ECONOMIC VIABILITY OF SMART GRID SYSTEMS

D.A. FOLARIN; J.D. SAKALA; E. MATLOTSE AND M. A. JEFFREY

DEPARTMENT OF ELECTRICAL ENGINEERING FACULTY OF ENGINEERING AND TECHNOLOGY

UNIVERSITY OF BOTSWANA

INTRODUCTION

BACKGROUND

SMART GRID DISTRIBUTION TECHNOLOGIES

BENEFITS OF SMART GRIDS

ASSESSMENT OF ECONOMIC BENEFITS OF SG

RESULT OF FIELD WORK

DISCUSSION OF RESULTS

CONCLUSION

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Smart grid (SG) is an electricity network that uses digital and other advanced technologies to monitor and manage the delivery of electricity from all generation sources to meet numerous electricity demands of customers.

It integrates modern tools and technologies from generation, transmission and distribution to all the way to customer devices and equipment.

Electricity plays an essential role in modern life, bringing benefits and progress in various sectors, including transportation, manufacturing, mining and communication sectors.

Electric power is vital for economic growth and quality Source: Jumbe, 2004 3

Power losses can be defined as the difference between the amount of electricity entering the transmission system and the aggregated consumption registered at consumer meter points.

From an operational point of view, power losses are an unavoidable cost of the transfer of energy across electricity transmission and distribution networks . (source: Naveen, 2013)

However, the power losses need to be minimized, as they enforce

an additional demand and energy load on the system.

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Classification of Losses:

Technical Losses: are losses of energy emanating from the dissipation of heat in electrical networks (lines, cables, transformers and other elements of the grid).

Also referred to as physical ( or ohmic losses) I2R or copper losses.

Non-Technical Losses: are losses associated with electricity

that is delivered, mostly for consumption, but which is not paid for. Also referred to as “hidden” losses; the illegal absorption of

electricity (energy theft); non-metered supplies, errors in metering, billing and data processing.

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Measurement Functional

Process Topology of Loss measured in KWh

Energy Purchased A

Energy Consumed B

Technical loss=(A-B) Distribution

Network

Energy Reading, Billing and Dist.

Of Bills

1st Type of Non Technical Losses = (B-C) Unbilled Energy

2nd Type of Non Technical Losses = (C-D) Unpaid Energy

Energy Billed C

Energy Paid D

Payment Outstanding

Losses occur due to technical and commercial reasons.

Minimising either Technical or Commercial Losses may not serve the purpose of any distribution utility and requires a simultaneous action on all of them

Figure 1: Losses in Distribution System. 6

Real time situation awareness

Fault location, isolation and service restoration

Substation automation

Smart metering

SCADA/DMS

Installation of IED

Renewable Energy Sources (Source: NIST, 2009)

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Facilitate the connection and operation of all generators sizes and technologies,

Consumer participation,

Options of supply choice for consumers,

Clean energy environment,

Improvement in reliability, quality and security of supply,

Fosters market integration. (Source: NIST, 2009)

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The analysis can be broadly divided into two categories namely:

Economic Appraisal (Monetary):takes into account all costs and benefits that can be expressed in monetary terms and takes into account a communal perspective.

This includes; allowing for the future incorporation of distributed energy resources, influence on electricity prices and tariffs and environmental cost.

Qualitative Impact Analysis (Non-monetary): contains externalities

that are not quantifiable in monetary terms.

This involves the cost and benefits resulting from wider social impacts like security of supply, improvements to market operational and consumer participation. (EU – US, 2013)

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Technical-Losses LEVEL FOR PEAK POWER LOSSES

S/No SYSTEM-COMPONENT Target-Level

%

Maximum Tolerable %

Technical Losses of a network

are results of:

1 Step-up transformer and

EHV transmission system.

0.50 1.00

(i) Network configuration.

(ii) Parameters and

specifications of the equipment

used in the network.

(iii) Network operation

parameters.

The energy loss was derived

based on utilization pattern.

2 Transformation to

intermediate voltage level,

transmission system and

step-down to sub-

transmission voltage level.

1.50 3.00

3 Sub-transmission system

and step-down to

distribution voltage level.

