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L’énergie dans le développement de la Nouvelle-Calédonie

 | 
Yves Le Bars
, 
Elsa Faugère
, 
Philippe Menanteau
, 
et al.

New energy production and storage technology

New energy production and storage technology

Testo integrale

1We must first remember that the issues involved in energy production and storage will vary according to the different needs of the industrial, housing, and transport sectors. Furthermore, there are many energy production solutions available from existing resources. Because of this, we will spend most time examining technologies that use resources that exist or are economically available in New Caledonia. Our proposal is to establish connections between production (and storage) technology, available resources (or those assumed to be available in the absence of full survey data), and needs.

2It should also be borne in mind that energy management, addressed in the first part of the report, takes priority over any development of new production technology because, to meet identical energy needs, it generally costs less to save energy than to develop new production methods. Moreover, as some energy production technologies, such as solar water heaters, also fall into the category of energy-saving technology, there are inevitable overlaps between energy management and new technology.

3Finally, we feel it may be helpful to explain that conversion efficiency is particularly important when using non-renewable, polluting resources, but that it is not as significant when using renewable resources such as the sun, wind, waves, etc. (although this is less true with biomass). For this last example, low conversion efficiency for renewable resources means that an increase in space and size is required; however, given the abundance of these resources, this is rarely a problem. There is an optimum efficiency level for these renewable resource conversion systems where both production and/or environmental costs are minimized over a life cycle.

  • 1 Calculations based on 230,000 inhabitants, 1,400 hours annually at full power and with a peak Watt (...)
  • 2 This bathymetry chart was done after a consultation with Pablo Chavance, fisheries expert of the Z (...)

Energy resources and usable potential
A rough estimate shows that an average solar radiation of approximately 2,000 kWh/m2 per year with relatively low seasonal variability (5 to 8 kWh/m2/day), will produce an annual rate of primary solar energy at ground level of approximately 3 Gtep (across 19,000 km2); i.e. 3,000 times the amount of primary energy consumed in New Caledonia in 2007.
Note that this solar energy can produce electricity, heat, or even fuel, via biomass, for example. Of course, the technology for converting this free resource into a final, usable form of energy is still expensive; however, its cost in the future will only decrease while the price of fossil fuels will only increase.
In France, each inhabitant has approximately 20 m2 of available roof space. If we assume that the same amount of surface area is available in New Caledonia, and each m2 of roof was equipped with photovoltaic cells, it would generate an annual total of 600 GWh of electricity; i.e. a similar amount as the rough estimate of current public electricity consumption. This could be done for an investment of approximately 300 billion CFP francs (2.3 G€)1.
Other available resources include:
Wind, which has an annual productivity of approximately 1,500 to 2,000 hours at full power making it a good resource for producing electricity or pumping water.
Biomass,. which is undoubtedly a valuable resource for producing gas, liquid, or solid fuels used in the transport sector or for generating electricity.
Ocean thermal energy conversion (OTEC), which uses the thermal gradient between the warm solar energy accumulated in the ocean’s surface water and its cold deep water to produce both electricity and cooling. While not a major potential resource for New Caledonia, it can still be useful because surface waters in this area remain above 20 °C all year and a bathymetric measurement shows a deep ocean floor beyond the coral reef2.
Wave power, produced when the wind blows over the surface water. According to a recent study, New Caledonia has favourable conditions in certain sites, such as Lifou and Maré, where measurements have been taken. Wave periods are fairly regular (approximately 8 to 9 s), which is good for floating wave-powered generators (for example, Pelamis and Searev); however, the energy produced by a wave is proportional to the square of its height, and the crest-to-trough heights for New Caledonia remain fairly modest (less than 2 m on average). This would produce approximately the same amount of energy as wind power (less than 2,000 hours annually).
Ocean currents (tidal effects). This resource does not appear to have much potential in New Caledonia. Studies conducted as part of the ZoNéCo program showed that currents are too weak to be realistically used.
Osmotic power. Osmotic power is the energy retrieved when fresh water is combined with salt water. A special membrane can be used to obtain the osmotic pressure generated when fresh water is mixed with salt water from the ocean; this pressure can be used to run a turbine. The conversion methods conceived in the early 1970s remain in a very early stage of development, and we have decided to exclude any further analysis of these technologies from this report.
Geothermal energy. Geothermal energy is produced by heat released from the Earth’s core through its crust. In certain generally volcanic geological areas, the heat that escapes can be very intense and there may be reservoirs of extremely hot water (above 150 °C) that can be used to generate electricity through steam turbines or cooler water (below 100 °C) suitable for low-grade heat use. In New Caledonia, the only information we found was from a 1981 thesis that cited several hot springs (at Crouen, in southern Canala, Nakety and Thio, as well as Prony). Their temperatures were between approximately 30 and 43 °C and may reveal deeper resources.
Although the latest resources found could help produce heat, cold, or hydrogen, they are currently being considered for electricity generation.
The 2007 Enerdata report, commissioned by the New Caledonia Department of Mines and Energy (DIMENC) to create a decision-making tool for evaluating energy mix scenarios, provides an assessment of hot water fields and the potential of renewable resources for electricity production.

Figure 5 Estimate of potential electricity production (in MW) from renewable resources by 2015
Source : Enerdata.

Note

1 Calculations based on 230,000 inhabitants, 1,400 hours annually at full power and with a peak Watt price of € 5.

2 This bathymetry chart was done after a consultation with Pablo Chavance, fisheries expert of the ZoNéCo program (http://www.zoneco.nc/) and a meeting in Nouméa with Jérôme Lefevre.

Indice delle illustrazioni

Legenda Figure 5 Estimate of potential electricity production (in MW) from renewable resources by 2015Source : Enerdata.
URL http://books.openedition.org/irdeditions/docannexe/image/1044/img-1.jpg
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