Strategies to Reduce Ontario s Electricity Grid s GHG Emissions Using CHP Systems

Transcription

1 Presented at the EMC/NRCan Energy Summit, Vaughan, May 31, 2018 Strategies to Reduce Ontario s Electricity Grid s GHG Emissions Using CHP Systems Aqeel Zaidi, P.Eng., CEM, CMVP Energy Solutions Manager Enbridge Gas Distribution Aqeel.Zaidi@enbridge.com

2 Outline 1. What s the rationale for CHP GHG reduction when on-site gas consumption increases 2. How grid electricity Demand and Supply outlook affects CHP s role as a GHG reducing technology 3. How CHP can reduce GHG emissions 4. Key findings of a report on CHP GHG reduction assessment, completed by Power Advisory for Enbridge and Union Gas. 5. Flexible CHP 6. Conclusions

3 Rationale for CHP GHG Reduction CHP reduces draw from the entire gas system just like it reduces draw from the bulk electric grid 1. CHP significantly reduces demand from the electricity grid: 1. Basis for eligibility under CMD programs: The Conservation First Framework (CFF): 1. CHP does not reduce electric load on site, reduces draw on the entire electricity grid 2. Similarly CHP does not lower gas use at site, but reduces draw on the entire gas system 2. Gas-fired CHP projects submitted after July 1, 2018 are excluded from CDM to align government s climate change policies : Ontario s Long-Term Energy Plan (LTEP) No details provided to explain why CHP does not align with climate change policies, although acknowledged that it reduces grid demand 2. Cited London DE gas-fired CHP as an example that help address the climate challenge 2. Which generation source is impacted when CHP reduces draw from the grid?

4 Which Fuel will likely be Displaced with CHP? Fuel that balances the grid Nuclear provides base-load, runs 24/7 Hydro generally runs as based load, however fills demand during certain periods Renewables such as wind and solar can provide significant generation, but are intermittent Natural gas primarily fills the electricity generation needs between base load, intermittent generation, and demand

5 Avoided GHG Emissions Confusion about which grid emission factor should be used to assess GHG impact 1. Average grid emission factor = TTTTTTTTTT GGGGGG eeeeeeeeeeeeeeeeee TTTTTTTTTT GGGGGGGGGGGGGGGGGGGG ffffffff aaaaaa ssssssssssssss (NNNNNNNNNNNNNN,RRRRRRRRRRRRRRRRRR,FFFFFFFFFFFF) Average grid GHG emission factor = 7.1 MMMM 160 TTTTT = 44 gm/kwh 3. GHG emission from central gas plants = 400 gm/kwh 4. Need for a standard avoided emission factor for CHP projects 5. Avoided emission factors should consider the impact of : 1. seasonal and time of use periods 2. imports and exports, spinning reserves, ramping, grid resiliency etc. 6. Avoided emissions factors should be based on future generation mix and operation of the grid

6 Electricity Demand Outlook Highly Variable: Four different outlooks (source OPO 2016) Outlook A declining demand from 2015 Outlook B flat demand Outlook C & D higher demand outlooks driven by deeper electrification Deeper electrification will very likely increase gas electricity generation CHP could play a bigger role in generation mix

7 Installed Capacity (excluding expired contracts) Nuclear refurbishment will change generation sources starting 2020 Source: Power Advisory LLC, Dec. 19, 2017 Final Report, prepared for Enbridge and Union Gas SLIDE 7

8 Nuclear Refurbishment Schedule (ieso) Nuclear refurbishment heavily influences the Supply Outlook for existing generation 2500 MW shortfall Pickering shut down in 2024 removing 3000 MW of baseload generation Significant shortfall beyond 2020 SLIDE 8

9 GHG Emission Forecast for Ontario's Energy Production (2017 LTEP) Emissions expected to double suggesting longer operation of gas plants SLIDE 9

10 Gas Plants Expected to Run Longer starting 2020 CHP could reduce run time of central gas plants, reducing GHG emissions 1. Demand expected to grow due to increased electrification Option C/D 2. Non-emitting base load generation expected to shrink due to refurbishment and Pickering closure beyond Renewables and battery storage could fill some gap, but central gas plant will be needed in the LTEP time frame to High efficiency CHP offers an excellent solution to reduce Province wide GHG emission by displacing generation from less efficient gas plants 5. Site vs. Source perspective is required to understand CHP GHG benefits: 1. Methodology proposed by U.S. EPA and CHP Partnership, February 2015, Fuel and Carbon Dioxide Emissions Savings Calculations Methodology for Combined Heat and Power Systems

11 How CHP Saves Natural Gas Site vs. Source Separate Heat & Power (SHP) 76 units Nat. Gas Gas-fired Power Plants Eff = 45% Conventional Generation Electricity Line losses 5% Electricity = 32.4 units Thermal = 42.4 units Electricity Combined Heat and Power CHP 100 units Nat. Gas 54 units Nat. Gas Boiler Eff=78% Heat Heat Total gas consumption = 130units Overall efficiency = 57% Total gas consumption = 100 units Overall efficiency = 75% Gas Saving = 30 units or 23% of gas used in SHP (Annual savings depend on operating hours of power plants and CHP) Note: All values reported on higher heating value SLIDE 11

