Global electricity demand, generation, grid system, and renewable ...

Overview

Global electricity demand, generation, grid system, and renewable energy polices: a review M. Hasanuzzaman,1* Ummu Salamah Zubir,1 Nur Iqtiyani Ilham1,2 and Hang Seng Che1 The rising concerns on the impacts of greenhouse gas (GHG) emissions and global warming have forced the world to search for alternative clean and green energy resources. Renewable energy is one of the most sustainable forms of energy, and is an increasingly popular replacement to fossil fuels. In line with this, the world has witnessed tremendous growth in renewable energy technologies as well as unprecedented adoption of renewable-based electricity generation in the past few decades. This review paper focuses on the global energy demand, power generation, electricity production, electrical grid system as well as current global polices to move forward for renewable energy-based power generation. This work compiles the latest literature (i.e., journal articles, conference proceedings, reports, etc.) on global energy demand, power generation, electrical grid system as well as current global polices related to renewable energy. From the review, it is found that renewable energy is one of the potential resources to fulfill the future energy demand with mitigating GHG emissions and global warming. It is also found that many polices has been implementing globally to promote renewable energy-based power generation. © 2016 John Wiley & Sons, Ltd How to cite this article:

WIREs Energy Environ 2016. doi: 10.1002/wene.222

INTRODUCTION

N

owadays, the world is concerned about the future of energy. The developments of modern human life have been heavily relying on the energy produced from fossil fuels, whose resources are fast depleting due to the nonreplenishable nature as well as unsustainable consumption. Over the years, production and consumption of fossil fuel-based energy have taken their toll on the environment, particularly through the emission of toxic and greenhouse gas (GHG) such as carbon dioxide, nitrogen oxide, and

*Correspondence to: hasan@um.edu.my; hasan.buet99@gmail.com (Attn: Dr. Md. Hasanuzzaman) 1

UM Power Energy Dedicated Advanced Center, Level 4, Wisma R&D, University of Malaya, Kuala Lumpur, Malaysia

2

Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), Johor, Malaysia Conflict of interest: The authors have declared no conflicts of interest for this article.

other volatile organic compounds. As a matter of fact, GHG emission has been steadily increasing every year that is shown in Figure 1.1 It is inevitable that carbon dioxide emission will continue to grow as long as fossil fuels continue to be the primary contributor in the energy mix.2 In the Copenhagen Climate Change Conference in 2009, the world leaders had pledged the commitments to drastically reduce GHG emission, as an effort to reduce the impact of global warming. In the more recent 2015 Unite Nations Climate Change Conference in Paris, the participating member countries have agreed to slash GHG emission to keep global temperature rise within 2 C of the preindustrial level. This not only call for a drastic reduction in reliance on fossil fuel-based energy, but also a swift switch to alternative energy sources to ensure a continued and sustainable development of the world. As a replacement to conventional fossil fuelbased energy, renewable energy is seen as a potential

© 2016 John Wiley & Sons, Ltd

Overview

wires.wiley.com/energy

utilization of renewable energy on the electricity delivery system are explored as well, outlining the corresponding challenges and opportunities.

GLOBAL ENERGY AND ELECTRICITY SCENARIO Global Energy Demand and Production F I G U R E 1 | Global CO2 emission by fuel.1 alternative, due to its limitless and clean energy supply (e.g., solar, wind, geothermal, biomass, hydro etc.) which can be used for electricity generation, heating/cooling systems, or directly utilized in the form of bio products.3–6 Despite the advantages over fossil fuels, the relatively high cost remains as the main obstacle that hinders the wide spread use of renewable energy sources (RES) in the world.7 Substantial research and development efforts have been devoted to improve the technology and reduce the price of renewable energy systems to a level competitive to conventional fossil fuel systems. Many policies and regulations have been created to ensure fast application of renewable energy worldwide and to shift the usage from fossil fuels to renewables. The aim of this paper is to review the worldwide electricity generation and consumption based on fossil fuels and renewable energy resources. Subsequently, each renewable resource is detailed on its generation, consumption, recent installed capacity, and its projection. Policies, strategies, and targets related to the use of renewable energy are also discussed. Furthermore, the impacts of the increasing

Energy is a basic need for social development and economic growth in modern society, and fulfilling the ever increasing global energy demands is a serious concern.8–10 Figure 2 presents the world energy consumptions by fuels from 1989 until 2014.11 Over 70% of the world’s electrical energy used today is generated by combusting fossil fuels.12 It is shown in Figure 2 that only 2% of energy is produced from other renewables sources.11 Tables 1 and 2 show the world fossil fuels production and consumption respectively, from 2009 until 2014.11 Both figures increase each year with oil remains as the dominant fuel. Recent fossil fuel production is recorded at 11,281.4 million tones of oil equivalent and its consumption has a total of 11,158.4 million tones of oil equivalent, globally. Figure 3 shows the shares of primary energy from 1965 until 2035 where fossil fuels, especially oils, remain the world’s dominant fuels. However, the fact that renewable energy increases at a faster pace as compared to other fuels is also visible from Figure 3. Among the fossil fuels, it is expected that the consumption of natural gas will continue to rise while the use of oil and coal are expected to fall, such that by 2035 all the three fossil fuels have the similar market share around 26–28%. According to the British Petrol (BP) Statistical Review of world Energy, the most recent estimation of the world

