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Household Energy Independence Through Microgeneration & Microgrids

Solution Overview

Wellington City Council is investigating options for incentivising uptake of technology that will build household energy independence, which could include microgeneration, battery packs, solar roofs, small-scale wind, tidal energy and neighbourhood microgrids.[2][3] This approach can generate economic opportunity, positioning Wellington as a leader in alternative technologies and building on the city's existing reputation as a low-carbon city.[2] A more decentralised energy network that includes multiple small-scale generation sources will perform better in an earthquake or a storm and will have an added benefit of reducing reliance on fossil fuels in Wellington.[2]

Technical Components

Microgrids are self-sufficient and can operate independently or in conjunction with the larger grid.[4] These systems can run on different types of renewable energy sources, including solar, wind and hydro power.[4] In New Zealand, most residential homes would use a solar system between 1.5kW – 4kW.[1] P2P energy systems allow individuals and communities to generate, share and trade energy among themselves, creating a decentralised energy market and allowing for more efficient energy use and distribution.[4] The Government expanded the permitted voltage range for New Zealand's electricity networks from +/- 6% to +/- 10% to help manage the changing flow of electricity sent back to the grid from rooftop solar, as well as growing levels of electric vehicle (EV) charging.[5] Modelling suggests that expanding the voltage range could boost solar investment and overall generation by 507 GWh through increased solar connections.[5]

Implementation Details

Wellington City Council does not require a building consent for most solar panel installations, provided the work is undertaken by a suitably qualified person who provides an Energy Works Certificate for the work.[1] The Government clarified that a building consent is not needed to install rooftop solar panels on existing residential buildings.[5] Councils are required to process building consents for new homes with solar panels within 10 working days, down from the standard 20 working days.[5] A 3kW grid-connected solar power system costs around $8,000 in New Zealand and is popular because it helps reduce electricity costs while remaining relatively affordable.[1] A panel-only no battery 4kWh solar system costs around $10,000.[1] Battery systems for a standard house cost around $10,000 in New Zealand, and these prices are expected to reduce.[1] The Wellington City Council will work with Wellington Electricity and the Commerce Commission to investigate incorporating network resilience in price setting mechanisms as part of making the energy network less vulnerable.[2] Microgrids often require significant amounts of land for the installation of renewable energy sources, such as solar panels or wind turbines, and some communities may resist development due to concerns over land use, visual impact, or potential disruption to wildlife habitats.[4]

Benefits and Impacts

Research from Te Herenga Waka—Victoria University of Wellington shows that microgrids, both grid-connected and off-grid, can be cost effective when optimised and in Aotearoa New Zealand can be on par or even more cost effective than traditional power.[4] Case studies from Aotea Great Barrier Island, Rakiura Stewart Island and the town of Ohakune in New Zealand demonstrate that implementation of microgrids and P2P energy systems has the potential to improve energy resilience and save communities money in their electricity bills.[4] 82 percent of Wellington's electricity comes from renewable sources, chiefly from a windfarm located within the boundary of Wellington City.[2]

Climate Adaptation Relevance

A more decentralised network that includes multiple small-scale generation sources will perform better in an earthquake or a storm.[2] This approach directly addresses Wellington's vulnerability to natural disasters by creating energy systems that can continue operating independently when the main grid is disrupted, enhancing the city's overall resilience to climate-related extreme weather events and seismic activity.

Business Analysis

Research demonstrates that microgrids can be cost effective when optimised and in Aotearoa New Zealand can be on par or even more cost effective than traditional power.[4] The Government has implemented regulatory frameworks to support solar adoption, including clarifying that building consents are not needed for rooftop solar panels on existing residential buildings and requiring councils to process building consents for new homes with solar panels within 10 working days.[5] Wellington's approach can generate economic opportunity, positioning the city as a leader in alternative technologies and building on its existing reputation as a low-carbon city.[2] Battery system prices for standard houses, currently around $10,000, are expected to reduce, improving the financial viability of household energy independence solutions.[1] The Council will work with Wellington Electricity and the Commerce Commission to investigate incorporating network resilience in price setting mechanisms, potentially creating financial incentives for decentralised energy adoption.[2]

Sources