The Future of Rainwater Harvesting in Buildings SCI

The Future of Rainwater Harvesting in Buildings SCI, Belgrave Square, 23 rd February 2011 Rainwater harvesting for the 21 st Century: Challenges & Opportunities Dr. Sarah Ward Associate Research Fellow Centre for Water Systems University of Exeter

Overview Challenges • Conflicting Messages • Unclear Guidance • Energy Consumption in Context • Uncertainty on scale and skill Opportunities • Assessing Receptivity/Acceptability • Perceptions of Health and Safety • Evidence for Water Saving Efficiency The Way Forward?

Challenge Conflicting Messages: Cf. SH – RWH needed for L 5/6 (80 l/p/d) (DCLG, 2006) Vs RWH increases CO 2 footprint of buildings (EA/NHBC, 2010) Latter only assesses Average Incremental Carbon Cost: • Does not include wider environmental or socio-economic cost-benefits e. g. shadow price of water, stormwater attenuation (new research available), resilience, adaptability • Uses ‘future scenarios’, but does not assess emerging retrofit gravity systems i. e. ‘future systems’ • Carefully consider ALL aspects before it’s ruled out!

Challenge Unclear guidance on water-energy trade-offs: • RWH is not the only water-saving technology that can increase energy/carbon consumption Do we stop installing low waterhigh energy appliances?

Challenge Energy Consumption in Context: Innovation Centre RWH System, University of Exeter: < 0. 1% of total building energy consumption E = energy consumed CO 2 = carbon dioxide emitted Cost = cost of energy used SM = Simple Method IM = Improved Method M = Measured Mains = mains water equivalent LCA = full embedded & operational impact * = Australian Study (domestic systems; Gardner et al. , 2008)

Challenge Uncertainty on scale and skill: In the UK SMEs represent 99. 1% of all enterprises, 59. 4% of private sector employment and 50. 1% of turnover – a lot of buildings/water use! Interviews with SMEs: Non-implementers/Implementers; Retrofit/New Build Five Implementation Deficit Categories 1) Expertise and Advice 2) Guidance and Support 3) Visibility and Access 4) Confidence and Communication 5) Finance and Consultation “Needed to know so much about all this technical stuff, which was all too much, both time and stress-wise. ” (Retrofit) “The system is not well organised enough to support everything and you’re left to sort it out. ” (New Build) “. . . feeling like the guinea pig…” (both)

Why aren’t more SMEs engaging with SWM/RWH? • Primary reason: complexity of process – information gathering, support and implementation

Opportunity Assessing Awareness: Receptivity Broadclose (Bude) & Innovation Centre ‘…don’t see it advertised; get solar panel things through the door, but not for water’.

Opportunity Assessing Awareness: Acceptability • Having to pay for regular maintenance • Having disruption to my home/life during installation • Willingness to pay was less than estimated cost Broadclose & Innovation Centre

Opportunity Perceptions of Health and Safety: Innovation Centre System Building Design Features Microbiological Quality

Opportunity Perceptions of Health and Safety: • Aside from misconnections, health risk is minimal

Opportunity Evidence of Water Saving Efficiency: (i) ~£ 1500/year saving (ii) Capital PBP = 11 years (tank installed is oversized) Innovation Centre System • Greater visibility of REAL data for REAL systems at DIFFERENT SCALES

21 st Century RWH: The Way Forward? A Clear Vision • Innovation • Research • Partnerships Reliable, central, independent source of information required Increase stakeholder consultation and engagement activities Increase efficacy of RWH for UK stakeholders e. g. enhance technical relevance by developing new products

Conclusions • Move beyond focus on current system configurations • Consider financial, technical and social perspectives • Use opportunities to innovate systems and implementation models to overcome trade-offs, challenges and obstacles • Find a ‘vision’ for RWH in the UK fit for the 21 st century – provide a direction for ‘re-designing RWH’

The Future of Rainwater Harvesting in Buildings SCI, Belgrave Square, 23 rd February 2011 Rainwater Harvesting for the 21 st Century: Challenges and Opportunities QUESTIONS? Sarah Ward sw 278@exeter. ac. uk