F I G U R E 2 | Global energy consumption by fuels based on British Petrol (BP) Statistical Review of World Energy 2015.11 © 2016 John Wiley & Sons, Ltd

WIREs Energy and Environment

Global electricity demand, generation, grid system, and renewable energy polices

TABLE 1 | World Fossil Fuel (Oil, Coal, and Natural Gas) Production from 2009 Until 201411 World Fossil Fuel Production Year Fossil Fuel

Unit

Oil

million tones

3885.8

3975.4

4008.1

Coal

million tones oil equivalent

3412.7

3604.3

3869.4

Natural gas


2697.5

2009

TOTAL

2010

9996

2011

2012

2013

2014

4116.4

4126.6

4220.6

3912.9

3961.4

3933.5

2888.6

2990.3

3049.9

3077.6

3127.3

10,468.3

10,867.8

11,079.2

11,165.6

11,281.4

2012

2013

2014

TABLE 2 | World Fossil Fuel (Oil, Coal, and Natural Gas) Consumption from 2009 Until 201411 World Fossil Fuel Consumption Year Fossil fuel

Unit

Oil

million tones

3922.9

4041.8

4085.4

4133.2

4179.1

4211.1

Coal


3451.9

3611.2

3777.4

3798.8

3867.0

3881.8

Natural gas


2009

TOTAL

2010

2679.1

2879.7

2943.8

3017.8

3052.8

3065.5

10,053.9

10,532.7

10,806.6

10,949.8

11,098.9

11,158.4

50

Percentage (%)

40

30

20

10

0 1965

1983

2000

2018

2035

Year Oil Nuclear

Coal Natural gas

2011

Renewable Hydro

F I G U R E 3 | Shares of primary energy from 1965 until 2035.13 consumption for most types of primary energy resources was 12,928.4 million tones of oil equivalent, which is equivalent to 150,357 TWh in 2014.11 To accommodate this constantly rising demand, it is important to diversify our sources of energy and, at the same time, improve energy efficiency.

Global Electricity Demand and Production Electricity is used as high-grade energy that facilitates the utilization of many advanced technology, products, and services that enhances our quality of life and elevates economic productivity. Often enough, the growth of gross domestic product (GDP) is

correlated to the rise in electricity consumption. However, it is worth noting that the amount of energy needed for a unit of GDP between the year 2012 and 2035 is expected to decline by 36%, meaning that more value can be created with less energy in the future due to the development of energy efficient technologies.13 The rise of electricity consumption occurs mostly in countries outside of the Organization for Economic Cooperation and Development (OECD) due to strong- and long-term economic growth that affects energy demand. On average, total electricity generated by non-OECD countries experiences an average growth of 3.1% per year in the reference case, where specifically non-OECD Asia (including China and India) shows an average 3.6% annual increase from 2010 to 2040. In contrast, the growth of total net production in the OECD countries increases by an average of 1.1% annually from 2010 to 2040.14,15 Table 3 and 4 present the total electricity net consumption and generation respectively, according to the Enerdata’s Energy Statistical Yearbook 2015 from the year 2008 until 2014.16 It shows an increasing trend between the latest years, with the global energy demand expected to increase up to 33% by 2030. Moreover, the global energy consumption is seen accelerating up to 45 billion MW in the year 2007 and is further projected to increase by a rate of 49% to 218 billion MW by 2035.17 The


Overview


TABLE 3 | Total Electricity Net Consumption (Terra Watt-hours)16 Total Electricity Net Consumption (TWh) Country

2008

2009

2010

2011

2012

2013

2014

17,451

17,349

18,553

19,123

19,576

20,053

20,302

USA

3907

3725

3893

3883

3831

3830

3830

Canada

573

531

533

545

532

543

538

Europe

World

3389

3231

3381

3336

3344

3320

3226

France

461

448

472

443

454

460

430

Germany

543

514

547

541

540

533

516

Spain

261

247

250

249

246

237

233

United Kingdom

350

330

337

326

325

324

310

Russia

843

808

851

856

875

870

873

Middle East

638

677

743

764

802

840

883

Africa

529

528

561

586

588

599

602

Asia

5908

6199

6849

7341

7745

8161

8439

2989

3223

3626

4052

4326

4656

4833

China India

619

669

727

803

869

920

998

Japan

980

951

1016

955

938

922

903

93

103

111

112

121

129

135

213

217

220

223

221

220

221

Malaysia Australia

TABLE 4 | Total Electricity Net Generation (Terra Watt-hours)16 Total Electricity Net Production (TWh) Country World USA

