To the Editor:
Albert Colone’s letter in your Dec. 20-21 editions suggested a “municipal microgrid” might be something the different factions in the energy discussion could all agree on. The letter touched on technical matters that deserve discussion.
We need to understand that a “microgrid” refers to a local electric grid that can be isolated and continue to function for an extended period even when the larger grid goes down. Of course, the main grid is very reliable so, in fact, we don’t need a microgrid.
Colone writes that solar panels and wind turbines could provide electricity and heat for a complex at the railyards with gas used only as back up.
First, because of intermittency of solar and wind power, any microgrid that must support several buildings or run in “island mode” (off the main grid) for an extended period must primarily rely on hydropower or gas.
Second, solar and wind produce electricity, not heat. Generating heat from electricity – like your toaster does – has a less-than-even coefficient of performance (COP), meaning for every 10 kW of electricity you pay for, you might only get 8 kW worth of toast.
We see now that no wind-and-solar microgrid in the railyards could realistically provide heat and electricity for more than a good-sized dog kennel, and it would need significant battery backup even for that.
Commercial “combined heat and power” (CHP) systems – including microgrid applications – are driven by gas turbines. A 25mW CHP “microgrid” could power a chunk of downtown Oneonta. It would require 6 million cubic feet of gas – that’s 15 CNG “bomb trucks” – daily to keep it running.
But that might not be the worst part. If you only needed heat, you’d still have to run the turbines and generate electricity. If you didn’t need heat, you’d have to dump that part of your system’s energy even though you were paying for it.
Yet, even that might not be the worst part. This plan would mean that we postpone making necessary changes to our energy systems to cut emissions and stem global warming. Who would be against a CHP microgrid? I’ve got my hand up.
There are sensible solutions, though. Wind and solar provide electricity that gets “net metered,” meaning we get paid back for any energy we push onto the grid beyond our needs. We’d still pull juice from the main grid, but we’d sometimes be pushing electricity back onto it.
You could use the Susquehanna River or even municipal water or sewage systems for geothermal energy to heat or cool downtown businesses. That would be renewable energy: local, reliable, inexpensive. Geothermal heat typically has a coefficient of performance of 5, meaning for 1 unit of electricity you get 5 units of heat. It would not be a microgrid, but it would be smart.
The fact is, we don’t need a microgrid. But we do need to understand basic energy concepts and start using our heads to power our region into a sustainable future.