Policy Successes: Almost every jurisdiction worldwide has implemented renewable energy targets but they are all based entirely on percentages of consumption. These targets have been able to be met from intermittent sources, mainly PV and wind because the targets are mostly lower than the penetration levels likely to cause network problems.
Policy Failures: The failure to couple these targets to any dispatchability requirement has provided little incentive for the development of effective storage technologies and at the same time started to create a bow wave of future network management problems. The issue of base load generation replacement by renewables has essentially been ignored. In Australia, if you look at any RFP issued by any state or territory more than 12 months old, not one of them places any premium on dispatchability. They were all designed to enable arbitrary targets to be met at the lowest cost. The attitude appears to have been to achieve the arbitrary targets as quickly as possible, then worry about the consequences later.
Policy Changes: The European Union led the way by introducing policies under the Strategic Energy Technologies (SET) Plan in 2007 to encourage dispatchable renewables. The Finkel report is the first definitive document to highlight the issue. It has also had a remarkable impact on the awareness of policy makers to the need for renewable energy storage. Two new words previously unknown have become common place – “dispatchability” and “baseload”!
Implementing Policy Changes: So the race is on. Which storage technology will win? The answer is – a few! It was disappointing to read the editorial in the November/December issue of Energy Source and Distribution naming batteries, Hydro or Hydrogen as the three leading contenders. Thermal Energy Storage was not mentioned.
The Technologies: The field of eligible storage technology contenders is getting narrower when the following key evaluation criteria are applied:
• capital cost
• service life
• locational flexibility
• network service capability.
The case for Thermal Energy Storage rests on its ability to readily satisfy each of the above criteria. Thermal Energy Storage is compared with Batteries and Pumped Hydro, being the three technologies currently capable of deployment in the NEM. Thermal Energy Storage systems can meet all four of the key evaluation criteria and the presentation provides the quantitative evidence to support this conclusion.
3 key takeaways from this presentation:
1. Low capital cost per unit of energy stored and long service life gives TES a much lower throughput cost than electric batteries.
2. TES has no locational constraints like pumped hydro.
3. TES has significant added benefits because it utilises synchronous high inertia steam turbine generators which are capable of providing the full range of network ancillary services.