Storage – a Pathway to a 100% Renewable Future

Energy

Malcolm T. Jacques, New Energy Options, Melbourne, Australia

The Impact of Intermittent RE

• More Back-Up Power.• More Balancing Reserves• More Transmission Capacity

Back-Up Power Requirements

Balancing Reserves

Transmission Capacity

• Wind farms located in the sparsely populated North.

• WE can exceed local area demand.

• On windy days WE must be exported South.

• Additional transmission capacity needed as more WE installed.

Limitations of Existing Grids

• Grids designed for dispatchable power• RE is intermittent and non-dispatchable.• Intermittency is normal for Gas, Water,

Grain, Information, etc.• Intermittency is not a fundamental problem.• More a consequence of history.

Is RE Limited to 20% ?

• 20% RE accepted maximum.• Government Policies Targeting >20% RE.• RE Industry needs to demonstrate that 20%

RE is NOT a limit.• Storage needed for >20% RE.

The Solution – Storage

• Electrical energy cannot be stored – a myth.• Proven storage technology is available.• “Business-as-usual” attitude - more

balancing reserves and transmission capacity will be needed.

Electrical Energy Storage

“Cost effective energy storage will be a key enabling technology for the stable operation of a liberalized energy market, for competitive energy pricing, and for the introduction of RE sources.” European Commission Report 2002.

Advanced Storage Systems

• Pumped Hydro• Compressed Air Energy Storage (CAES)• Advanced Chemical Storage.

Pumped Hydro- Dinorwig, Wales• Situated on edge of

Snowdonia National Park• Commissioned in 1984• 6 x 288 MW generators• Shutdown to full load 90s• Standby to full load 16s• Reservoir capacity 9 GWh

– 5 hours gen full-load• Average head 520m• Loading rate 50 MW/s

- Coal 10MW/min

Pumped-Hydro Recent Developments

• Vatenfall, Goldisthal 1060 MW plant –“used to supply last-minute power and make up for fluctuations in supply from wind farms across Germany”

• Variable speed synchronous generators• Mini-Pumped Hydro (Water towers)

Compressed Air Energy Storage (CAES)

Mini - CAES

Chemical Storage Systems

• Conventional Batteries- Pb/Acid, Ni/Cd, NAS, Li/Ion

• Flow Batteries/Rechargeable Fuel Cells- Polysulphide Bromide (Regenesys, UK)- Vanadium Redox (VRB, Japan/Canada)- Zinc Bromine (ZBB, USA)

• Fuel Cells (Hydrogen Storage)

Conventional Batteries

– Ni/Cd – 40MW, Golden Valley, Alaska provides balancing reserves to grid.etc.

Flow Batteries - 30MW Wind/Storage (VRB) Project - Hokkaido.

VRB Flow Battery System

The installed cell stack consists of 108 “Single Cells” stacked as shown on left.

Installed cell stacks and electrolyte tanks as shown below.

Cell Stack

Electrolyte Tank

Cell Stack

Single Cell

J-Power 30MW Wind/Storage Project

J-Power Wind/Storage System

• 30 MW installed wind capacity.• VRB Flow battery storage.• 4 MW for 1.5 hrs, or 6 MW for 20 mins.• Storage capacity ~ 20% of installed wind capacity.• Discharge/charge time of 1.5 hrs.• Reduces intermittency & smooths output.

Fuel Cells- Hydrogen Storage

• Norsk-Hydro, Utsira, Small Norwegian Island. 1.2 MW Enercon Wind Turbines

• Prince Edward Island, Canada.

Wind/Hydrogen

• H2 as transportation fuel for Germany?• H2 needed to replace oil ~ 23 Mt.• Electricity needed to produce H2 ~ 1100 TWh.• Electricity consumption 2005 ~ 600TWh.• Installed wind capacity needed ~ 418 GW.• Wind capacity 2005 ~ 17 GW.• Massive infrastructure changes needed.

Status of Storage Technology

• Pumped Hydro adopted by utilities.• Other storage technologies not adopted.• Other storage technologies at same stage as

wind power 10 years ago.• Need similar programs to encourage and

accelerate adoption of storage of RE. • RE/H2 expensive replacement for oil.

A Realistic Target for Storage

• Eliminate intermittency.• Make RE dispatchable.• Reduce RE back-up and regulation reserves.• Realistic target is total elimination of RE

regulation reserve requirements by 2015.• Will also reduce back-up requirements.• How much storage needed?

RE Regulation Reserve Requirements

• Dena grid study projections - 2015.• Max negative reserve - 5500 MW. Provide

by feeding RE to storage.• Max positive reserve – 7000 MW. Provide

by feeding RE from storage.• 7000 MW of storage needed by 2015.• Equivalent to ~ 3% of installed capacity.

Conclusions• RE is intermittent and non-dispatchable.• RE increases back-up and regulation reserve

requirements.• Storage can make RE dispatchable.• 7000 MW of storage needed to eliminate RE

regulation reserve ~ 3.5% of 2015 capacity.• Without storage RE will be limited to 20%. • Government policy/programs needed to encourage

development of dispatchable RE systems.