Combined Heat and Power and Distributed Generation

Combined Heat and Power (CHP) is my favorite energy solution.

Large scale electric generation is most often a huge waste of energy resources.  Electric generation needs a kind of energy intensity to spin a turbine to spin an electron flow and as a result roughly half the input BTU’s are released as ‘waste’ heat.  Heat is not a bad thing, the problem is, we often site plants in rural areas where the heat is not used. Second, moving the electron stream over powerlines, another 15% of the input BTUs are lost as friction on the line.  That means, when you plug in an appliance to your wall socket, your one unit of energy pulled required 3 units to make.

There are roughly 60 centralized, large-scale power plants in NYS (coal, hydro, natural gas, nuclear) and we are part of a national grid system where we push and pull electricity to and from VT, NJ, PA and Canada across massive powerlines.  That is why, a plant failure in Ohio can cause a brown-out in NY– the inter-state flow was crippled and the demand drained the system.

However, there are wonderful examples of systems that use the waste heat and reduce the losses to the grid lines.  In addition these examples begin building a distributed generation system. Distributed generation is a move away from a few centralized large scale plant toward developing lots of smaller plants along the grid.  Distributed generation diversifies the larger system, making the whole system less vulnerable to human or technical failure, terrorist attack or natural disaster.  That is, distributed generation is a diversified portfolio of scale (small to large), type (hydro to nuclear), timing (daylight solar capture to variable wind patterns) and location (near biomass resources, near particular energy demands) of energy generation.

CHP as part of a distributed generation is generally smaller scale but sized appropriate to the local demands so the electricity and heat are used thus reducing grid friction losses and waste heat losses.  Using the co-products from electricity,  CHP transforms 35% efficient systems to more than 80% for well-designed systems (that means our finite natural resources go twice as far, a great ROI both financially, ethically, and environmentally).

Ex. 1.  Cornell University CHP.  Cornell has just recently moved from a coal based CHP to a natural gas based CHP in order to reduce it’s greenhouse gas footprint.  They generate electricity as the co-product based on the univeristy need for heat. That is, there is little waste heat, bc the plant is scaled to cull the highly priced electricity off the top and direct the ‘waste’ heat to warm campus through a maze of steam tunnels across campus.  Unlike most electric generation in NYS which is only 35% efficient, the Cornell plant is ~80% efficient as the ‘waste’ heat is used on campus and the electricity is used on campus reducing the grid line friction losses.

Ex. 2.  Boston University was heating a gigantic swimming pool.  Heat generation is 80-90% efficient – so why bother putting in CHP?  Well, bc there is waste heat generated all over the place in order to produced electricity.  Why not localized that waste heat at a swimming pool and earn money from the high value electricity.  I believe, BU, is actually making money from their electricity (savings or sales) while they heat their swimming pool.

Ex. 3.  Lyonsdale Biomass in Lyons Falls NY is a wood biomass powerplant that used to be a CHP system.  That is their waste heat used to go to a pulp plant across the way to dry the paper that was being produced.  It is unclear to me why this stopped, but the paper plant is now using natural gas heat and I’m throroughly bummed.  What kind of economic, political, or technical hang-up is involved in this regression of logic?

Ex. 4.  East River Electric Generating Station on 14th St in NYC uses natural gas to generate a large portion of NYC’s electricity, and a lot of the waste heat (no I don’t know how much) is used by neighboring businesses and buildings.