- Joined
- 14 February 2005
- Posts
- 15,103
- Reactions
- 16,899
As discussed a few pages ago, here's an example of how a community could cut CO2 emissions by 20% (compared to 2008 levels) by 2020.
I'm focusing only on energy use here and not counting methane from cows etc. That's primarily due to difficulty getting the data etc.
My purpose here is to give an example of what would be required in a physical sense to achieve the target. It is not my intention to propose that these are the best or only means of reducing emissions.
Also I'm assuming:
1. That the reduction must be permanent. That is, emissions don't jump up again in 2021 etc.
2. That "business as usual" means 2% annual growth in overall energy demand and 4% overall economic growth (the difference between the two reflecting improving energy efficiency)
3. That the economically cheapest methods will be the ones used except where they are presently off-limits for some reason (eg dams in the wilderness). In that case, they will be used only if there is no realistic alternative.
4. Any supply side measures (eg wind farms) already built specifically to address the CO2 issue are assumed not to have been built under a "no action" scenario. That is, we've already taken some limited action to cut CO2 and I'm calculating this out of the figures.
So here's the scenario for Tasmania. I'll post some data for some other states later. All figures are approximate.
2008 (assuming average weather and without CO2 reduction measures already taken).
Energy from oil: 37 PJ (736,000 tonnes carbon)
Energy from hydro: 37 PJ (2,000 tonnes carbon)
Energy from coal: 15 PJ* (380,000 tonnes carbon)
Energy from wood: 8 PJ (assumed to be carbon neutral - trees replanted and use of waste wood)
Energy from gas: 5 PJ (72,000 tonnes carbon)
TOTAL: 102 pj (1,190,000 tonnes carbon)
*Includes 4 PJ burnt in other states due to Tas net electrcity imports. Rest is used locally for non-power generation purposes in industry.
2020 "no action" scenario:
Energy from oil: 47 PJ (935,000 tonnes carbon)
Energy from hydro: 37 PJ (2,000 tonnes carbon)
Energy from coal: 32 PJ* (813,000 tonnes carbon)
Energy from wood: 6 PJ (assumed to be carbon neutral)
Energy from gas: 22 PJ** (317,000 tonnes carbon)
TOTAL: 144 PJ (2,067,000 tonnes carbon)
*Includes 21 PJ burnt in other states due to Tas net electricity imports.
**Includes 13 PJ burnt in Tas for electricity generation.
Comment: Total energy use rises from 102 PJ to 144 PJ, an increase of 41%, despite an increase in actual delivered energy of only 27%. This reflects the increasing reliance on fossil fuel power generation verus the present high reliance on (far more energy efficient) hydro-electric generation. That is, the difference is due to energy losses at thermal power stations.
Total carbon emissions from energy rise 74%, again reflecting the increasing reliance on coal and gas-fired power generation to meet all increased demand from a very low (historically zero) base for non-hydro generation.
To achieve a 20% reduction on 2008 levels would require that total emissions not exceed 952,000 tonnes of carbon from energy-related purposes.
As is apparent from the figures above, non-power generation sources in themselves exceed the emissions target in 2020. That thus leaves no option, in practice, other than to reduce non-electricity emissions to some extent whilst reducing electricity generation emissions close to zero (given the greater difficulty of reducing non-electricity emissions)
Replacing all coal use (except at TEMCO where there is no alternative) and some oil use (virtually all heavy vehicles) with natural gas would see the situation alter as follows for non-electricity fuel use::
Energy from oil: 35 PJ (697,000 tonnes carbon)
Energy from coal: 1 PJ (25,000 tonnes carbon)
Energy from gas: 31 PJ (446,000 tonnes carbon)
TOTAL: 1,168,000 tonnes carbon - an 2% reduction on 2008 levels.
It is thus clear that fuel switching between fossil fuels, the "easy" option, can not in itself achieve the emissions targets. There is thus a need for far greater reliance on renewables (in practice electricity).
Switching boiler fuel uses to electricity and retaining the use of gas in heavy transport results in the following outcome:
Energy from oil: 35 PJ (697,000 tonnes carbon)
Energy from coal: 1 PJ (25,000 tonnes carbon)
Energy from gas: 12 PJ (173,000 tonnes carbon)
TOTAL: 895,000 tonnes carbon from non-electricity energy uses, 25% below total energy emissions in 2008 thus leaving modest room for electricity-related emissions.
