Electricity System in Society

MA9001 – Introduction to EnergyTopic #2 – Electricity System in Society

Week 2 (3 hours)

presented by

H B Gooi, PEngAssociate ProfessorSchool of Electrical & Electronic Engineering

13 August 2014

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Contents

1. Overview of Electrical Energy Systems;

2. Generation, Transmission and Distribution ofElectricity;

3. Environmental Impact of Overhead Transmission Lines;

4. The Singapore Scenario.

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References1. Environment Impacts of Transmission Lines

http://psc.wi.gov/thelibrary/publications/electric/electric10.pdf

2. EMA’s Statement of Opportunities 2012 and 2011http://www.ema.gov.sg/media/files/publications/soo/EMA_SOO_2012.pdfhttp://www.ema.gov.sg/ema_soo/index.html

3. EE3015 – Power Systems & Protection Lecture Notes

4. EE8085 – Electricity for Modern Society

5. EMA-MOE Energy for Educators Forum - Factsheet on Power the Power Sector in Singapore

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6. H B Gooi, P L So, E K Chan, E Toh and H Gan “Towards aSustainable, Economic and Secure Electricity Supply inSingapore”, IEEE Power & Energy Magazine, Vol. 10, No. 4,pp. 65-74, Jul/Aug, 2012, USA.

Overview of Electrical Energy Systems

• Electricity may be generated from (1) traditional non-renewable fossil fuels such as gas, oil and coal or (2) renewable sources such as sunlight, wind, hydro power, biomass, geothermal heat and tidal waves.

• Most traditional generating sources produce electricity through synchronous generators.

• Climate change concerns coupled with high oil prices and increasing government support are driving increasing renewable energy legislation, incentives and commercialization.

• Renewable technologies are also suited to rural or remote areas.

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Schematic of Coal-fired Generating Station

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Generation, Transmission and Distribution of ElectricityThe structure of the electric power or energy system is very large & complex. Nevertheless, it can be divided into five basic subsystems.

• Energy source may be – coal, gas or oil (fossil fuel) – fissionable material (nuclear)– water in a dam (hydro)– renewable sources

EnergySource(Fuel)

EnergyConverter

(Generator)

TransmissionSystem

DistributionSystem

Load(Energy

sink)

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Generation, Transmission and Distribution of Electricity (Contd)• Generator that transforms non-electrical energy to

electrical energy; usually rotating-machinery type; power output from few kilowatts to a few thousand MW; voltage levels 440 V to 25 kV.

• Transmission system transports generated energy from generating stations to major load centers; voltage levels of 115 kV to 765 kV (less than 138 kV usually referred to as sub-transmission system); overhead lines & underground cables.

• Transformers are used to change voltage levels (to high over transmission system & low over distribution system, etc).

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Generation, Transmission and Distribution of Electricity (Contd)• Distribution system transports transmitted energy from

transmission system to users; voltage levels typically 1 kV to 33 kV.

• Loads: industrial, commercial, residential, farm, etc.

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Environmental Impact of Overhead Transmission Lines

• Aesthetical Effects • Agricultural Land• Airports and Airstrips• Electric and Magnetic Fields• Endangered/Threatened and Protected Species• Audible Noise• Property Owner - ROW Compensation and Property

Value• Radio and Television Reception

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Underground Cables• Singapore has 100% cable network except in rural areas• Cables have conductors insulated from one another and

enclosed in protective sheaths• Advantages of Underground Cable Network

– Could be used in urban areas where overhead lines cannot be installed with appropriate clearances.

– Allows for a shorter route than that of overhead.– No sighting of transmission poles - aesthetically pleasing.

• Disadvantages of Underground Cable Network– Increase in soil disturbance.– Increased construction and repair costs. – Oil-filled underground cables can leak and contaminate surrounding

soils.

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The Singapore Scenario

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Singapore Oil, Gas and Electricity Industry

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Fuel Mix for Electricity Generation Others include diesel, Syngas and refuse incineration

• Singapore is one of top three oil-refining centers and the third largest oil trading hub in the world.

• Natural gas is imported via long pipelines from from Peninsular Malaysia and Indonesia.

