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Energy And Water - Scottish Water's Approach To Energy Management And Development

Congress: 2015
Author(s): Christopher Toop (Dunfermline, UK)
Chris Toop, General Manager – Energy
BSc MSc(Eng.) MBA CEng FICE


Keyword(s): Sub-theme 9: Water allocation among competing uses and users,
Oral:
Abstract

INTRODUCTION

Scottish Water provides over one billion litres of high quality water to over five million customers every day. In providing this vital service to customers we're one of Scotland's largest energy users, consuming c450GWh per annum. Increasing demand for water services coupled with rising energy prices saw our total cost of power in 2014/15 exceed £45m. However, our water resources, topography and treatment processes mean that we have significant potential to maximise value from our assets and reduce the long-term cost to customers.

This paper will demonstrate how Scottish Water is benefiting from a four prong approach to energy management and development that is entirely compatible with providing a high quality water service while enhancing our environment.

APPROACH AND METHODOLOGY

Our 3-pronged approach to energy management and development is to:
- Reduce energy consumption by improving the capability of our assets and operations.
- Increase self-generation through innovation & technologies that maximise value from our asset base.
- Host private renewable energy investment on our estate.

By 2018, we aim to be hosting the generation of renewable energy amounting to over twice the amount we consume annually via a combination of self-investment and facilitation of private investment on our assets. In doing so we are looking at our treatment works, water networks and catchments very differently to the past, and increasingly as potential energy factories. We are now on a journey towards self-sufficiency, where it is economical and environmentally appropriate to do so.

RESULTS

Consumption: We have installed over 4000 automated energy meters to provide continuous real time data at our operational sites. Significant savings are now being achieved by optimising our treatment processes and operation of the assets, replacing energy-intensive equipment with biological or low-carbon technologies and installing real-time control to shift electricity load to cheaper tariff periods. As a result we have effectively off-set new energy demand whilst improving the quality of water for customers.

Renewable energy self-generation: Over the last two years we have significantly expanded and diversified our renewables portfolio, including:

Wind turbines to power on-site water and wastewater treatment works.
Food waste and sewage anaerobic digestion to transform waste products into energy.
Doubled our hydro capacity to harness power from our water resources.
Photovoltaic panels on roof space and our estate to reduce energy imported from the grid.
Biomass boilers to heat buildings.

As part of this innovative programme we installed the world's first water trunk main 'Difgen' hydro turbine to capture the energy removed via pressure management within the water network. Our food waste plant was the first large scale plant built in Scotland to convert waste into energy on an abandoned wastewater treatment works, helping to prevent the release of greenhouse gases from historic landfill disposal.

We are also hosting private renewable investment on our land in the form of large wind farms. We are facilitating this investment where it is compatible with protecting water quality and other water users. The benefits are a discounted energy cost or annual income to Scottish Water whilst contributing to national renewable targets. 350GWh of renewable energy is already operational on our estate whilst a further 550GWh is presently consented and 260GWh in development.

CONCLUSIONS

The diversity of our renewable asset base ensures that whatever the weather we're always generating power.

In 2013 we achieved the lowest operational carbon water and wastewater service compared to the ten English and Welsh water & sewerage companies. Over the past 7 years greenhouse gas emissions have fallen by 18% despite continued service improvement and growth. More effective leakage management, energy efficiency and renewables have all supported this reduction. As a result, we are saving over £7m per annum for customers while improving services.

As a result of our energy strategy, we're contributing towards mitigating climate change by reducing carbon emissions, securing greater service resilience and reducing the long-term cost of water and wastewater services to customers.

2011 IWRA - International Water Resources Association office@iwra.org - http://www.iwra.org - Admin