12 All values reported on higher heating value How CHP Saves GHG Emissions Site vs. Source 76 m 3 /hr Nat. Gas 419 gm/kwh 54 m 3 /hr Gas-fired Power Plants Eff = 45 % Conventional Generation Separate Heat & Power (SHP) Nat. Gas 301 gm/kwh Boiler Eff = 78% Electricity Line losses 5% Heat Electricity = 340 kw Electricity Thermal = 1.52 MMBtu/hr Heat Combined Heat and Power CHP 100 m 3 /hr Nat. Gas Total gas consumption = 130 m 3 /hr CO2e emissions = 0.24 tonne/hr = 720 gm/kwh Total gas consumption = 100 m 3 /hr CO2e emissions = tonne/hr = 553 gm/kwh CO2e Reduction = 167 gm/kwh of displaced electricity from gas plants (Annual savings depend on operating hours of power plants and CHP)

13 CHP GHG Impact Analysis for Ontario Grid Power Advisory Report Jointly sponsored by Enbridge and Union Gas Estimated GHG impact for the LTEP time frame to 2037 Power Advisory s models takes into account the impact of: Imports and exports Ramping, startup/shut-down of gas plants Estimated avoided GHG emissions as a function of net demand Net demand = Ontario demand - Ontario non-fossil generation (i.e., nuclear, hydro, wind, solar and bio-energy) Net demand = (Fossil generation + Imports) - Exports Net demand can be positive (i.e., additional supply is needed) or negative (i.e., Ontario has a surplus for export) CHP can have an impact only when net demand is positive SLIDE 13

14 Quantitative Assessment Five CHP Profiles 1. Baseload 24 x 7 - year-round 2. Industrial 24 x 7 Monday Friday 3. Residential space heating only 4. Residential space heating in conjunction with air source heat pump Net Zero Energy Emission (NZEE). CHP runs when outside temp drops below -4 C 5. Responsive and flexible CHP SLIDE 14

15 CHP Impacts on GHGs Industrial CHP would reduce emissions in all scenarios from 2020 onward The average overall GHG benefit over 20 year planning period is estimated to range from 0.06 tonnes / MWh (outlook B) to 0.16 tonnes / MWh under deeper electrification scenarios like outlook D Source: Power Advisory LLC, Dec. 19, 2017 Final Report (Enbridge and Union Gas) SLIDE 15

16 Residential NZEE CHP Results mchp reduces GHG emissions when operating in flexible GHG reduction mode Residential mchp used for space heating when ambient temperature drops -4 C (25 F) ASHP runs when ambient temperature above -4 C (25 F) Source: Power Advisory LLC, Dec. 19, 2017 Final Report (Enbridge and Union Gas) SLIDE 16

17 CHP Emission Reduction Potential Power Advisory - GHG Emission Impact Analysis Completed for Ont. High efficiency CHP offers system-wide GHG reductions over the 20 year time horizon. Dispatchable flexible CHP could respond to market signals for deeper GHG reductions The average GHG emission reduction during period varies from 50 to 230 gm/kwh. Source: Power Advisory LLC, Dec. 19, 2017 Final Report (Enbridge and Union Gas) SLIDE 17

18 Key Findings of Power Advisory Report Reducing the occurrences of surplus baseload generation will improve the emission avoidance of DG CHP Starting 2020 and beyond, base-load generation is expected to shrink due to refurbishment and shutdown of nuclear plants, Central gas plants are expected to run longer to meet supply short fall of base-load generation and increased demand due to deeper electrification Ontario s peak electricity demand may shift from summer to winter due to electrification of space heating High efficiency CHP can reduce bulk grid GHG emissions by displacing central gas-fired generation Responsive DG CHP (e.g., ability to response to market signals) offers the best opportunity to reduce GHG emissions and decrease peak demand needs SLIDE 18

19 Flexible CHP Concept Flexible CHP systems that can automatically and seamlessly provide needed grid services could offer deeper GHG reductions Source: US DOE, Advanced Manufacturing Office, Office of Energy Efficiency and Renewable Energy SLIDE 19

20 Highlights of US DOE White Paper on Flexible CHP Systems Vision: Manufacturers deliver grid services to improve bottom line As intermittent energy sources like wind and solar become more prevalent, the need for grid services becomes even greater Keeping the grid stable becomes far more complex and time sensitive as variable generation resources play a larger role in meeting the usual fluctuations in demand. The new, flexible CHP systems must interact seamlessly with the grid, and this interaction must be fully automated. A concentrated research and development (R&D) effort is required to develop these critically needed technologies SLIDE 20

21 Conclusions Central gas plants are expected to run longer to meet supply short fall of base-load generation and increased demand due to deeper electrification High efficiency CHP can reduce bulk grid GHG emissions by displacing central gas-fired generation A responsive flexible CHP system that can automatically and seamlessly interact with grid could offer deeper GHG reductions. CHP should be considered in future mix of electricity generation, just like other DG technologies CHP has the same impact of reducing demand from the grid as other forms of distributed generation such as Solar PV, Wind, therefore deserves to be treated accordingly. SLIDE 21