2.25 4.50

4 Distribution lines and

service connections

4.00 7.00

Total Power- Losses 8.25 15.50

Table 1: Technical Losses (Source: Naveen, 2013)

Period in year 2007 2008 2009 2010 2011 2012

Generation/Sent-

out/Import in (GWh)

3,120 3,210 3,369 3,414 3,551 3,590.9

Unit Sales in (GWh) 2,777 2,889 2,917 3,151 3,118 3,197.7

System Losses in (GWh) 343.0 327.1 381.3 333.3 433.0 393.2

% System Losses 11 10 12 10 12 12

Selling Price

(Thebe/kWh/Unit)

28.7 31.7 36 36 48 57

Total Losses in (mPula) 98.44 103.69 137.27 119.99 207.84 224.12

Table 2a: Analysis of System Losses in Botswana Power Corporation (BPC) 2007-2012

Period in year 2007 2008 2009 2010 2011 2012

Generation/Purchases/Sent

-out in (GWh)

5,145.6 5,799.4 6,052.2 6,771.3 7,259.0 7,943.7

Unit Sales in (GWh) 3,909.1 4,315.8 4,481.5 4,972.4 5,285 6,079.0

System Losses in (GWh) 1,236.5 1,483.6 1,570.7 1,798.9 1974.0 1,864.7

% System Losses 24.03 25.58 25.95 26.57 27.19 23.47

Selling Price

(Cedi/kWh/Unit)

0.12 0.13 0.14 0.20 0.23 0.22

Total Losses in (mCedi) 148.38 192.86 219.90 359.79 454.02 410.24

Table 2b: Analysis of System Losses in Electricity Company of Ghana(ECG) 2007-2012

Period in year 2007 2008 2009 2010 2011 2012

Generation/Purchases/S

ent-out in (GWh)

22,256 20,766 20,329 24,362 26,999 28,890

Unit Sales in (GWh) 20,419 18,886 18,620 21,932 24,205 25,385

System Losses in (GWh) 1,837 1,880 1,709 2,430 2,794 3,505

% System Losses 8.25 9.05 8.41 9.97 10.40 12.13

Selling Price

(Naira/kWh/Unit)

0.50 0.65 0.75 0.80 0.85 0.85

Total Losses in (mNaira) 918.5 1,222 1,282 1,944 2,375 2,979

Table 2c: Analysis of System Losses in Power Holding Company of Nigeria (PHCN) 2007-2012

The years under study are chosen from 2007 to 2012:

The losses are determined using the expression as

illustrated in figure above. Rate of losses are determined using percentage,

Total losses are calculated for each country based on the

rate of energy sales in GWh. 14

YEAR/COUNTRY

2007 2008 2009 2010 2011 2012

Botswana ( Total Losses in US m$)

8.86 9.33 12.35 10.80 18.71 20.17

Ghana ( Total Losses in US m$)

37.10 48.22 54.98 89.95 113.51 102.50

Nigeria ( Total Losses in US m$)

4.59 6.11 6.41 9.72 11.88 14.90

0

20

40

60

80

100

120

2007 2008 2009 2010 2011 2012

TOTAL LOSSES IN US m. dollar

BOTSWANA

GHANA

NIGERIA

It is recommended that the utilities consider adopting smart grid technologies to realise the following improvements: - Reduction of power losses which are high.

Reduction of interuptions due to faults which leads to higher sales.

Improved economy due to intelligence of power network,

Easy restoration with installation of IEDs.

Guaranteed security of supply with Intelligent universal transformer(IUT),

Two – ways communication medium between the utilities, substation and consumers.

All the above improvements emanate from adoption of smart grid technologies and will lead to economically viable power systems of developing nations of Africa.

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Work is ongoing: In particular

To determine cost implication of adopting smart technologies,

To evaluate monetary benefits of each of the country under study,

To quantify the value of non-monetary benefit,

The above outcome will strongly justify the economic viability of the study.

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The power losses in countries studied are in general above the target level.

This is mainly due to non-technical losses since technical losses are normally below the target levels by design.

Adoption of smart grid technologies in the distribution systems will help quantify and reduce non-technical losses.

Adoption of smart grid technologies in the distribution systems in general improves system operations and economic viability of the power systems.

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THANKS FOR LISTENING

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