global freshwater demand for electricity generation …...global freshwater demand for electricity...

Global freshwater demand for electricity

generation under low-carbon scenarios

Michela Bevione, Laurent Drouet, Massimo Tavoni

35th International Energy Workshop

1st June 2016, Cork, Ireland

Global freshwater demand for electricity generation under low-carbon scenarios

Summary

• Introduction

Overview on global water use

Water and energy nexus

• Implementation of the water module in WITCH

Data

Methodology

• Results

Baseline scenario

Policy and technology constraint scenarios

• Conclusions

1


Introduction: Global water withdrawal by sectors

All economic sectors need water: agriculture, industry and most forms

of energy production are not possible without water.

2

Municipal 11%

Industry 19%

Agriculture 70%

Source: FAO Aquastat Database (2010)

Electricity generation:

15% of world’s total water

withdrawal (IEA,2010)


The energy and water nexus

• Energy and water are strongly interdependent, as water is required

throughout the whole electricity generation process.

• Electricity demand has been rapidly increasing in the last decades,

and a further electric-sector expansion could intensify the inter-

sectoral competition for freshwater.

• On the other hand, a lack in water supply would negatively affect

the power generation sector, e.g. in the 2009-summer one third of

the French nuclear power plant were put out of action because of

water shortages caused by a heat wave.

3


The WITCH model

WITCH (World Induced Technical Change Hybrid) is an integrated assessment

model designed to evaluate the impacts of climate policies on global and regional

economic systems.

4

LACA

USA

CAJAZ

SSA

KOSAU

INDIA

EASIA

CHINA MENA SASIA

TE OLDEURO

NEWEURO

The WITCH regions strategically interact using a game theoretic set-up.

For each region the model generates the optimal mitigation and adaptation

strategies to 2100, by maximizing the welfare of each region.


The production function

In each region the final good (Y)

is produced using capital (K),

labor (L) and energy services

(ES). Capital and labor are

aggregated using a Cobb-

Douglas production function.

This nest is then aggregated

with energy services with

a CES production function.

Each coalition will choose the

optimal inter-temporal mix of

technologies and R&D

investments in a strategic way.


The implementation of the water module

The water module has been implemented outside the optimization

process, by associating water demand intensities to the energy

technologies modeled in WITCH.

Water demand has been evaluated in terms of:

• Water withdrawal: the amount of water taken from a water body.

• Water consumption: the amount of water withdrawal that is not

returned to the source and no longer available for reuse (consumed

through evaporation)

Both freshwater and seawater demand is modeled in WITCH.

6


Water demand in the power generation sector

Water is required throughout the whole electricity generation process, but only

the operational water demand is considered in this analysis.

7

Wind and solar energy:

Cleaning processes

Boiler feed and cooling (CSP only)

Hydroelectric generation:

Electricity generation

Reservoir storage

Thermoelectric and nuclear generation:

Boiler feed

Cleaning flue gases

Steam cooling and condensing

Fuel acquisition

Plant construction

Plant operation

Fuel disposal


Thermoelectric and nuclear generation: cooling systems

Water demand of thermoelectric and nuclear plants varies according to cooling

technologies.

8

Freshwater

Saline water

Freshwater

Freshwater

-

Once-through

system

Recirculating

tower

Cooling pond

Dry tower


Data: Cooling system breakdown

Kyle (2013) provides data on regional cooling system shares for:

- 2005: assigned to the base year plant stock in WITCH;

- future periods: assigned to new installations from 2010 on.

9


Water intensities in thermoelectric and nuclear power

10

W𝑎𝑡𝑒𝑟 𝑖𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦 =𝑊𝑎𝑡𝑒𝑟 𝑑𝑒𝑚𝑎𝑛𝑑

𝑁𝑒𝑡 𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦 𝑔𝑒𝑛𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝑚3

𝑀𝑊ℎ

Nuclear

Gas

Oil & Biomass

Coal

Gas

Nuclear

Oil & Biomass

Coal

Hydropower

Source: Macknik (2012)


Calculation methodology

Non-biomass renewables:

𝑊𝑤𝑖𝑡ℎ,𝑐𝑜𝑛𝑠 = 𝑄𝑒𝑙 ∗ 𝐼𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦 𝑛𝑒𝑡 𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦

where:

• 𝑄𝑒𝑙 is the net electricity generation

• Withdrawal and consumption intensities are expressed in m3/MWh of net electricity

Thermoelectric and nuclear power plants:

𝑊𝑤𝑖𝑡ℎ,𝑐𝑜𝑛𝑠 = 𝑄𝑒𝑥𝑐 ∗ (

𝑗𝑐𝑜𝑜𝑙

𝐼𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦 𝑒𝑥𝑐𝑒𝑠𝑠 ℎ𝑒𝑎𝑡, 𝑗𝑐𝑜𝑜𝑙 ∗ 𝑠ℎ𝑎𝑟𝑒𝑗𝑐𝑜𝑜𝑙)

where:

• 𝑄𝑒𝑥𝑐 is the plant excess heat to be removed

• Withdrawal and consumption intensities expressed in m3/MWh of excess heat

• Cooling systems shares

An improvement in the energy efficiency of the plant implies a lower excess heat to the

condenser, and then a reduction in the cooling water demand.

11


Baseline: Global water demand by technologies

12

Seawater

cooling

Wet tower

Hydropower


Baseline: Uncertainty on global freshwater demand

13

Without

hydro

FAO

estimates


14

Baseline: Global freshwater demand by energy sources


Baseline vs RCP37: Global freshwater demand

15

Climate policy: radiative forcing target at 3.7 W/m2 in 2100

-33%

-24%

-33%

-30%

-16%

-18%


Baseline, RCP37 and RCP37_NukePO: Water demand

16

Technological constraint: nuclear phase-out obtained by assuming no further

investment into nuclear capacities after 2015

-42%

-40%

-8%

-7%


Baseline, RCP37 and RCP37_NukePO: Electricity mix

17


Conclusions (1)

• Water withdrawal and consumption strongly depend on the global

electricity demand and generation mix.

• The renovation of the power plant stock produces reductions in

global freshwater demand as new plants have higher efficiencies in

both energy and water usage.

• Hydropower plays a dominant role in water consumption and the

uncertainty on its consumption coefficient drastically intensify the

uncertainty on global water consumption estimation.

18


Conclusions (2)

• The introduction of a mitigation policy (RCP37) generates a

reduction on both freshwater withdrawal and consumption, as a

consequence of the reduction in the energy demand.

• The combination of the RCP37 policy and the nuclear phase-out

generates a reduction in freshwater withdrawal and consumption,

due to the higher share of electricity produced through low water-

demanding energy sources (gas, wind and solar).

19


Thanks for your

attention!

The research leading to these results has received funding from the European Union’s Seventh Framework

Programme [FP7/2007-2013] under grant agreement n. 308329

global freshwater demand for electricity generation …...global freshwater demand for electricity...

Documents