sectoral economic costs and benefits of ghg mitigation - IPCC
sectoral economic costs and benefits of ghg mitigation - IPCC
sectoral economic costs and benefits of ghg mitigation - IPCC
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Renewable Energy<br />
the contrary, cumulative research for photovoltaic increases regularly throughout the period as do<br />
biomass <strong>and</strong> wind research, with lower levels <strong>of</strong> cumulative R&D.<br />
Figure 10 Cumulative PERD, renewable technologies (10 6 $90)<br />
4 500<br />
4 000<br />
3 500<br />
3 000<br />
BIOMASS<br />
SOL PV<br />
SOL POWER<br />
SOL HEAT<br />
WIND<br />
2 500<br />
2 000<br />
1 500<br />
1 000<br />
500<br />
0<br />
1973<br />
1974<br />
1975<br />
1976<br />
1977<br />
1978<br />
1979<br />
1980<br />
1981<br />
1982<br />
1983<br />
1984<br />
1985<br />
1986<br />
1987<br />
1988<br />
Figure 11 “Stock to Flow” ratio for PERD, key technologies<br />
160<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
1974<br />
1975<br />
BREEDER<br />
FUSION<br />
LWR<br />
BIOMASS<br />
SOL PV<br />
SOL THERM<br />
WIND<br />
1976<br />
1977<br />
1978<br />
1979<br />
1980<br />
1981<br />
1982<br />
1983<br />
1984<br />
1985<br />
1986<br />
1987<br />
1988<br />
1989<br />
1990<br />
1991<br />
1992<br />
R&D stock-to-flow ratios <strong>and</strong> the maturity <strong>of</strong> technologies<br />
1989<br />
1990<br />
1991<br />
1992<br />
1993<br />
1994<br />
1995<br />
1993<br />
1994<br />
1995<br />
The ratio <strong>of</strong> past cumulative R&D to current R&D flow can be defined as a “ R&D stock-to-flow<br />
ratio”. It measures the number <strong>of</strong> years that are necessary for a doubling <strong>of</strong> cumulative research,<br />
if the annual budget is supposed constant. The lower this ratio is, the higher the incremental rate<br />
<strong>of</strong> increase in cumulative research, <strong>and</strong> conversely. In some sense this ratio provides an indicator<br />
<strong>of</strong> the speed in the renewal <strong>of</strong> technological knowledge. In the process <strong>of</strong> R&D programs<br />
development, the stock-to-flow ratio is low for a new technology <strong>and</strong> then increases if the annual<br />
spending is not increasing; a mature technology will thus probably show a high R&D stock-t<strong>of</strong>low<br />
ratio, corresponding to a lower rate <strong>of</strong> increase in knowledge.<br />
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