This page describes how we plan for our future electricity needs.
In thinking about our future electricity needs, we see:
- an economy becoming increasingly reliant on electricity, with increasing expectations of a reliable supply
- transmission technology changing, enabling us to utilise our existing assets better
- technology enabling far more interaction with and by consumers
- increasing amounts of remote and intermittent (like wind) generation being built.
The impact of this on the National Grid – our high voltage transmission network – will be:
- our grid will need to endure
- we will need to use new technologies to get the most from our existing assets before we build more
- where we have certainty, and to ensure our grid remains resilient and robust, we will need to expand the grid
- technology will also help integrate the whole electricity supply chain from generator to consumer
- greater deployment of technology in our assets and systems, and greater integration of the industry will change the skills we need from our people.
Establishing a ‘need’
Our major projects often begin many years before their commissioning. The process begins with identifying a ‘need’ – a transmission issue (like lack of transmission capacity to meet future demand) that requires a solution.
In determining the need, we consider the following factors:
- the existing National Grid (such as line, equipment ratings)
- demand (existing and forecast)
- generation (existing and committed)
- the technical planning requirements for operating the grid (known as the Transmission Code)
- any existing Grid Support Contracts (providing non-transmission solutions).
Following identification of a need we identify possible options to resolve the need; these may include:
- replacement lines or equipment
- new lines or equipment
- upgraded lines or equipment (like thermal upgrades)
- Grid Support Contracts (like for demand side management or standby generation)
Analysing options and selecting a solution
We select the preferred solution using a cost/benefit assessment. The assessment focusses on the whole-of-life cost of each investment option to identify the one which maximises net electricity market benefit.
The complexity, cost and criticality of the project helps determine the rigour of the assessment. The Capex Input Methodology defines the ‘Investment Test’ – the detailed assessment required for Major Capex Projects. Our investment approval process requires that we follow the same principle when assessing smaller projects, but the level of detailed analysis may be lower.
The assessment typically covers a 20 year period, but because the economic lives of our assets can be many decades, we also take into account a longer term strategic view, as detailed in our Transmission Tomorrow document.
The Investment Approvals Process document is available below.
Transmission Planning Report
Every two years we publish a Transmission Planning Report – our look ahead over the next 15 years on issues potentially affecting demand and generation on New Zealand’s power system and our solutions planned or possible over that time to resolve them.