Tag Archives: storage

Fighting the last war: Study finds solar + storage uneconomic now  | from Utility Dive

“A Rochester Institute of Technology study says a customer must face high electricity bills and unfavorable net metering or feed-in policies for grid defection to work.”

Yet…this study used current battery costs (at $350/KW-Hr), ignoring probably cost decreases, and then made more restrictive assumptions about how such a system might work. It’s not clear if “defection” meant complete self sufficiency, or reducing the generation portion (which in California about half of electricity bill.) Regardless, the study shows that grid defection is cost-effective in Hawaii, confirm the RMI findings. Even so, RMI said it would take at least 10 years before such defection was cost-effective in even the high-cost states like New York and California.

A more interesting study would be to look at the “break-even” cost thresholds for solar panels and batteries to make these competitive with utility service. Then planners and decision makers could assess the likelihood of reaching those levels within a range of time periods.

Source: A study throws cold water on residential solar-plus-storage economics | Utility Dive

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Repost: Lessons From 40 Years of Electricity Market Transformation: Storage Is Coming Faster Than You Think | Greentech Media

Five useful insights into where the electricity industry is headed.

Source: Lessons From 40 Years of Electricity Market Transformation: Storage Is Coming Faster Than You Think | Greentech Media

Getting EV owners to participate in electricity storage

Do we really need more storage for our renewables?

PG&E has been running a series of “advertorials” on clean energy in the Sacramento Bee and other papers. Today’s on the need for electricity storage caught my eye. I’m not sure that we need new storage in California, at least not large-scale, in the immediate future.

The PG&E article describes an event in February 2014 when California generated more energy, much of it from solar and wind, than consumers were using. PG&E raises this as a concern that should be addressed so as not to lose that energy. But PG&E’s premise ignores one critical point–California is not isolated–it’s connected to many other states.

California is the largest electricity consumer in the Western Interconnection (with 10 other states and parts of Canada and Mexico). However the state only represents 30% of Western load. All of those states have weaker directives on renewables and greenhouse gas emissions, and most have much larger portions coming from high-emitting coal-fired plants.

When California overgenerates from renewables, it exports that power to those other states. This leads to a reduction in natural gas and coal use. When California needs power, it imports power as it has been doing for decades. In other words, the rest of the Western Interconnect is already acting like a storage device. The Southwest utilities have long exported excess coal-fired power overnight to California at low prices. Now California can turn the tables. PG&E may not be getting renewable portfolio standard (RPS) or greenhouse gas reduction credits for those exports, but they reduce GHG emissions in other states.

This situation is similar to the recent rise in petroleum production in the U.S. The country now exports refined products thanks to advances in extraction technologies. Congress is considering whether to allow the export of crude oil.  For both California and the U.S., the concept of exporting energy has been inconceivable up to now. Time to rethink our paradigms?

Cheap energy storage may be parked in your garage

One of the key questions about how to bring in more renewables is how do we provide low-cost storage? Batteries can cost $350 per kilowatt (kW) and pumped storage somewhat lower. Maybe we should think about another potential storage source that will be very low cost: automobiles.

California has about 24 million autos. The average horsepower is about 190 HP which converts to about 140 kW. Let’s assume that an EV will have on average a 100 kW engine. Generally cars are parked about 90% of the time, which of course varies diurnally. A rough calculation shows that about 2,000 GW of EV capacity is available with EVs at 100% of the fleet. To get to 22 GW of storage, about 1% of the state’s automobile fleet would need to be connected as storage devices. That seems to be an attainable goal. Of course, it may not be possible for the local grid to accommodate 100 kW of charging and discharging and current charging technologies are limited to 3 to 19 kW. So assuming an average of a 5 kW capability, having 20% of the auto fleet connected would still provide the 22 GW of storage that we might expect will be required to fully integrate renewables.

The onboard storage largely would be free–there probably are some opportunity costs in lower charging periods that would have to be compensated. The only substantial costs would be in installing charging stations and incorporating smart charging/storage software. I suspect those are the order of tens of dollars per kW.