How to cut electricity costs and help meet renewable goals

Energy efficient technologies could play a pivotal role in New Zealand’s ongoing transition to 100 per cent renewable electricity generation, with the widespread uptake of these technologies having the potential to help meet renewable goals.

Recent Energy Efficiency and Conservation Authority (EECA) modelling has found the most optimal and cost-effective highly renewable electricity system is a “hybrid” scenario, comprising new renewable generation and investment in energy efficient technologies.

The EECA has advised that different mechanisms could encourage uptake of energy efficient technologies, including regulations that phase out inefficient technologies and incentives such as subsidies.

At an individual household level there is already significant incentive to adopt energy efficient options across a range of applications, which can help cut electricity usage and provide ongoing savings.

The role of energy efficiency in meeting renewable goals

The government is targeting 100 per cent renewable electricity (including geothermal) in a normal hydrological year by 2035, with the EECA looking at the role energy efficient technologies, including LED lighting and heat pumps, can play in meeting renewable goals.

The EECA report, Energy Efficiency First: The Electricity Story, looks at the potential for energy efficient measures to contribute to achieving renewable percentages of over 95 per cent in New Zealand’s electricity system.

The report considers a number of different scenarios, with the EECA advising upon its release:

“EECA’s modelling finds widespread uptake of energy efficient technology in factories, businesses and homes would mean a lot less new renewable generation would need to be built to supply New Zealand with very high levels of renewable electricity.”

EECA Chief Executive Andrew Caseley described energy efficient technologies as “a key solution hiding in plain sight”, and it is worth noting that the technologies covered in the report are very much proven and widely available.

LED lighting

Consumers should carefully consider the type of lighting appropriate for their household, and keep in mind that more expensive upfront options may well prove to be cheaper in the long term.

The EECA advises that if all homes and commercial properties used only LEDs there would be a 30-35 per cent reduction in lighting electricity use, while for the average home, installing LEDs can be expected to cost around $200-$400, leading to savings of $100-$300 per year.

As advised via the EECA’s Energywise website, LEDs are the most efficient and longest-lasting lighting option, being good for all general household use.

Energywise advises:

  • Most LED bulbs cost less than $10, while some cost as little as $3.
  • Compared to standard incandescent bulbs, LEDs use up to 85 per cent less energy for the same light output.
  • LEDs should last about 15,000 hours, which is around 15 times longer than a standard incandescent bulb (based on manufacturer claims).
  • When turned on, LEDs provide instant, full brightness.
  • LEDs are available in many different types, and are available as dimmable and non-dimmable bulbs, and bulbs capable of changing light colour or brightness (even without a dimmer switch).

Consumers should consider the range of options available when shopping for LEDs and research particular brands in assessing what kind of performance can be expected.

Energywise additionally advises that:

  • Consumers should ensure the base of the new bulb is the same as the one being replaced (such as a bayonet or screw fitting for a standard bulb).
  • LED packaging usually indicates the equivalent incandescent bulb wattage that produces a similar brightness, with the chances being that an LED will appear brighter than the equivalent incandescent due to the beam angle of LEDs being narrower, with the light coming out more focused.
  • The lumens number is a measure of the light output of a bulb, with the wattage measuring its energy usage (with both appearing on most packaging), which can help consumers determine which bulb uses the least energy for the most light output.

Heat pumps for space heating

The type of heating technology used to keep a home warm is a critical decision for consumers, with the potential for significant increases in power bills over the winter months.

The EECA advises that it is likely to cost $2,500-$4,000 to convert the main living areas of an average home to heat pump space heating, which is likely to lead to consumer savings of $300-$600 per year.

Energywise advises that heat pumps are the most efficient way of using electricity to heat a home, however that some models are much more efficient than others, with the Energy Rating Label indicating how efficient a model is (with red stars for heating efficiency and blue stars for cooling).

Of the different types of heat pumps, Energywise advises:

  • Single-split systems are the most commonly used in New Zealand households, with these systems being air-to-air, comprising an indoor unit connected to an outdoor unit, designed to heat the room they are installed in, rather than the whole house.
  • Multi-split heat pumps heat multiple rooms, comprising an outdoor unit servicing multiple indoor units in different rooms.
  • Ducted heat pumps deliver central heating, blowing heated air through ducts into multiple rooms, with some providing central control and others allowing for heating of selected rooms.

It is certainly worthwhile researching particular brands and models and consulting with heating specialists when looking to purchase a heat pump.

Energywise recommends:

  • Choosing a quality brand sourced from a reputable supplier, offering at least a five-year parts and labour warranty.
  • Make sure a heat pump is correctly sized for the room it is intended to heat and correctly installed, ensuring optimum performance.
  • Make sure it is right for the climate it will operate in (asking a supplier for advice about how it will perform in progressively colder temperatures), and right for the environment (in certain areas, such as geothermal or coastal areas, it will need to have suitable protection against corrosion).

Heat pumps for water heating

When it comes to water heating, energy efficient heating is critical in cutting electricity usage and costs – and, as with space heating, there is the potential for costs to climb over the winter months as households increase hot water usage.

The EECA advises that if all current electrical space heating and water heating was delivered via heat pumps savings of around 40 per cent could be expected for these end uses.

As noted via Energywise, most households will over the course of a year spend more money on heating water than space heating.

Energywise advises that heat pump water heaters employ a similar technology to heat pump space heaters, only using electrical energy to move rather than make the heat, which makes them much more efficient than traditional electric and gas heaters.

As with heat pumps for space heating, it is worthwhile researching particular brands and models and consulting with heating specialists when looking to purchase a heat pump for water heating.

Energywise advises:

  • There are two different types of heat pump water heaters, with split systems having the compressor unit outside and the hot water tank generally inside (although the tank can also be located outside the house separately), and all-in-one units, comprising the compressor and tank together, usually sitting outside.
  • Actual efficiency will depend upon the make of the heat pump system, quality of installation, average temperatures where you live and location of the compressor unit.
  • The warmer the air outside, the more efficiently a heat pump will generally run.
  • Consumers living in colder parts of the country should confirm that a system is designed to operate at low temperatures, asking to see performance results at different temperatures. If a heat pump won’t operate in colder temperatures, and frequently needs to use an electric booster or backup element it can be more expensive to run.
  • Heat pumps used in certain areas, such as geothermal and coastal areas, will need suitable corrosion protection.

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