It’s a well reported fact that electricity margins are tighter than they have been for a number of years and there has been growing interest in how we balance energy supply and demand. Chris Kimmett, Commercial Manager at Open Energi, explores some of the key issues.
Almost all of the UK’s grid balancing has traditionally been done by coal and gas. But the EU’s Large Combustion Plant Directive has limited running hours at a number of plants and several coal-fired plants are scheduled to close some or all of their units in 2016. The impact is already apparent, with the UK providing coal-free power for the first time on a number of days in May.
Add to this the solar and wind explosion, which has seen solar providing up to 7GW at one point already this year. By 2020 National Grid’s Future Energy Scenarios indicate that small-scale, distributed generation will represent a third of total capacity in the UK. Tomorrow’s electricity landscape will look very different to that of today.
The transformation of the energy system away from centralised generation to small-scale, distributed power means that speed of response to changes in energy supply and demand will be more important than ever. Indeed, while most people are focusing on the tight capacity margin between supply and demand, the real challenge could come from generators being unable to respond within the required window to balance instantaneous shifts on the grid.
For more than 12 months, energy data analysts at EnAppSys have been monitoring grid frequency and analysing large deviations which, if not managed, can lead to instability. EnAppSys’ director Paul Verrill says that while we need to ensure the system has sufficient supply to meet demand, the real threat could come from this second issue: a lack of capacity able to deliver additional power within the required timeframe.
Agility and flexibility
Grid agility and flexibility will be essential as we move away from models of centrally dispatched generation. This is especially pertinent given the results of new research by Open Energi, National Grid and Cardiff University, which suggests that smart demand side response (DSR) technology can meet the UK’s crucial grid balancing requirements faster than a conventional power station.
The research paper, which formed part of a collaborative research programme between Open Energi, National Grid and Cardiff University, titled Power System Frequency Response from the Control of Bitumen Tanks, looks at the feasibility of DSR to provide a significant share of frequency balancing services.
To test the scale of the opportunity for industrial heating loads to provide dynamic frequency response to the power system, bitumen tanks (which contain the glue that binds our roads together) equipped with Open Energi’s Dynamic Demand technology were tested in combination with National Grid’s model of Britain’s transmission system.
The research found that Dynamic Demand deployed at scale is able to contribute to the grid frequency control in a manner similar to, and, crucially, faster than that provided by traditional peaking power generation – not to mention more cleanly and cheaply.
Field tests showed that full response could be provided in less than two seconds, as compared to 5 – 10 seconds for a thermal generator. Large scale deployment of Dynamic Demand will reduce the reliance on frequency-sensitive generators and ensure that the grid stays balanced in a cost-effective, sustainable and secure manner.
More recently the collaborative research programme has continued to investigate additional load types including melting pots, used in foundries to store molten metal, and water pumps, used for water and sewage processing and for canal water level management. The results of the research, to be published in forthcoming research papers, demonstrate that Dynamic Demand provides fast and reliable frequency response across multiple load types.
The research simulations help to shape National Grid’s understanding of DSR as a replacement for frequency-sensitive generation and will help in planning their requirements for grid network operation in the future – with huge impacts on the future of our energy mix.
When launching Power Responsive, National Grid said: “The move to a low carbon economy coupled with rapid advances in technology and innovation are transforming our electricity supply. But supply is only half the story. The challenge now is to exploit new opportunities to radically evolve our energy system by changing the way we use electricity.”
And this is why the research findings are so significant. With more renewables and decreased thermal generation, ‘inertia’ on the Grid will decrease, making frequency more unstable. To counteract this effect we need faster response of the kind provided by Dynamic Demand.
Demand side response is intelligent energy usage. By knowing when to increase, decrease or shift their electricity consumption, businesses and consumers will save on total energy costs and can reduce their carbon footprints. It is the smart way to create new and efficient patterns of demand that provides much needed capacity without the need to lay a single brick.