Solar Energy Opportunities N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv 1 CLA Renewable Energy Seminar 1 st March 2011 Solar Thermal Solar Photovoltaic The performance of these technologies The challenges of integrating solar energy into buildings to make most effective use of the resource. Life Cycle Issues 1 Recipient of James Watt Gold Medal for Energy Conservation

2 A Partnership between – Broadland District Council – University of East Anglia Launched by publicity with an open meeting attended by ~120 Aims –To promote Solar Water Heating by a community to enable bulk discounts Required a minimum of 50 participants to sign up within 3 weeks Over subscribed in 22 minutes! Subsequently 9 properties not found to be suitable –To develop skills for installing Solar Hot Water Heaters in the region Technical Opportunities: Solar Thermal: The Broadsol Project

Solar Collectors installed 27th January 2004 Annual solar collection kWh/annum 3 Solar Thermal: The Broadsol Project

4 Technical Solutions: Solar Thermal Energy: Performance

5 Technical Solutions: Solar Thermal Energy Up to 15 installations were monitored at 5 minute intervals for periods up to 15 months Mean Monthly Solar gain for 11 systems Some 2 panel systems captured twice the energy in summer months as other 2 panel systems. 3 panel systems

The Broadsol Project Three panel systems captured only 13% more energy compared to two panel systems Effective use is not being made of surplus in summer 6

Measured Overall System Efficiencies – including storage System Efficiency of 2 panel systems is generally higher than 3 panel systems 2 panel 3 panel 7

8 8 Tilt Angle variations are not significant in region 0 – 45 o in summer In winter optimum angles are between 45 o and 90 o Optimum orientation in East Anglia is SSW South West is almost as good as South Solar Thermal: Performance of Panels

9 9 More Solar Energy is Collected when Hot Water use is greater. Sky became hazy at ~ 11:00 Substantial hot water demand at 13:30 Normal heat loss from tank if there had been no demand shown in black kWh extra heat collected. Note: further demand at 18:30 leading to further solar collection. Even more solar collection would have been possible had collector been orientated SW rather than S BS27: 15/05/ kWh 0.911kWh 1.157kWh0.083kWh

Technical Issues requiring awareness raising: Tank with small residual hot water at top of tank in early morning If Central Heating boiler heats up water – less opportunity for solar heating. Zone heated by solar energy 10 Solar Thermal Energy captured when combined with central heating

Tank with small residual hot water at top of tank in early morning No hot water provided by central heating boiler. Gain from solar energy is much higher. More solar energy can be gained if boiler operation is delayed. Boiler ON/OFF times should be adjusted between summer and winter for optimum performance 11 Technical Issues requiring awareness raising:

12 The Broadsol Project: Store Temperature Variations Education of how to get best out of solar HW systems is needed. Need to adjust timing of central heating boiler over late Spring, Summer and early autumn. On day 1, if boiler supplied hot water before solar gain was sufficient, top of tank would be heated to 55 o C and reduce the potential solar gain by ~21%. On day 2, the loss would be negligible as temperature at top was already over 55 o C. If the store temperature throughout was as low as 20 o C having been drawn off for a bath late on previous evening the loss in potential solar energy gained for having early operation of the boiler can approach 40%. Day 1Day 2

The last Government announced a Renewable Heat incentive which would be beneficial for Solar Thermal Installations and provide a financial incentive. Thus small scale (<20kW) solar thermal would potentially benefit owner by 18 p per kWh and last for 20 years. In the Comprehensive Spending Review the Government indicated it is still committed to such an incentive and is due to bring forward its plans within the next month. Solar Thermal: The Renewable Heat Incentive 13

Technical Solutions: Solar PhotoVoltaic Zuckermann Institute for Connective Environmental Research. (ZICER) Low Energy Building of the Year Has heat demand ~ 20% of building of its size: 34 kW of Solar Photovoltaic on roof and facade 14

Solar Rosette Diagram for East Norfolk/Suffolk Tilt N NE E SE S SW W NW N Azimuth <

Mono-crystalline PV on roof ~ 27 kW in 10 arrays Poly- crystalline on façade ~ 6.7 kW in 3 arrays ZICER Building Photo shows only part of top Floor 16

17 Peak Cell efficiency is ~ 9.5%. Average efficiency over year is 7.5% Mono-crystalline Cell Efficiency Poly-crystalline Cell Efficiency Actual Efficiency of PV Cells Peak Cell efficiency is ~ 14+% and close to standard test bed efficiency. Most projections of performance use this efficiency Average efficiency over year is 11.1% Inverter Efficiencies reduce overall system efficiencies to 10.1% and 6.73% respectively

Load factors Output per unit area Little difference between orientations in winter months Performance of PV cells WinterSummer Façade~2%~8% Roof~2%~15% Across UK average load factor is 9 – 11% based on analysis of ROC data 2009 – i.e. if system is 1kW peak the average annual output will be ~ 0.1* 1 * 8760 = 850 kWh However, solar radiation does vary by +/-30% for one year to next.

