How solar owners can make smart electricity decisions

Solar system installations have been on the rise in recent years as more and more New Zealanders seek to tap into the power of the sun. Beyond installation, however, it is important to proactively manage household electricity usage to ensure that you get the most from your system.

Electricity Authority figures released towards the end of last year show that more than 15,000 homes around the country are generating their own electricity, drawing on renewable sources including solar, wind power and small-scale hydro.

Almost 3,300 homeowners had installed solar panels in 2017, up more than 10 per cent year-on-year, and as homeowners increasingly look to residential generation the electricity market is in turn evolving, with retailer offerings becoming more diverse.

Unlike other forms of renewable generation, solar power represents an accessible option for many households, both urban and rural, however whether it is ultimately a financially worthwhile investment will be determined by a variety of factors.

To ensure you get the most from your solar system, it is important to not only undertake appropriate maintenance, and to adopt a considered approach to electricity usage, but to also keep up to speed with both market and technology developments, which may deliver additional value.

No barriers: Simple solar maintenance

Many of the factors that determine whether a solar system will be a beneficial investment over the long term should, of course, be assessed prior to purchase, by talking to experts and utilising tools such as the Energy Efficiency and Conservation Authority’s Energywise solar calculator.

Post-purchase, simple solar maintenance will help to ensure that you continue to gain value from your system over the course of its lifespan.

  • Maintain access – of course, positioning of solar panels is critical in ensuring ongoing value. As advised via Energywise, to make the most of the available sunlight, solar panels should face north as much as possible.

Those living in heavily developed urban areas may need to consider innovative placement of panels to ensure shading from neighbouring buildings is kept to a minimum, while over time it is important to ensure that potential barriers to sunlight do not become a factor. Ongoing maintenance may well be necessary to ensure continued unimpeded access to sunlight, such as regularly pruning trees and ensuring that panels remain out of the zone of falling debris.

  • Basic maintenance – in terms of upkeep of solar panels, Energywise recommends that, while most panels will work for 25 to 30 years or more with little maintenance, panels should be cleaned periodically for best performance, removing dirt and other debris such as leaves, observing that:

“Very little cleaning might be needed in areas with high rainfall and better air quality, but more cleaning may be necessary in areas with poor air quality.”

Meanwhile, Energywise advises that over the lifetime of a solar system, its inverter (which converts direct current [DC] electricity generated by panels into alternating current [AC] for household use) may need to be replaced, recommending that consumers talk to solar experts to determine their best option.

Smart electricity usage

There are a number of steps that households with solar systems can take to make the most of the energy their systems generate.

Of course, solar energy is generated during the day, and it makes sense to concentrate as much electricity usage as possible during daytime hours, which may mean altering previous patterns of usage and developing more suitable routines.

Energywise recommends the following:

  • Using appliances, such as washing machines and dishwashers, during the day.
  • Showering in the morning rather than the evening, which “can bring added gains as solar electricity, rather than purchased electricity, is used to heat the water in your cylinder”.
  • Owners of electric vehicles should look to charge their vehicles during the day.

Of course, households running energy efficient appliances have the potential to further reduce their total electricity usage, potentially allowing for more efficient usage of solar-generated energy and reducing the need to draw on grid power.

It is worthwhile keeping in mind long-term running costs when making an appliance or lighting purchase, weighing up the potential costs against the initial purchase price, particularly in the case of appliances such as refrigerators, heat pumps and air-conditioning units, which have long lifespans.

Energywise offers consumers tools to help determine appliance and lighting running costs, while the Energy Rating Label, which includes a star rating and an annual average energy consumption figure, is displayed on all new whiteware appliances, televisions, computer monitors and heat pumps for sale.

While energy efficiency is dependent upon a number of factors, a greater investment at the point of purchase could lead to savings in the longer term.

Solar-focused retailer offerings

If you’re generating excess solar energy, it is possible to feed electricity back into the grid, and for households with systems, or for those considering installing a system, it is worthwhile taking into account both the buy-back and electricity rates on offer from retailers.

As advised via Energywise: “When considering solar, consider the buy-back rates on offer. You may need to switch from your current retailer to access a buy-back rate. The retailer offering the best buy-back rate may not necessarily charge the lowest for the electricity they sell.”

Meanwhile, new market models are emerging, which utilise residential energy generation and battery storage, with the potential to provide consumers more control over how they consume electricity.

  • Peer-to-peer trading – the growing use of solar panels and the development of battery storage technology has seen peer-to-peer electricity trading become viable.

Via a peer-to-peer platform, households with solar panels could choose when and at what price to sell their excess energy, while households without panels could buy the solar energy generated by other households.

  • Virtual power plants (VPPs) – VPPs have the capacity to integrate diversified small-scale generation, comprising a network of solar and battery systems.

Last year energy generator and retailer Contact Energy advised that it would undertake a VPP trial in Wellington, encompassing installation of solar and battery systems in a number of homes.

“The technology will allow the residents to harness the power of the network of solar generation and batteries and be rewarded for the energy they produce when the electricity grid is under pressure at peak times,” Contact advised of the trial at the time.

Whether pairing battery technology with a solar system is an economically viable option will depend upon individual household circumstances, and it is certainly worthwhile weighing up the long-term benefits of installing a storage system versus the initial costs.

Battery technology continues to be developed, and solar system owners interested in pairing their system with battery storage should keep an eye on developments as the market evolves in the coming years.

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