Local Energy Storage

The project Local energy storage (LES) will develop and demonstrate a LES based on an unique power conversion and control concept combined with commercial batteries to enable higher local production of renewable energy, make the user take full advantage of own electrical production and last but not least stabilize feeder lines in the low voltage grid as more and more renewable energy is injected to the grid. The commercial viability of the new LES concept will be optimized and demonstrated. The grid company°s in Denmark have seen growing problems with the power quality with the increase in PV-penetration in the last years. Increasing renewable power production has impaired the power quality. Sometimes the quality is impaired so much the PV- inverters disconnect from the grid, due to the power quality being outside the range of the inverter settings resulting in disability to feed power to the grid. Another typical impact is that the customers experience a high grid voltage due to the PV-plants. This leads to lower durability in utility items, which is most commonly seen with light bulbs becoming defective faster than you would normally expect. To prevent this grid companies will normally adjust transformers or strengthen the grid by laying down
bigger cables in the area where the power quality is at its boundaries. This is very expensive. By implementing a LES system near the source of the problem they can postpone a needed strengthening of the grid. This will be a better solution than making a guess on how the grid will be challenged in the future and sizing the cables and perhaps transformers based on this. In some cases the strengthening of the grid may be avoided by, via analyzing equipment, getting to know the grid operating conditions better and moving the energy producers or consumers from one phase to another. But in most cases the economically viable and straight forward way to improve the power quality is simply to install a LES system, and the value of this for the grid companies
will be investigated. System owners with hourly based net metering can improve the profitability in the PV-plant by
time-Shifting PV power from periods with high production and low consumption to periods with low production or high consumption. This way the value of a produced kWh rises from the 2014 feed in tariff (FIT) of 1.16 kr. to 2.20 kr. with own consumption. One of the targets for this project is to investigate what the capital and operating expenses should be in an optimal system and make an economical and technical model to help predict these variables. Danish legislation is decreasing the FIT with 14 øre/yr./kWh over the next 6 years and at the same time energy cost will rise with approximate 4-5%/yr. which will make the incitement to own- consumption even higher in the future. For PV-system owners not under the net metering with F IT
of 1,16kr/kWh the incitement to be own-consumers exists already if the total cost of owner ship is lookin feasible.