An introduction to supply and demand in the grid
In the UK there’s an infamous phenomenon known as TV Pickup. During the breaks of popular television programs a large number of people will simultaneously boil their kettle to make a cup of tea, producing a huge demand spike which requires the UK’s national grid to rapidly produce a burst of electricity from pumped water storage reserves and fossil fuel plants.
The TV Pickup phenomena illustrates a key requirement of electricity grids: they require precise instantaneous balancing between total supply (electricity production) and demand (electricity consumption) — the amount of electricity we produce has to match the amount of electricity we consume at every second of the day.
In the past this balance has been primarily met by matching the supply to the demand; we produce just as much electricity as we consume. In this way of thinking demand is viewed as the unalterable variable in the demand-supply equation. Power plants generate the correct amount of electricity to satisfy instantaneous demand across the grid. In most circumstances this balancing is met primarily by natural gas turbine generators which are able to vary their generation capability extremely quickly, called ‘peaking plants’ or ‘peakers’.
As we move away from fossil fuels towards renewable energy such as solar and wind the balancing act becomes more difficult; we are moving towards a system of increasingly unpredictable demand and supply while lacking the peaking plants to offset it. We can’t control how hard the wind blows or how intensely the sun shines.
This problem is well illustrated by the graph below, a supply/demand curve known as the ‘duck curve’. It shows the net load on the grid over a day in March in sunny California, illustrating the disconnect between generation and demand as a result of the increase uptake of solar generation.
There are two primary solutions to this problem:
- Build energy storage systems, such as batteries, to store energy when its in surplus and to discharge it when its in deficit.
- To automatically match the electricity demand as closely as possible to the available supply.
GridDuck is so-named because we consider it our mission as a technology startup to help flatten this duck — to make the supply and demand curves match without the need for environmentally damaging peaking plants and to minimise the construction of costly energy storage systems.
To read more about the importance of squashing ducks see this vox article:
https://www.vox.com/2016/2/12/10970858/flattening-duck-curve-renewable-energy
Demand Response
Demand Response is a catch-all term for solutions which shift the balancing problem from the electricity suppliers to the electricity consumers; it gives the operators of electricity grids the capability to change the aggregate demand on their network. The aggregate of all consuming appliances which are capable of partaking in demand response schemes effectively become virtual assets they can control.
For example in the event that the weather results in a loss of generation of solar and wind, the grid could lower the demand on the network by instructing a major consuming appliance such as blast furnace to switch off, or to consume less electricity for a period. In terms of balancing this is exactly the same as turning up a peaking plant, but without the environmental negatives.
This connection between supply and demand is one aspect of what is known as the Smart Grid.
Most customers would not be happy if their lights and computers are routinely told to switch off when they want to be on, so it’s best to consider appliances which can be interrupted for short periods of time without any impact on the end-user. HVAC (Heating, ventilation, and air conditioning) systems are commonly considered excellent appliances for demand response; there will be a negligible impact if the compressor in a fridge or the heating element in a hot water element is switched off for several minutes. The thermal capacity of the system means the fridge will not heat up very quickly and the water in the boiler will not cool down.
The problem is how to connect tens of millions of these appliances across the world to national grids to contribute to the Smart Grid.
For more reading on Demand Response Civil Solar have an excellent article with more detail:
https://www.civicsolar.com/support/installer/articles/introduction-demand-generation-demand-response
How GridDuck enables Demand Response at scale
GridDuck is an Internet of Things (IoT) Energy Management System (EMS). This means our system is designed to connect appliances to the Internet, via IoT technology, and to manage and monitor their energy consumption from anywhere in the world. Specifically, we have designed it to enable customers to reap the benefits of remote monitoring and control, but to also give the ability to share appliances with the Smart Grid for the purposes of Demand Response.
Our system involves distributed data warehousing and a sophisticated collaborative environment enabling the sharing of data, roles and permissions to different organisations. For example the manager of an estate of businesses might initially find value in being able to remotely monitor all their electricity consumption from their head office, and then to be able to implement basic changes such as scheduling of appliances remotely.
Furthermore, integration with upcoming Time-of-Use pricing tariffs introduces support for coarse retail market directed demand response. By encouraging appliances to use more electricity at times when electricity is cheap and less at times when electricity is expensive the customer would save money and across a grid it would enable an automated general energy consumption shift to times of peak solar production.
We also enable direct integration with demand response aggregators (organisations which specifically seek out large assets which are appropriate for demand response), utilities and DNOs (network operators, who need to balance the supply/demand curve within local substation areas).
For the aggregators, utilities and DNOs this opens up a whole world of already-connected appliances which are a cost-effective and environmentally beneficial substitute for investment in interconnection infrastructure, battery storage and peaking generation facilities.
For clients this integration means that on top of being able to monitor and control their own appliances they can reap the benefits of taking additional revenue from the demand response markets which already exist. They are also well positioned to take advantage of future flexibility incentive schemes.
Our Dream
Our dream is an entire planet of appliances intelligently connected to flexibility schemes at every scale: individual buildings, local substation regions and national generation balancing.
Additionally, by connecting electricity consumers with their retailers we can help match their consumption to their retailer’s market position. We can minimise the additional costs that environmentally conscious electricity customers on 100% renewable energy tariffs bear.
If you’re interested in getting involved with the Smart Grid check us out at https://gridduck.com
