Rainwater harvesting one way of delivering deep reductions in potable water use

Transcription

1 Rainwater harvesting one way of delivering deep reductions in potable water use North West Cambridge Community Rainwater Scheme The long-term potential for deep reductions in household water use

2 Presentation outline North West Cambridge Development What is it What s happening there and why Performance of the system Long-term potential for deep reductions in household consumption Project context Summary of key points Role of rainwater harvesting Scenarios Recommendations 2

3 North West Cambridge Development overview 150 hectare University of Cambridge development providing 1,500 homes for University staff 3,000 properties in total of various types from postgraduate halls to private homes Also a primary school, community centre, health centre, supermarket and local shops, hotel,care home and sports complex All homes will be built to the Code for Sustainable Homes Level 5 80 l/h/d, hence rainwater 3

4 Drainage and flood control The development meets requirements for runoff via SUDS and rainwater harvesting system plus some traditional attenuation 60,000m 3 useable volume in lagoon Some of the 50 hectares of green space is designed as flood plains for 1:100 year event (with CC) Hard and soft landscaping environment: swales, brown roofs 50 ha of green space and corridors store and release water slowly Rainwater is stored in lagoon(s), then treated and pumped into supply for toilet flushing and irrigation. 4

5 Non-potable water treatment and supply Sand filters then UV treatment. Then stored before pumping into supply Storage 1.5 days supply300 m3 in tanks d/s of lagoon and pumping Lagoon level monitored in plant house used for switch to mains supply 5

6 Metering and other data Non potable supply is 90% of price of potable Other data: Weather data Lagoon storage/level Non-potable plant inlet and outlet (after storage) DMA meter data for potable supply 6

7 Research objectives Determine if rainwater harvesting can achieve a potable household water consumption rate of 80 l/person/d at NWCD. Estimate non-potable household consumption; Estimate variation in potable and non-potable consumption by property type, size, occupancy and other variables; Assess the micro-components of water use for potable and non-potable consumption; Evaluate other uses of non-potable water on site particularly for landscape irrigation; and If necessary, inform options that may be required in the future to achieve the potable consumption rate of 80 l/person/d. 7

8 Methods Analyse hourly meter data for potable and non-potable supply to every property Collect property and occupancy data Develop a micro-component model for potable and non-potable water Model non-potable water supply versus weather Model non-potable supply versus demand Use metered standpipe data to analyse irrigation consumption and weather variables. Further information: 8

9 The long-term potential for deep reductions in household water use (and the role of rainwater harvesting) Artesia project delivered for Ofwat April

10 Project scope and objectives Water company s communication pipe Water company s water main Focus on household consumption and supply pipe leakage Assets owned by the water company, who are also responsible for repairs Property boundary Water company s boundary valve A Customer s underground supply pipe Assets owned by the property owner, who is also responsible for repairs B Customer s internal plumbing Leaks here are the responsibility of the property owner and are included in household consumption Leaks here are included in water companies reported leakage Analyse How homes use water today, including a detailed breakdown of the types of use, and how usage varies by region, and by property type. Illustrate Water company data and forecasts of current and future PCC for , and up to Consider The potential for current and future technologies, and behaviour change to reduce demand. What technology and other interventions have worked well, and less well, in the UK and from international examples and experience.. Demonstrate Propose The options available to make deep reductions to PCC over the next fifty years. Consider how usage varies by region, and by property type. The current leakage from supply pipes. The potential to reduce this leakage over a fifty year period, and the options for supply pipe leakage reduction. 10

11 Context for taking a 50 year forward look at deep reductions in household water demand Population growth and climate change pressures Potential for increase in demand of 0.5bn litres per day The Water UK Long Term Water Resources Planning report (Water UK 2016) Potentially ambitious levels of demand management relying on significant behaviour change and innovation Ofwat statutory duties and PR19 objectives Focus on customer service, affordable bills, innovation and resilience Waterwise (2017) strategy for the UK A 5 year strategy where all people, homes and businesses are water-efficient, and where water is used wisely, every day, everywhere Household consumption varies from house to house and region to region. These variations can be influenced by: household occupancy, property type, age of occupants, socio-demographic factors, household or individual values towards water use, whether households pay via a meter, weather, and the methods used to measure and estimate household consumption. Note: Throughout this study we have used the household consumption metric per capita consumption or PCC for consistency with historic data. 11

