Sustainable specification

by Bill Clark
NBS Technical Author

Building services engineers have a major part to play in promoting sustainable development and have a responsibility to design systems that reduce the environmental impact of a building, throughout its whole life cycle. NBS Technical Author Bill Clark explains how NBS work sections
can help construction professionals in the specification of renewable energy systems.

Renewable energy is a fundamental part of the Government's longer-term plan to reduce CO₂ emissions. In the 2003 Energy White Paper, ‘Our energy future – creating a low carbon economy’, the Government pledged to cut current carbon dioxide emissions in the UK by 60% by 2050 and this pledge was reiterated in the Energy White Paper, Meeting the energy challenge, published in May this year.

In the short term the Government plans that by 2010 the amount of electricity generated from renewable sources in the UK will increase to 10% of total demand, whilst the long term objective is to double this by 2020.

Planning Policy Statement 22 Renewable energy sets out the Government's policies for renewable energy, which planning authorities should take into account when preparing local development documents and when taking planning decisions. Twenty three local authorities currently include requirements for the generation of up to 10% of a development’s predicted energy requirement from an on-site renewable source (often referred to as the ‘Merton rule’). A further 142 others are at various stages of either implementing or assessing the feasibility of similar arrangements - although recent press speculation suggests that the Government is coming under pressure to reverse its policy.

In the meantime building services engineers need to keep up to date with the newest forms of technology and become more involved in the design and specification of renewables.

Typical renewable energy systems suitable for on site include small scale wind turbines, photovoltaic cells, solar panels, biomass heating, and combined heat and power plant. NBS specification products cover a wide range of construction topics and several allow you to specify the most popular renewable energy systems and products.

S35 Biogas supply systems: This section deals with biogas supply systems. Biogas is obtained from municipal solid waste (landfill gas), sewage, farm slurry, and/ or process waste.
S42 Liquid biofuel supply systems: Liquid biofuel supply systems supply fuels derived from crop plants. These include biodiesel from plant seed oil, and ethanol (or methanol) from fermenting grain, grass, straw or wood. Biofuels can also be produced from wood chips, crop residues and other agricultural and industrial waste.
T24 Solid fuel boilers: This section deals with solid fuel boilers suitable for burning conventional solid fuel such as coal, or biomass or solid waste such as wood chips, wood pellets, logs, municipal solid waste, industrial solid waste and hospital waste.
T25 Combined heat and power systems: This section deals with the system of recovering heat, liberated in combustion from generating electricity, as usable heat rather than rejecting it to atmosphere. Combined heat and power (CHP) equipment includes a prime mover driving a generator to produce electrical power, and heat exchangers to transfer heat for space heating and hot water. Absorption cooling can also be achieved.
T26 Solar collectors: Solar collectors are designed to absorb the sun’s energy and transfer this to a water heating system. The solar collectors absorb heat from the sun, which heats up a fluid passing through the panel in pipes. The fluid is then piped through a hot water tank to heat the hot water supply.
T40 Heat pump systems: Heat pumps supply more energy than they consume, by extracting heat from their surroundings. They can also be used for cooling, space heating, pre-heating domestic hot water, heat recovery and humidification in domestic, light industrial and commercial projects. Ground source heat pumps are receiving increasing interest in America and Europe but are relatively new technology in the UK. They represent a very carbon-efficient form of space heating.
V13 Small scale wind generating systems: Small scale wind generating systems, typically from 500 W to 25 kW, convert kinetic energy from wind directly into electricity for use in buildings.
V14 Photovoltaic systems: Photovoltaic (PV) generating systems convert the energy contained in the light from the sun directly into electricity for use in buildings. The section covers ‘grid connected’ systems for buildings which are connected to the local electricity network, and stand-alone systems for buildings where network power supplies are unavailable.

For further information about the Government’s Energy White Paper visit the Department for Business, Enterprise and Regulatory Reform at www.berr.gov.uk.

For further information about PPS 22 visit the Department for Communities and Local Government at www.communities.gov.uk.

Written September 2007