Last week, the sprawling 4 hectare Bakken Hale estate, a private residence on the island of Hawaii owned by the founder of the medical device giant Medtronics group, installed a big solar array and battery storage system that will make it the largest renewables-based off-grid system for a private home.
The Bakken Hale installation includes a 170kW solar array and 1MWh of Aqueous Hybrid Ion batteries from US battery developer Aquion Energy. It will serve an average load of 23kW and peak load of 42kW (this is some house!). Just to compare, the average load for suburban homes is less than 2kW.
The estate is currently powered entirely by generators fuelled with propane generators, more commonly used with stoves and blow-torches. That costs it around $US50c/kWh. The installers say that the estate will have around 3-days of full autonomy, and the back-up generators will only be needed around 3 per cent of the time.
The estate is located on the environmentally sensitive Kona Coast, and owner Earl Bakken, 91, says he wanted to demonstrate that using a solar and battery-powered microgrid is the best solution now.
“This installation will enable us to meet our around-the-clock power needs with solar generation and will reduce our fossil fuel usage by 97 percent,” Bakken says. Bakken knows something about battery technology because he is credited with developing the portable pace-maker and apparently wears one himself. He says he chose Aquion’s battery products because they are non-toxic, and long-lasting.
Jonathan Matusky, the product manager for Aquion Energy, says demand for battery storage is growing, and Hawaii and Australia are the two leading markets, because of their high electricity prices, big solar resource, and the independent nature of consumers.
“A lot of our batteries sold right now are for off grid residential solar space,” he told the Australian Energy Conference in Sydney. And Australia is one of its biggest market, accounting for around 1/6 of the 5MWh of storage it has delivered to date. A new delivery in Australia soon will take the local installation to around 1MWh.
“Australia is going to be on leading edge of energy storage adoption. Hawaii is similar, and you see customers deciding to take their homes completely off the grid, because of how expensive the electricity is, how cheap the solar is, and how fed up they are with utility.”
“This market is very much real and it makes sense for customers. And it will open up in next year or so.”
For further details of the Bakken Hale installation: The system is designed to generate 350 MWh per year silently from the sun, with little maintenance for 20 years. Over that time, the system will reduce carbon dioxide emissions by more than 5,000 metric tons. The batteries will charge from the solar array during daylight hours, and discharge to provide nighttime power on a daily 8-hour charge/16-hour discharge cycle.