Mind the power gap - how to keep the lights on

National Grid Control Centre

In an article published in Facilities Management Magazine, Chris Marsland, Technical Director for ENER-G Combined Power Ltd, explains how to prepare for power outages and the critical role CHP has to play in avoiding the risk of blackouts.

The National Grid's Winter Outlook 2014/15 shows that electricity average cold spell supply margins have dropped to 4.1% - the lowest level in eight years.

In response, the electricity system operator is planning to re-activate three existing power stations and reduce network demand via the new Demand Side Balancing Reserve (DSBR), which incentivises businesses to reduce energy usage or switch to their own generation during periods of peak network demand. This is intended to provide an additional 1.1 GW of capacity to increase the de-rated average cold spell margin to 6.1%.

The DSBR scheme will pay large energy users to voluntarily cut back their demand during specific, high-demand times such as winter weekday evenings between 4pm and 8pm. Large energy users have the option to switch off non-essential equipment, such as lighting, or could switch to off-grid power sources such as Combined Heat and Power (CHP). In practice, this is not much different from the schemes the National Grid has run to switch off wind farms when there is a surplus of power on the grid.

Cordi O'Hara, Director of Market Operation for National Grid, said: "Our analysis shows gas supplies to be in a strong position. Supply sources are diverse, network capacity is healthy and gas storage is well stocked. The electricity margin has decreased compared to recent years, but the outlook remains manageable and well within the reliability standard set by Government.


Be prepared

Despite reassurances, many organisations are adopting contingency planning to avoid power outages - either due to possible electricity shortages during periods of peak demand, or adverse weather conditions.

In order to ensure that your data is not lost and that your core business functions remain intact in the event of a power outage, you should:

  1. Produce an inventory of all electronic equipment that should be protected.
  2. Identify which equipment needs uninterrupted power and how long it needs to be operational.
  3. Determine the power demand of keeping this equipment operational for the desired time.


The case for CHP in improving energy resilience

A CHP unit can be set up to operate in 'island mode' (isolated from the grid) if the mains supply fails, providing a secure power source.

In addition, CHP provides a sizeable number of financial, operational and environmental advantages over traditional solutions. CHP systems can reduce electricity costs by approximately one third while providing firms with carbon legislation compliance, reductions in CO2 emissions and lower SOx emissions.


Your checklist - contingency planning

  • Consider what technology needs to run off-grid in the event of a power outage.
  • Calculate how long it would need to run for and how much power it would require.
  • Consider your options for backup power - there may be a case for CHP installation.


Smart CHP could plug future electricity supply gaps 

As a popular source of on-site generation, CHP is already playing an important role in reducing network demand and is a key plank of National Grid's DSBR, but it could play an even greater role in keeping the lights on. Smart networks of CHP units could provide a solution to the UK's possible winter power capacity constraints.

Rather than taking the backward, and potentially, costly step of bringing old fossil fuel power stations out of 'mothballs', clusters of existing CHP assets could be configured to communicate via a decentralised smart-grid. This could plug potential capacity gaps with the added benefit of decarbonising electricity supplies since CHP is more than twice as efficient as conventional power generation."

Research undertaken by ENER-G in partnership with Advanced Digital Institute; Flexitricity; Smarter Grid Solutions and UK Power Networks has demonstrated the potential of such CHP Virtual Power Plants.

The research consortium has undertaken extensive simulation and modelling, using real data from ENER-G CHP systems and UK Power Networks' London electricity network. This has demonstrated the scale of the opportunity to use complex software and a central control system to tap into existing distributed generation capacity. By linking demand and supply in this way peaks in electrical demand can be relieved.

Active Virtual Power Plants - linking highly energy efficient CHP units via a decentralised smart-grid - can provide the low carbon, cost effective answer to modern energy challenges.


Promoting grid stability due to intermittent renewables

Another threat to continuity of power supplies is the increase of renewable capacity,   which can be an intermittent supply due to the nature of solar and wind sources. Consultation is currently underway on the European Network Code on Requirements for Grid Connection (RfG), which aims to promote grid stability. It seeks to ensure consistent, reliable supply by power generators across Europe, enabling transmission system operators to ensure they are able to access a sufficient amount of energy to balance the differences between supply and demand on their network.

This legislation is intended to ensure the generators provide the necessary stability to prevent power outages. Under RfG, new European Grid Codes will be introduced, which will necessitate modification to generating equipment, including CHP, to accommodate future connection to electrical grids.