Sunday, July 16, 2017

green polution

There is a source of pollution nobody seems to notice.  A huge quantity of green waste is allowed to rot on the ground in Hawaii, conservatively 60,000 tons a year* (*my estimate) No doubt others will challenge my figures, but they’re the best I can find.  Sure it makes topsoil, in about 100 years, but it makes pollutants, methane and carbon dioxide (CO2) immediately.

Hawaii, like most places, has energy issues, but environmentally friendly options.  Wind and solar are popular but they have limits too; neither can be depended upon when the need is greatest.  Solar needs sunlight, but peak demand is in the evening.  Wind is fickle.  The turbines only work in a relatively narrow speed range, if the wind is too slow they can’t make usable power, if it’s too fast they can break.  Some efficient inexpensive storage is needed. Unfortunately all known methods for storing electricity are expensive or inefficient.

There are a number of technologies that can turn that green waste, a fuel, into electricity, and while storing electricity is difficult, storing fuel is not.  We have been doing it for eons. Green waste is not only available it is abundant.  Hawaii County Environmental services collects 40,000 tons of green waste annually converts it to mulch, hauls it 40 miles and gives it away.  That pales compared to undocumented green waste rotting by the roadside.  The total green waste is probably over 100,000 tons a year*.  Half the people I know have a secret “puka” where they dump green waste rather than burn gas to drive 40 miles to Puuanhulu.  I alone dispose of a thousand pounds a year from my house lot.  Then there is the timber from trees that Helco has to cut to protect power lines.  No the diesel fuel to haul it to a power plant is not prohibitive; I did the calculations.  Burning 100,000 tons of green waste - renewable biofuel- could generate about 290 megawatt hours* of electricity a year, about what we need.  If those numbers sound absurd, consider that Hawaii used to export over a million tons of sugar a year (Wikipedia) and burn a comparable amount of the bagasse, waste to generate electricity.  The idle Hu Honua plant was built to burn bagasse; then converted to coal and recently began conversion to burn logs.  Anything that will burn and release energy, can be used to fuel a power plant. (Babcock and Wilcox) Yes, there are more sophisticated ways to turn waste to electricity, or even motor fuel.  Why not?

Now one objection that comes to mind is that burning creates CO2, but so does rotting.  Rotting also creates methane a greenhouse gas ten times as powerful as CO2.   A power plant that can turn green waste to energy can also do it with garbage and trash.  If adding recyclable paper, to the mix can make it viable that should not be arbitrarily ruled out.  Granted there are concerns that in order to make such a plant viable there would be a temptation to burn recyclable material. So?

I support recycling but just as there is a wasteful mentality there is a recycle-at-any-price mentality that leads us to pay $140 a ton to ship low value recyclable materials to the mainland where most of it will hopefully be recycled.  On the other hand using paper for fuel - worth maybe $40 a ton* - is summarily rejected. So the actual cost to recycle it is about $180 a ton. There is an environmental impact of shipping it 2600 miles.   

Recycling is a means to achieve a goal. It should not be the goal.  Otherwise we could recycle more by insisting on more wasteful packaging. Sometimes the highest and best use of surplus material is to extract the energy.  The measure is not how much we recycle, but how little we consume unnecessarily.  What do you think?

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