BATTERIES FOR SOLAR ENERGY SYSTEMS

CHICAGO -- California is no stranger to rolling blackouts. When Charles and Elke Hewitt installed a solar electric system with batteries for emergency backup power on their home this April, they were shocked when Southern California Edison rejected their application for grid connection under their net metering program. And the Hewitt family was not alone. Soon all homeowners with solar electric systems with battery backup in California could be affected by Edison’s stance on backup power.

Edison informed the couple their application for grid connection was denied because the batteries they used to store energy for emergency backup power when the grid went down were considered “power generators” and not energy storage devices, said Charles Hewitt. Edison said Hewitt did not qualify for their net metering program because the utility could not distinguish between power produced by the solar panels and power produced by the batteries, which it considers a nonrenewable source of power, he said. Edison explained their policy had not changed. It was the equipment that had changed. Members of the solar industry refute Edison's position.

“We were excited to use our system and stop paying electric bills,” he said. “Summers are peak production for solar and now we are told we can’t use our system. I have thousands of dollars of PV system sitting on my roof that now I can’t use.”

The 3.7 kilowatt solar electric system installed on the Hewitt home in Santa Barbara uses an Outback grid-tied 48-volt battery system for backup power. Hewitt said his battery bank only stores power; it doesn’t produce it. The problem is, the system uses an inverter/charge controller design that does not allow batteries to be separated from the system, he said. In other words, if he disconnects the battery bank from the system, the system won’t work.

When asked if the utility could be worried homeowners will charge batteries during off-peak hours and then sell excess power back to the grid during peak hours (buy low/sell high), Hewitt rejected this idea. “This is a pretty small battery bank,” he said. “Our batteries are metal nickel hydride batteries. There aren’t a whole lot of kilowatts you can pull out of those batteries before they are ruined and they are very expensive. If Edison thinks homeowners will be using these batteries to cheat a few dollars off our electric bill is nonsense. The main reason people get backup systems is for emergency backup power only when the grid goes down.”

The Outback inverter Hewitt uses has been on the California Energy Commission approved equipment list for eight years and hundreds of these systems have been approved, he said. Now Edison is saying all battery backup systems need more review. Homeowners with battery backup solar electric systems are being asked to pay $800 as part of that review, he said. “Edison is sending small systems through the same review process as large megawatt systems,” he said. “Apparently other utilities are jumping on the bandwagon and they plan to go back and remove credits from all homeowners with backup systems.”

Hewitt filed a complaint with the California Public Utility Commission, but the complaint was rejected. He filed an appeal in mid-July.

Other hThe world’s largest solar companies have filled three floors of the Moscone Center in downtown San Francisco this week with solar gear, everything from next-generation solar panels to robots that assemble solar cells. But it’s the batteries, which can store the electricity produced by the solar panels, that have emerged as the real stars of this year’s Intersolar North America show.

Battery giants, eager startups, solar firms and European power players all showed off battery products that they hope to sell to homeowners, businesses and utilities in the U.S. These batteries can connect to solar panel systems and store energy during the day to be used later at night. Such battery systems can also be used for backup power in the event of a grid blackout, or also paired with an electric vehicle.

A grid batteAt a booth at Intersolar staffed by Korean electronics giant LG, curious attendees flocked around a battery that LG had quietly placed on a wall with just a few lines of basic information. “Are there any brochures for this?” numerous passersby asked the booth attendants, eager for any data on the device.

LG’s Joon Son, manager of the Solar Products Planning Team, told me that the LG energy storage system will go on sale in Europe in 2015, and if there’s demand, in the U.S. in 2016. The product contains a lithium iron phosphate battery that Son said LG procured from another company. LG said it hadn’t set the target price yet.

The battery weighs 121 lbs, and has a capacity of 2 kWh, but can be scaled up to 18 kWh (9 modules). The product can also be monitored remotely with a smartphone and can be plugged into any clean energy source, like solar panels.

Solar and Batteries

When some people think about solar, they might think that they will become free from “The Man,” because a battery will allow them to store any excess power they generate, thus taking them off the grid. While this is possible with solar, it doesn’t make much financial sense for most people. Allow us to explain:

• Grid Tie Solar

  Most solar systems are “grid tied” these days. That means when the system is generating power during the day, any excess power it makes is fed back into the grid through something called “net metering.” Your meter spins backwards and the utility credits you for that power. At night or on overcast days, you’ll use grid power instead of solar, but your utility doesn’t charge you until you’ve used up all the credit you generated through your panels. More on grid tie solar.