12 Past consumption Trend in historic household consumption Consumption of water in the 1960s was around 85 l/head/day and has seen a gradual increase over time to just over 155 l/head/day in the Since 2006 there has been a downward trend in overall PCC. The increase from 1960 is due to the combined and inter-dependent effects of technology and behaviour, notably increased personal washing (transition from weekly bathing to daily showering) and more frequent clothes washing. Proportions of household end-use consumption The reductions in household consumption since 2005 are the result of downward pressures from: reductions in toilet cistern sizes increases in water efficiency activities (probably as a result of the Water Savings Group initiative) increases in meter penetration (leading to lower household consumption) There are competing pressures from: increases in personal washing leaking WCs 12

13 Current consumption Proportions of the water balance Minor components (5%) Geographic PCC (l/head/day) values for 2015/16 Micro-components of water use for 62 households (per capita consumption) Total leakage (22%) Non household consumption (20%) Household consumption (55%) 70 If all the water produced for household consumption every day was put into water bottles and laid end to end they would circle to the earth about 70 times. Averages tend to mask a large variation in consumption from house to house. The average is skewed by a small number of high consumption households. 13

14 Current forecasts of future consumption, supply pipe losses & metering Future PCC forecasts by region (dry year annual average) South East Central South West North Region England and Wales: South East: South West: Central: North: If the average demand reduction seen in the next 10 years is maintained to 2045, the PCC in 2065 would be about 105 litres/head/day Customer supply pipe leakage trends The current CSPL average 22% of total leakage CSP losses are currently about 8% of the total household demand Customers are often unaware that they have responsibility for the customer supply pipe, and repairs or replacement of the asset can be complicated by needing to access and work within a customer s property, with potentially expensive reinstatement costs Metering penetration Current E&W meter penetration about 54%, rising to 86% at

15 Stakeholder engagement We identified 38 stakeholders from water companies, government, regulators, trade bodies, academics and NGOs We sent them an questionnaire with four questions We received 25 responses We then conducted eight representative follow-up interviews 1. What level of consumption (e.g. per person per day) could be achieved in 50 years time? 2. What would be your overall vision for making deep reductions in household consumption in the next 50 years? 3. What enablers (which might be legislative/regulatory/policy, technical or behaviour related) would be need to deliver this? 4. What do you think are the barriers to achieving this? PCC aspirations in 50 years time 85 l/head/day can be easily achieved in houses with meters and water recycling for toilet flushing....our family of four use 70 litres PCC and by no means are we water martyrs despite my best intentions - there are daily showers and kids occasionally leaving taps on! litres per person per day and we may not have a choice in 50 years time if current water quality/availability and energy trends continue. the fifty year challenge is to get most people to use a little bit less through pretty rudimentary behaviour change and water efficiency technology, and the key bit is to get those fewer large users to use a lot less. 15

16 More stakeholder feedback overall vision for making deep reductions in household consumption Stop water companies being the main point of contact for customers with regards water efficiency there is a conflict of interest between revenue and water efficiency. Focus on wastage engineer as much unnecessary use out of the system as possible. We need a plastics moment so that the penny drops and people understand the value of water. what enablers are needed to deliver this? "New building standards from CLG, mandatory water labelling from DEFRA, behavioural incentives from cabinet office, white paper on water efficiency and abstraction reform." "...unless customers are engaged and understand why they need to reduce their water use, the other enablers are not likely to help to achieve the objective of reducing PCC." What do you think are the barriers to achieving this? Willingness and fully engaged Government/regulatory/communi ty partners is vital for deep reduction in household consumption. Demand management activities often have uncertain outcomes, making them far less appealing to water companies. Much simpler to look for a new supply. It is difficult in the UK to walk into a home improvement store and get any information about which shower head is more efficient. How can we expect people to save water if they don't have this information? "Mandatory water labelling. This could be the single-most powerful tool to reduce PCC with time. Remove dropvalve WCs from market to eliminate leaking WCs." 16

17 Measures for reducing household consumption We conducted research which identified approximately 80 different measures for reducing household consumption. The measures were grouped into 7 response categories. They were then scored based on an estimate of how many years until they could deliver widespread benefits (even if they exist as a measure now), and the level of potential water saving. Response category Affect consumer choice in water using practices Examples Smart metering, tariffs, pay-per-use appliances Community effluent re-use Community rainwater harvesting Deliver greater efficiency Change public perceptions about water Ultra low flush toilets, recycling showers Incentives, home water reports, smart bills, social norms and feedback Waterless WCs Affect consumer choice in purchasing decisions Compulsory water labelling, rebates, scrappage schemes Water neutrality Recycling showers Affect the governance, funding or regulation of water service providers Water neutrality, supply pipe ownership, natural capital accounting, utility bundling Ultra low flush WCs Affect resource provision Community rainwater harvesting, Reduce amount of water available for public water supply Reduce water wastage Fix leaky loos, ban sale of drop valve toilets, leak detectors, smart water using devices Compulsory product labelling Some of these options are available and being delivered now 17

