Energy and Water Management

Lecture Week 5 23/8/16 by Paul Osmond

Buildings use 40% of global energy, 25% of global water, 40% of global resources and emit over 30% of Green House Gas (GHG) emissions.

Extensive water use reduction over the years 2000-2010 in Australia due to drought and water restrictions, so these figures have started to climb again. It’s important we relearn the operations we had in place to reduce water use when it was necessary, so we don’t get back to such a desperate time again. Let’s go back to those 3 minute showers!

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Standards for energy auditing:

  • AS/NZS 3591.1 Energy Audits – commercial buildings
  • AS/NZS 3591.2 Energy Audits – industrial and related activities
  • AS/NZS 3591.3 Energy Audits – transport related activities

Objectives of these standards are to set out processes for both energy using organisations as well as for energy auditors to follow when undertaking audits, to identify opportunities for cost-effective investments to improve energy performance.

Type 1 – Basic energy audit

  • quantitative overview of energy consumption and energy intensity, GHG emissions
  • End use breakdown to > 20% of total consumption, identification of anomalies
  • Suitable for smaller sites or as scoping audit for larger sites
  • Identify no-cost & low-cost opportunities with payback periods of ≤ 2 years, overview of more capital intensive opportunities
  • Accuracy sufficient for low cost operational expenditure
  • Indicative savings calculated through rules of thumb / industry benchmarks

Type 2 – Detailed energy audit

  • Quantify full range of opportunities, paybacks ≤ 4 years, ROI for each initiative expressed as simple payback
  • Comprehensive review of equipment, systems and operational characteristics to enable quantified energy saving recommendations
  • Detailed energy balance to >10% of total consumption
  • Accuracy sufficient for operational expenditure or medium scale capital investment
  • Collection of sub-meter data, and may also involve on-site measurement
  • Reconcile energy savings against daily end use consumption profiles

Type 3 – Precision subsystem audit

  • Focused on process or subsystem level (e.g. for a building = HVAC, lighting etc)
  • Typically organisations with high / complex energy consumption profile
  • Significant on site measurement and monitoring
  • Calculate savings by reconciling against detailed energy use breakdown
  • Paybacks > 4 years, ROI expressed as simple payback
  • Costs and benefits developed to high level of accuracy, input from auditee

Auditee engagement with auditor

The degree to which the auditee engages with the auditor is absolutely crucial to the success of results from the audit. Audits best implemented in context of an Energy Management System (EnMP).

  • Pre-audit activities:
    • Scoping the audit – type, budget, payback period, level of accuracy, availability of data
    • Quotes for capital costs
    • Selection of auditors
    • Information to be provided
  • During the audit:
    • Site access and OHS
    • Provision of information
    • Availability of auditee personnel
  • Post-audit:
    • Decision whether to undertake more detailed audit
    • Preparation, implementation of prioritised / costed action plan
    • Assignment of management representative to oversee
    • Regular monitoring
    • Communication of benefits

Some useful rules of thumb and conversions:

  • Commercial building =150-300 kWh/m2/yr
  • 1 L/sec free air @ 700kPa = approx 300W load
  • Electric Water Heating = approx 13 litres/kWh
  • 1 deg C Δ in refrigeration = approx 10% energy
  • Efficient commercial lighting = 8-10W/m2
  • 1kWh = 0.92kg CO2
  • One car produces 4.5 tonnes CO2 per year

A common method used to identify and evaluate energy efficiency opportunities is the energy mass balance (EMB). “A method of accounting for the materials and energy entering and leaving a site or fleet and its processes, systems or equipment, and the energy and material flows, energy conversions and energy use within the site or fleet and its processes, systems or equipment” (DRET -Department of Resources, Energy and Tourism; now Department of Tourism).

An ISO 50001 EnMS:

  •  Addresses energy supply; measurement, documentation, and reporting of energy use; and procurement and design practices for energy-using equipment, systems, and processes.
  • Does not itself state specific performance criteria with respect to energy.
  • Applies to all factors affecting energy use that can be monitored and influenced by the organisation.
  • Is designed to be used independently but can be aligned or integrated with other management systems.

DECC (2009) produced a document of “low hanging fruit” of typical energy efficiency opportunities, such as delamping, improving controls and maintenance, and educating staff.

Cost Effectiveness: Typically, 25% reduction in building energy use and greenhouse emissions and annual return on investment of 7-15% and the US Department of Energy claim that $1.00 invested in energy efficiency generates $2.32 in local economic activity.

We can also wipe out half of our budget deficit through the 2004 Commonwealth White Paper on Energy which identifies $9.4b net economic benefit to Australia from investing in energy efficiency by 2020.

Measurement and Verification (M&V)

Energy savings cannot be measured directly by meters or instruments; but actual energy use can be measured directly before a retrofit and again after the retrofit. Factors such as weather, occupancy and production levels influence measured variation of energy use over time, irrespective of whether an energy conservation measure (ECM) has been implemented

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Water Audits and Water Management Plans

No standard exists for water audits. They are generally classified as basic and detailed. Generally, 26% of water use can be attributed to leakage: taps, toilets, urinals, pipes, mains etc.

Check out energy use in real time at UNSW by going to the Live Energy Project and selecting the building you’d like to look at. It updates every 20 minutes.

Energy Performance Contracting

An energy service company (ESCO) is engaged to improve the energy efficiency of a facility, with the guaranteed energy savings paying for the capital investment required to implement improvements. The ESCO evaluates the level of energy savings which could be achieved, and offers to implement the project and guarantee those savings over an agreed term. The theory is that this is a win-win situation with a shared risk. Screen Shot 2016-08-23 at 7.48.17 PM.png

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Building Rating Systems

Green Star

Mission: to develop a sustainable property industry for Australia and drive the adoption of green building practices through market-based solutions

Objectives: to drive the transition of the Australian property industry towards sustainability by promoting green building programs, technologies, design practices and operations as well as the integration of green building initiatives into mainstream design, construction and operation of buildings

As at August 2016: 1319 certified projects; 21,000,000+ square metres


NABERS is a national rating system that measures the environmental performance of Australian buildings, tenancies and homes.

In 2010 GBCA, the federal government and the NSW OEH signed an MoU to work together to improve technical consistency between NABERS and Green Star. Accredited NABERS ratings can be used as inputs for credits in the appropriate Green Star category of the Performance rating tool.

Sustainability and Property Value
  • Knowledge of green/sustainable building rating tools (other than Green Star) is still low
  • Valuers and investors need a clear demonstration of the sustainability credentials of a building before they are willing to reflect this in an increased market value for that asset
  • Relatively small proportion of the market from which to draw evidence
  • Occupierswanttoknowthatthesustainabilityattributesofthe building are being delivered both from a design perspective and from an as built and ongoing operation perspective
  • Requiresagreaterbodyofresearchtodeveloprobustmeasuresof sustainable buildings which are designed, built and operated to achieve the sustainability objectives of all parties

Integrated Building Assessment

Existing design and assessment tools do not address the many economic, social and performance facets over the life span of a building, and do not provide assessment results for all dimensions of sustainable development

Design and assessment tools can be complemented by the use of case studies, best-practice programs, guidelines, labels, checklists, codes & regulations, building / energy passports, valuation reports, post- occupancy evaluation studies, consumption benchmarks, etc.

Further Resources

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