Water & Wastewater Treatment Magazine
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www.wwtonline.co.uk | WWT | AUGUST 2018 | 19 MCPD – THE FACTS • The Medium Combustion Plant Directive (MCPD) was introduced by the EU in December 2015 and applies to generators and plants with a thermal input of 1MW to 50MW. It addresses a perceived gap in the control of emissions because larger plants (over 50MW) are already covered by the Industrial Emissions Directive, while smaller appliances such as heaters and boilers are covered by the Ecodesign Directive. • The UK government supported the MCPD as a way of improving air quality and it was transposed into UK law in January 2018. New plants will have to be compliant from 20th December 2018; all existing plants of over 5MW must be compliant by 1st Jan 2025; and all existing plants over 1MW must comply by 1st Jan 2030. • The directive sets limits on the emission of sulphur dioxide, nitrogen oxides and particulates (dust) into the air. The exact limits operate on a sliding scale depending on plant size, but the UK legislation as dra ed by Defra includes a tougher absolute limit on nitrogen oxide emissions (190mg/Nm3) which is specifi cally designed to prevent the continued success of diesel-fi red reciprocating engines in the capacity market. • There has been rapid growth in the use of small scale, fl exible power generators in the last few years, many of which are diesel generators emitting high levels of nitrogen oxides. Some water companies have a large numbers of such generators which they use as back-up power sources and as a way of making money through demand- side response (DSR) arrangements, through the mechanism known as the Capacity Market. • There is an exemption for plants which are used for backup generation, provided they are operated for no more than 50 hours per year, but they will lose this exemption if they enter into a capacity or balancing service agreement. WATER COMPANY VIEW " Behind-the-scenes energy security and supply is a pivotal part of our work to ensure our customers receive safe, cost e cient and sustainable water and wastewater services. In order to maintain a robust and economical energy supply to our treatment and network facilities, we employ a variety of strategies and technologies. In addition to the renewable energy from our solar and wind turbine business, we also have around 190 diesel generators, and a • eet of combined heat and power (CHP) engines across our sludge digestion facilities to provide a level of energy resilience. "The diesel generators are primarily used for emergency back-up to our key treatment and network facilities to ensure continuation of service during incidents of power supply loss. As a company we continually look for innovative ways to utilise our assets, which bene„ t our customers either through the services they receive, or bills they pay. As part of this approach we utilise some of our existing diesel generators in the energy balancing service market, and / or to avoid Triad charging periods. The introduction of the MCPD and Speci„ ed Generator Control Regulations has required the company to review the impact of these requirements across our business, especially the impact on our diesel generators and the functions that they perform. A cost bene„ t analysis is being carried out to determine if it is economically viable to upgrade the engines to meet new emission standards, or if we apply operational controls. "As the longer term future of Triads, and the bene„ ts of participating in the energy balancing service market is unclear, any movement to a later compliance date will give more certainty around the cost bene„ t of upgrading our diesel engines, or retro-„ tting emission clean-up technology. In the short term diesel generators will continue to provide a cost eŽ ective solution to provide emergency back-up to key water and wastewater facilities, although the continuation of these engines in the energy market is limited. Longer term, United Utilities is looking into alternative technologies such as batteries, and bio- diesel generators." "In the short term, diesel generators will continue to provide a cost-eff ective solution." Martin Williams, Regional Asset Manager (Energy Services) United Utilities