Electricity production and consumption

Typical Domestic Electrical Load??? Typical Daily Domestic Demand Profile (www.dti.gov.uk)

Conventional lighting Typical Domestic Electrical Load Typical Daily Domestic Demand Profile (www.dti.gov.uk) Average = c.12kWh/Day Conventional lighting Activity related load Base load

Components of domestic electrical load Base load Alarm systems Control systems Fridge/freezers Essential stand-by items Telecomms Clocks etc., Activity related loads Radio/TV/HiFi Small appliances Washing machines PC/Modem/Printer Fans, Pumps, Activators Etc., Components of domestic electrical load Excluding thermal loads Mostly cold fill Cooking Kettle Coffee Maker Microwave Oven/grill Hobs Lighting After and before sunrise Weekday Weekend

High efficiency lighting Cooking etc., Activity related load Base load High efficiency lighting

What to do with the surplus power?

2007 ESB Night saver tariff (including VAT)

49 kWh/m2/yr Good match between PV surplus and thermal demand for > 25% of time

x 2.5/3.4

Financial and environmental performance

ESB plus gas plus PV gives lowest CO2 emission Standing charge = 50% of total cost ESB night saver plus PV gives lowest running cost

ESB Night Saver gives lowest running cost solution Savings with PV = 2.5 x Savings with Solar Thermal ESB plus Gas gives lowest CO2 emission solution CO2 reductions with PV = 4 x CO2 reductions with Solar Thermal

Looking at electrical load in more detail Fridge & Freezer c.40% PC etc., > 15% TV, VCR >15% Base load c.15%

Essential services – on 24/7 Separate circuits Heating and hot water On during periods of solar surplus and at night time Essential services – on 24/7 Security lighting Alarm systems Control systems Fridge/freezers Essential stand-by items Telecomms Clocks etc., Activity related – on when occupied Lighting Radio/TV/HiFi Small appliances PC/Modem/Printer Fans, Pumps, Activators Etc., Other 24/7 loads Cookers Washing machines VCR/DVD-HDD Timer controlled devices Possible daytime only operation Schedule plus switches in bedroom and at entrance door

Load with controlled activity related circuit Assuming 85% occupancy

Figures for controlled activity related circuit plus PV CO2 emissions down by 42% Running costs down by 36%

As previous slide with heating load reduced by 50% through use of better insulation and heat recovery CO2 emissions down by 62% Running costs down by 50%

Good match between PV surplus and thermal demand for c.50% of time 33 kWh/m2/yr Good match between PV surplus and thermal demand for c.50% of time

Water based heating systems Standard system + PV compared with Biomass/DHS system Standard system + PV 23% lower emissions 18% lower cost Assuming biomass emissions = 10% natural gas

Lowest capital and running cost Standard control and heat load Cool Power control and reduced heat load Lowest capital and running cost

ESB Urban Domestic plus Storage Heating ESB Night Saver Lowest capital and running cost ESB Urban Domestic plus Gas ESB Night Saver plus PV Lowest capital and running cost ESB Urban Domestic plus Gas plus PV ESB Urban Domestic plus DHS ESB Night Saver plus PV Lowest capital and running cost ESB, Gas plus PV Lowest CO2 ESB Urban Domestic plus DHS Optimised electrical loads plus reduced heat load