1. 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

2. 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
Reduction of annual energy operating costs
Reduction of CO2 emissions
Conclusions

3. 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…

4. 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.

5. SPM one-line diagram: The Smart Polygeneration Microgrid (SPM) Project
- 400 V distribution system (ring network, 500m long)
five switchboards

6. SPM planning, supervision & control system
The Smart Polygeneration Microgrid (SPM) Project
SPM planning, supervision & control system

7. SPM ICT infrastructure
The Smart Polygeneration Microgrid (SPM) Project
SPM
ICT infrastructure

8. 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

9. 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

10. SPM & SEB inside the Savona Campus of the University of Genoa
SEB is an “active load” of the SPM
SEB is an energy “PROSUMER”

13. Storage-related research activity
SPM OPTIMAL SCHEDULING
DEMS uses
costs and revenues functions;
forecast of electric and thermal energy demand;
operative constraints (equipment ratings, maximum power ramp, etc.);
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

14. Production from dispatchable sources PV Production & Demands
Storage-related research activity
Production from dispatchable sources
PV Production & Demands
Storage state of charge variation on a typical winter day

15. 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

16. Including also maintenance cost
AS-IS scenario: energy consumptions and operating costs
Including also maintenance cost

17. ˜ 37% delivered by SPM and SEB generation units
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

18. SPM / SEB energy consumption and production
Assumptions:
winter operation for mGTs,
2000 hours at rated power
absorption chiller turned off

19. Calculation of the total operating costs for the 2 scenarios
where:
; Mf_k = m3 natural gas used by each mGT
and Cm and pf being respectively the maintenance cost and the natural gas price for the mGTs

20. Calculation of the total operating costs for the 2 scenarios

21. Calculation of the CO2 emissions for the 2 scenarios
where:
  ef-n = 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 = (natural gas oxidation factor);
LHV=9.7·10-3 MWhpe/m3 (natural gas lower heating value).

22. Calculation of the CO2 emissions for the 2 scenarios

23. 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)

24. 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

25. Thank you for the attention Vale! Federico Delfino
University of Genoa – ITALY
Dept. of Electrical, Naval & ICT Engineering
Vale!