2008

2009

2010

2011

2012

2013

2014

20,268

20,207

21,526

22,218

22,718

23,276

23,636

4386

4188

4378

4350

4291

4302

4330

Canada

635

612

603

638

634

652

640

Europe

3387

3221

3364

3295

3295

3264

3162

France

574

535

569

560

564

575

562

Germany

640

596

633

613

630

635

616

Spain

314

295

302

294

298

286

278

United Kingdom

389

377

382

367

364

357

333

Russia

1040

992

1038

1055

1071

1062

1064

Middle East

786

826

893

916

968

1005

1051

Africa

627

630

676

700

725

741

753

Asia

6897

7236

7953

8550

8933

9415

9760

China

3482

3742

4208

4716

4994

5369

5583

India

848

917

979

1075

1128

1194

1296

Japan

1083

1050

1117

1051

1034

1016

996

98

116

125

129

134

145

151

243

249

252

253

249

248

249

Malaysia Australia




Electricity production - 2014 Unit: TWh

Year: 2014 Unit: TWh

Highest ten

Below 100

China

5583

100 to 200

United States

4330

India

1296

Russia

1064

Japan

996

Canada

640

Germany

616

Brazil

584

France

562

South Korea

540

200 to 900 900 to 4000 Above 4000

F I G U R E 4 | Electricity domestic production in 2014.18

Electricity domestic consumption- 2014

Unit: TWh Below 100 100 to 200

Year: 2014 Unit: TWh Highest ten China

4833

United States

3830

India

998

Japan

903

500 to 3000

Russia

973

Above 3000

Canada

538

Brazil

524

Germany

516

South Korea

499

France

430

200 to 500

F I G U R E 5 | Electricity domestic consumption in 2014.18 International Energy Outlook 2013 (IEO2013) estimates that the world energy consumption will increase by 56% between the year 2010 and 2040.14 Figures 4 and 5 show electricity domestic production in 201418 The growth in electricity consumption is usually associated with the enhancement of energy efficiency, market globalization, modernization, rapid development in technologies, and high industrialization penetration. However, from the aspect of

economic development, Ref 19 suggests that per capital electricity production is not necessarily a good indicator. For instance, Commonwealth Independence State (CIS) produced two times greater of per capital electricity compared with South America (CIS = 0.49 kWh per unit; South America = 0.26 kWh per unit) but yet the capita income of CIS is not reflected by its per capita electricity production.19 The mix of electricity production varies from country to country, and is very much dependent on the


Overview


Denmark Germany Italy Ireland Spain Portugal Belgium Austria Sweden Great Britain Netherlands Greece Norway France Finland Poland Croatia Romania Czech Republic Hungary Serbia

30.42 29.81 24.46 24.07 22.52 21.75 20.97 20.21 19.67 19.18 18.21 17.67 16.53 15.85 15.63 14.21 13.12 12.90 12.83 12.02 6.07 0

8.75

17.5

26.25

35

Cent/kWh

FI GU RE 6 | Electricity prices for EU countries.24

50%

38%

25%

13%

0% 2006

2007

2008

2009

United States

2010

2011

2012

2013

European Union

F I G U R E 7 | Residential electricity prices in EU and USA.25

availability of sources and the demand of each region. In 2013, Denmark had produced 30,615 GWh of electricity, with 17,334 GWh of it generated from RES (i.e., wind turbine, photovoltaic, and hydroelectric) and 12,281 GWh more generated from central power stations.20 In line with their policies toward mitigating the climate change issue, Denmark is aiming to have 100% of its electricity generated from RES by 2050.21,22 Nuclear power is regarded as a nonpolluting element for electricity production. However, the cost to build the power plant is tremendously expensive and required high safety standard operating procedure. Any failure on the operation and equipment will have catastrophic impacts on the environment and surrounding population, such as seen in the recent accident at Fukushima Nuclear Power Plant.23 The price of electricity depends on the cost of generation, transmission and distribution, as well as government’s subsidies, policies, regulation, and many

other factors which vary from country to country. Figure 6 illustrated the electricity prices in Europe24 in Euro (€). Denmark has the highest electricity tariffs, with the consumers paying an average of 30.42 cents/ kWh. This is followed by Germany with 29.8 cents/ kWh, which is almost twice more expensive than its neighbor, France, whereby the cost is only 15.85 cents/kWh. A relatively lower electricity prices are found among the less developed Eastern Europe members of the EU, such as Czech Republic (12.83 cents/ kWh), Hungary (12.02 cents/kWh), and Serbia (6.07 cents/kWh). A comparison of electricity prices between EU and USA, as shown in Figure 7, was discussed.25 Owing to taxes, user fees and renewable energy technology investment, the electricity cost in EU has risen significantly over the year, reaching twice that of USA by 2013. This pattern is projected to be increased in the following years if the issues on the subsidiaries between RES and non-RES, energy policies, regulatory barriers not being tackled wisely.