18 Examples of measures available, being delivered or developed now Propelair toilet Watersmart customer engagement and data analytics Orbital Systems recycling showers July 2018 Miele bundles Green Redeem customer rewards Southern Water Institute of Water - South West Meeting - Rainwater Harvesting NW Cambridge development Anglian Water The 40 litres PCC house

19 Scenario development and description S-0. Current ambition There is progress regarding public awareness of future water scarcity issues (via planning control) and there is also reasonable progress to increase the efficiency of water using devices and deliver behaviour change via increased metering, voluntary water labels, and stricter product regulation. We developed five scenarios to show how different response measures could affect consumption and the long term drivers of customer service, resilience, innovation and affordability in the context of climate change and population growth pressures in Scenario zero is effectively business as usual. The other four scenarios then deliver deeper reductions in PCC over the next 50 years. S-1. Unfocused frugality The public do not perceive water scarcity as a problem and there is limited regulatory intervention or organisational innovation to limit resource availability or constrain water use. Technology fails to deliver efficiency or reduce wastage and as a result households need to conserve water. S-2. Localised sustainability Water scarcity is widely recognised as an important issue. Markets in water resources and water services results in widespread competition and local providers delivering integrated water services. This positively influences consumer behaviour in purchasing and use of water using devices. S-3. Technology and service innovation Market-driven high-tech solutions drive very high levels of water efficiency and reduces water wastage, e.g. through home automation and waterless fixtures and fittings. A new focus blurs the lines between regulated utilities and home services, including smarter tariffs and pay-per-use. S-4. Regulation and compliance Water service providers do not adapt to water scarcity, despite increased public awareness of the issue. Regulators apply strict controls on water availability and usage via punitive controls for companies. Sophisticated tariffs and other behavioural measures are used to limit water use. 19

20 Scenario modelling outputs micro-components PCC (l/head/day) Modelled micro-components of household water use for England and Wales in 50 years for each of the five scenarios 20

21 Effect of different scenarios on total household water demand Now ,886 Household demand Ml/d 10,523 8,831 7,366 6,057 4,372 3,482 5,110 Current PCC 140 l/head/day If PCC remains at 140 l/head/day If PCC trend in draft WRMPs continues Scenario 0 Current ambition Scenario 1 Unfocused frugality Scenario 2 Localised sustainability Scenario 3 Technology and service innovation Scenario 4 Regulation and compliance PCC = 120 PCC = 105 PCC = 86 PCC = 62 PCC = 49 PCC = 73 The graphic above shows the effect of different scenarios on the total amount of water demanded by households from the distribution system (that is household consumption and customer side supply pipe losses). The volumes quoted are Ml/d, and assume current ONS population growth for England and Wales. The dotted line represents the volume used now. 21

22 Recommendations 1 Develop current initiatives. Water companies and other service providers should continue to develop and widen current initiatives such as smarter home visits, targeted customer messaging and innovative ways of customer engagement. 2 Leadership and communication. Government should define who will provide strategic leadership on demand reduction. Develop a leadership group including stakeholders from all relevant sectors. 3 Metering. Support companies to implement customer metering via progressive metering; ultimately revising legislation to allow compulsory metering schemes anywhere. Water labelling. Implement a mandatory Leaky loos. Develop a national programme water labelling scheme for new water using to reduce losses from leaky loos and products to encourage innovation in product eventually stop their installation. design. This would combine with stricter product regulations, and increase the water efficiency of products over time. Customer supply pipes. Establish a task force on customer supply pipes with the objective of developing a plan to reduce losses and manage these assets for the long term. 7 Behaviour change. Identify the best methods to encourage behaviour change via research on a range of behaviour-based response measures designed to influence consumer choice in purchasing and using water using products. 8 New development and growth. Work with stakeholders to encourage or require new developments to include rainwater harvesting, water reuse and be water neutral. 9 Open data. Make performance data available at a more detailed level to all. Encourages people to innovate, provides academia with data to work with, and allows all stakeholders to see performance and successes. 22

23 Thanks!

24 Useful links NW Cambridge further information: Ofwat full report: 24