Breakthrough in Energy Storage from the University of Wisconsin
Here’s an exciting development that lies squarely on the intersection of the main problems we face in making the migration from fossil fuels to renewable energy. Combining solar energy with storage, it’s a device that converts incoming solar energy directly into chemical energy, stored in the electrolyte within a flow battery.
There are several strategies associated with integrating large amounts of energy from variable resources, and storage is only one. For instance, high voltage power transmission potentially enables us to connect our energy sources, whenever and wherever they’re available, with load over huge distances. Storage solves the problem in the opposite manner, enabling us to create self-sustaining microgrids wherever we choose.
The exciting thing is that so much is happening so quickly in this space. It’s true that integrating huge volumes of solar and wind are a challenge; it is also true that solutions are popping up all around us.
It looks promising, but let’s not become too excited so soon. It’s several very big steps between a successful laboratory test and production.
An interesting development but without the numbers the promise that it “could be more efficient” suggests only a small savings in the wiring from solar cell to flow battery.
Breath,
It’s so recent that probably there haven’t yet been any tests to determine its efficiency.
I would find it difficult to believe that the researchers did not calculate efficiency as part of their work. While I agree with your previous comment there is nothing particularly new here. We have PV cells, we have flow batteries. This just combines them. While there were surely engineering issues to resolve this does not seem to represent a “scientific breakthrough.”
I was disappointed that there was not a middle step that was cut from the process. I would have considered it on another level if the flow battery was charging the electrolyte without the use of a conventional silicon chip. IE the solar to electrical conversion takes place within the electrolyte. This is a development I am expecting, but this is not it. Thermal storage has already had developments in this direction with a solar activated chemical heat battery.
The other direction things could go would be to combine the solid state chip with a solid state battery which may be some variation on an EDLC.
I see it as a good thing that research on energy storage, including batteries is continuing. However, I think that too much is expected of storage systems.
Although adequate storage systems could make it possible to get reliable power from intermittent sources of power, such systems would not eliminate the high costs resulting from the need to over-build regardless of how much storage there is. For example, if renewables had a capacity factor of 1/3, then they would have to be over-built by a factor of three. The costs of that degree of overbuilding, combined with the need for huge storage capacity, would make renewables cost far more than nuclear.
But regardless of what power sources are used, a modest amount of storage would make load following easier and more efficient. That is sufficient reason to continue research on energy storage systems.
Craig,
I agree, it’s very encouraging that a wide variety of storage devices and strategies being researched and developed.
Although such development are very promising and optimistic, it must also be conceded that many will never reach commercialization, or make it past laboratories. (What works on a small controlled scale, can’t always be up-scaled)
I also thought the name of the Alma mater for these young scientists was also interesting, the “King Abdullah University of Science and Technology in Saudi Arabia” !
Frank I don’t think you can derive an overbuild ratio based upon a capacity factor especially without considering available storage. This is primary because “Renewable energy” is not a single item. It is a collection of technologies with different potential usages. In some cases the CF is a misrepresentation of the usefulness to for-fill our overall power requirements.
I think we both understand that the capacity factor is the ratio of actual output compared to potential output if operating at 100% capacity. Usually it is measured over the course of a year. It gives some idea of useful and total idle time over the measured period. But a plant operating at 30% capacity for 100% of the time would give the same CP as a plant operating at 100% capacity for 30% of the time.
Utility companies have historically over built the number of plants to meet the peak power output required. The peak power demand is usually in the middle of the day. While there can be additional residential demands in the early evening this is in the absence of daytime commercial and industrial loads.
Geothermal energy has a capacity factor depending in the neighborhood of 90% and so is about equal to what we expect from a nuclear power plant. They operate 24/7 and can easily take over base load duties. The low hanging fruit of geothermal has been volcanic related. A recent series of wells in Iceland hit magma, the holy grail of geothermal and we can expect more of this using deeper wells in many unexpected locations. What is called “dry well,” “engineered” or “enhanced” geothermal will likely have lower CF but never-the-less be useful for power 24/7
A solar power plant will probably never have a capacity factor over about 30% to 40% without storage because it is producing less power at either end of the day and nothing at night. But if we were to consider its capacity factor only during peak daytime hours I would expect it to be much higher. Depending upon factors like weather, climate, latitude and the resulting isolation a “capacity factor” of 90% during peak demand periods would not be surprising. So instead of building peaking gas turbine plants to come on during the peak demand we build solar power plants and they would essentially be a drop in replacement. A difference would be that gas turbine plants carry a startup maintenance cost that would be absent for solar.
Solar thermal power plants have a very easily engineered storage capacity in molten salts. This will essentially raise the CF to between 50% to 80%
We are heading in the direction of a 50% capacity Factor for Wind Power. Of all the potential renewable energy sources a technological solution may be most helpful to wind power.
But how much of a new technological storage solution would we really need for 100% renewable energy? Geothermal mostly doesn’t need it. Solar PV takes the place of peaking plants with only a modest overbuild. Solar thermal has a solution that only needs implementation. And the most beneficial amount of storage would be to cover the early evening demand. That only leaves wind to fill in the holes and Isentropic PHES seems to be as good a solution as pumped hydro: https://www.youtube.com/watch?v=sIxt6nMf-IQ
Our present pumped hydro usage (2015) was about .12% of all electric production. http://www.eia.gov/electricity/monthly/current_year/february2016.pdf Both Wind and Solar PV have the advantage of being able to incrementally build a power plant as long as the land is available. The start up times are also relatively short.
So to suggest that some averaged CF dictates the overbuild ratio seems to be an oversimplification at best and possibly wholly inaccurate.