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PROSIDING 2011© HASIL PENELITIAN FAKULTAS TEKNIK Arsitektur Elektro Geologi Mesin Perkapalan Sipil Volume 5 : Desember 2011 Group Teknik Elektro ISBN : 978-979-127255-0-6 TE8 - 1 FEASIBILITY STUDY ON SOLAR ENERGY SYSTEM INTEGRATED TO SULTRABAR SYSTEM ( Studi Kelayakan Pembangkit Listrik Tenaga Surya Terintegrasi Ke Sistem Sultrabar) Sri Mawar Said & Rachmat Santosa Jurusan Teknik Elektro Fakultas Teknik Universitas Hasanuddin Jl. Perintis Kemerdekaan Km. 10 Tamalanrea - Makassar, 90245 Telp./Fax: (0411) 588111 e-mail: [email protected] Abstract It is a well known fact that the Republic of Indonesia in general and the Sulawesi Selatan province in particular is experiencing a crises of electrical energy. ‘Considering the importance of electrical energy supply for the welfare of the people, in particular for their economic activities, it is absolutely necessary that all possible efforts should be studied and their executions considered targeting the elimination of the electrical energy crises or at least the amelioration of its negative impacts. Considering that the country is tracked by the equator, it will not be difficult to imagine that it is rich in solar energy sources. The problem is, the utilization of solar energy in Indonesia is still at the minimum level, in other words barely existing. Cases in many other countries, in particular the US, are different. In those countries the uses of solar energy are well promoted and totally encouraged through well designed and socialized programs. It is the above situation that has given us the idea to conduct this study. The goal is to widen the opening of the curtain that covers the possible utilization of solar energy to ameliorate the electrical energy crises in the Sulsel (Sulawesi Selatan) province whose power system is integrated with those of the Sulbar (Sulawesi Barat) province and the Sultra (Sulawesi Tenggara) province, hence the term Sultrabar system. This study covers studies on the gap between demand and supply of electrical energy in Sulsel, the availability of solar energy utilization technologies to produce electricity that can meet demand for electrical power in this region, as well as the economic feasibility of those technologies to be integrated to the Sultrabar system. This is but a preliminary and summary study to be followed by more detailed studies. Keywords: Solar energy, photovoltaic cells, system integration, solar panel, concentrated solar power, parabolic mirror. INTRODUCTION The Electricity Situation in Sulsel. Generating Capacities Sulawesi Selatan System. With regard to the generating capacity of the Sulawesi Selatan system, at the moment the Sulawesi Selatan system has 169 generating units, consisting of 7 hydro generating units and 162 thermal generating units. Out of those 169 generating units, 46 units are owned by the PLN while 123 units are owned by private companies or rented. In term of capacity, the generating capacity owned by PLN is 346 mW and the private companies own 390 mW. Figure 1 gives the existing generating system of Sulawesi Selatan. The whole existing generating capacity has an installed capacity of 736 mW (see Appendix 1). Peak Load Growth in Sulawesi Selatan. The daily load curve of the Sulsel system can be seen on Figure 2 here below. The figure makes it obvious that peak loads of the Sulsel system are increasing from year to year, as is common and already expected beforehand. Peak load in 2001 is around 400 mW, and ten years thereafter, in 2009, the peak load of the Sulsel system has already reached 560 mW. So there is a load increase rate of around 40% in a decade.

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PROS ID ING 2 0 1 1 © HASIL PENELITIAN FAKULTAS TEKNIK

Arsitektur Elektro Geologi Mesin Perkapalan Sipil

Volume 5 : Desember 2011 Group Teknik Elektro ISBN : 978-979-127255-0-6

TE8 - 1

FEASIBILITY STUDY ON SOLAR ENERGY SYSTEM INTEGRATED

TO SULTRABAR SYSTEM

( Studi Kelayakan Pembangkit Listrik Tenaga Surya Terintegrasi Ke

Sistem Sultrabar)

Sri Mawar Said & Rachmat Santosa

Jurusan Teknik Elektro Fakultas Teknik Universitas Hasanuddin

Jl. Perintis Kemerdekaan Km. 10 Tamalanrea - Makassar, 90245

Telp./Fax: (0411) 588111

e-mail: [email protected]

Abstract

It is a well known fact that the Republic of Indonesia in general and the Sulawesi Selatan

province in particular is experiencing a crises of electrical energy. ‘Considering the

importance of electrical energy supply for the welfare of the people, in particular for their

economic activities, it is absolutely necessary that all possible efforts should be studied and

their executions considered targeting the elimination of the electrical energy crises or at

least the amelioration of its negative impacts. Considering that the country is tracked by the

equator, it will not be difficult to imagine that it is rich in solar energy sources. The problem

is, the utilization of solar energy in Indonesia is still at the minimum level, in other words

barely existing. Cases in many other countries, in particular the US, are different. In those

countries the uses of solar energy are well promoted and totally encouraged through well

designed and socialized programs. It is the above situation that has given us the idea to

conduct this study. The goal is to widen the opening of the curtain that covers the possible

utilization of solar energy to ameliorate the electrical energy crises in the Sulsel (Sulawesi