So technically, it is possible to achieve the 20% emissions reduction target without major disruption. But the only realistic way to do it is for a major increase in the use of the state's renewable energy resources.
Now, the question that would dominate Tasmanian politics in a rather massive way if this were actually to happen. What needs to be built to get that renewable electricity and achieve the 20% overall emissions cut?
We will still be able to use 4PJ of gas for power generation in order to meet the 20% energy-related emissions reduction exactly. That leaves the overall situation as follows:
Energy from oil: 35 PJ
Energy from existing hydro: 37 PJ
Energy from coal: 1 PJ
Energy from existing wood uses (primarily home heating): 6 PJ
Energy from gas: 16PJ
Energy from new renewables: 26 PJ
So, how to get the electricity?
Wind: Woolnorth (already built due to the CO2 issue), Musselroe, Heemskirk, Robbins Island and another 6 presently unidentified large wind farms. That will push wind to its realistic limit within existing hydro system capacity.
Hydro: Existing plant efficiency upgrades (already done due to the CO2 issue) plus one of the following options:
19 new schemes, none of which is particularly large and one of which is (just) inside a protected area.
OR
3 new dams, which combined would flood virtually the entire length of the Franklin River rather than just the lower third that was the subject of intense debate a quarter century ago.
OR
Burn approximately 4 million tonnes (green weight) of wood per annum as fuel.
In conclusion, yes we can achieve the 20% reduction in energy-related carbon emissions BUT:
1. It requires enormous capital ($ billions) to build the alternatives. Availability of such capital is highly doubtful.
2. It will have a very significant non-CO2 impact on the environment.
3. Politically it would incredibly difficult. Anything involving the Franklin is certain to spark protests across the nation and perhaps even internationally. Likewise anything involving the burning of 4 million tonnes of wood (though ironically it was environmental campaigners who first proposed this). 19 small dams would be possible, if only due to the impracticality of blockading 19 sites at the same time, but actually building that many schemes in little more than a decade is itself problematic given their geographically dispersed nature.
As I said, this isn't meant to be in any way perfect. I'm simply trying to illustrate that there's a lot more to it than changing a few bulbs and catching the bus to work. The only reason for choosing Tasmania is having the data at hand - but the principle that it's not going to be easy applies everywhere.
I'm focusing only on energy use here and not counting methane from cows etc. That's primarily due to difficulty getting the data etc.
My purpose here is to give an example of what would be required in a physical sense to achieve the target. It is not my intention to propose that these are the best or only means of reducing emissions.
Also I'm assuming:
1. That the reduction must be permanent. That is, emissions don't jump up again in 2021 etc.
2. That "business as usual" means 2% annual growth in overall energy demand and 4% overall economic growth (the difference between the two reflecting improving energy efficiency)
3. That the economically cheapest methods will be the ones used except where they are presently off-limits for some reason (eg dams in the wilderness). In that case, they will be used only if there is no realistic alternative.
4. Any supply side measures (eg wind farms) already built specifically to address the CO2 issue are assumed not to have been built under a "no action" scenario. That is, we've already taken some limited action to cut CO2 and I'm calculating this out of the figures.
So here's the scenario for Tasmania. I'll post some data for some other states later. All figures are approximate.
2008 (assuming average weather and without CO2 reduction measures already taken).
Energy from oil: 37 PJ (736,000 tonnes carbon)
Energy from hydro: 37 PJ (2,000 tonnes carbon)
Energy from coal: 15 PJ* (380,000 tonnes carbon)
Energy from wood: 8 PJ (assumed to be carbon neutral - trees replanted and use of waste wood)
Energy from gas: 5 PJ (72,000 tonnes carbon)
TOTAL: 102 pj (1,190,000 tonnes carbon)
*Includes 4 PJ burnt in other states due to Tas net electrcity imports. Rest is used locally for non-power generation purposes in industry.
2020 "no action" scenario:
Energy from oil: 47 PJ (935,000 tonnes carbon)
Energy from hydro: 37 PJ (2,000 tonnes carbon)
Energy from coal: 32 PJ* (813,000 tonnes carbon)
Energy from wood: 6 PJ (assumed to be carbon neutral)
Energy from gas: 22 PJ** (317,000 tonnes carbon)
TOTAL: 144 PJ (2,067,000 tonnes carbon)
*Includes 21 PJ burnt in other states due to Tas net electricity imports.
