Download - Simon Troman, IT Power (Australia) - CASE STUDY | Solar hybrid power stations - Reducing diesel fuel bills

Solar hybrid power stations Reducing diesel fuel bills

About IT Power

•  Founded in 1981 •  Offices in UK, India, China, Argentina, Australia •  Over 50 specialist staff •  In Australia: offices in Canberra, Sydney and Adelaide

About IT Power

Inception Feasibility Design Tendering Construction Maintenance

Design Review

Quality Assurance

On-site Project Management

Project Review

Independent Commissioning Engineering

Strategy Policy

Regulation

Economic and

Financial Analysis

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Key regions: Pacific

101 on solar / diesel hybrid power generation

•  Diesel generator efficiency usually varies between 2 and 4 kWh / litre depending on size, loading and temperature.

•  At $1.20/litre a mini-grid averaging 3.5 kWh / litre has a fuel cost of more than 34c / kWh.

•  Medium to large scale PV installations typically have a levelised cost of energy of around 20-25c / kWh.


•  Small off-grid loads (lights and telecommunications) cheapest to replace diesel generation with PV and a battery bank.


•  For larger off-grid loads the lowest cost remote power generation option is now typically a diesel/PV hybrid.

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•  Cheapest configuration will depend on location, demand loads, age and efficiency of the existing generators etc.


Three broad diesel/PV hybrid design options: •  PV fuel-save (no battery storage, providing

~10% annual load contribution), •  PV fuel-save plus (sometimes utilising a

small amount of battery storage, providing up to 25% annual load contribution), or

•  PV primary (utilising a large amount battery storage, providing >50% annual load contribution).

‘PV fuel-save’

•  Sized to supply about 30% of the average midday load. •  Diesel generators run continuously. PV reduces their loading during the day. •  No batteries or specialist integration equipment. •  Lowest initial capital cost. •  Reduce annual fuel bills by around 10%.

‘PV fuel-save plus’

•  Intelligent control system that occasionally spills some PV output to ensure that the generators are kept sufficiently loaded.

•  Diesel generators still run continuously, but over the year, the PV makes a much larger contribution.

•  Sometimes include a small battery bank to optimise loadings.

‘PV primary’

•  Large battery bank able to meet load with all generators off. •  Relatively high integration costs •  Highest annual contribution from renewable energy sources •  Economically viable for smaller loads or where diesel costs are unusually

high or supply is uncertain.

Optimal PV / diesel hybrids systems are site specific

•  Recent work undertaken by ITP showed that the PV primary option (which requires a large battery bank) had the lowest lifecycle cost for loads up to about 500 kWh per day.

•  PV Primary now the lowest lifecycle cost for many small grids in Australia

•  As the load increases above this, the PV fuel-save plus option had the lowest cost.

Achieving grid stability

Stability Issues

•  Static Issues •  Feeder capacity •  Reverse power flow •  Voltage rise / sag •  Reactive power management •  Harmonics

•  Dynamic Issues •  PV power output fluctuations

•  Power quality (short term fluctuations) •  Reserve generation requirements (longer term fluctuations) •  Voltage flicker

•  Fault behaviour

Static Solutions

•  Reduce system size •  Change transformer settings •  Update relay settings •  Replace transformers •  Upgrade feeders •  Require inverters with reactive power control

Dynamic Solutions

•  Reduce system size •  Install power limiting technology •  SCADA and control systems •  Generator dispatch strategy •  Short term local storage •  Short term central storage •  Medium term storage (if insufficient spinning reserve)

NOTE: Power system modelling and control system design is vital to successful to solution

Today’s solution should keep in mind the long term goals

Investment Barriers

•  Investors do not make electricity supply investment decisions based solely on Levelised Cost of Electricity. Short investment timeframes an issue (especially mining sector)

•  Some perceive solar as a threat to reliability. •  Power Purchase Agreements may help overcome

barriers, however, this approach has not yet lead to a project in the mining sector

•  Support from ARENA seems likely to help demonstrate technology and novel financing arrangements.

Case Study 1 – Samoa. PV Fuel Save


•  ~195,000 people •  GDP per capita ~$6,300 USD •  Two main islands, Savai’i and Upolu •  60% elec from diesel, 40% hydro

ITP + EPC + MFAT study into stability, penetration, land use, optimal design etc – aiming for large roll out of PV


•  Medium to large scale grid connected systems

•  Feasibility study, detailed design, tender docs and eval of 550kW grid-connected PV (EPC)

•  250kW roof-top grid-connected PV (MFAT)

•  Feasibility, detailed design, tender doc eval and technical PM - total 2.35MW ground mount grid-connected PV (MFAT)

•  Technical assistance for IPP project aiming for 4MW PV with storage (EPC)

•  100% renewable energy roadmap study completed (MFAT)

Case Study 2 – Tonga PV Fuel Save Plus


•  ~15,000 people •  Midday load ~ 650 kW •  2 x 600 kW, 1 x 300 kW, 2 x 186 kW

generators


•  Uses SMA Fuel Save Controller

•  Centralized 512 kWp PV system next to power station

•  Generators loaded to a minimum of 30%

•  Installation completed by Ingenero in November 2013

Case Study 3 – Tokelau. PV Primary


•  ~1,400 people on three atolls •  GDP per capita ~$1,000 USD •  No significant land > 2m above sea level •  Remote location: 24-hour voyage by sea

from the nearest island to Samoa. No air transport.

•  Using NZ funding to pay for diesel


•  ~1 MW of PV distributed across three atolls

•  2.5 days of battery storage •  Existing generator grid

used •  Systems installed in 2012,

providing >90% of atolls’ energy needs from solar power

•  Total project cost was roughly NZD 8.5 million

Where to next – high penetration renewables?

•  Capital cost of displacing diesel with a range of complementary renewable energy technologies is falling

•  In most cases LCOE already better than diesel

•  ITP was involved in a study of 100 per cent renewable energy for Samoa that showed a combination of hydro, wind, biomass, PV and short-term battery storage would minimize electricity cost and greatly increase % RE.

•  The falling cost of battery storage in particular may soon lead to a paradigm shift away from diesel generation.

Conclusions

•  Small amounts of intermittent RE does not require any network augmentation

•  Larger amounts of RE will require solutions but storage is usually not the first choice

•  Storage will be required when spinning reserve is not sufficient

•  New grid architecture (i.e. Inverter formed grids) and storage are require for intermittent RE to make a significant contribution

RE only

Inverter control

Power quality storage

Diesel off storage

Other techs required

Load shifting storage

Southern Cross House, 6/9 McKay St, Turner, ACT PO Box 6127 O’Connor, ACT 2602 [email protected]

p +61 (0) 2 6257 3511 f +61 (0) 2 6257 3611 itpau.com.au

IT Power Renewable Energy Consulting

Thanks very much for your time and interest