Figure 2. Sample Calculation of the Efficiency
of Combined Heat and Power vs. Separate
Heat and Power.
200
180
Units;of;energy;consumed;by;plants
160
140
120
100
80
60
40
20
Thermal production losses
Electricity
generation
losses
CHP losses
Delivered
thermal
energy
Delivered
thermal
energy
Delivered
electricity
Delivered
electricity
0
Separate;Heat;Combined;Heat
&;Power;(SHP);&;Power;(CHP)
Source: FVB Energy Inc., based on Elliott, et al,
CHP Savings and Avoided Emissions in Portfolio
Standards, 2009 ACEEE Summer Study on Energy
Efficiency in Industry.
the recommended methodology, can be
calculated as shown in table 1.
It is extremely important to note that
this is only one sample calculation. There
are many variations not only in CHP configurations (affecting CHP efficiency and
power to heat ratio) but also in power
pool characteristics (affecting the efficiency
of generation, transmission and distribution of grid power).
Making a Good Idea Better
We have come a long way in expanding the congressional portfolio standard
discussion to include CHP. The two federal
portfolio standard bills discussed above
would be major steps forward. These bills
would even stronger in moving the U.S. to
renewable energy if ‘renewable negawatt-hours’ were made eligible for energy-efficiency credits (EECs). (I suggest EECs rather
than RECs because such renewable thermal
facilities would function like an efficiency
measure, reducing requirements for grid
power rather than providing a supply of
renewable power to the grid.)
Renewable energy can be used to
produce thermal energy (heating or cooling) that would otherwise be provided with
electricity, thereby displacing grid power
in the same way as an efficiency measure.
For example, solar energy can be used to
produce chilled water, thereby avoiding the
generation, transmission, distribution and
consumption of electricity for conventional
air conditioning. Another example would
be displacement of electric heating with
heat produced with biomass, landfill gas,
solar energy or other renewable resources.
By including renewable negawatt-hours, a portfolio standard can encourage
additional creative energy solutions that
are every bit as effective in stimulating use
of renewable energy as renewable power
generation technologies.
District Energy Implications
Many district energy systems can benefit from existing state portfolio standards
and proposed federal standards. All these
standards provide an economic incentive to
install renewable power generation, usually
by specifically enabling nonutility entities
to receive RECs regardless of whether the
electricity is transmitted over the interstate
transmission system. A major opportunity
for district energy systems results from
existing state portfolio standards that allow
CHP to qualify as an electricity efficiency
measure. Both federal bills discussed above
would enable a nonutility entity to receive
EECs as long as that entity implemented
the CHP and the utility did not pay a
“substantial portion” of the cost. It is also
notable that both bills provide credits for
both power generation and thermal output
from biomass CHP.
Portfolio standards hold the potential
for a net positive impact for district systems
– a large benefit from implementation of
CHP and/or renewable power generation
that more than outweighs the potential
negative impact of higher electricity prices
resulting from implementation of such
standards. If you operate a district energy
system, I strongly urge you to explore how
to take full advantage of the benefits of
portfolio standards.
Mark;Spurr is legislative
director of IDEA. He also
is president of FVB Energy
Inc., a U.S. consulting
firm specializing in district
energy and CHP business
development, engineering
and marketing. FVB has
offices in Minneapolis, Minn.; Seattle, Wash.;
Manama, Bahrain; Edmonton, Toronto and
Vancouver, Canada; and in Stockholm,
Västerås and other cities in Sweden.
Spurr represents the United States on the
executive committee of the International
Energy Agency Implementing Agreement
on District Heating and Cooling, including
Implementation of CHP. He may be reached
at mspurr@fvbenergy.com.
Order Your Best Practice Guide Today
IDEA’s District Cooling Best Practice Guide is a valuable reference tool for
district energy professionals worldwide. To order, complete the form at
www.districtenergy.org/district-cooling-best-practice-guide
US$395, plus shipping and handling.
Questions? Contact Len Phillips at
len.idea@districtenergy.org, (508) 366-9339.
