The infuriating inconsistency of network electricity carbon intensity Andrew Peacock Heriot Watt University

World Resources Institute recommend that the grid electricity emission reduction factor should be calculated thus: ER baseline = ω.BM + (1-ω).OM CO 2 Emissions Saving Methodology

World Resources Institute recommend that the grid electricity emission reduction factor should be calculated thus: ER baseline = ω.BM + (1-ω).OM CO 2 Emissions Saving Methodology

BM – Build Margin emission rate Assumes that the electricity reduction measure will reduce the need for future capacity A proportion of the reduction is then assigned to the deferment of this added capacity FIRST CONFUSION What new plant is planned in the UK?

Installed Plant in the UK (2007/8) Source: National Grid 7 year statement, 2007

Planned new plant (2013/14) Source: National Grid 7 year statement, 2007

Planned new plant (to 2020) However Coal – 14.2 GW of new coal plant is in various stages of development Build Margin emission rate for; Coal(45% efficient plant)0.776kgCO 2 /kWh CCGT(50% efficient plant)0.412kgCO 2 /kWh Will coal be resurgent? Principal uncertainty – 3 rd Revision of the EU Emission trading scheme DEFRA Guidance 2007 – Build Margin Rate = 0.43kgCO 2 /kWh (Assumed for a CCGT Plant)

World Resources Institute recommend that the grid electricity emission reduction factor should be calculated thus: ER baseline = ω.BM + (1-ω).OM CO 2 Emissions Saving Methodology

World Resources Institute recommend that the grid electricity emission reduction factor should be calculated thus: ER baseline = ω.BM + (1-ω).OM CO 2 Emissions Saving Methodology

Operating Margin Emission Factor Assumes that the electricity reduction measure will reduce demand SECOND CONFUSION What carbon intensity do we assign to the negawatts?

System Average Carbon Intensity

DEFRA Guidance – 5 Year rolling average – 0.523kgCO 2 /kWh

Not all plant will respond If we exclude nuclear – approximate “load following” 5 year rolling average = 0.671kgCO 2 /kWh

Different Carbon intensities that could be used FactorDescriptionCarbon Intensity (kgCO2/kWh) BMEfficient Coal Plant0.776 Efficient CCGT Plant0.412 DEFRA (CCGT plant)0.430 OMSystem average0.523 Annual “Load following”0.671

World Resources Institute recommend that the grid electricity emission reduction factor should be calculated thus: ER baseline = ω.BM + (1-ω).OM CO 2 Emissions Saving Methodology

World Resources Institute recommend that the grid electricity emission reduction factor should be calculated thus: ER baseline = ω.BM + (1-ω).OM CO 2 Emissions Saving Methodology

Third Confusion Weighting factor,  Guidance Weighting Factor,  CFL LightingSolar Panel – 1.5kW DEFRA00.5 World Resource Institute 0.920

Third Confusion Weighting factor,  Approx 2.9GW of maximum system peak demand is due to domestic lighting. This will fall to approx 1.45GW with banning of incandescent bulbs in 2010 No effect on system capacity Guidance Weighting Factor,  CFL LightingSolar Panel – 1.5kW DEFRA00.5 World Resource Institute 0.920

Effect on savings from CFL Lighting and Solar-PV Using DEFRA Guidance

Effect on savings from CFL Lighting and Solar-PV Can be 76% higher Can be 53% higher Spread of possible BM and OM figures

Conclusions Deriving a simple number for Carbon intensity of network electricity that suits all technologies is impractical and will mislead The recognised international metric discussed here could be employed One approach might be to assign factors to technologies based on this standard procedure This has been a talk largely about the present – the future is more difficult still

Further Complication Time variant nature of carbon intensity Wednesday 26 th January 2005

Time variant nature of carbon intensity Wednesday 26 th January 2005

Demand side response to reduce gradient change has the capacity to alter operating protocols that could yield reductions in CO 2 intensity of network electricity Time variant nature of carbon intensity