Selatan) province whose power system is integrated with those of the Sulbar (Sulawesi

Barat) province and the Sultra (Sulawesi Tenggara) province, hence the term Sultrabar

system. This study covers studies on the gap between demand and supply of electrical energy

in Sulsel, the availability of solar energy utilization technologies to produce electricity that

can meet demand for electrical power in this region, as well as the economic feasibility of

those technologies to be integrated to the Sultrabar system. This is but a preliminary and

summary study to be followed by more detailed studies.

Keywords: Solar energy, photovoltaic cells, system integration, solar panel, concentrated

solar power, parabolic mirror.

INTRODUCTION

The Electricity Situation in Sulsel.

Generating Capacities Sulawesi Selatan System.

With regard to the generating capacity of the Sulawesi Selatan system, at the moment the Sulawesi Selatan

system has 169 generating units, consisting of 7 hydro generating units and 162 thermal generating units. Out

of those 169 generating units, 46 units are owned by the PLN while 123 units are owned by private companies

or rented. In term of capacity, the generating capacity owned by PLN is 346 mW and the private companies

own 390 mW. Figure 1 gives the existing generating system of Sulawesi Selatan.

The whole existing generating capacity has an installed capacity of 736 mW (see Appendix 1).

Peak Load Growth in Sulawesi Selatan.

The daily load curve of the Sulsel system can be seen on Figure 2 here below. The figure makes it obvious that

peak loads of the Sulsel system are increasing from year to year, as is common and already expected

beforehand. Peak load in 2001 is around 400 mW, and ten years thereafter, in 2009, the peak load of the Sulsel

system has already reached 560 mW. So there is a load increase rate of around 40% in a decade.

Feasibility Study on Solar… Sri Mawar S. & Rachmat S.

Arsitektur Elektro Geologi Mesin Perkapalan Sipil

ISBN : 978-979-127255-0-6 Group Teknik Elektro Volume 5 : Desember 2011

TE8 - 2

At such load increase rate, clearly the PT. PLN, as the authority in electricity in Inonesia, must continuously

add new generating units. As a matter of fact several generating units owned by PLN have been operating at

100% capacity and this simply can not go on. Therefore PLN has made plans for new generating units to be

built in 2011 - 2016. Figure 3 shows the plans. For details of the plans see Appendix 2.

Figure 4 then shows the superimposing of peak load growth and generating capacity growth as planned by

PLN. From this figure it should become clear that more should be done, including the construction of solar

energy systems, certainly by PLN itself but perhaps also by individuals, cooperatives and private companies.

They may build solar energy systems for their own use and sell the excessive energy produced to the PLN.

Figure 1. Generating units in Sulsel.

Figure 2. Daily load curve, Sulsel system 2001-2009

Figure 3. Plans for new generating units in Sulawesi Selatan

PROS ID ING 2 0 1 1 © HASIL PENELITIAN FAKULTAS TEKNIK

Arsitektur Elektro Geologi Mesin Perkapalan Sipil

Volume 5 : Desember 2011 Group Teknik Elektro ISBN : 978-979-127255-0-6

TE8 - 3

SOLAR ENERGY SYSTEMS INTEGRATED TO THE EXISTING GRID.

Solar Energy Systems

Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly

using concenrated solar power (CSP) plants. Concentrated solar power systems use lenses or mirrors and

tracking systems to focus a large area of sunlight into a small beam. Photovoltaics convert light into electric

current using the photoelectric effect.

Commercial concentrated solar power plants were first developed in the 1980s, and the 354 MW SEGS CSP

installation is the largest solar power plant in the world and is located in the Mojave Desert of California. Other

large CSP plants include the Solnova Solar Power Station (150 MW) and the Andasol solar power station (100

MW), both in Spain. The 97 MW Sarnia Photovoltaic Power Plant in Canada, is the world’s largest

photovoltaic plant.

Integration of Solar Energy Systems to Existing Grids

Significant reliance on weather dependent resources like solar will require a change in grid operating

paradigms. The electric power system has developed historically with thermal power plants as the main source

of generation. Nearly 90% of the installed generation capacity in the United States is comprised of dispatch-

able natural gas, coal or nuclear power resources. The situation in Sul-sel province of Indonesia is not much

different. The addition of significant quantities of weather dependent and variable sources of power will

require changes to many of the practices and policies that are oriented around dispatch-able thermal plants.

