Pump station and Power Optimisation. 8th Mar 12

Transcription

1 Pump station and Power Optimisation 8th Mar 12

2 Scope for Energy savings Over 55% of all energy used in local authorities is by water services, and typically over 50% of this is for pumping plant. Historically, there is lack of information on plant performance and actual costs. Only measure is main ESB meter. Often the relevant engineers don t see the power bill and if they do, it is just a cursory look or sign off. Energy bills seen as uncontrollable. No focus on Energy awareness in the past

3 Energy Management Basic Steps Have to measure before you can improve! Collate Data, last 12 or 24 month power bills and establish Baselines Carry out a plant power audit, examine the power load over the entire range of operation. Understand the energy bill, the load characteristics, and the operating constraints. Examine individual pump/plant item performance Key: A new Cost awareness of individual plant items/processes.

4 Life Cycle costs of a water pump

5 Single Objective : Cost Minimisation Main areas to Evaluate Electrical load movement in time, to maximize utilization of low cost tariff Electricity peak demand reduction. Power Factor Correction and Power Optimisation Energy efficiency improvements from pumping plant.

6 Example: Water Treatment Plant 4 Intake Pumps 15kW, DOL 3 High Lift Pumps, 2 x 96kW, 1 x120kw VSD These pumps make up 80% of total power load Pumps run approx 18hrs/day Monthly bill approx 32k, 384k per annum. Establish an Energy Performance indicator for each pump Output Input Water Volume m3/hr Kilowatt hours kwh

7 Pump EPI ID NO. Value EPI Pumps 1&2 Magmeter flowrate 438 m3/hr Pressure 8.8 bar 2.3 P1 Power absorbed kw P2 Power absorbed kw Pump 1 Magmeter flowrate 258 m3/hr Pressure 8.1 bar 2.61 P1 Power absorbed Kw Running a single high lift pump shows a 13% improvement in Energy performance

8 Results By maximising running time during night rate the estimated savings are 18k/annum By running the pumps slower on continuous operation the maximum Import charge can be reduced with estimated savings of 14k/annum. Intake pipe 1 had recently been cleaned out. Delivery via full bore in this pipe 1 showed a 9% energy performance improvement over Pipe 2. ie. Approx 2k/annum Highlift pump No.4 was over 10% more efficient than No. 3 This equates to a difference of 800/ month or 9600 per annum. The power factor on site is By optimising this there is a saving of approx 3500, by removing low PF surcharge and reducing MIC surcharge

9 2 Aspects Voltage management and Power Quality. Power Optimisation Voltage management : reduce the voltage level from that of the incoming supply. Nominal EU voltage is now %/- 6%. (216V -253V) Simple resistance load : reduce the voltage by 5% and you achieve power savings of 10%. Other load sources such as modern high frequency lighting are considered voltage independent : No Saving Essential :proper load survey to establish opportunity for savings. Potential - Industrial /Commercial installations 8-15% Utility 3-10%

10 Power Quality Main Benefits from Optimisation; reduces harmonics, transients, phase imbalance, power dips and increases power factor. Improve voltage stability Reduce power factor penalties and kva demand charges Reduce electrically related down-time Far greater life cycle for plant motors and machinery Provides greater surge protection

11 Water pumps do wear! Using VSD s where appropiate; typically large scope for savings, also additional benefits, reduces hammer, increases motor protection. Pump Wear: A quick rule of thumb; 1% deterioration on head/flow curve per year Though it tends to be faster for the first few years, e.g. 10% drop in the first 5-6 years. Efficiency coating: typically at least half the efficiency gains following refurbishment and coating are obtained from the coating process. Typical savings on an old pump are 10% in power efficiency. Efficiency gains on new pump in order of 2-3%

12 A major European Union study of pumps recommended: Select pumps according to duty requirements Measure pump performance regularly Replace or refurbish poorly performing pumps Polish or coat pump surfaces Use automatic pump scheduling / pump selection software targeting efficiency 1. European Commission, Study on improving the energy efficiency of pumps, February 2001, AEAT-6559/ v 5.1

13 Summary Substantial Energy savings available A power audit will highlight opportunities Start with low hanging fruit - Operational Changes. Establish a pumping regime to minimise costs within operational constraints.. Look at profile of power load and power supply for optimisation savings Audit individual pump and plant, for efficiency savings. CSL will undertake all or part of the Audit above and provide a report with payback periods based on Power bill.