Giving a little back

Photo: ODT.
Photo: ODT.
Electric vehicles could one day help to reduce "peak demand" for electricity, Scott Wills writes.I recently bought a weedeater to replace the problem-prone and costly last model, which was out for repair yet again.

Weedeaters are typically fragile things, powered by two-stroke engines that are easily damaged by poor attention to the right mix, by old fuel or simply moisture in the tank.

If it’s not the motor, it could be the spark plug, the air filter, the clutch, or some other part of this complex bit of internal combustion engine technology.

However, my new weedeater is electric, powered by a 56-volt, 4-amp hour lithium-ion battery.

Voltage is a measure of electrical power and amp hours refer to duration of work (how long it will work for before recharging), and I had fun finding out what this meant last weekend.

Lack of a clutch, for example, isn’t an issue.

It’s just "on" or "off".

I had been running it for 15 minutes, thinking to myself "OK, but not quite the power" when I discovered "mode 2" (perhaps I should have read the instructions).

I soon understood what power 56 volts could give me.

And when it ran out of juice 30 minutes later, there was no slow down, it just stopped.

Easy at that point to swap out the battery for a fully charged one and carry on.

Battery technology is what is driving, literally, many of the transformations in society at present.

At the household level, it’s not just replacement weedeaters.

For some time now we’ve been using cordless drills, and the batteries have only become better, lasting longer and becoming faster to recharge.

Transport, too, is increasingly becoming seen as part of the household system.

While a car with an internal combustion engine requires a visit to a petrol station for fuelling, an electric vehicle can just juice up at the house or at work.

Done carefully, fuelling an EV can be not only affordable, but particularly advantageous if night rates are used.

The secret to EVs, of course, is battery technology.

And while the battery pack in most EVs is only available for charging at present, it is likely that soon all EVs will have a charging and discharging function.

The implications of this are enormous.

Imagine, for example, several EVs in any one street, with battery storage and the ability to discharge electricity back into the local grid via household bi-directional meters.

The car would then become not only a means of transport, but also a mobile power pack.

We’d have the ability to kick-start the grid after a malfunction, or to get power to key institutions in the event of a crisis or breakdown in electricity supply.

Instead of the main Transpower network of the national grid feeding electricity from the big hydro, wind, geothermal or thermal plants into the local networks, we’d be able to manage local electricity generation from small-scale wind, household solar and micro-hydro much better.

We’d be able to produce electricity close to where it is needed and displace the electricity required from large, distant power stations.

We’d be able to create a resilient electricity "web".

The idea of decentralising our electricity supply through local energy systems has been around for a while now, but it is only relatively recently that we’ve had enough of the components in place for it to become a realistic or achievable goal.

The storage of electricity in batteries, including mobile electricity storage in electric vehicles, will be useful for crisis situations.

But that storage has the potential to solve many of the problems created by "peak demand" as well.

"Peak demand" is a short period that occurs every day from late afternoon to early evening in New Zealand, when everyone switches on a power hungry appliance (the oven usually) and collectively draws a heap of electricity from the grid.

Our whole electricity supply network has to be built and upgraded to cope with peak demand, even though it is only a short period of the day.

If we were able to use our EVs or other battery storage systems to ease the daily peak, by feeding electricity back to meet household need, investment would shift from large-scale fixed infrastructure to data management.

The technical possibilities are with us now and some people are already using battery storage to regulate household demand from the local grid and lower peaks.

Storage can play its part at the community level as well.

Enercon, a leading manufacturer of wind turbines, has been supplying electricity storage solutions along with its turbines in recent wind developments.

Wind power is already a good match for the electricity demand of households, but its value can be greatly increased if the variability of generation can be ironed out.

When locally generated electricity can be fed into the local network with a short time delay (short-term storage), it trims or erases peak load.

The good part about this technology is that it is already in use.

Enercon has developed a connected battery storage system in combination with the Husahagi wind farm as a commercial development in Denmark’s Faroe Islands.

The battery storage provides grid stability and reliability while allowing greater use of renewable energy.

The door is opening to a whole new world of possibilities.

This new world will be quieter and more "local", ideally supplied by green electricity with local generation and local storage.

I’ll recharge my weedeater’s batteries from my solar panels, or from electricity provided by a community wind farm.

My EV (I don’t own one yet) will interact with my household system and feed electricity in when our demand is greatest, thus reducing peak load.

It is an exciting time to be investing in a sustainable future.

- Scott Willis is the project manager of Blueskin Energy Ltd. Each week in this column, one of a panel of writers addresses issues of sustainability.

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