• To meet the growing demand for electricity and enhance its energy security, Singapore commenced commercial operation of the LNG terminal which has a throughput capacity of 6 Mtpa and room for expanding up to 15 Mtpa.

Source: EMA

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Source: EMA

Location of LNG Receiving Terminal (Jurong Island)

Singapore LNG Terminal Facility

• Electricity consumption is linked to GDP.• Maximum demand has increased by almost 73% from

3,485 MW in 1995 to 6,041 MW in 2009. • Demand is expected to increase at an annual rate of 2.5

to 3.0% from 2010 onwards. Electricity demand in 2010 was 41,200 GWh. Peak demand in 2012 was around 6,639 MW.

Electricity Demand

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Total Annual Electricity Demand Trends (Forecast is based on GDP and population projections)

Source: EMA

Distribution of Power Plants in Singapore • Singapore’s generation capacity has grown at an average

annual rate of around 3 per cent from 2003-08.• About 70% of Singapore’s generation capacity is located

in the western part of Singapore.• Land has been set aside for a new generation plant to be

built in the northeast region.• Singapore power grid is connected to TNB System via two

submarine cables with transmission capacity of 250 MW each.

15Source: EMAGMR

Projected Reserve Margin

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• Singapore’s minimum reserve margin is set at 30% above the annual peak demand based on LOLP of 3 days/year.

• With indicative new generation plantings in the pipeline, the reserve margin is projected to be above 30% over the next ten years.

Projected Reserve Margin (as of June 2011)

Source: EMA

Singapore Electricity Industry Structure

SP: SingaporePower

EMA: Energy Market Authority

EMC: Energy MarketCompany

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To understand how demand side management (DSM) can benefit Singapore, one needs to understand how the market clearing process works.

Source: EMA

• Currently the load demand in Singapore is very inelastic.• DSM can help to change its elasticity as customers have

the option of using their own generation or deferring the use of electricity.

National Electricity Market of Singapore

Market Clearing Price (MCP)Inelastic demand

Staircase prices are electricity price offers submitted by Gencos.

The system demand shown by the vertical line is the half-hourly load forecast value obtained from Power System Operator (PSO) of EMA.

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Source: EMA

• With the incorporation of DSM via microgrids and/or the associated energy management systems, the demand is no longer a vertical line.

• As can be seen from the left diagram, when demand is elastic, the electricity MCP is generally lower.

• By introducing more competition among Gencos (Government’s job), the electricity MCP is generally lower as can be seen from the right diagram.

• Vesting contracts, a form of price regulation, were introduced in 2004 to check market power.

Demand Elasticity and Competition

Quantity (MWh)QE

PE

Quantity (MWh)

PE

QE

Supply

Demand

Supply

Demand

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Electricity Tariff in Singapore

For Q3 2014, Low Tension Tariff: 25.68 ¢/kWh. High Tension Small Tariff: Contracted and uncontracted capacity charges are 7.49 & 11.24 $/kW/Month; kWh peak, off-peak period and kVARh charges 23.67, 14.40 & 0.59 ¢.

Source: SP Services

Grid Performance

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Electricity Cable Tunnel Project

Source: EMA

• To meet the future increase in demand for power supply and to ensure the continued reliability and security of the network, Singapore Power is embarking on a $2 billion project to build cross-island transmission cable tunnels.

• Two tunnels, one running East-West (16.5 km) and another North-South (18.5 km) for a total of 35km in length, will be built 60 m underground. The project commenced in 2013 and is scheduled for completion in 2018.

• The tunnels are designed to facilitate faster and more efficient maintenance and replacement of existing and future cables. The frequency of road-digging works (for future cable replacement and repair) will be minimized, resulting in less traffic congestion and disruption to the public.

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Clean Energy Initiatives in Singapore• Solar Energy

– Singapore is located in tropical sunbelt with an average solar yield of 1,150 kWh/kWp/year.

– Potential to tap on solar energy for power generation.– Energy from solar would be intermittent and highly variable due to

heavy cloud cover.

Solar PV System on a HDB Building 23

Source: EMA

Grid Tied Solar PV System • Solar PV manufacturers in Singapore: Norway’s

Renewable Energy Corporation, Germany’s Solar Energy Power and Singapore-based Eco-Solar.