F I G U R E 8 | Consumption trend and projection by fuel.29 In terms of impacts to the environment, EIA forecasted a rise of energy-related CO2 emissions in the world from about 31 billion metric tones in 2010 to 45 billion metric tones in 2040, which is a whopping 46% increase within 30 years’ time.14 Such increase of GHG emission leads to global warming which is closely associated with issues such as extreme weather patterns, melting of polar ice caps, increase in sea level and more acidic ocean. Policies and regulations need to be enforced in limiting fossil fuel use and to cut GHGs. According to the recommendations by the United Nations’ climate change panel, the global GHG emissions need to be lessening at the upper end of a range of 40–70% by 2050 compared to the level in 2010. Kyoto Protocol was formulated for emission reduction targets during United Nations Framework Convention on Climate Change in December 1997 mainly for developed countries who have high levels of GHG emissions. Its first commitment period was from 2008 until 2012, followed by the second commitment period from 2013 until 2020. During the first commitment period, a reduction of GHG emissions by an average of 5% from the 1990 levels was committed by 37 industrialized countries and the European Community.26 During the second commitment period, the involved countries are committed to reduce GHG emissions by at least 18% according to 1990 levels.27 For Malaysia, the target is set to achieve 40% reduction of carbon emission by 2020.28 These resolutions to tackle the global warming issue were reinforced in the recent Unite Nations Climate Change Conference in Paris. In order to achieve these targets, one of the solutions is to promote the use of renewable energy to replace fossil fuels.

Renewable Energy-Based Electricity Production Renewable energies are very potential and environmental friendly. But still now, about 80% of energy comes from fossil fuels that are shown in Figure 8.29 Table 5 shows the renewable energy consumption in major countries and also globally from the year 2009 until 2014. Figure 9 shows the estimated renewable energybased global electricity generation at end of the year 201430 where about 22.8% of electricity is generated by renewable energy resources. Table 6 shows the renewable electric power generation global capacity at end of the year 201430 where about 1712 GW of electricity is generated by renewable energy resources. However, renewable energy-based electricity generations are raising in popularity, especially in developed countries. According to the Figure 8, the fastest fuel growth is seen in renewable (6.3% per annum), followed by nuclear (1.8% per annum) and hydroelectric power (1.7% per annum).29 In the USA, the renewable energy consumption is increasing at about 20% each year. In China, an exponential increase can be seen, where its share of global renewable energy consumption increases from 5% in 2009 to 17% in 2014. Nevertheless, other Asian countries are still lagging behind in terms renewable energy utilization. For instance, the consumption of renewable energy in Malaysia has been stagnant for the past 6 years, at only 0.3 million toe. Meanwhile in the Middle East, most of the country did not opt for renewable energy yet. This is mainly due to the abundant supply of fossil fuels, which makes up around 98% of the region’s energy mix.31


Overview


TABLE 5 | Global Renewable Energy Consumption from 2009 Until 201311 Year Country

2009

USA

2010

33.6

2011

38.9

2012

45.0

2013

50.6

58.7

2014 65.0

Canada

3.4

4.1

3.9

4.8

4.8

4.9

Europe

61.5

71.3

86.2

101.9

114.7

124.4

France

2.8

3.4

4.4

5.5

5.9

6.5

Germany

17.2

19.0

24.0

27.5

29.3

31.7

Spain

10.7

12.5

12.6

15.0

16.3

16.0

4.5

5.0

6.5

8.1

11.1

13.2

Middle East

0.1

0.1

0.1

0.2

0.2

0.3

Africa

1.1

1.3

1.4

1.6

1.8

2.9

Asia

30.7

39.3

53.7

66.4

82.5

94.2

6.9

13.1

24.6

33.8

46.1

53.1

United Kingdom

China India

6.3

7.6

9.2

11.0

12.5

13.9

Japan

6.8

7.2

7.5

8.2

9.5

11.6

Malaysia

0.3

0.3

0.3

0.4

0.3

0.3

Singapore

0.3

0.3

0.3

0.2

0.2

0.2

South Korea

0.5

0.6

0.7

0.7

0.9

1.1

1.7

2.0

2.4

3.0

3.7

4.1

Australia World (Renewable resources) World (Fossil fuels)

142.2

168.0

205.6

242.9

283.0

316.9

10,053.9

10,532.7

10,806.6

10,949.8

11,098.9

11,158.4

* Renewable sources including, wind, geothermal, solar, biomass and waste, and not accounting for cross-border electricity supply. Converted on the basis of thermal equivalence assuming 38% conversion efficiency in a modern thermal power station.