19 All arrays of cells on roof have similar performance respond to actual solar radiation The three arrays on the façade respond differently Performance of PV cells on ZICER 19

Orientation relative to True North 20

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Arrangement of Cells on Facade Individual cells are connected horizontally As shadow covers one column all cells are inactive 22 If individual cells are connected vertically, only those cells actually in shadow are affected. Cells active Cells inactive even though not covered by shadow Way in which cells are connected must be considered.

Solar PhotoVoltaic: Technical Solutions: Inverters are only 91% efficient Computers and other entertainment use DC. Power packs are inefficient LED lighting can use DC Need an integrated approach – houses with both AC and DC with heat recovery from central inverter/rectifier? 23 Integrated use of PV generated energy

24 Feed in Tariffs – Introduced 1 st April 2010 Energy SourceScale Generation Tariff (p/kWh)Duration to 31/03/2012after 01/04/2012(years) Solar PV≤4 kW new Solar PV≤4 kW retrofit Solar PV>4-10kW Solar PV> kW Solar PV>100kW - 5MW Solar PVStandalone Existing PV generators transferred from RO99to 2027 On February 7 th 2011, Chris Huhne announced that there would be an urgent review of PV schemes this year > 50 kW prior to the scheduled review next year – with the likelihood that such schemes would not be eligible for FITs. However, he did state “The Government will not act retrospectively and any changes to generation tariffs implemented as a result of the review will only affect new entrants into the FITs scheme. Installations which are already accredited for FITs at the time will not be affected.” - implying at even if the degression rate is increased – those already on the scheme will not be affected.

25 Feed in Tariffs – Export and Issue of Deeming Payment for tariffs will be from a levy on Utility Companies which MAY see a cumulative rise in bills of around £1 billion or more. In addition there will be a payment of 3p per kWh for any electricity exported as opposed to consumed on premises. BUT an export meter is needed to identify this. Householder will save on imported electricity at ~ 10 – 12p per kWh, so optimum financial model may not be to generate as much as possible i.e. for each unit generated and consumed it is worth = 53.3p /kWh for each unit exported it is worth = 44.3 p/kWh If no export meter is fitted – a transition arrangement of deeming that 50% of generation will be exported will be made - that may well not be as attractive to consumer.

Life Cycle Issues for PV Array on ZICER Building Embodied Energy in PV Cells (most arising from Electricity (~80%) use in manufacture) - SPAIN Array supports and system connections - GERMANY 135 On site Installation energy (UK)52 Transportation between manufacture and UEA 6 km Total tonnes CO 2 / kWp Mono-crystalline CO 2 (kg/ kWp) Poly-crystalline CO 2 (kg/ kWp) As manu- factured UK manu- facture As manu- factured UK manu- facture Carbon Factors for Electricity Production Spain ~ kg / kWh UK and Germany ~ 0.53 kg/kWh Energy Yield Ratios Life time of Cells Mono-crystalline Cells As add on retro-fit Integrated into design

27 Solar Thermal – Installations can reduce energy requirements for hot water. – But careful consideration of timing of normal hot water system is needed for optimum performance. Solar PV systems – Need care in design to ensure optimum performance. – Consider integration of use via INTERNAL DC networks to avoid unnecessary losses. The new Feed in Tariffs should help economics, but optimum returns will come for early adopters. However: The effective cost to society to reduce 1 tonne of CO 2 in a small scale system is over £700 tonne < £100 per tonne for onshore wind ~ £20 per tonne for cavity insulation Solar Energy Possibilities: Conclusions

This presentation will be placed on the Internet from tomorrow at: N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv And Finally Lao Tzu ( BC) Chinese Artist and Taoist philosopher “If you do not change direction, you may end up where you are heading.”