Download Energy for water for food

Energy for water for food
Declan Conway
[email protected]
Overview
• Why is this of interest?
• How significant are GHG emissions
from water use?
• Case study: Energy for water for food
production in China
Collaborative work with CAAS
Integrating climate change, water availability and
socio-economic scenarios
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Climate Change
CO2 fertilization effects
Water Availability
Agricultural land
conversion
• All drivers together
Xiong et al., 2009
Chinese Academy of Agricultural Sciences
The need for integration
Change in total cereal production with different
combinations of drivers
Only climate change:
 Without CO2, modest negative
impacts by 2050s
Change in total cereal production with different
combinations of drivers
Climate change and
water:
 Water is a
significant limiting
factor for future
cereal production
How significant are GHG emissions
from water use?
• Water is heavy………
• Water and wastewater often requires
treatment…..
• Water has high specific heat capacity:
end use heating is energy intensive…..
What is energy required for?
Energy use is high……
• UK roughly 3% of electricity used by water industry.
• Water-related energy use in the US accounts for nearly
5% of total GHG emissions.
• Proportion is even higher in the UK mostly associated
with end uses of water, such as heating.
• In countries with extensive irrigation energy use for
abstraction and conveyance can be high:
– Estimates for India suggest emissions from lifting water for
irrigation as much as 6% of total national emissions.
• In the US, agriculture is the largest business consumer
of electricity, annual cost of almost US$1.2 billion
Energy use is under-recognised
• Poor definition of system boundaries
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LCA studies of specific processes, technologies and sites
Range of units / lack of data
Failure to include end use such as heating
Few comprehensive ‘system’ scale assessments
• Very few peer reviewed publications
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Grey literature from water industry
No discussion in IPCC
Gap between research community and industry/practionners
Increasing recognition in US (California) of water-energy
connections
– Little attention to mitigation-adaptation linkages
Energy for water for food
– Irrigation and energy use
– Globally, irrigation accounts for around 20% of the
arable land area, but contributes 40% of the
global harvest
China’s waterenergy nexus:
Greenhouse-gas
emissions from
groundwater use for
agriculture
Figure 1 | Methodological
steps and data input for the
estimate of GHG emissions
Figure 2 | Location of the 11 survey provinces and 366 survey villages
Many villages are located near each other and may appear as one point on the map
Location of the 11 survey provinces and 366 survey villages
Provincial level results
GHG emission rates
reflect the mix of pump
lift and power source
Considerable
differences with a
range of 0.15 –
0.60kgCO2e/m3
Total GHG emissions =
33.1MtCO2e (0.58% of
national total)
Key points
• Important to link food-water-energy
• Energy use is under-recognised
– System boundaries, lack of data
– Disparate communities: water resources/climate
research water industry/practionners
• Energy use is high……
– Water is heavy, and has high specific heat capacity
• Energy for water for food
– Irrigation and energy use
– Food production policy targets: integrate
adaptation and energy use
Thank you
Figures taken from:
Rothausen, G. and Conway, D. Greenhouse gas emissions from energy use in the water
sector. Nature Climate Change 1, 210–219.(2011)
Wang, J., Rothausen, G., Conway, D. et al. China’s water energy nexus: greenhouse gas
emissions from irrigated agriculture. Environmental Research Letters (In press)
Xiong, W. et al Future cereal production in China: The interaction of climate change,
water availability and socio-economic scenarios. Global Environmental Change 19, 3444. (2009)
Implications for policy…..
• GW abstraction is an important source of GHG
emissions; rapidly increasing and largely
unregulated
• Water scarcity in China is already driving
policies to improve water conservation;
– potential exists to promote co-benefits of water
and energy saving to meet national planning
targets
Factors affecting energy use for
groundwater irrigation