As water companies embrace wind energy, Steve Mustow describes how to tackle the challenges of installing turbines
The water industry consumes around 2% of the power used in the UK, and is seeking to reduce its carbon footprint as well as energy costs. It is increasingly achieving both objectives by installing renewable energy technologies to help power its operations.
Yorkshire Water, for example, now produces sufficient renewable energy to meet around 10% of its electricity needs and aims to increase this to 14% by the end of 2015, while Thames Water consumed 1,264GWh of energy (excluding heat) in 2009/10, 15% of which the company generated on its own sites using renewable sources.
In 2011/12, Severn Trent generated 212GWh of renewable energy from sewage gas, energy crops and hydro, which satisfied about 24% of the firm’s electricity demand, and the company aims to generate 30% of its energy from renewable sources by 2014/15.
In the wind
The majority of water firms’ renewable energy generation is provided by combined heat and power (CHP) plants, which utilise the gas generated by the wastewater treatment process. However, several firms are installing wind turbines on their land or leasing their land to energy firms to construct wind farms.
Thames Water’s £200 million upgrade of the Crossness sewage treatment works in east London includes the installation of a wind turbine that will generate up to half the energy needed to power the site.
Yorkshire Water has installed wind turbines at its Loftsome Bridge site near Howden and at its wastewater treatment works at Saltend in Hull. The turbine in Hull reduces the company’s carbon emissions onsite by about 1,150 tonnes every year – the equivalent of taking 20% of the firm’s fleet cars and vans off the road.
Scottish Water has the largest installed capacity on its land, however, through the Whitelee wind farm development near Glasgow. This was built by and is owned and operated by ScottishPower Renewables. Scottish Water has also identified other potential sites for turbines.
A survey by consultants WYG in 2009 found that of 22 participating water companies, nine indicated that they either had planning permission for wind turbines and/or were actively pursuing initiatives at specific sites. Updated information reveals:
- Anglian Water is planning to build three wind turbines on its land during the 2012/13 financial year.
- South West Water has installed a single 100kW wind turbine at its Lowermoor wastewater treatment works in north Cornwall.
- Severn Trent Water has identified a number of its sites as suitable for harnessing wind power, and hopes to generate 54GWh of electricity from wind by 2015. It has submitted planning applications at seven sites, and has secured planning consent to construct single wind turbines at its Wanlip sewage treatment works in Leicestershire and Newthorpe sewage treatment works in Nottinghamshire. It hopes the Wanlip turbine will be up and running in 2013.
- Wessex water is considering the potential of installing four wind turbines at its Bristol sewage treatment works, which could generate a total of 20GWh each year.
Opportunities and constraints
Despite these developments and plans, WYG also found in 2009 that some companies had considered installing wind turbines but had decided against it due to various potential difficulties, including: obtaining planning consent; limited space at operational sites; site-access difficulties; grid-connection issues; and noise regulations. Many of these are the same issues that other wind farm developers have to address, and they are complex and difficult to resolve.
One way forward is for developers to adopt a staged approach, identifying sites that have the greatest opportunity for wind energy. The key constraints associated with each of these sites should then be assessed to determine whether they can be overcome. As a result, any barriers to the project will be revealed at an early stage and work can be stopped before major costs have been incurred.
For example, a water company might have a number of sites where it is considering installing wind turbines. An initial feasibility study, involving desk-based research and initial site walkovers, would rank the suitability of the sites, allowing the most suitable ones to be selected for further, more detailed consideration.
This involves undertaking comprehensive survey, modelling and consultation work. The feasibility study might, for instance, indicate that ecological, radar and noise issues are most likely to prevent the installation of turbines. At the next stage, the developer would have to conduct initial ecological surveys, undertake noise monitoring and modelling and start detailed consultation on radar issues. If the results demonstrate that the development is likely to be viable, further studies can then be carried out.
Such a staged process can be linked to the formal planning application procedures. Most large-scale wind farm developments require an environmental impact assessment (EIA), and the initial scoping phase of the EIA fits with the feasibility/post-feasibility stage of the development process, while the detailed phase of the assessment links to the development design stage. The environmental statement, which reports the results of the EIA, is then prepared in time to accompany the planning application.
Mitigation design is a key element of both EIA and the development design process. It is often possible to avoid or compensate for the constraints identified earlier, although this may involve costs.
It might be possible, for example, to avoid or reduce certain environmental issues, such as noise, shadow flicker, landscape and visual, archaeological and ecological impacts, by careful siting of wind turbines and selection of appropriate turbine models and heights. However, this can potentially reduce installed capacity and, if so, the impact on financial returns needs to be considered.
As the 2009 WYG survey results and the earlier examples demonstrate, wind power is a feasible renewable energy option for water companies to exploit. However, installing wind turbines is more appropriate to some organisations than to others, as the main requirements are an adequate wind resource and sufficient available land to allow selection of sites with the greatest potential for wind power development.
In England and Wales, whether or not wind farm developments fall within “regulated business” is seen as an issue by some water companies. The situation, however, is different in both Scotland and Northern Ireland, where the water companies are not regulated in the same way and this could partly explain why large wind farms are being considered or have already been constructed on water company land in those countries.
Ofwat, the regulator for water companies in England and Wales, set out its views on whether wind turbines can be funded as part of water companies’ regulated business in a 2008 document entitled PR09 Treatment of renewable energy. This clarifies that proposals for investment in renewable energy can be considered as part of the regulated business if:
- the process or technology has natural synergies with the functions of the appointed business, such that it does not make economic sense to separate the energy generation function from the core appointed business;
- any incremental costs associated with renewable energy generation are cost beneficial;
- the main function of the assets remains delivery of the appointed business function; and
- the appointed business benefits from any income streams associated with energy generation.
It also adds that where renewable energy is generated as a non-appointed business or is undertaken by an associate company, Ofwat expects the appointed business to be able to demonstrate that it is trading at arm’s length.
There is a significant potential for water companies to generate energy from wind in the UK. However, biogas and hydro-electric generation are likely to be the options that are considered first as water firms seek to meet their ambitious carbon-reduction targets at the same time as having to meet increasingly stringent environmental requirements.
As Severn Trent points out: “[The company] faces an increasing need for energy, to ensure supply resilience as a consequence of climate change and ever tightening quality standards. Maximising renewable energy generation from sewage, water and our landholdings is an essential part of our strategy to minimise greenhouse-gas emissions.”