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Services fromvariable renewables

HIGH REF VIA HIGHER RPF

High REF: typically requires higher RPF (or demand shift..)

RAR portfolio: 15-20% REF ⇒ 70-100% RPF

Denmark, SA: 20-30% REF ⇒ 100% RPF

𝑅𝐸𝐹 =𝐸𝑟𝑒𝑛 𝑡𝑜 𝑙𝑜𝑎𝑑𝐸𝑙𝑜𝑎𝑑

𝑅𝑃𝐹 =𝑃𝑟𝑒𝑛 𝑡𝑜 𝑙𝑜𝑎𝑑𝑃𝑙𝑜𝑎𝑑

Source: “Renewable Power and Energy Fractions Revisited: Insights from ARENA’s RAR Portfolio” APVI APRSC 2018, Sydney, Australia

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HIGH REF VIA HIGHER RPF

Increasing REFyear: higher VRE, multiple techs, storage

Times of high (100%) RPF: VRE (+storage) to deliver all/most services to grid

Transitions / hand-overs important

Source: “Renewable Power and Energy Fractions Revisited: Insights from ARENA’s RAR Portfolio” APVI APRSC 2018, Sydney, Australia

SPECTACULAR GROWTH: WHY NOT THINK ABOUT CURTAILMENT?

5EKISTICA.COM.AU

Forecasts

(BNEF via IEA)

PV Wind PV + Wind Cost (BNEF)

in 2004: 2030 100 GW 300 GW 400 GW

in 2016: 2030 1,000 GW (10X) 1,100 GW (3.7X) 2,100 GW (2.1 TW)

2018 ~500 GW 592 GW ~ 1,100 GW (1 TW) US$2.30T

in 2018: 2022/3 ~1,150 GW ~850 GW ~ 2,000 GW (2 TW) +US$1.23T

PV curtailment is already felt in most markets where PV contribution to REFyear > 2-3%.

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PV 2018-2022: http://www.solarpowereurope.org/global-market-outlook-2018-2022/

Wind 2018-2022: http://files.gwec.net/files/GWR2017.pdf

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Shell’s Sky scenario• Massive transformation of economy(ies)

• PV to play huge role. From 0.5 TW (cumulative, 2018) to:

• 6.5 TW cumulative (2035)

• 1 TW/y thereafter

• Impact on RE technologies: more optimistic views starting to become norm

• Net Energy emissions to reach 0 by 2070. (IPCC: 2050 for all sectors)

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VRE TRANSITION IN AUSTRALIA

Australia among world leaders for rooftop/behind-the-meter PV uptake

Utility-scale market for wind & solar has lagged vs comparable countries

(USA, Germany, Spain, …)

Rapid utility-scale VRE capacity additions: Australia > World

1 GW total in early 2018 ⇒ 3 GW late 2018 ⇒ 9 GW in 2020

⇒ challenges for all market participants

Source: AEMO observations: Operational and market challenges to reliability and security in the NEM, March 2018

Curtailment is here today and it’s here to stay

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CURTAILMENT: WHAT & WHY

Generator delivering less power than its possible/permitted maximum.

Normal for traditional (fossil) generation: market dispatch

VRE: Premise to date has been PV and wind deliver 100% of power all of

the time

⇒ Built into financial models: curtailment = lost revenue (nasty surprise)

VRE curtailment causes:

• Overgeneration vs demand

⇒ most attention spent here

• Lack of flexibility of other grid actors (generators): ramp rates, …

• Local issues – e.g. transmission line loading

• Rules: minimum amount of synchronous generation online + min limits

of these generators

• Forecast (errors): both demand and generation

Embracing curtailment: unlocking services, addressing concerns

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PARADIGM SHIFTS

Paradigm shifts to reach 100% REF:

• Wind and solar: embrace curtailment (step away from 100% energy),

unlock services for the grid …and get paid for these

• Utilities, grid operators: asynchronous grids (with high VRE) can be

safe/reliable

• This also depends on less synchronous generation being required

at all times (rules)

VALUINGCURTAILMENT

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Future: why curtail variable renewables?

• Flexibility (down & up)

• Certainty of generation ⇒ PPAs, less variability

• Contribute to grid stability: voltage, reactive power, frequency

Example: 140 MWDC, 100 MWAC inverters, with 80 MWAC connection agreed

Traditional DC:AC ratio is 1.4:1, new DC:AC ratio is 1.75:1

Build up value stack: certain ⇒ least certain

Long-term guaranteed (20 MW between 10h and 15h)

Variable/spot market: day-ahead, intraday + spill or arbitrage

𝐿𝐶𝑂𝐸 =σ𝑡=1𝑛 𝐼𝑡 + 𝑂𝑡 + 𝐹𝑡

1 + 𝑟 𝑡

σ𝑡=1𝑛 𝐸𝑡

1 + 𝑟 𝑡

Costs

Risk

Time

Energy

Source: REservices project

(www.reservices-project.eu)

Forecasts (blue & red lines):

example with 97.5%

exceedance probability.

(Only 2.5% probability of

P<Pforecast)

Embracing curtailment: services enabled

PV SERVICES: AUTOMATIC GENERATOR CONTROL

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First Solar – NREL study on

300 MWAC PV plant in

California (CAISO)

10% of Pnom headroom

(curtailed)

AGC:

• low absolute error

(±5 MW or ±1.67% of Pnom)

• fast response (~1 MW/s or

0.3% Pnom/s)

Source: “Demonstration of Essential Reliability

Services by a 300-MW Solar Photovoltaic Power

Plant” – NREL/TP-5D00-67799, March 2017

PV SERVICES: SEPARATE P & Q CONTROL

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Active power (P-f) control can be separate/independent from reactive power control (Q-V)

Source: “Demonstration of Essential Reliability

Services by a 300-MW Solar Photovoltaic Power

Plant” – NREL/TP-5D00-67799, March 2017

PV SERVICES:RAMP RATES

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Power curtailment: ramp rates at ±30 MW/min (±10% of Pnom/min)

Source: “Demonstration of Essential Reliability

Services by a 300-MW Solar Photovoltaic Power

Plant” – NREL/TP-5D00-67799, March 2017

(PV) INVERTERS: FASTER & MORE ACCURATE

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First Solar – NREL study on 300 MW PV plant in California (CAISO)

PV: ~24 percentage points better than best conventional generation

Source: “Demonstration of Essential Reliability

Services by a 300-MW Solar Photovoltaic Power

Plant” – NREL/TP-5D00-67799, March 2017

NEXT STEPS

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What is needed?

✓ Forecasts (& accuracy)

✓ Using forecasts appropriately

✓ PV & wind operational changes

✓ Mindsets: paradigm shifts for PV & wind, grid

operators, regulators, markets, financiers

• How to evaluate (or measure) when curtailed?

⇒ Contracts, monitoring, …

✓ Valuation of (VRE) flexibility

✓ Valuation of (VRE) reliability (Forced outages)

• Beware of unintended outcomes

• Anti-islanding & grid stability

⇒ Requirements changed as REF ↗• LGCs & (voluntary) curtailment

• Transition(s) synchronous – inverter-based grids

The future is bright… yet

Haste thee slowly to 100% RE

An over-reliance on past successes is a sure

blueprint for future failures – Henry Petroski

THANK YOU

EKISTICA.COM.AU