Studies of increased levels of solar (and wind) generation show that the variability and uncertainty associated

with weather dependent resources can be managed with increased operating reserves, increased access to

flexibility in conventional generation plants, better management of electricity between adjacent electrical areas

(balancing areas), access to other sources of flexibility in power systems, including demand response and

energy storage, and incorporation of forecasting of solar generation into system operations. With 10 – 20% of

electricity derived from photovoltaic (PV) and concentrating solar power (CSP) systems, the electric power

system will have to be planned and operated differently. Solar’s variability and uncertainty requires new

sophistication of real-time operations and planning practices. Maintaining reliability and the most economic

dispatch will undoubtedly lead to new strategies to manage the grid. The need to evolve new grid operating

paradigms becomes even more significant as solar generation is likely to be concurrently deployed with a

substantial amount of wind generation.

Solar electricity has unique attributes, relative to conventional generation, that need to be accounted for to

reach high penetrations of solar. The primary characteristics of solar relevant to system operation and planning

are variability, uncertainty and capacity value. While there has been little measurement data available for

analysis of variability and geographic diversity on different temporal and spatial scales in different climatic

regions, there are some general characteristics that are known about the solar resource.

With respect to power system operations, the most relevant characteristics of solar generation is the output

variability and rate of change (ramping) over different time periods, and the predictability of these ramping

events. Figure 5 illustrates the high degree of variability and high ramp rates that can occur on a single PV

plant over a short time frame (seconds to minutes) due to passing clouds. Figure 2.1 also shows that the

Figure 4. Peak load growth and generating capacity in Sulawesi Selatan 2010-2020.

Feasibility Study on Solar… Sri Mawar S. & Rachmat S.

Arsitektur Elektro Geologi Mesin Perkapalan Sipil

ISBN : 978-979-127255-0-6 Group Teknik Elektro Volume 5 : Desember 2011

TE8 - 4

aggregate of multiple solar plants over a wide geographical area has far less variability and smaller short-term

ramp rates, demonstrating one way to mitigate short-term variability issues.

The variability and predictability of solar electric generation depends on the degree of correlation of cloud-

induced variability between solar plants (the component of the variability due to the movement of the sun in the

sky will of course be correlated between all plants). The correlation between solar plants, in turn, depends on

the locations of solar plants and the regional characteristics of cloud patterns. Generally, the variability of solar

plants that are further apart are less correlated, and variability over shorter time periods (minutes) is less

correlated than variability over longer time periods (multiple hours) (Murata et al. 2009). The decrease in

correlation with distance leads to much less variability (smoothing effect) and much more accurate forecasts of

solar plants aggregated over a region relative to the scaled output of a single solar plant. It should be noted that

in absolute terms the variability and forecast error will increase with increasing quantities of solar.

Unlike PV systems, most CSP plant designs have inherent thermal storage that greatly reduce or eliminate

short-term variability. Parabolic trough plants using oil as the heat-transfer fluid and modern direct-steam

systems with integrated steam storage vessels can typically operate with no solar input for a period of roughly

half an hour (Steinmann and Eck 2006). Dish CSP plants have less thermal inertia than the other CSP

technologies, and thus the output of these plants can vary much more with passing clouds.

Some CSP plant designs have multi-hour thermal energy storage, allowing them to generate electricity even

during periods with low or zero solar input. This provides operating flexibility and the ability to shift solar

generation into the evening hours or other periods to better match the load profile and provide more value. The

additional capital costs for multi-hour thermal storage must be justified by the reduced levelized cost and/or

increased value of power delivered by the plant (Sioshansi and Denholm 2010). A number of cost projections

indicate that the addition of thermal storage will reduce the leveled cost of solar energy for parabolic trough

plants (DOE and EPRI 1997; Sargent & Lundy 2003; Stoddard et al. 2006). Thermal storage with molten-sa28

lt power tower plants is projected to produce even more pronounced reductions in the levelized cost of energy

relative to power towers without storage.

With the exception of dish plants, existing CSP plant designs can also be readily augmented with fossil-fueled

generation, providing either short- or long-term dispatchable output in the absence of solar input. The operating

Solar Energy Generating Systems (SEGS) plants in Southern California, for example, include natural gas fuel

augmentation.

With respect to system planning, the most relevant characteristic of solar is the correlation of solar power with

periods of high electricity demand, and therefore high system risk. The correlation between solar resources and

high demand affects the capacity credit that can be assigned to solar generation for the purposes of generation

resource planning. The capacity credit assigned to the generation resource indicates the fraction of its nameplate

capacity that contributes to the overall capability of the system to reliably meet demand. The capacity credit of

new solar plants is expected to be greatest where electricity load and solar production are strongly correlated.

Electricity demand in most of the U.S., and particularly in the Southwestern U.S., is the greatest during summer

afternoons when solar insolation is also generally high. Figure 7-3 illustrates the coincidence of electricity load

and modeled solar output for a CSP plant with no storage or with six hours of thermal storage.

