Meadows where we have a considerable amount of generation.

The are financial benefits to a local community using a smart grid. It can manage the generation, flow and storage of electricity to obtain higher payments for generators (often referred to as ‘Prosumers’), and lower bills for consumers. Having a community-owned battery in the system would allow for electricity to be purchased from the main grid at night when it is cheap and then used within the smart grid during peak times when it is expensive. It also means that excess energy produced by local photovoltaic systems at times like lunchtime when the sun is hottest and the take up of electricity is not at its peak, can also then be stored for use in peak times.