Damage and Loss Assessment
The Electrical Sector
J. Roberto Jovel
2 Aug 08 RJovel 2
Contents
1. Disasters and the electrical sector: types of effects
2. Cases of lower production, sales and revenues of electricity
3. Procedures for the assessment of losses
4. Information requirements and sources of information
DISASTERS AND THE ELECTRICAL SECTOR
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Types of Disaster Effects
The electrical sector, as all other essential service or lifeline, is affected by disasters of all kinds
Following a disaster, it sustains damage to its physical assets– Power plants– Transmission lines and substations– Distribution grids
In addition, losses occur into the sector´s economic flows- Lower production and revenues- Higher operational costs- Unexpected expenses to meet temporary requirements
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Comments on Damage
The assessment should contain a breakdown of damage in each of the components or subsystems of the electrical sector, – Power generation plants– Transmission subsystems– Distribution grids
And an indication of the most realistic time period required for each component to return to pre-disaster conditions and capacity, taking into consideration the availability of required spare parts and equipment and of financing
The assessment of damage is done by civil or electrical engineers
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Comments on Losses
In the electrical sector losses occur until:– Full capacity and supply has been re-established in
all system components (internal constraint), or– Consumer demand (In all sectors) has been restored
to pre-disaster levels (external constraint)(Examples of each case will be discussed in following
slides)Therefore, the estimation of the period of recovery in
each case – based on the best information available at the time of the assessment – is of special relevance
The assessment of losses is a more difficult and complex task than that of estimating damage, and requires the cooperative participation of civil and electrical engineers as well as economists
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Cases of Lower Revenues in The Electrical Sector
Case 1: Damage to Electrical System Components Only
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 180
20
40
60
80
100
120
140
Demand Supply
Time After Disaster, months
De
ma
nd
an
d S
up
ply
of
Ele
ctr
icit
y, M
illio
n K
Wh
/mo
nth
Losses in sales of
electricity
Repairs
Case 2. Destruction of City without damage to Electrical Sector
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 180
20
40
60
80
100
120
140
Before disaster After disaster
Months after Disaster
De
ma
nd
of
Ele
ctr
icit
y, m
illio
n K
Wk
pe
r m
on
th
City Reconstruction
Losses in sales of
electricity
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Cases of Higher Operational Costs
Higher operational costs may be incurred into when– A damaged power plant must be substituted by
another one that has higher unit operational costs (Hydro versus thermal)
– Power and energy must be imported from another nearby system at prices that are higher than the damaged system´s own production costs
– Overtime payment of personnel and related increased costs are incurred for the immediate rehabilitation stage following the disaster, to re-establish service
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Procedure for the Assessment of LossesIn the Electrical Sector
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Step 1. Analyze sector performance prospects under normal conditions
• The electricity company normally has projections of performance of the electrical sector system components for the current year
• Should those projections not be available for some reason, or when the analysis must cover smaller geographical areas, the electrical specialist undertaking the assessment should develop such expected performance, including inter alia– Overall or consumer sector historical sales, by
volume and value– Expected rate of growth of demand
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Step 2. Projection of post-disaster electricity demand
Since recovery of total electricity demand depends on the speed of reconstruction of damaged assets in all consumer-sectors (industrial, agriculture, residential, etc), the electrical sector specialist must work in close cooperation and coordination with specialists of these other sectors
A demand/supply recovery curve is to be developed on the basis of such close consultation and coordination, taking special care to be as realistic as possible in regard to the timing of the staged reconstruction and recovery of activity in the consumer-sectors
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Step 3. Projection of future electricity supply
Case I: One or more power plants have been put out of commision due to damage, but alternative plants are available on stand-by mode
In this case, electricity supply is only suspended briefly until the alternative units can be brought into line
However, unit generation costs of the alternative power plants are normally higher than the ones of the damaged units
The resulting increase in operational costs, over the time required for the damaged power unit to be repaired, must be estimated
In addition, if the alternative power capacity belongs to an independent nearby system, the cost of interconnection must be ascertained and accounted for as a loss
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Step 3. Projection of future electricity supply..
Case II: When damaged components of the electrical system cannot be substituted promptly by stand-by facilities, and power supply must be discontinued
In this case, the electrical sector specialist, in close cooperation with construction/maintenance engineers of the affected electrical enterprise, must estimate the time required to bring back into line the affected system components, taking into consideration all normal constraints
Once this is done, the sector specialist must estimate the losses in revenues due to the non-sale of electricity to consumers, taking into consideration demand and rates
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Step 4. Estimate total losses
Total value of losses can be obtained by the addition of the individual losses described before
To do that, compare the performance of the sector before the disaster with that for the situation prevailing after the disaster1. Compare projection of revenues before and after
the disaster, for the length of time required to achieve full recovery, and ascertain revenue losses
2. Determine increased operational costs arising from the use of alternative power sources and from inter-connecting to nearby electrical systems having idle capacities
3. Add both estimates to obtain total losses for the sector
As indicated previously, production losses occurring in consumer-sectors due to lack of electricity are to be estimated in those sectors
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Information and Sources
Information Required
Historical electricity sales (KWh), per consumer-sector
Historical electricity rates (US$/KWh), per consumer-sector
Electricity sales projections, per consumer sector
Electricity rate projections, per consumer-sector
Length and coverage of service interruption due to disaster
Typical Sources
Electrical utility enterprises, public and private
Regulating body or institution
National energy institution
National economic planning institution or ministry
Annual reports of performance by privately-owned electrical enterprises
Application to Kenya drought
For years 2008, 2009, 2010 and 2011
1. Determine annual decline in electricity production due to drought
2. Determine average energy production costs of – Hydropower – Geothermal– Diesel– Other types of generators
3. Estimate higher, overall costs of electricity generation of system to compensate for lower hydropower generation due to drought
4. Estimate annual amounts of energy not served to consumers due to load shedding scheme
5. Estimate impact on balance of payments due to required imports of fuel
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