**Includes 13 PJ burnt in Tas for electricity generation.
Comment: Total energy use rises from 102 PJ to 144 PJ, an increase of 41%, despite an increase in actual delivered energy of only 27%. This reflects the increasing reliance on fossil fuel power generation verus the present high reliance on (far more energy efficient) hydro-electric generation. That is, the difference is due to energy losses at thermal power stations.
Total carbon emissions from energy rise 74%, again reflecting the increasing reliance on coal and gas-fired power generation to meet all increased demand from a very low (historically zero) base for non-hydro generation.
To achieve a 20% reduction on 2008 levels would require that total emissions not exceed 952,000 tonnes of carbon from energy-related purposes.
As is apparent from the figures above, non-power generation sources in themselves exceed the emissions target in 2020. That thus leaves no option, in practice, other than to reduce non-electricity emissions to some extent whilst reducing electricity generation emissions close to zero (given the greater difficulty of reducing non-electricity emissions)
Replacing all coal use (except at TEMCO where there is no alternative) and some oil use (virtually all heavy vehicles) with natural gas would see the situation alter as follows for non-electricity fuel use::
Energy from oil: 35 PJ (697,000 tonnes carbon)
Energy from coal: 1 PJ (25,000 tonnes carbon)
Energy from gas: 31 PJ (446,000 tonnes carbon)
TOTAL: 1,168,000 tonnes carbon - an 2% reduction on 2008 levels.
It is thus clear that fuel switching between fossil fuels, the "easy" option, can not in itself achieve the emissions targets. There is thus a need for far greater reliance on renewables (in practice electricity).
Switching boiler fuel uses to electricity and retaining the use of gas in heavy transport results in the following outcome:
Energy from oil: 35 PJ (697,000 tonnes carbon)
Energy from coal: 1 PJ (25,000 tonnes carbon)
Energy from gas: 12 PJ (173,000 tonnes carbon)
TOTAL: 895,000 tonnes carbon from non-electricity energy uses, 25% below total energy emissions in 2008 thus leaving modest room for electricity-related emissions.
So technically, it is possible to achieve the 20% emissions reduction target without major disruption. But the only realistic way to do it is for a major increase in the use of the state's renewable energy resources.
Now, the question that would dominate Tasmanian politics in a rather massive way if this were actually to happen. What needs to be built to get that renewable electricity and achieve the 20% overall emissions cut?
We will still be able to use 4PJ of gas for power generation in order to meet the 20% energy-related emissions reduction exactly. That leaves the overall situation as follows:
Energy from oil: 35 PJ
Energy from existing hydro: 37 PJ
Energy from coal: 1 PJ
Energy from existing wood uses (primarily home heating): 6 PJ
Energy from gas: 16PJ
Energy from new renewables: 26 PJ
So, how to get the electricity?
Wind: Woolnorth (already built due to the CO2 issue), Musselroe, Heemskirk, Robbins Island and another 6 presently unidentified large wind farms. That will push wind to its realistic limit within existing hydro system capacity.
Hydro: Existing plant efficiency upgrades (already done due to the CO2 issue) plus one of the following options:
19 new schemes, none of which is particularly large and one of which is (just) inside a protected area.
OR
3 new dams, which combined would flood virtually the entire length of the Franklin River rather than just the lower third that was the subject of intense debate a quarter century ago.
OR
Burn approximately 4 million tonnes (green weight) of wood per annum as fuel.
In conclusion, yes we can achieve the 20% reduction in energy-related carbon emissions BUT:
1. It requires enormous capital ($ billions) to build the alternatives. Availability of such capital is highly doubtful.
2. It will have a very significant non-CO2 impact on the environment.
3. Politically it would incredibly difficult. Anything involving the Franklin is certain to spark protests across the nation and perhaps even internationally. Likewise anything involving the burning of 4 million tonnes of wood (though ironically it was environmental campaigners who first proposed this). 19 small dams would be possible, if only due to the impracticality of blockading 19 sites at the same time, but actually building that many schemes in little more than a decade is itself problematic given their geographically dispersed nature.
As I said, this isn't meant to be in any way perfect. I'm simply trying to illustrate that there's a lot more to it than changing a few bulbs and catching the bus to work. The only reason for choosing Tasmania is having the data at hand - but the principle that it's not going to be easy applies everywhere.