• It Means You Probably Don’t Need Batteries

  You don’t need batteries for your solar system if you’re already connected to the grid. It’s an option, but not one that most people use these days because the batteries are still very big and bulky. They’re also expensive and need to be replaced every five to ten years, depending on the type and how well you take care of them. Battery technology is evolving and solar batteries may become a more viable option someday, but for most people right now, it’s more practical to simply tap the grid in off hours.

• Net metering – The Virtual Battery

  Net metering is like a virtual battery. The utility keeps track of any extra power your solar panels produce, which spins your electric meter backwards. Then at night, you simply use grid power on the credit you earned while supplying the utility company with power during the day. Net metering is maintenance-free and typically costs around $5 per month in administrative fees.

• What about ”?

  It’s true, our name has “off the grid” in it. It’s just a metaphor. We want to take at least one block’s worth of grid energy usage out of every city per campaign, but the bottom line is that we’re here to help you buy solar panels for your home.

Solar Battery Back-up Systems

We understand that some people are interested in solar batteries in the interest of disaster preparedness, and because this is America, you’re free to spend your hard earned money any way you want. Here are a few things to consider in your decision though:

• Battery back-up systems are reliable for those “what-if situations.”
• However, those “what-if” situations are fairly rare. The American electric grid is over 99% reliable, and using a battery would mean you’ed be spending an extra $5,000 to $10,000 every 10 years for the 1% chance that you will need battery back up.
• The Copper Stripboard contains rows of copper tracks. Each track is electrically separate from its neighbour. It contains holes for your components. The boards I supply are larger than needed, this will allow you to expand the system at some future date.
  
  The Batter Holder ... errrr holds your batteries.... and comes with two pins, one for the positive and one for the negative ends, they will be soldered into the stripboard.
  
  100 Ohm resister - at one point this was needful in the kit as the LED couldn't cope with some of the voltages in the experiments - however the new LEDs do and the resistor is simply in there because it is advertised as such! Maybe you will have need of it when you expand the system.
  
  LED - this is a high intensity light emitting diode. 3.2-3.6V forward voltage, with 10000mcd at 20ma. A LED must be placed in the circuit the correct way around. The longer leg should receive current from the positive terminal/direction.
  
  1N5817 DIODE - this diode allows current to flow in only one direction - this prevents battery power discharging through the solar panel at night. It drops about 0.2V from the system. This blocking diode also needs placing in the circuit in the correct orientation. The diode has a circular band across its barrel at one end of the diode. This should be closest to the negative/ground.
  
  WWelcome to the solar backlash. In Grist’s “Utilities for Dummies” series last year, David Roberts prophesied that solar and other renewables could “lay waste to U.S. power utilities and burn the utility business model, which has remained virtually unchanged for a century, to the ground.” And lo, it is coming to pass — though not without a fight from the utilities first.
  This May, Barclays downgraded its rating of America’s electricity sector from “market weight” to “underweight.” Its rationale? Solar — or, more specifically, the great leaps that are happening or expected to happen in technology for storing the energy that solar generates. While the solar industry took a roller-coaster ride over the last decade, the R&D that went into electric cars created the killer add-on it was waiting for: really awesome batteries.
  It’s not a coincidence that Tesla formed a sales partnership last year with the solar panel development giant Solar City. The two companies are basically smushing solar panels and fancy electric cars together to create a Transformers-like superhouse that could join with similar houses to form a microgrid, no utility necessary. In their utopia, a house could be powered in the off-hours by the battery from the car parked in the garage. Or, if you’re not car people, you could just buy the battery. Tesla is claiming that the cost of their batteries will drop in half by 2020.
  For this reason, it’s not surprising that some utilities are specifically going after solar arrays with batteries. In California, utilities are demanding that any solar panel installation that features batteries add an extra meter just for the battery(which adds about $1300 to the overall cost of the installation) before it can be allowed to sell electricity back to the grid.
  PG&E, the company that owns California’s biggest utility, refuses outright to buy energy from customers that have both solar panels and batteries, as does San Diego Gas & Electric. The utility companies argue that such storage systems could, in theory, be used fraudulently: Consumers with solar panels could fill their batteries directly with power sourced from the grid during times when the power is cheap and th