Evaluating Costs and Benefits of a Smart
Polygeneration Microgrid Project in a University
Campus
Stefano Bracco*, Federico Delfino**, Fabio Pampararo**, Michela Robba***
and Mansueto Rossi**
University of Genoa - ITALY
*Dept. of Mechanical, Energy, Management & Transportation Engineering
**Dept. of Electrical, Naval & ICT Engineering
***Dept. of Informatics, Bioengineering, Robotics & Systems Engineering
federico.delfino@unige.it
Outline of the presentation
• The Savona Campus: a research & teaching facility of the
University of Genoa
• The Smart Polygeneration Microgrid (SPM) project
• The Smart Energy Building (SEB) project
• Economic & Environmental Analysis
o
Reduction of annual energy operating costs
o
Reduction of CO2 emissions
• Conclusions
The Savona Campus: a R&T facility of the University of Genoa
• 50,000 square meters
• courses from the Faculties
of Engineering, Medicine,
and Media Sciences
• laboratories, research
centers and private
companies (several
operating in the
environment &energy
field)
• library, residences,
canteen, café, etc…
The Smart Polygeneration Microgrid (SPM) Project
•
Special project in the energy sector funded by the Italian Ministry of Education,
University and Research (amount 2.4 M€)
•
SPM is a 3-phase low voltage (400 V line-to-line) “intelligent” distribution system
running inside Savona Campus and connecting:
•
2 mCHP Gas Turbine (95kWe, 170 kWth) fed by natural gas;
•
1 PV field (80 kWp);
•
3 CSP equipped with Stirling engines (3 kWe; 9 kWth);
•
1 absorption chiller (H2O/LiBr) with a storage tank;
•
1 electrical storage: NaNiCl2 batteries (100 kWh)
•
2 PEV charging stations.
The Smart Polygeneration Microgrid (SPM) Project
SPM one-line diagram:
- 400 V distribution system
(ring network, 500m long)
-five switchboards
The Smart Polygeneration Microgrid (SPM) Project
planning
& management
DEMS
SPM planning,
supervision &
control system
SICAM
supervision
& control
IEC 61850
field data acquisitions &
local automation
RTU
TM 1703 ACP
The Smart Polygeneration Microgrid (SPM) Project
SPM
ICT infrastructure
The Smart Polygeneration Microgrid (SPM) Project
Main goals:
• to build a R&D facility test-bed for both renewable and fossil
energy sources
• to promote joint scientific programs among University,
industrial companies and distribution network operators
 Day-ahead production scheduling of dispatchable
sources and storage exploiting renewables forecast and
optimization techniques
• to optimize thermal & electrical energy consumptions,
minimizing the CO2 emissions, annual operating costs and
primary energy use of the whole University Campus
The Smart Energy Building (SEB) Project
•
Special project in the energy efficiency sector funded by the Italian Ministry for
Environment (amount 3.0 M€)
•
SEB is an environmentally sustainable building connected to the SPM, equipped by
renewable power plants and characterized by energy efficiency measures:
•
Geothermal heat pump
•
PV plant on the roof (20 kWp)
•
Micro wind turbine (horizontal axis, 3 kW)
•
High performance thermal insulation
materials for building applications
•
Ventilated facades
SPM & SEB inside the Savona
Campus of the University of
Genoa
• SEB is an “active load” of the SPM
SEB is an energy “PROSUMER”
Storage-related research activity
• SPM OPTIMAL SCHEDULING
DEMS uses
o costs and revenues functions;
o forecast of electric and thermal energy demand;
o operative constraints (equipment ratings, maximum power ramp, etc.);
o forecast of the renewable units production by resorting to weather services and
historical records
to compute a scheduling for dispatchable sources including storage, which
minimizes the daily energy costs. The optimization process has a time-horizon of 1 day
(typical of a day-ahead energy market session), subdivided in 15 minutes time-intervals.
The optimization method is based on linear programming.
• This research line results at the storage level in an automatic production shifting
application
Storage-related research activity
PV Production & Demands
Production from
dispatchable sources
Storage state of charge variation on
a typical winter day
Economic & Environmental Analysis
• Two different scenarios are considered
AS-IS
Without SPM & SEB
TO-BE
With SPM & SEB
• Electrical Energy
→ National Grid
• Thermal Energy
→ 2 boilers (gas,1000 kWth)
• Electrical Energy
→ National Grid + SPM + SEB
• Thermal Energy
→ 2 boilers + SPM + SEB
AS-IS scenario: energy consumptions and operating costs
Including also
maintenance
cost
TO BE scenario: share of electricity and heat generation
ELECTRICITY
˜ 37% delivered by
SPM and SEB
generation units
HEAT
˜ 25% delivered by
SPM and SEB
generation units
SPM / SEB energy consumption and production
Assumptions:
-winter operation for mGTs,
2000 hours at rated power
-absorption chiller turned off
Calculation of the total operating costs for the 2 scenarios
C T _ A S  IS  E E C A S  IS  e pp  T E C A S  IS  T E S pp  C m _ A S  IS
C T _ T O  B E  E el _ G rid  e pp  E th _ B oiler  T E S pp  C m _ T O  B E 
  E el _ SP M  E el _ SE B    e f 

M
f _k
pf
_k
k  C 65 , C 30
where:
E el _ G rid  E E C AS  IS  E el _ EH P  E el _ SPM  E el _ SEB   E el _ SEB 
E th _ Boiler  T E C AS  IS  E th _ SPM  E th _ SEB ; M = m3 natural gas used by
f_k
each mGT
and Cm and pf being respectively the maintenance cost and the natural
gas price for the mGTs
Calculation of the total operating costs for the 2 scenarios
Calculation of the CO2 emissions for the 2 scenarios
C O 2 _ A S  IS  E E C A S  IS 
C O 2 _ TO  BE  E el _ G rid 
e f n
 el _ G rid
e f n
 el _ G rid
 T E C A S  IS 
 e f  NG
e f  NG  O f
 B oiler  L H V
 E th _ Boliler
Of  
+  M
  Boiler  LH V k  C 65 , C 30
f _k
where:
ef-n = 0.465 tCO2/MWhel (the emission factor of the Italian electrical mix);
ηel_Grid =0.9 (national electrical grid efficiency);
ef-NG = 1.961·10-3 tCO2/m3 (natural gas emission factor);
Of = 0.995 (natural gas oxidation factor);
LHV=9.7·10-3 MWhpe/m3 (natural gas lower heating value).



Calculation of the CO2 emissions for the 2 scenarios
Economic & Environmental Analysis
Economic and environmental benefits provided by the system SPM + SEB can be
further increased by:
• using the mGTs in trigeneration asset (resorting to the absorption chiller) in order to
cool the library of the Savona Campus (now cooled by means of an electrical heat
pump) during summer months (+ 600 working hours for the mGTs with respect to the
examined case)
Conclusions
• The “Sustainable Energy” R&D infrastructures under construction at the Savona
Campus of the University of Genoa have been described and the main research
lines that can be investigated by means of their use have been outlined
• An approach has been presented to assess the Campus operating costs, CO2
emissions and primary energy saving on a yearly time-scale
• It has been shown that the Smart Polygneration Microgrid (SPM) and the Smart
Energy Building (SEB) contribute to increase the overall energy efficiency of the
Campus, lowering its environmental impact
• It should be underlined that the revenues obtained by the improved energy
performances of the whole Campus can be then employed to financially support
research activities and to yearly upgrade the two pilot plants SPM + SEB