Renewable power net additions to capacity 140 120

GW

100 80 60 40 20 0

2006

2007

2008

2009

2010 Year

2011

2012

2013

2014

FI GU RE 9 | Estimated renewable energy share of global electricity production, end-2014.30

ELECTRICITY DELIVERY SYSTEM Fundamentals of Electrical grid Electricity grid is an infrastructure that enables the delivery of electric power from the source of power generation, i.e., power plants, to the end users or consumers. The power plant typically produces 50 or

60 Hz alternating current (AC) electricity at voltages ranging from 11 to 33 kV,32 before being transmitted and distributed to the end users. Figure 10 illustrates the conventional radial topology of the common electric grid that consists of three main parts, namely generation, transmission, and distribution.33 Long transmission cables are used to deliver




TABLE 6 | Renewable Electric Power Global Capacity (GW), Top Regions/Countries, 201430 Technology

World

Bio-power

93

Geothermal power

12.8

Hydropower

1055

Ocean power

177

Concentrating solar thermal power (CSP) Wind power Total renewable power capacity (including hydropower)

GENERATION

BRICS

36

29

1

0.1

124

0.5

Solar PV

EU-28

0.2 87

4.4

2.3

China

United States

10

16.1

~0

3.5

Germany

Italy

Spain

Japan

India

8.8

4

1

4.7

5

0.9

0

0.5

0

~0

463

280

79

5.6

~0

~0

~0

0

0

32

28

18

38

18.5

5.4

23

3.2

~0

2.3

0

0.2

0.2

~0

1.6

0

370

129

144

115

66

39

1712

380

668

433

185

92

TRANSMISSION

18

8.7 50

17.3 ~0

23 49

22

45

0

0

2.8 54

22 76

DISTRIBUTION

Industrial Consumers

Power Station Transmission Lines Distribution Transformers

Power Transformers

Distribution Network Commercial Consumers

Power flows from generation to

Residential Consumers

distribution

* Further step-down of voltage from medium voltage (MV) to low voltage (LV) at distribution network is not shown here

FI GUR E 10 | Radial topology of electricity supply.33

power from the generation ends to the distribution ends, which are usually far apart. One distinct characteristic of the radial topology is the power flow which is unidirectional, i.e., from the generation to the distribution. The energy lost while transmitting and distributing electricity is one of the main concerns for utility operators. Generally, up to 8% energy losses are reported worldwide from generation to consumer through transmission and distribution lines.34 To reduce the transmission losses, it is better to transmit electrical power at higher voltage, which can be done either using high voltage alternate current (HVAC) or high voltage direct current (HVDC) technologies. Despite being widely adopted, HVAC technology

suffers from several drawbacks, such as a higher I2R losses at a longer distance, limited transmission line span (especially for submarine cable), severe fault current, and stability problem.35,36 According to,37 for a 100 miles 765 and 345 kV transmission lines, the respective allowable I2R losses are within 1.1 and 0.5%. The drawbacks of HVAC can be mitigated with the use of HVDC transmission system. Compared to HVAC, HVDC possess advantages such as better conductor utilization, lower I2R losses for a longer span, lower losses for submarine cables as well as smaller transmission tower footprint as depicted in Figure 11.38 Furthermore, HVDC is often used to interconnect asynchronous grids, i.e., grids with difference


Overview


Typical transmission line structures for approximately 2000 MW

50 m

100 m

+ 500 kV DC

2 × 500 kV AC

F I G U R E 11 | Requirement of space for high voltage direct current (HVDC) and high voltage alternate current (HVAC) overhead transmission line tower.38

FI G UR E 1 2 | The geographical routes and layout of the Gulf Cooperation Council (GCC) interconnection.39 operating frequencies. For instance, the Gulf Cooperation Council Interconnection Authority (GCCIA) implemented a 400 kV HVDC grid to allow asynchronous interconnection between six gulf members.39,40 The geographical routes and layout of the Gulf Cooperation Council (GCC) interconnection are shown in Figure 12. Recent developments in electricity delivery systems are inclined toward having smarter and more reliable grid systems. Previously, European electricity grid was managed separately at national level, with little or no information sharing between different Transmission System Operators (TSO).

