Psce 2011 Article final

part of the methodology. The current method for solid biomass 
operational consumption measurement is usually derived from 
the amount of steam produced versus the constant: Tons of 
biomass per Tons of steam. This last term is a very common 
parameter available at the manufacturer boiler data sheet. The 
amount of produced steam is measured via temperature, 
pressure and flow transmitters. It is usually integrated into 
Tons/hour and is available as a digital data at the boiler control 
system.
However, this current practice in cogeneration industry is 
too simplistic while it premises the boiler performance as flat 
for any amount of steam produced per hour. Thus, the 
proposal is to measure the real biomass consumption of the 
boiler per unit of time. This is not an available data at current 

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6 
biomass cogeneration systems. The measurement of biomass 
consumption when it is in liquid or gas state is quite simple to 
obtain using available known flow meters. But when talking 
about solid biomass, specifically sugarcane bagasse which 
presents variable density in different feeding situations, a 
precise measurement process can be difficult to obtain. 
Therefore, it is needed to establish a routine that can help each 
cogeneration owner to find its unique biomass feeding 
standard. This routine is composed by the following steps: 
Step 1: Elaborate the biomass feeding diagram for the 
boiler. 
Step 2: Study the dosing system technology. 
Step 3: Prepare 
an experiment 
of biomass flow 
measurement within a period of time. 
Step 4: Establish adequate parameters for measurement 
time base and number of samples. 
Step 5: Execute the experiment. 
Step 6: Construct the behavior curve for biomass feeding. 
Establish dependence relations between feed rate and other 
stated variables. 
Step 7: Model the measurement system using available 
instrumentation. Choose instruments capable to transmit data 
in a real time base using a predetermined industry control 
system communication protocol for field instrumentation. 
Step 8: Implement the measurement system. 
Step 9: Execute empirical tests. 
Step 10: Validate the biomass feeding procedure. 
The proposed steps are based on the so called PDCA cycle 
and are intended to cover the large variety of feeding systems 
for biomass fired boilers. 
5)
 
Measurement integration 
After measurement of all terms needed to obtain the 
operational energy efficiency, it is needed to integrate them 
into the cogeneration control system using the calculation 
equations. There is a wide range of supervisory and control 
system products compliant with this need and capable to keep 
a database accessible through TCP/IP protocol connections. 
Thus, the efficiency data would be available in typical 
computer networks, accessible to others through VPN client 
links or even disclosed through the owner website. 
VI. C
ONCLUSIONS
The proposed methodology is intended to work as a 
calculation and measurement guide for cogeneration owners 
interested to manage the overall energy efficiency of their 
plants. It permits them to use it on continual improvement 
programs as proposed by ISO. It intends also to work as real 
time efficiency data disclosure from cogeneration agents to 
others, what could bring this issue to public domain. 
After all, the presumed benefits of utilization of the here 
proposed methodology are listed below. 
-
Obtaining of a supply side energy management tool for 
power plants; 
-
M&V application for energy savings accountability; 
-
Optimization of energy production costs; 
-
Low carbon policy achievement; 
-
Real time efficiency database of cogeneration plants 
pushing public policy improvement (PURPA, etc.); 
and 
-
Smart Grid contribution on transparency for public 
agents and customers. 
A study case is being carried out for a group of four sugar 
cane bagasse cogeneration plants in Brazil. All the stated 
points of the methodology are being observed so for 
calculation as for measurement. The routine for achievement 
of bagasse feeding standard for each plant is going to be 
applied. Many other challenges are expected during the 
experiments implementation, measurements execution, and so 
on. However, the presentation of here stated ideas can be 
useful for other similar initiatives in other generation units 
around the world. 
A further possible work after the application of the 
methodology for small cogeneration plant groups is the 
standardization of measurement routine and accuracy, that 
would permit to achieve accreditation for the applicability of 
this process to the entire cogeneration sector.
After the establishment of a cogeneration historic database 
along the time, advances can be better controlled through 
future public policies like technology substitution incentives. 
Some emerging solutions for energy efficiency improvement 
are listed below. 
-
Process waste heat recovery applications; 
-
Substitution of fossil fuels due to Co-firing with 
biomass; 
-
Biomass 
gasification 
creating 
combined 
cycle 
possibility for biomass; 
-
Enzymatic 
Hydrolysis 
raising 
biomass 
energy 
transformation efficiency; and 
-
Biomass Torrefaction raising calorific power [11]. 
VII. A
CKNOWLEDGMENT
The authors gratefully acknowledge the contributions of: D. 
M. Neto, for his contribution to process and thermodynamic 
analyses and A Nissimoff, for his contribution to grammar 
review. 
VIII. R
EFERENCES
[1]
Energy Policy Act of 2005, Public Law 109-58-Aug.8, 2005.109
th
Congress of the United States of America, 2005. 
[2]
Energy Independence and Security Act of 2007. 110
th
Congress of the 
United States of America, 2007. 
[3]
IEA – International Energy Agency, “Towards a more energy efficient 
future – Applying indicators to enhance energy policy”, OECD/IEA, 
2009. 
[4]
U.S. Environmental Protection Agency, “Cogeneration Unit Efficiency 
Calculations – Technical Support Document for the Final Clean Air 
Interstate Rule”, OAR-2003-0053, March 2005. 
[5]
Directive 2004/8/EC of the European Parliament and of the Council, 
Official Journal of the European Union, 21.2.2004. 
[6]
Commission of the European Communities, “Action Plan for Energy 
Efficiency: Realising the Potential”, COM(2006)545 final, Brussels, 
19.10.2006. 
[7]
COGEN Europe, “Response to the European Commission consultation 
on the review of the Energy Efficiency Action Plan”, 16.07.2009. 
[8]
ANEEL – Electric Energy National Agency, “Normative Resolution 
nº235”, Brazil, November 14, 2006. 

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7 
[9]
ISO/DIS 50001, “Energy management systems – Requirements with 
guidance for use”. Draft International Standard, International 
Organization for Standardization, 2010 
[10]
G. J. Van Wylen, “Fundamentals of Classical Thermodynamics”. São 
Paulo: portuguese translation of 4
th
american edition, Edgar Blücher 
Ltd., 1995, p. 608. 
[11]
EPRI – Electric Power Research Institute, “Generation 2009 Annual 
Overview”, March 2010, p. 61. 
IX. B
IOGRAPHIES