COST MODEL | BATTERY STORAGE In the near future, we could see electric vehicle owners being paid when they connect to the Grid and agree to controlled charging on the transmission network during triad periods the three, halfhour periods with the highest system demand between November and February, which National Grid uses to determine TNUoS charges to business customers. This higher cost band can be avoided with a battery-storage system, so represents a cash inflow to an operator. The DUoS charge is added to all business electricity bills, is set by your DNO, and is time-banded to encourage levelled demand. It can be mitigated through use of a battery-storage system. Battery storage can also be used in conjunction with a time-of-use tariff, such as Economy 7, for arbitrage and load shifting to cheaper periods. A battery-storage operator can also draw revenue from the savings made in reducing its Capacity Market Levy charges a government levy to improve supply security. The final cash inflow an operator will see in the current market is from providing a FFR to the Grid. Once negotiated, this can be a good source of revenue, but it is set to be phased out over the coming years. In Table 1, these inflows and outflows are calculated against an initial investment in three scenarios, and the final return generated. The analysis does not take into account the benefit of a solar PV generation system paired with the storage system. The storage system is assumed to be a 1.8MW, lithium-ion battery system, with a two-hour supply time. The data shows that significant returns can be recognised, even without a solar PV system, only when all incentives are taken advantage of in the current market conditions. These are benchmarked figures, but clearly show that there is a strong commercial case to be made for battery-storage systems. CJ expenditure (opex) over the period of planned operation. This includes annual maintenance to ensure battery health; physical maintenance from 10 years onwards; additional insurance premiums; and the largest opex the replacement cost once the lifetime of the battery has expired (every 13 years in this example). These are significant cash outflows, but can be outweighed when the correct inflows are planned and agreed. The main inflows to an operator are the savings generated via arbitrage (peak shaving), and the avoidance of the Transmission Network Use of System (TNUoS) and Distribution Use of System (DUoS) charges. The TNUoS charge is for using the electricity transmission network and applies solely to business users and generators. It is based on the share of demand ABOUT THE AUTHORS Authors Peter Baxter and Will Holland are part of the specialist MEP cost management team at Aecom Engineering Services, which provides cost estimating, procurement and cost management of building services installations. Trusted Technology Partner Jan Hansen - Director www.sav-systems.com 46 March 2019 www.cibsejournal.com CIBSE Mar19 pp44-46 Cost Model.indd 46 22/02/2019 16:41