Storing power could blow away intermittent inefficiency allegations

Storing the electricity generated from renewable sources and releasing it to the grid as and when it is needed could revolutionise renewable sector business models and blow away allegations of intermittency that often dog the wind power sector in particular, a Canadian energy management company has claimed.

At present, most electricity generated by both the renewable and traditional sector is transmitted immediately to the grid, including power generated at off-peak times. As a result, wind power has often been subject to allegations of inefficiency due to the intermittent nature of the wind itself.

If the wind isn’t blowing at peak times, the argument goes, then the wind turbines are not contributing to the power in the grid. However, if wind farms could store all the power they generate at off-peak times, during the night for example, and then control the way and time it is released, it would not only enhance the revenue streams they could receive, but also remove the intermittency claims.

Now, a Canadian energy management firm claims to be able to do just that. EPOD International has secured two pilot projects with wind power developers in Canada and the US to test their proprietary energy storage system, the EMT.

This has been developed specifically to store commercial volumes of electric power for later use or resale. The pilot aims to capture and store up to 100% of the power generated during off-peak periods when prices are at their lowest and resell it to the grid during peak demand. It also allows wind power developers the chance to offer guaranteed volumes of wind power at fixed times, known as ‘firm capacity’.

“This isn’t rocket science,” EPOD’s Managing Director Brett Walker told edie news, “lead-acid batteries have been around for nearly a hundred years. However, they are very inefficient. Its how you put the power in and take it out again that counts.”

For the EMT, this is accomplished in four stages through the use of EPOD’s power management and power conversion technology. The power can be generated either as AC or DC, stored as DC, and then converted back to AC for transmission to the grid with little or no loss of power along the way, Mr Walker said.

“Obviously it is more efficient if it is generated as DC, stored as DC, and then converted to AC but it is fairly immaterial which way, the crucial thing is the control it gives to producers. We’ll no longer have to listen to these lame-duck arguments about renewables.”

EPOD has spent the past three years on R&D for the EMT and its first trials will be switched on and active in January 2006.

The company is now seeking a European partner for trials of its EMT systems particularly in larger wind markets such as Spain and UK.

“We believe we can create a tipping point where wind becomes more reliable than thermal plants as we can steadily control the discharge of power,” Mr Walker said.

In a separate blow to the intermittency debate, the UK was this week found to have the best wind resource in Europe. The report, commissioned by the DTI from the Environmental Change Institute at Oxford University, analysed hourly wind speeds collected by the Met Office at 66 locations across the UK since 1970, and found that the wind always blows strongly enough to generate electricity somewhere in Britain.

It also showed that winds tend to blow more strongly when demand is highest, during the day and winter months.

UK Energy Minister Malcolm Wicks said: “This new research is a nail in the coffin of some of the exaggerated myths peddled by opponents of wind power.”

By David Hopkins

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