Consequently, the responds toward to any contingencies are slow due to the insufficient flow of information exchange.41 The European blackouts in 2003 and 2006 have affirmed the importance of having adequate real-time information and communication between TSOs,42,43 and motivated the transformation of EU grid management. Currently, the European Network of Transmission System Operators for Electricity (ENTSO-E) and Coordination of Electricity System Operators (CORESO) are responsible for coordinating the interconnection system and operation between the TSOs within the EU. ENTSOE, which consists of 42 TSOs from 35 countries




within Europe,44 is the largest interconnected system in Europe which covers more than 220,000 km of 400 and 200 kV lines that supplies electricity to 23 countries in Europe, and delivers about 3000 TWh of electrical energy the consumers yearly.44–46 ENTSO-E has formulated various security actions to ensure continuous interoperability among all TSO, accommodate the support to TSOs in term of technical operation, policies, monitoring, reporting, and security of principle.47 While the formation of ENTSO-E is motivated by the need for a unified regulation of European electricity market, CORESO is established mainly to safeguard the power supply security for European region.48 Through the Data Acquisition and Display System’s (DADS) tool, data collection and analyzing becomes easier, allowing CORESO to notify the respective TSO on any abnormalities as well as the remedial actions that can be taken.49,50

Impacts of RES to Electrical Grid As the penetration of RES increase, the power grid system evolves as well. Even though synchronous generators are still being used in some of the renewable energy systems, other renewable energy systems, particularly solar Photovoltaic (PV) and wind, uses power electronics converters that have distinctly different characteristics. Conventional understanding on generators’ behaviors, such as stability and power swing, may not be directly applicable on these new power electronics generators (PEGs). Furthermore, large renewable energy power plants, such as wind farms and solar farms, are known to create power quality issues such as voltage fluctuations, flickers due to their intermittency, as well as harmonics distortion issues due to the use of power electronics converters.51 For small capacity generators, power variation due to intermittency can be absorbed with little impact. However, as the level of penetration increases, mitigations are necessary to ensure the integrity of the electricity supply. These include the need to perform power forecasting, install back-up conventional generators, increase transmission capacity to neighboring regions, introduce energy storage systems, etc.52 Even though large RES systems, such as solar farm or wind farm, are usually installed at the generation end (directly coupled at the transmission level) as in conventional grid, small and medium size RES systems can be installed at the distribution ends as ‘distributed generators’ (DGs). The presence of DGs introduces new challenges as well as opportunities to the grid operators. Some of the impacts of renewable DGs on the distribution network include change of

short circuit capacity, stability issues, voltage level of integration and interconnection, voltage waveform deviation, power quality, and changes in protection system requirements.53 The geographical routes and layout of Desertec Project are shown in Figure 13.54 The use of HVDC opens new opportunities for the integration of RES into conventional power grid. For wind energy, HVDC transmission has been applied on offshore wind farm projects such as the BorWin1, DolWin1, and the upcoming DolWin2 projects in the North Sea. Compared to onshore counterpart, offshore wind farms enjoy better wind resources, less constraints on space usage, at the same time give less noise and visual impacts. However, the remote offshore location requires long submarine cables for power transmission. In such situation, HVDC transmission is used to overcome the high losses that would otherwise incur if HVAC is used. Another example is the Desertec project, which is a collaboration project between EU and North Africa to harness the various renewable energy resources in remote desert areas. In this project, HVDC transmission is used to facilitate long-distance power transfer throughout the regions involved. Upon completion, the project is able to generate and supply the electricity demand within 40 years to almost half of Europe, North Africa, and Middle East.

Grid Codes for RES Integration In the early days of renewable energy integration to the grid, anti-islanding requirement is a compulsory feature for grid connected PEGs, where the PEGs have to be disconnected from the grid within specified minimum duration during any grid abnormalities. Such scheme essentially returns the grid to its conventional structure familiar to the grid operators, in order for them to handle the abnormalities and restore the grid to its normal state. Furthermore, the anti-islanding scheme avoids any unintentional energizing of the grid during scheduled outages, which may cause fatal accidents to the servicing crews.55,56 As the penetration of renewable energy increases, such anti-islanding scheme alone no longer suffices, as it will trip off large renewable energy power plants and impairs grid stability. In the light of this potential threat, the grid operators have imposed additional requirements for low voltage ride through (LVRT) or fault ride through (FRT) for wind and solar energy generations. Under the LVRT or FRT scheme, the wind and solar power plants should remain connected to the grid during grid disturbances. Figure 14 shows the typical LVRT schemes and the IEC anti-islanding protection


Overview


DESERTEC-EUMENA Concentrating solar power

Hydro

Photovoltaics

Biomass

Wind

Geothermal

CSP collector areas for electricity World 2005 EU-25 2005 MENA 2005 TRANS CSP Mix EUMENA 2050

F I G UR E 1 3 | The geographical routes and layout of Desertec Project.54 1.00

Voltage level (p.u.)