• Selected Solar PV Installations: Glaxo Wellcome Manufacturing (57 kWp), Changi Budget Terminal (250 kWp), and Khoo Teck Puat Hospital (150 kWp).

Illustration Courtesy of Phoenix Solar24

Installed PV Capacity in Singapore

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• As of 2012, a total capacity of 9,989 kWp of grid-connected solar PV systems has been installed in Singapore.

• The non-household sector constituted about 92.1% (or 9,199 kWp) of total capacity, with the remaining capacity contributed by household installations.

Source: EMA

Biofuels• Finnish oil refiner Neste Oils has invested S$1.2 billion

to establish the world’s largest commercial-scale biodiesel production facility in Singapore.

Waste to Electricity Plants in Singapore

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Wind Energy• Wind speeds in Singapore are generally low (avg < 1 m/s).• Wind speed increases with elevation.• A residential wind turbine’s cut-in speed is typically 3 m/s

though a newly developed small turbine requires 2.5 m/s.• For the turbine to reach its rated capacity, typically a

wind speed of approximately 12 m/s is needed.

Skystream 3.7 single-phase 2.4-kW wind turbine at EEE

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Intelligent Energy System Project at NTU

28Source: EMA/Accenture

EMA’s Smart Meter Trials

Pre-paid scheme testing - Owner needs to top-up the credits in the meter when the balance becomes low.

Source: EMA

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Consumer Display Unit used in EMA’s Trials

- Households were provided with real time information on their electricity usage.- Awareness of this information alone resulted in a reduction in electricity

consumption by about 2%. In addition with differential pricing, these households shifted about 10% of their usual electrical load from peak periods to off-peak periods, thereby enjoying savings in their electricity bills.

Source: EMA30

Overall IES Solution


IHD, Home Automation


Consumer Energy Portal Project at NTU

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• WHAT is a Consumer Energy Portal (CEP)? It serves as a platform for utilities to provide web access to

electricity consumers. The energy services provided by utilities include:

Energy usage monitoring - usage for each day of thebilling period.

Energy cost monitoring - energy cost to date, projectedenergy cost and historical cost.

Energy saving tips - for educational purposes. Outage detection/notification. Distributed generation (DG) aggregation. Time of Use (ToU) pricing scheme implementation. Home Energy Management System - electrical appliances

can be controlled and monitored via CEP.


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• WHY NTU needs CEP? To improve Electricity Billing System

• Reduce cost due to electricity billing services.• Real-time electricity consumption will be collected remotely

and automatically through smart meters (SM).• Network Management System (NMS) is setup to manage

the smart meters and consumer’s data. To lower electricity bills

• Introduce Demand Response Management (DRM). ToU implementation and selection

• Energy plan selection to suit consumer’s lifestyle. Future smart grid implementation

• Consumers load profile analysis• Integration of alternative energy sources.


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Nanyang Meadows

Nanyang Terrace

Nanyang View

Network Management Server (NMS)

NTU Local Area Network (LAN)Last Mile Communications Internet

Staff Quarters

Communications Methods between CEP and Smart Meters

Consumers

Bi-directional

Intelligent Micro-Grid with Renewable Energy Technologies for Pulau Ubin

Source: EMA

• The off-grid concept displaces the diesel generators currently being used by organizations, small businesses and individual homes on the island of 10 square km.

• The project would showcase how clean and renewable energy can be deployed in an environmentally, socially and economically sustainable manner for an off-grid community.

• Pulau Ubin hosts a number of plug and play test-bedding facilities for various clean and renewable energy solutions. This will help elevate Singapore as a “living laboratory” to research, develop and demonstrate new energy technologies.

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Intelligent Micro-Grid with Renewable Energy Technologies for Pulau Ubin (Contd)

Source: EMA

• A consortium comprising Daily Life Renewable Energy Pte Ltd and OKH Holdings Pte Ltd has been appointed to design, build, own and operate (DBOO) the microgridinfrastructure.

• Following the launch of the micro-grid test-bed, more than 30 residents and businesses have signed up for electricity from the micro-grid.

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A Smart Grid for Intelligent Energy Use

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http://www.youtube.com/watch?v=YrcqA_cqRD8&feature=related

Documents

Electricity System in Society