Martin Poole, Epuron Pty Ltd - CASE STUDY | TKLN – High penetration solar-diesel hybrid systems in 3 remote NT communities

TKLN Solar

High Penetra3on solar-‐diesel hybrid systems in 3 remote Northern Territory communi3es.

1.  High penetra.on solar – introduc.on and benefits

2.  Overview of technology used

3.  Diesel savings and power delivered

4.  Lesson learned

5.  Current and future applica.ons

17 March 2014 Epuron Pty Ltd


TKLN Solar – High penetra3on solar

TKLN Solar

… is the company which owns & operates solar power stations at 3 locations in the NT. The initial of each site is in the name:

Ti Tree – 324 kWp Kalkarindji – 402 kWp Lake Nash – 265 kWp (also known as Alpurrurulam)

= 991 kW of solar PV

Lake Nash also has 3 wind turbines adding 45kW to the mix

T

K

LN

There are many defini.ons but we mean a solar power system which:

  Supplies up to 85% of kW which equates to around 30% of kWh (annual basis)

  Requires integra.on into another system


High penetra3on solar

1. Diesel fuel savings.

Diesel powered grids are oQen:

  Expensive to operate -‐ with high, unpredictable and oQen vola.le fuel costs

  Remote – expensive to deliver fuel to and to service   Can be cut off in the wet season – security of supply

Solar integrated into diesel grids reduces

each of those risks and adds other benefits:

  Known costs for an annual quan.ty of energy for 20 years

  Reduced emissions (local and global)


High Penetra3on Solar -‐ Benefits

TKLN Solar, to quote PWC from their recent ARENA-‐funded handbook:

“… is an example of the technical and financial viability of displacing significant volumes of diesel with high penetra.on solar using commercially available components”

Under a 20 year Power Purchase Agreement PWC purchases an amount of energy per annum (MWh) from TKLN Solar Pty Ltd (a wholly owned subsidiary of Epuron Pty Ltd)


High penetra3on solar

At each site there is an energy storage system called a Grid Stability System (GSS) to supplement solar output.

When clouds reduce solar output rapidly the GSS supplements output to reduce the effec.ve rate of change, providing sufficient .me for the diesel generator to adjust to the increasing load and, if required, start a larger generator.


Overview of the technology used

Because the system is high penetra.on it is important to be able to dump excess solar as required to maintain system stability.


Overview of technology used

An SMA Power Reducer device regulates output from zero to 100% using a number of steps. At Kalkarindji, the largest Solar Power Sta.on, a step size is 25kW.


Overview of technology used

  Diesel generated setpoint was rounded to 1 kW every second

  GSS would reduce the solar to match it or reduce to step size below.

  20 seconds required to make the reduc.on

  setpoint would have sent further 20 signals by the .me achieved.

The solar now follows a diesel generated setpoint which is maintained for one minute to ensure the solar does not jump unnecessarily by 25kW increments.



Ini.al design refinements:

  methods for controlling string inverters

  Communica.ons improvements allowing :   sub-‐second

communica.on to inverters

  Linear control

A difficult solar day with irradiance dropping instantly from 250 kW to 50 kW but the GSS smooths output enough for the diesels.



The opera.on of the baferies is cri.cal to the smooth interface with the diesel.

Baferies are expensive so must be controlled for maximum efficiency.



TKLN -‐ full year Output

-‐ over 1.3GWh

Diesel saved

– around 400kL


Diesel savings, energy delivered

0

100,000

200,000

300,000

400,000

500,000

600,000

kWh

litres

Research shows that as solar system array sizes increase there is an averaging effect that reduces the magnitude and rate of change.

ARENA is currently funding research into the varia.ons in instantaneous weather effects around Alice Springs.

Site specific resource data required

  Lifle data available at design stage

  Only publicly available 1s PV output in Hawaii

  showed worst case output varia.on over 1 min is 40%

  TKLN data has shown clouds can reduce solar output by up to 80% in 1 min

  Hawaii test site is five to six .me larger than any of the TKLN sites.


Lessons learned

Greater understanding of

  the interface with diesel in remote grids

  Response .meframes and latency

  Interpre.ng opera.onal features in agreements

  Data and site specific input requirements

  Risk alloca.on and detail

  Remoteness and weather impacts on opera.on and maintenance


Lessons learned

  All remote work is expensive so where possible all equipment and controls should be capable of being remotely operated.

  Good quality equipment and installa.on reduces O&M costs

  Retrofits are more expensive than design inclusions


Lessons learned

Remote diesel PV hybrids are infrastructure projects which always have unknown unknowns.

Working collabora.vely on issues is the:   fastest,

  most effec.ve,

  least cost way of moving forward,

and results in superior learning opportuni.es.


Lesson learned

The cheapest form of storage is diesel.

The cheapest way of controlling the ramp rate of PV when a cloud moves over the plant will be predic.on.

Un.l then, the GSS works well…

We have been working on predic.on using CloudCAM and my colleague from Fulcrum3D will talk about that tomorrow.


Lessons learned

Hot with occasional storms = very fast growing weeds, a key cost in O&M


Lessons learned

Current and Future Applica3ons

  TKLN Solar could be replicated in many offgrid

loca.ons across Australia and beyond

  Scaleable

  Take advantage of any bafery technology

  Cloud detec.on and predic.on likely to reduce

storage capex and opex – CloudCAM



The Renewable Energy Target (RET) supports high penetra.on solar diesel hybrid systems.

The main value driver in remote diesel grids is the displacement of diesel. Other benefits include:

  Encouraging private investment in infrastructure

  Reduc.on vola.le diesel costs, transport costs

  Security of energy supply

  Diversity of energy supply

  Emissions reduc.ons

  Pushing up the learning curve


Treasurer, Joe Hockey has said;

… it is now the turn of the private sector to generate economic growth and create new jobs, something governments must facilitate.

Solar hybrid systems are ideal for private ownership:

  Ins.gate new design

  Encourage investment

  More impetus to make systems work and overcome issues

ARENA/ CEFC involvement:

  Encourages informa.on sharing

  Which enables improved system design

  Encourages good quality compe..on

  Drives down costs



  Formed in 2003 in response to John Howard's MRET legisla.on of 2001.

  Started in wind energy and now fully opera.onal in solar power

  Employs 24 people from its office in North Sydney, 13 of whom are recent graduate engineers

  Has catalysed over $470 million of investment in Australia

  Designed, built, owns and operates TKLN Solar

  Owns and operates Uterne Power Plant

near Alice Springs


Epuron – who are we?

The projects were partly funded by the Commonwealth RRPGP, administered in the NT by the Department of Resources

Power and Water Corp – PPA counterparty

MPower – GSS contractor Conergy – overall EPC contractor

O&M contractors – Ben F, Ben O, Mick and Nookie

and the Communi3es of Ti Tree, Kalkarindji and Alpurrurulam

Some images from the PWC “Solar Diesel Grid Handbook”, 2014


Acknowledgments

Epuron Pty Ltd

Thank you

Mar.n Poole [email protected]

17 March 2014

Martin Poole, Epuron Pty Ltd - CASE STUDY | TKLN – High penetration solar-diesel hybrid systems in 3 remote NT communities

Technology