0.90

RENEWABLE ENERGY POLICIES Italy (Total power ≥ 6 kW)

Germany Japan (Residential applications)

0.70 1

IEC anti-islanding protection

0.45 0.30 0.20

2

0 0.15

1.00

1.50 Time (second)

3.00

F I G U R E 14 | Examples of Low voltage ride through (LVRT) and anti-islanding protection requirements for small solar PV systems.57

requirement for small PV systems.57 For some grid operators, wind and solar farms are required to inject reactive power for grid voltage support during voltage dips. Figure 15 shows the reactive current requirements imposed by E.ON Germany for wind farm.58

In the current market, renewable energy tends to be more expensive than fossil fuel that hinders its widespread adoption. To drive down the price of renewable energy to be competitive with fossil fuel, governments’ support in the form of renewable energy policies is of paramount importance. An energy policy may be in the form of legislation, guidelines for energy conservation, international treaties and investment incentives, taxation, and other public policy techniques.59 These will reduce the entry cost for renewable energy and increase market adoption, which will then help to bring down the price of renewables. It is necessary for the costs of renewable power to keep falling in order to decrease the subsidy requires per unit of power to maintain its rapid growth.1

Renewable Energy Policies in Asia Many Association of Southeast Asian Nations (ASEAN) countries had adopted short-term and longterm policies independently in the recent years. In




Reactive Current Injection, ΔIQ (% of nominal current IN)

Dead band around reference voltage

+100%

ΔU UN -50%

-10%

+10%

-100%

+50% Conditions: Reactive currrent/voltage gain k = ΔIQ/ΔU ≥ 2 (k=2 in this case) Rise time 20 ms Maximum available reactive current IQ_MAX= IN

F I G U R E 15 | Reactive current requirement during Low voltage ride through (LVRT) for E.ON Germany.58 2015, a collective decision had been made by the Member States of ASEAN regarding the share of renewable energy in the region’s fuel mix. The target is set to increase up to 23% of renewable energy in the regional fuel mix by 2020. The decision was taken during the 33rd ASEAN Ministers on Energy Meeting on October 7, 2015.60 Another promising solution for renewable energy in the ASEAN region is Energy Market Integration (EMI). It is to relieve the current immobilization of its renewable energy resources and to serve the fast increasing demand for electricity in the region. One of the plans is to integrate regional power market or in other name, cross-border power trade, which means that richer countries can import renewable-based power from poorer countries that have excess renewable energy resources due to its geographical conditions.61 The growth rate of electricity consumption in ASEAN countries is more than twice the average growth rate of global electricity consumption. This could pressure on the supply side both for power generation and power transmission capacities in these countries. In order to promote renewable energy in the ASEAN region, many efforts have been made by each ASEAN member country to a different extent and using various measures.

strategies is the European Union’s 2020 targets on renewable energy and GHG emission which were agreed by all EU countries in 2007. The targets are to reduce carbon emission by 20% by 2020 and also to reach 20% shares of RES in EU’s total final energy consumption by 2020.62 Each Member State has their own National Renewable Energy Action Plan aligned with the EU’s 2020 targets. As a matter of fact, financial support and subsidies have significant impacts on the renewable energy industry. For example, the high feed in tariffs for wind power in Germany attracted huge investments in wind power industry, despite German’s low mean wind speed.63 On the contrary, there are only minimal installations of wind power in Norway due to the very limited support for wind power, despite its favorable wind conditions.63 In France, Feed-in Tariff (FiT) was introduced in July 2006 where renewable energy producer could sell the electricity for any kWh of electric energy produced from renewable energy resources to the government.59 Other additional supports to promote renewable energy in France include tax incentives and green loans.64

Renewable Energy Policies in America Renewable Energy Policies in Europe European Union (EU) had worked continuously to achieve world leadership in climate policy. One of its

The United States of America had implemented their own current policy which is known as the Energy Independence and Security Act 2007 regarding conservative and renewable energy consumption and


