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Why Our Antiquated Power Grid Needs Battery Storage
Lucas123 writes: Last year, renewable energy sources accounted for half of new installed electric-generation capacity (natural gas units made up most of the remainder). As more photovoltaic panels are installed on rooftops around the nation, an antiquated power grid is being overburdened by a bidirectional load its was never engineered to handle. The Hawaiian Electric Company, for example, said it's struggling with electricity "backflow" that could destabilize its system. Batteries for distributed renewable power has the potential to mitigate the load on the national grid by allowing a redistribution of power during peak hours. Because of this, Tesla, which is expected to announce batteries for homes and utilities on Thursday, and others are targeting a market estimated to be worth $1.2B by 2019. Along with taking up some of the load during peak load, battery capacity can be used when power isn't being generated by renewable systems, such as at night and during inclement weather. That also reduces grid demand.
Trouble is you need very large tanks of water, or to seperate them a long way. For instance a house might use 2 kWh overnight, that's about 7 MJ.
Round trip efficiency for pumped hydro system is around 88%, call it 100, and call g 10. So you need a tower or hill 350m high with 2 tons of water in it, or if you prefer, a swimming pool, 2*5*10m suspended 6 metres above your current pool. So, that's a fair bit of unlikely, just to power one house.
Most sensible big hydro locations have already been gobbled up, they made sense decades ago.
Don't forget that adding solar panels is a virtuous cycle with respect to HVAC. You're not only capturing energy, but you're also not dumping that solar load onto your roof and attic. Here in Albuquerque, some of my friends that have put panels up found that even before the panels went live, their electric bills dropped 20+% just due to the panels providing shade for a portion of the roof. Then they found that their solar panels were oversized since they hadn't expected that reduction, and exceeded house demand essentially from 8am to 6pm. Most of them are providing above 90% total load month to month, even in the winter (natural gas heating). Another panel or two and some energy storage and they'd be there.