STOR filling the gap

The debate surrounding STOR (Short Term Operating Reserve) is gaining momentum but while the combatants trade blows about the ‘best solution’, STOR is already filling the UK power deficit.

The concept behind STOR is simple: as we decommission old, dirty power stations our main generating capacity falls. The UK needs a backup infrastructure in place to provide power at peak times. STOR is that backup infrastructure. It is, in essence, insurance against disaster just like the fire escapes we add to buildings and the backups we take from our computers.

STOR draws power from two sources: backup generators at sites such as hospitals and municipal centres or custom facilities built specifically for the STOR service.

Criticisms of STOR are based on interpretations that are contentious at best. It is demonised as a backup system for wind farms. By linking the two, STOR critics hope to draw wind farm objectors to their party.

But the need for STOR is prompted by the fall in our main generating capacity not by the unpredictability of renewable energy. Ofgen’s June 2013 report states that our reserve capacity will be just 2% by winter 2015. Some form of backup is critical; contributions from renewable sources are a side-issue.

STOR is also portrayed as a dirty source of power at a time when we’re meant to be reducing carbon emissions. This misses the point. STOR generators do nothing most of the time; when they’re not running they’re not polluting.

STOR addresses many of the other challenges that face us. Power is best generated near to the towns and cities that need it. STOR facilities can be built near – or even in – population centres.

Our need for backup generating capacity is urgent because successive governments have failed so spectacularly in their forward planning. If we take Ofgen’s crisis point of winter 2015 as a deadline, it is beyond unlikely that traditional or renewable stations will get planning approval in that time, let alone start generating power. STOR sites can meet that deadline.

Other arguments are more technical. When the National Grid’s main capacity is fully stretched its backup systems need to be able to rapidly feed power to the grid. STOR sites are typically contracted to provide power within 20 minutes.

The only other way to provide such backup power reliably is to run traditional power stations as a ‘spinning reserve’ i.e. they’re running as normal – with the associated carbon footprint – but only supplying power at peak times. This wasteful system, not STOR, warrants the description “insane”. STOR sites sit idle most of the time, polluting nothing and disturbing no one.

If STOR has a weakness it is in its commercial terms. Its electricity is quoted as being many times more expensive than ‘normal’ power. Critics also object to paying STOR providers for being on standby; they’re paid to do nothing. But this is the essential nature of backup systems.

Whether the costs are accurate or not (and there is plenty of debate about that), critics miss the point again. STOR is necessary. STOR is the most efficient solution to a real and imminent problem. If it’s uncomfortably expensive it’s just another example of poor planning followed by poor procurement.

Piers Rendell, Divisional Director (Engine Control), IPU Group.

IPU supply engine control solutions for diesel generator sets to the STOR industry.