Overview


projection. This act was signed into law in December 2007 which then influenced many energy institutions and programs. The legislation targets to increase the production of renewable fuels, to reduce the country’s dependence on oil, to expand energy security, and to mitigate climate change. In July 2015, President Obama proclaimed a national target for renewable energy, which is 20% of electricity generated in 2030 that will originate from renewable sources, excluding large hydroelectric and to increase the affordability of solar power in communities across the country.65 Other target includes powering more than 6 million homes with renewable electricity by 2020.66 The government plans to triple the capacity of solar and other renewable energy systems that are installed in federally subsidized housing by 2020. There is also a fund of $520 million collected from charities, investors, states, and cities for solar and energy-efficiency projects that lower-income communities managed.67 Although there are several policies on renewable electricity, there are no specific policies for renewable heating/cooling at the national level. Nevertheless, there are investment tax credits for relevant technologies.66 In New York, the State has its own Energy Plan that was released in June 2002. The target is to increase the use of renewable energy in New York by 50% by 2020. Later on in 2009, the 2002 State Energy Plan had been revised and the State released a new 2009 New York State Energy Plan. Regarding renewable energy, the plan sets to expand solar and wind energy projects while doubling the States production of natural gas, a less polluting fossil fuel than coal.68 Meanwhile in California, its legislative bodies have passed a law to extend its renewable energy target (RET) from 33 to 50% by 2030 in September 2015. Currently, California managed to produce 30% of its electricity from renewable energy.69 There are many supports and aids created to reach all the targets above. This paper mentions only some of them that are still in force. In 2009, The American Recovery and Reinvestment Act (ARRA) was created to provide a financial aid for renewable energy and energy efficiency projects. The provisions include a cash grant to replace the federal production tax credit for wind, geothermal and biomass as well as the investment tax credit mainly for solar and small wind projects. The investment tax credit has been extended through 2016 with current 30% level and will become 10% again in 2017.66 In October 2012, it was recorded that grant programs were available in 16 states and 2 U.S. territories (Puerto Rico and

the U.S. Virgin Islands) and loan programs were given to 37 states and the U.S. Virgin Islands to develop the renewable energy.66

Renewable Energy Policies in Australia The electricity generated from fossil fuels such as oil, natural gas, and coal reaches up to 90% of the total electricity production in Australia. However, this has made Australia the highest GHG emitter per capital globally.70 The first renewable energy policy in Australia is the Mandatory Renewable Energy Target which was established in 2001 with the initial target of sourcing 2% of the national electricity mix from renewable energy. In 2009, a new portfolio called RET had been designed to increase of 20% share for renewable energy electricity mix by 2020.71 There are two types of strategy to achieve these targets that are Large-scale Renewable Energy Target (LRET) and Small-scale Renewable Energy Scheme (SRES). LRET focuses on reaching 41,000 Gown of renewable generation from power stations by 2020. Moreover, LRET creates a financial incentive to establish and expand renewable power stations in order to achieve the target. For SRES, although it has no specific target, it has financial incentive for solar panels, wind and hydro system, solar water heaters, and air source heat pumps installment in residents.71 There is also the National Solar Schools Program (NSSP) that offers grants of up to AU$50,000 per school to install PV panel and other renewable power systems. The program projects to install 20–40 MP of PV by 2015. Currently, there are seven cities (Moreland, Perth, Adelaide, Blacktown, Alice Springs, Central Victoria and Townsville) that are named Solar Cities. The project is established for public to get involved in achieving RE target, where residents can volunteer’s roof space for PV systems which could be installed. The most popular policy support in Australia is the Feed-in Tariff (FiT), but only for PV-generated electricity which had encouraged many households to use small PV systems. There is still no Federal FiT yet, but it is available and varies between States and Territories across Australia. The tariff rate has changed over time, ranging between 8 to 60 c/kWh depending on the jurisdiction and size of the system.72 Apart from country specified renewable energy policies, efforts have also been made on international level to promote the use of renewable energy. For example, the International Renewable Energy Agency (IRENA), which founded in 2009 as an intergovernmental organization,




promotes adoption and sustainable use of renewable energy by providing advice and support to it 143 states members on renewable energy policy, capacity building, and technology transfer. The Renewable Energy Policy Network for the 21st Century (REN21) is also a famous global renewable energy organization which have multistakeholder policy network. Many internationally recognized reports on renewable energy industry, policy, and market development has been produced by REN21 that helps many renewable energy development researches around the world.73

CONCLUSION Over the past few decades, worldwide demand for power generation from RES has increased significantly as most of countries strive to reach their respective emission reduction goals. With the rising awareness of environmental responsibilities as well as the falling price of RES technologies, countries all over the world are trying to exploit renewable energy more than before to bring the benefits for their societies. The following conclusions can be summarized from this paper as follows:

• Fossil fuels generate pollution and GHGs that are harmful to humankind. • Renewable energy is unlimited, clean, and never come to an end. • Most of European countries are designing renewable-based power generation. • Electricity grid is one of the most import infrastructure to delivery of electric power from the source of power generation to the end users or consumers. • Continuous innovation from the industries partner, government, regulatory and standards bodies, and professional organizations with the academic research infrastructure is highly demand to ensure efficient electric grid system and security of energy supply. • Energy security, energy supply reliability, and economic prospects are the major factor for social development and to mitigate environmental impact. • Most of the countries have implementing different types of policies for renewable energy systems but still need to address appropriate system planning and operations.

ACKNOWLEDGMENT The authors would like to acknowledge the financial support from the University Malaya Research Grant (UMRG) scheme (Project No: RG150-12AET) to carry out this research.

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