2. Renewable Energy Packages
2.1 Package Selection
The renewable energy options considered in this report were based on the Ministry of Economic Development's view of those technologies with the greatest potential for uptake. The reviewers believe this reflects a sound commercial selection.
The following table lists the selected renewable packages, and emphasises alternative uses of the resources. Several have the ability to supply heat, a major component of the national energy mix.
Table 1: Selected Renewable Packages and their Potential Uses
| Resource | Electricity | Heat | Other Uses |
|---|
| Hydro | Yes | No | Irrigation (non-energy) |
| Geothermal | Yes | Yes | Minerals (non-energy), tourism |
| Wind | Yes | No | Minor recreational transport |
| Biomass (Woody) | Yes | Yes | Potential fuel source for transport, feedstock (non energy) |
| Biomass (Landfill Gas) | Yes | Yes | Potential fuel source for transport, feedstock (non energy) |
| Biomass (Other) | Yes | Yes | Potential fuel source for transport, feedstock (non energy) |
| Solar | Yes2 | Yes | Off grid energy |
The report focus is on the potential major contributors to a renewable energy future. Other renewable options, such as air and ground-source heat pumps will play a part in the future, but much research and development and then public education will be required to bring these into widely accepted commercial application. Future reports will be able to include these technologies as they move through their development phases, but for now they are omitted from this report as being too expensive and of limited extent.
Wave and tidal options have also been omitted from this report. Wave power developments in other countries have met with notable failures in recent years. NIWA has continued to research the potential resources around New Zealand's coastline. Some uptake may occur in future but will have to await renewed investor confidence on the international scene.
For discussion on each of these renewable resources and the associated technologies refer to the Summary Data Sheets of Appendix A. For further details, refer to the Data Reports of Appendix B.
2.2 Technological Status
As a rule, the technologies considered here and used for modelling may be considered as proven or commercial. Biomass gasification should be commercial in the timeframe of this report. Research and development, and prototype development is occurring in a number of areas (e.g. biomass pyrolysis) but these aspects have been omitted from consideration as cost projections inevitably have a high optimism factor.
Hydro and geothermal energy are both proven technologies. Having said that, changes are occurring in the design concepts. In the last 10 years a hybrid steam-binary cycle geothermal development has been proven (with applications in New Zealand), and improved designs for large geothermal condensing turbines have caused a price drop in real terms. While hydro technology is proven, some novel thinking has been demonstrated in Lower Waitaki River proposals for example. Lateral thinking such as this can lead to marked changes in development costs over those projected in this report.
One of the most notable advances in the last 10 years has been the development of wind energy. Capital costs have been dropping as worldwide uptake of this resource has accelerated and the technology has matured. This is now seen as being a significant contributor to New Zealand's energy future during the period under consideration with reliable performance in both technology and financial terms.
2.3 Renewable Energy Quantity Estimates
Resource quantity estimates have been based on recently published data. These cover resources for both heat and electricity. The resource assessments are approximate but represent considered views. The basis for these estimates is outlined in the respective resource reports (Appendix B).
The reviewers have developed a view on the uptake of resources. This has taken into account a wide range of factors including:
- Elimination of resources that will exceed 15c/kWh in terms of electricity supply cost, or $25/GJ for heat supply cost,
- Elimination of bulk generation opportunities that are remote from the grid, or in environments for which consents will not be obtained,
- Inclusion of distributed energy opportunities,
- Practicality of building or installing the options, and
- Previous expressions of interest/commitment (e.g. consent applications) by potential developers.
In the case of biomass, the opportunity for the supply of heat has been recognised to a limited extent, and a split has been indicated between supply for electricity and heat. In practice, heat supply may substitute for electricity generation or vice versa.
An assessment has been made of the current use of each resource. Where necessary, this current use has been subtracted from the total assessed resource to give potential uptake by 2012 or 2025 over and above the current usage. In other words, the energy potential given in this report represents potential uptake over and above the current datum.
Confidence levels have been applied to assessments as discussed above. The intention of these estimates is to outline a range of developments that are realistically fundable, consentable (in a positive policy environment) and buildable in the timeframes set by this report. Wherever possible, blue-sky options have been eliminated to give a focussed commercial view. However, a range of projections is possible and these have been rated from high to low confidence.
In some cases, resources have been calculated on a regional basis. However, the Ministry of Economic Development economic model, to which this report inputs, does not include regional effects so national aggregated totals are given in the following table. (Further detail may be found in the individual resource reports).
The following table summarises the assessed resources complying with these conditions.
Table 2: Potential Resource Available (Primary Energy Basis) at Less Than 15c/kWh (Electricity)/~$25/GJ (Heat)3 (PJ/y)
| Resource | Confidence4 |
|---|
| 2012 | 2025 |
|---|
| High | Medium | Low | High | Medium | Low |
|---|
| Hydro | 21 | 41 | 65 | 21 | 41 | 65 |
| Geothermal5 | 83 | 160 | 710 | 196 | 319 | 710 |
| Wind | 15 | 34 | 49 | 15 | 36 | 51 |
| Biomass (Woody) | 6 | 21 | 73 | 12 | 28 | 91 |
| Biomass (Landfill Gas)6 | 8 | 8 | 8 | 8 | 8 | 8 |
| Biomass (Other) | - | - | - | - | - | - |
| Solar7 | NA | NA | NA | NA | NA | NA |
Table 2 indicates the greatest potential resource for supply of renewable energy is geothermal followed by hydro and wind, then followed by woody biomass. Other technologies will make a contribution, although their overall impact will be minor. This does not diminish the potential of solar and other biomass contributions.
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