The increasing amounts of renewable energy that are being fed from wind and solar farms into the power grid makes it necessary to manage properly this influx so to maximize the energy harvesting and minimize disturbances to the frequency of the AC power transmission grid. Batteries are the prime candidates to store such energy efficiently and subsequently deliver it to the grid with an extremely fast response time and a minimum of induced frequency instabilities. In addition, batteries are also suitable for the management of peak power demands in industries and transportation networks and thereby will avoid high demand charge penalties and the necessary short-term start-up of power generation equipment that operates with fossil fuels. Several battery chemistries are commercially available to perform such storage duty, namely: lead–acid, lithium-ion, sodium–sulfur, sodium‒nickel-chloride, and vanadium redox. Next to local electricity tariffs, the success of battery energy storage also depends on the electrical performance and service endurance of the battery. A sound comparison between battery chemistries and designs offered in the market has, however, been hampered by the absence of a methodology to evaluate the candidates in a fair and efficient manner. Accordingly, in 2015, the International Electrotechnical Commission (IEC) raised the International Standard IEC 61427-2 Secondary cells and batteries for renewable energy storage ‒ General requirements and methods of test ‒ Part 2: On-grid applications. This action now offers a tool to compare and test such battery systems for four scenarios of grid-connected energy storage. The approach chosen for this comparison testing is that of considering the battery to be a black box and verifying that the selected battery chemistry, and then its commercial battery design, could fulfil the need of frequency-regulation, load-following, peak-power shaving, and photovoltaic energy storage time-shift service. The presentation will describe the basic procedures for this testing and give examples of test data obtained with lead‒acid batteries for selected application scenarios.
Herbert Giess has been involved in lead–acid battery research, testing and customer-support activities since 1975. He is the leader of the WG3 working group of the IEC Technical Committee 21 that is responsible for formulating standards for stationary and motive power lead–acid batteries. In this capacity, Herbert has guided the establishment of the IEC International Standards 61427-1 and 61427-2 that stipulate the general requirements and methods of test for secondary batteries for renewable energy storage in off-grid and on-grid applications, respectfully. Herbert is also an independent consultant for lead–acid battery research, testing and customer support activities.