Whitepapers

Derceto CTO, Simon Bunn, has paper selected for the prestigious peer reviewed IBM Journal

The 2009 IBM Journal of Research and Development focussed on Environmental Monitoring and Management.

Information technology plays critical roles in helping address environmental challenges. Topics for this diverse issue include the emergence of a new computing paradigm based on sensing and modeling, business management strategies and dashboards, carbon and emissions management, optimization of data center energy utilization, and applications relating to the optimization and monitoring of rivers, water pumps, and railroads.

This paper discusses data extraction from the large data sets created by water utility SCADA systems, including error detection and correction and the creation of data where no instrument exists using the concept of 'virtual instrumentation'.

Article written by Derceto CTO, Simon Bunn, for Australian Water Journal, June 2009

This paper discusses the application of a novel, fully automatic, operations optimisation software for treated water systems  first developed in 2000 and deliverd into the US in 2004. It summarises results from five years of operation in four major US water utilities. Although this system originally was anticipated to achieve most cost savings from electrical load management against tariff patterns it has been particularly effective at improving pumping efficiency. Results from the four case studies are presented showing how efficiency improvements can be generated from existing assets in pump stations with both matched and mixed size pumps. With improved efficiency comes a reduction in the greenhouse gas footprint of the utility, measured in thousands of tons per year.

Paper presented at the SIDISA 2008 conference in Florence Italy by Derceto CTO Simon Bunn

The use of advanced control to improve water quality and increase energy efficiency has long been a goal of water utilities following the introduction of centralised SCADA systems in the 80’s and 90’s.  In the US and UK 3% of all electricity production is used for water and wastewater systems, with more than 90% of the energy purchased being used for pumping.
This paper discusses the application of a novel, fully automatic, operations optimisation software addition to SCADA designed for treated water systems including results from many years of operation in four major US water utilities.  The software targets reduction of the energy cost to supply water to customers while maintaining agreed water quality and service constraints such as storage levels and pressures.  Although this system originally was anticipated to achieve most cost savings from electrical load management against tariff patterns it has been particularly effective at improving pumping efficiency. Results from the four case studies are presented showing how efficiency improvements can be generated from existing assets in pump stations with both matched and mixed size pumps.  With improved efficiency comes a reduction in the greenhouse gas footprint of the utility, measured in thousands of tons per year. The methodology used to quantify the CO2 savings is also presented.

Paper given by Derceto CTO Simon Bunn and Cary Hillebrand at the AWWA ACE 2008 in Atlanta GA

For water utilities, electricity is usually the second highest operating cost. With pumping dominating energy consumption, the prudent utility will make every effort to both install the most energy efficient pumps for the application, and to operate pumps in the most cost efficient manner possible. 
The characteristics of a typical centrifugal pump make this a difficult task and as time goes on the actual pump operating curve will migrate significantly from the manufacturer’s curve making it harder still. This presents a challenge to the operator to dynamically run pumps at more efficient points on their operating curves. It is recommended that when selecting an Energy Management System (EMS), typically used to schedule pump stations to leverage off peak tariffs, that it also be capable of planning the operation of pump combinations while maintaining defined system boundary conditions and meeting water production requirements.
Where a pump actually operates, and the degree of efficiency is dependent on the system curve, which is determined by the hydraulics of the system the pump is installed into.  The Total Dynamic Head (TDH) across the pump sets the operating point and is significantly affected by the water demand seen by the pump.  Even a small increase in TDH can drive the operating point a long way left or right on the curve with a subsequent drop in efficiency.  It is not uncommon to see pumps with a BEP of 85% efficiency actually operating at 60% efficiency or lower when operating with only a slight increase in discharge head over design.

Paper given at Aqua Enviro Conference in Birmingham, UK in 2008 by Laurie Reynolds (Mouchel Ltd)

Electricity consumption by water and wastewater utilities accounts for 3% of all energy consumption in the UK. Clean water pumping alone uses 4.4 billion kWh in the UK worth £200M in 2007. Between 90% and 95% of the electricity purchased is used for pumping. Energy efficiency investments can have excellent returns of 5% to 25% or better and have additional benefits in reducing the greenhouse gas footprint of the utilities. While significant progress has been made in analysing individual pumps and matching characteristics to actual duty requirements these have relied on a single duty reference point. In reality pump operating requirements is subject to highly variable seasonal and diurnal demand making it impossible to adequately cover all eventualities. Pumping facilities and water distribution networks have become highly interconnected and complex systems. Pumps therefore do not operate in isolation; in fact due to the incompressibility of water it is typical that any change in operation of one pump may affect the operating point of many other pumps in the distribution system. 

Presented by Derceto CTO, Simon Bunn, at WEFTEC 2007

The more than 60,000 water systems and 15,000 wastewater systems in the United States are among the country’s largest energy consumers, using about 75 billion kWh/yr nationally – 3 % of the annual U.S. electricity consumption. This figure of 3% is similar in Europe and the UK. Pumping is the prime user of power, typically 95% of the total energy purchases for water utilities are used by pumping plants. Water demand tends to peak in the same diurnal profile as energy demand thereby increasing the need for pumping during peak energy periods and consequently increasing the need for less efficient electricity generators to enter the market to supply energy. These tend to be high green house gas emitting thermal peaking stations driven by coal, diesel, oil or gas. During the off-peak night periods a greater proportion of energy production comes from base-load hydro, wind and nuclear power plants that have zero green house gas emission. Shifting energy use from peak to off peak therefore can significantly reduce the green house gas foot print of a water or wastewater utility with environmental benefits over and above cost savings achieved by purchasing cheaper energy.

Presented by Sarah Thorstensen at the AWWA PA section 2007 conference, Hershey, PA

Washington Suburban Sanitary Commission (WSSC) purchases the bulk of their $19M energy spend on the real time Pennsylvania Jersey Maryland (PJM) Interchange. A substantial portion of this is used for treatment and distribution of potable water.  In 2006 WSSC installed Derceto Inc’s Energy Management System to control electrical load at all points in the potable water treatment and distribution system to manage and where possible reduce the cost of energy purchases. The real time energy market offers considerably lower cost energy over-night compared to peak times during the day so load movement can lead to substantial savings. The energy management system also makes savings in efficiency, where less kWh are used to move the same volume of water through improved operation of the pumps on their efficiency curves.  The Derceto supplied system also takes maximum advantage of gravity favoring gravity flow valve stations over pumped stations where possible. The practical task of measuring energy kWh and dollar savings against a baseline proved to be one of the more difficult tasks during the project. Not only must the baseline be able to capture all these forms of savings, it also has the added complexity that water distribution systems are undergoing continuous changes, from equipment failures to new capital expenditure programs that can make it very difficult to measure savings where there is no "before" case to compare against. This paper describes the methodologies used for the development of an energy management system baseline and performance monitoring tool. Actual examples using real time and standard offer of service energy contracts are presented.

Energy costs for pumping is typically one of the largest expenses in a water utility’s operations budget. The capability to effectively forecast demand profile and schedule production can be beneficially used to guide the utility to procure energy products (electricity, diesel or natural gas) in a manner designed to contain costs.