Figure 5. Solar variability: 100 small PV systems across Germany 1995

PROS ID ING 2 0 1 1 © HASIL PENELITIAN FAKULTAS TEKNIK

Arsitektur Elektro Geologi Mesin Perkapalan Sipil

Volume 5 : Desember 2011 Group Teknik Elektro ISBN : 978-979-127255-0-6

TE8 - 5

The Economics of Solar Power Systems

Bloomberg New Energy Finance, in March 2011, put the 2010 cost of solar panels at $1.80 per watt, but

estimated that the price would decline to $1.50 per watt by the end of 2011. Nevertheless, there are exceptions--

Nellis Air Force Base is receiving photoelectric power for about 2.2 ¢/kWh and grid power for 9 ¢/kWh. Also,

since PV systems use no fuel and modules typically last 25 to 40 years, the International Conference on Solar

Photovoltaic Investments, organized by EPIA, has estimated that PV systems will pay back their investors in 8

to 12 years. As a result, since 2006 it has been economical for investors to install photovoltaics for free in return

for a long term power purchase agreement. Fifty percent of commercial systems were installed in this manner in

2007 and it is expected that 90% will by 2009. By 2020, PV power is expected to become competitive with

fossil fuel in many of the European countries, with costs declining to about half of those in 2010.

Concentrated Solar Power (CSP) facilities produce power more cheaply than photovoltaic systems and may

eventually be price-competitive with conventional power plants. The Ivanpah Solar Power Facility is expected

to produce power at costs comparable to natural gas.

Additionally, governments have created various financial incentives to encourage the use of solar power.

Renewable portfolio standards impose a government mandate that utilities generate or acquire a certain

percentage of renewable power regardless of increased energy procurement costs. In most states, RPS goals can

be achieved by any combination of solar, wind, biomass, landfill gas, ocean, geothermal, municipal solid waste,

hydroelectric, hydrogen, or fuel cell technologies. In Canada, the Renewable Energy Standard Offer Program

(RESOP), introduced in 2006 and updated in 2009 with the passage of the Green Energy Act, allows residential

homeowners in Ontario with solar panel installations to sell the energy they produce back to the grid at

42¢/kWh, while drawing power from the grid at an average rate of 6¢/kWh. The program is designed to help

promote the government's green agenda and lower the strain often placed on the energy grid at peak hours. In

March, 2009 the proposed feed-in tariff was increased to 80¢/kWh for small, roof-top systems (≤10 kW).

A publication by Solar Electricity Price shows that prices of solar electricity are as given by Table 2.1 below.

Considering that prices of electricity produced by conventional, mostly thermal, generating units in the US

varies from the cheapest at 5.58 c/kWh to the most expensive at 32.05 c/kWh (See Appendix 3) obviously the

prices of solar electricity are, to say it mildly, competitive.

Table 1. Solar electricity prices

CONCLUSIONS

Solar power systems are competitive in producing electricity for various uses, i.e. residential, commercial,

industrial.

Solar power systems can be integrated into the existing grids of the Sultrabar system provided the

electricity authority, namely PLN, is willing to change its operational paradigms.

Many things have still to be done among others making available skilled and dedicated human resources

concerned with the environmental issues, encouraging the people’s initiative to start installing solar power

systems at their homes etc.

The political will of the Indonesian government is crucial in order to

Feasibility Study on Solar… Sri Mawar S. & Rachmat S.

Arsitektur Elektro Geologi Mesin Perkapalan Sipil

ISBN : 978-979-127255-0-6 Group Teknik Elektro Volume 5 : Desember 2011

TE8 - 6

REFERENCES

Lew, D. and Milligan, M., 2009, “How do Wind and Solar Power Affect Grid Operations: The Western Wind

and Solar Integration Study” , 8th International Workshop on Large Scale Integration of Wind Power and on

Transmission Networks for Offshore Wind Farms, Bremen, Germany, October 14–15, 2009

Murata, A., H. Yamaguchi, and K. Otani. 2009. “A Method of Estimating the Output Fluctuation of Many

Photovoltaic Power Generation Systems Dispersed in a Wide Area.” Electrical Engineering in Japan, 166, no.

4: 9-19.

Sioshansi, R. and P. Denholm. 2010 The Value of Concentrating Solar Power and Thermal Energy Storage.

NREL/TP-6A2-45833. Golden, CO: NREL. http://www.nrel.gov/docs/fy10osti/45833.pdf

Solar Vision Study, Draft, May 28, 2010

Steinmann, Wolf-Dieter, and Markus Eck. 2006. “Buffer storage for direct steam generation.” Solar Energy, 80,

no. 10 (October): 1277-1282. 12

http://en.wikipedia.org/wiki/Solar_power