Why we manage load
Like roads, electricity networks have ‘rush hours’ where loading levels peak and capacity is fully utilised.
Orion's rush hours typically occur on cold winter mornings when residential load coincides with the start of the business day, and again on cold evenings when people arrive home from work and turn on their lights, heaters, and cook their evening meal. In our rural network peaks occur during summer months because of the large number of irrigation pumps connected to our network.
To see an overview of our current load levels, take a look at our load management dashboard.
One solution to cope with these relatively short periods of high loading is to expand our network's capacity - much like making roads bigger to handle more traffic. But this is very expensive, especially given that the additional capacity is not needed 98% of the time, and would mean price increases.
We think it makes better sense to promote other cheaper options, such as load management, where we reduce the electrical load on our network during periods of peak demand. We can do this by heating hot water cylinders at off-peak times, and through pricing that encourages off-peak electricity use.
We also operate an Irrigation Interruptibility Scheme where we pay rebates to customers who let us interrupt the supply to their designated irrigators during a capacity emergency to help us keep the power on for the wider community.
We have a ripple signalling system that allows us to send signals through the electricity network to ripple receivers at customers’ premises that switch appliances like hot water cylinders on and off.
We provide a number of different signals to manage load in different ways:
our peak control signals are sent out only when they are needed - when load is peaking. We start switching the appliances back on as soon as load levels start to fall and we aim to keep the duration of control as short as possible to prevent any noticeable effects on customers' hot water supply
our fixed time control signals are sent out every day, turning appliances such as water cylinders and night store heaters on when our loading levels are always low. This fixed time control permanently shifts load away from the daytime periods when peaks occur
our pricing signals provide incentives that reward customers who lower the amount of electricity they consume during our high-priced peak period. We provide ripple signals to tell customers that it's a peak period so that they can reduce their load and reduce their charges – this arrangement is more useful for larger business connections with special half-hour interval metering that records the reduced loading level during the peak period. We operate a separate set of pricing signals for our major customers and many of these customers lower their load, and use backup generation, to lower their electricity charges during our high-priced peak loading periods.
Ripple receivers are usually installed to take advantage of the cheaper pricing plans that are available. For more information about ripple control:
for customers, see our Ripple control option summary
for full technical details on the use of our ripple signals, including a schedule of our current switching times for night load switching, see our Ripple signal guide.
Hot water load management
We use ripple control of water heating to help us keep costs down, and this saving is passed on through lower electricity prices. We certainly don’t want people to run out of hot water, we just want to delay the reheating by a few hours until peak electricity usage passes. We operate the system to a set of service levels and we actively report on our performance on our load mangement dashboard. Because electricity usage varies so much as the weather changes, it is hard to always get this right.
It’s optional for customers to participate, and there are alternative pricing plans that provide more water heating, or uninterrupted water heating, but prices are a little higher.
Our target service level for peak control water heating option is to have water heating turned off for no longer than 4 hours in any 8 hours. This means that the water cylinder needs to be big enough to meet hot water needs for 4 hours, and then the element needs to be big enough to reheat that water in 4 hours. We only manage load on about 50 days each year, and on most of those days it’s only for a brief period, but on the coldest days we do hit the 4 hour service level.
Customers who have a water cylinder that isn’t big enough can still use the discounted pricing plans, but it does mean they will occasionally run out of hot water.
If you are running out of hot water but never have before, then it might be worth getting your system checked. Leaking or venting water systems cool down much more quickly, and this is often the issue, and can lead to high power bills. But if your situation has changed and you need more hot water, talk to your electricity retailer about changing to another option.
Night rate water heating
We use ripple control to turn on night rate water heating overnight, and we don’t make any changes to this during the winter season. The same amount of heating is provided all year.