Saturday, October 26, 2013

New Challenges for Renewables

2013 has served as a benchmark for solar and wind, as they have reached the long-awaited point where they are cost-effective and cost-competitive with most other sources of electricity generation.  Utilities everywhere, here and abroad, are jumping on the renewables wagon because they are now appearing to be the “best” new source of generation.  Led by California, and an ever-growing list of commercial and industrial entities such as Apple, Google, Oracle, Ebay, even Walmart) “microgrids are emerging as a credible threat to the dominance of America’s 100-year-old-plus utility monopoly. The small-scale versions of centralized power systems, once just used against blackouts, are now gaining thousands of customers as homeowners in states with high power costs turn to them as a way to manage rooftop solar systems, cut electricity bills and, in some cases, say goodbye to their power companies” (1) This is just the tip of the proverbial iceberg, and its rapid growth has identified two major issues that will need to be seriously addressed.

First is the “problem” of intermittency of generation.  The sun doesn’t always shine, and the wind doesn’t always blow; so the harvesting and storage of electricity from these sources is the next big challenge.  Up to now, solar has been very effective in supplying “peak electricity,” displacing costly fossil fuel generators.  But it has worked so well, that we are approaching times in some places where there is way more renewable electricity available than is demanded. (2) 

Electricity storage is not really a new concept (remember, we are using stored energy from photosynthesis in our oil and gas), and a variety of new and diverse systems will be needed in the future.  Back in the early years of nuclear power in California, PG&E proposed building the 2200MW Diablo Canyon twin nuclear reactors.  At that time, this power plant would produce about 20% of PG&E’s supply.  As with other large steam-driven generators, one cannot simply turn the system on or off to meet demand, such as a night.  If Diablo Canyon came on line, it would create a major problem with all the other generators in the state.  The solution was the construction of the Helms Project. (3) Two lakes at different elevations were identified in the Sierra Nevada Mountains, and a large tunnel was drilled between them.  The water from the upper lake is controlled and during the day is released through the shaft to spin generators below to make electricity.  However, this would eventually deplete the upper reservoir.  So at night, the 2200MW from Diablo Canyon is used to reverse-pump the water in the lower lake back up to the upper lake, so it can be re-released again the next day when the demand for electricity was up.  Pretty nifty!  Helms produces about 1000MW when running during the day, and requires about 2000MW for back-pumping; so it around 50% efficient…1000MW of nuclear electricity is “lost,” but that is electricity for which there is no demand in the California grid system, and is deemed “losable.”

California, and other states and utilities, are exploring a wide variety of energy storage systems.  Aside from pumped-storage of water, other technologies include compressed air storage in large cavities (such as those created by the extraction of oil and gas), batteries, ultra-high energy capacitors, and a whole range of new ideas.  My bet is on Hydrogen…use renewable electricity to hydrolyze water into H2, store it on site, and then run it in a fuel cell to created electricity and a waste product of pure water, which can then be reused.  Clean, fairly simple technology that already exists.  Inefficient?  Probably no worse that the 33% efficiency we get from traditional steam generation; and of course, the fuel is free and clean.  The main argument is cost, and the implementation of this technology…but this too, will be addressed and overcome as the true value of the benefits of renewable electricity is slowly absorbed into our energy economic reality.

The other big issue created by this rapid growth of local, micro-generation is its impact on utilities, who claim they are forced to maintain large, inefficient grids supplying fewer and fewer customers.  Also of concern is the price paid to individual generators who wind up putting electricity into the grid as their meters spin backwards. (4) This is reminiscent of what the automobile did to the horse industry, or what the cell phone has done/is doing to the land-line companies.  One main challenge is to modernize and upgrade our national and local grids to accept the new energy resources of the future.  Right-wing, fiscal conservative opposition is in full swing to defeat any recommended changes; but as renewables become mainstream, for economic and/or environmental reasons, electricity
supply and distribution will be very different in the future.  Already, California is leading the way with new regulatory ideas and laws to encourage the continued growth of renewables. 

The transition many have dreamed about is now upon us.  It will not be easy, and not without mistakes and problems.  It will take time, ingenuity, money, and most of all commitment for a safe, clean, affordable, and sustainable future.  And most important of all – it produces local jobs.  It is happening!

Some references:



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