Renewable Energy’s Progress: Good News
Here are several pieces of good news from all around the world, heralding breakthroughs in the use of renewable energy. It’s so good to see that this is happening.
The king of Morocco sounds like a heck of a good fellow, doesn’t he? I had two opportunities to go, but they both fizzled; maybe I’ll have a good excuse to see this landmark CSP project first-hand.
It’s good that work is still being done to develop energy storage systems. If the cost is low enough, they will be useful regardless of whether we get our power from coal, gas, uranium, thorium, the sun, or the wind. However, none of the linked-to articles proved that energy storage will ever be sufficient to make renewable sources of power practical. Until or unless energy storage is able to make renewable sources of power practical, it would be unwise to count on them.
Per one of the articles, the cost of battery storage is expected to fall below $400 per KW. I do not have figures to determine whether that is low enough to make huge scale battery storage practical. One of the factors is how much storage would be required. That would depend on assumptions regarding the weather.
One of the articles covers power to H2. It assumes that injecting H2 into the current natural gas grid would be a reasonable thing to do which I see as questionable. H2 is an escape artist; it is very difficult to confine it because it easily leaks out. Moreover, it gradually embrittles metals. It is doubtful that it could be injected into our current natural gas grid without creating serious problems. Moreover, power to H2 is still inefficient. So are the other methods to generate H2.
Compressed air storage is inefficient. One way given to boost the efficiency is to burn natural gas to heat the air in the recovery device; surely we do not want to do that!
Thermal storage using a mixture of molten salts (sodium nitrate and potassium nitrate) is a proven technology, but it remains to be seen how practical it would be to use it to store the huge amounts of energy required to compensate for unfavorable weather.
The efficiency of energy storage has a direct bearing on the cost of solar and wind systems. If energy storage is inefficient, then more power would have to be generated to compensate thereby increasing costs.
It is certainly possible that at some unknown future date energy storage systems will make wind and solar power practical. However, we have not reached that point yet and it may be that we never will. Therefore, it would be unwise to depend on it. Until or unless it occurs, we should be developing better nuclear power technologies to avoid the problems associated with our current pressurized water uranium reactors. And, as a temporary measure, we should be building more nuclear power plants of present design.
Frank,
See:
http://www.2greenenergy.com/2016/01/08/csp-thermal-heat-storage/
http://www.2greenenergy.com/2015/09/28/discussion-on-energy-storage/
http://www.2greenenergy.com/2015/11/19/affordable-grid-scale-energy-storage/
Cameron,
I read the material at all three of the links you included. The only one with which I was not familiar was using hot sand for heat storage. Obviously being able to store heat at a higher temperature increases thermodynamic efficiency, which is important. However, the technology for using sand to store huge amounts of heat is unproven. What they are proposing is circulating the sand, almost as if it were a fluid. At this point it is questionable whether that will be practical. The abrasiveness of sand and other problems could make it unworkable.
Also covered was the idea that interconnecting wind farms over a large area will result in reliable power. That concept has never been adequately tested. To test it adequately would require having wind monitoring stations at many of the locations where it would be practical to build wind farms. The data from the wind monitoring stations would have to be monitored over a period of years to determine whether the interconnecting wind farms would actually result in reliable power. Until that is done, those who support the concept are simply guessing and we should not be spending trillions of dollars based on guesses.
It is true that there is at least one solar system in successful operation that is able, by using heat storage, to produce power 24 hours per day. However, cloud cover could easily make the storage inadequate. How much heat storage would be required would depend partly on location so it is difficult to generalize.
With currently available technology, wind and solar power alone are not able to provide reliably for the power requirements of most large countries. Perhaps at some future date they will be able to, but we do not know that. We’ve been hearing for decades that the answer is hydrogen fusion reactors; the breakthrough is always 10 years away. That should alert us to the dangers of assuming that certain technologies will definitely become available in the near future.
I am reminded of an olde saying which we would be wise to keep in mind: “Don’t count your chickens before they hatch.”.
We are a long way from converting all our energy systems to 100% solar + wind power. This being the case, we do not yet need sufficient storage to back up 100% of demand at night and when the winds are light.
There are a large number of ways we can integrate substantial quantities of intermittent renewbles without going 100% of the way.
Hydro – most hydro plant has inherent flexibility and has built in storage. Such plant can be operated to balance the grid. In this way, Norway, Sweden and some alpine nations use the flexibility of their hydro generation to balance the large quantity of solar and wind power in Gernany and Denmark.
Demand response – a number of industrial processes as well as water distribution can be largely carried out when convenient to the grid so providing frequency response and managing local voltage. For shorter periods of regulation, large air conditioning and refrigeration plant can be briefly boosted or turned off with little or no noticable effect. In these ways, demand can be increased or reduced by a substantial margin as required.
Biomass / biogas – whilst biomass and biogas can in most areas provide only a small proportion of energy demand, in some cases, energy production can be scheduled when most needed. Wood, straw, and other dried biomass can be stored for months or even years, whilst biogas can cost effectively be stored for at least a few hours.
Geographical diversity – In Europe, there are a large number of electrical interconnections linking Scandinavia with Germany, Netherlands etc all the way down to Morocco. In this way, an excess or deficit of power in one place can be matched to the opposite in another area. True, this will not in every case work 100%, however the statistical likelihood of a match increases the bigger the geographical area and the larger the interconnection capacity. (Toss a coin 10 times, you will get an average of 5 heads and 5 tails with a fairly large margin of error. Toss a coin a million times and whilst the chance of an individual head or tail does not change, the margin or error is far lower in comparison to the number of coin tosses.
Stationary battery storage – primarily for frequency response, residential and commercial solar, and the deferral of power line upgrades.
Battery storage in vehicles – the increasing fleet of electric vehicles will at some point be able to offer some degree of vehicle to grid.
Finally, run of river hydro and geothermal can deliver baseload power.
With the above possibly 70 to 80% of all energy demand can be met with zero to low carbon energy sources with the remainder covered by a relatively modest contribution from the least harmful fossil fuel – natural gas.
In these ways, possibly 80 to 90% emission reduction can be achieved.
The final 10 to 20% will be much more challenging as a reliable grid looks for 99.999% availability. To achieve this with zero emissions through long winter periods with very little wind over a large geographical area will require a lot of storage, and probably not be cost effective – the last GWh would possibly only be needed a couple of times a century.
Excellent points, Gary – thanks.