Choosing low carbon and renewable technologies

This page provides an initial overview of the technologies available to reduce carbon emissions. More detail on each of the technologies can be found on separate pages.

A biomass boiler in a new housing development at Cross Street South, Wolverhampton. Photo by Stephen McLaren.

The choice of energy technologies occurs at all scales of implementation, but can be most effectively steered at regional, city and neighbourhood scales.

The list below explains how ‘renewable’ different energy generation systems are. The definition of renewable is currently consistent with the building regulations, Code for sustainable homes and BREEAM definititions. Individual planning authorities can have a local or regional definition of renewable energy that differs from this.

Heat

• gas fired boilers – fossil fuel source
• biomass fired boilers – low carbon or renewable source (‘carbon neutral’ energy source but with a low CO2 fuel emission factor to recognise the CO2 emissions embodied in growing/processing/transporting the biomass)
• direct electric heating – fossil fuel source (generally fuelled by electricity which is usually fossil fuel generated, but could be from renewable sources)
• solar thermal panels – renewable energy source
• heat pumps – various (can be fuelled by electricity, gas or oil derived from fossil fuel, low carbon or renewable sources)
• air, ground or ground water source heating and cooling – different sources for heat pumps to provide low carbon or renewable heat (generally not wholly renewable technologies as the electricity used to run the system is usually fossil fuel generated. The renewable heat component is considered to be the difference in the heat output and the electrical energy input once the CO2 emissions of the electricity used have been allowed for). The warmer the source, the greater the quantity of heat produced for the same amount of electricity used
• inter-seasonal thermal storage – low carbon or renewable source yet to be extensively used in the UK. Can be passive as utilized in passive annual heat storage buildings (three examples exist in Mile End Park, London) or a particularly efficient form of ground or ground water source heat pump system. May soon be the only larger form of ground source heat pump system consented by the Environment Agency (see EA policy document GP3, policy 10-1)

Heat/electricity

• gas-fired combined heat and power - low carbon heat and power
• biomass/waste fired combined heat and power – lower carbon heat and power (‘carbon neutral’ energy source for the biomass element but with a low CO2 fuel emission factor to recognise emissions embodied in growing/processing/transporting the biomass)

Electricity

• grid-derived standard electricity – generally fossil fuel source given the current grid generation mix, but will be increasingly fuelled from renewable sources – 35 per cent renewable sources by 2020 compared to 5 per cent currently.
• grid-derived renewable electricity – renewable source (but would not currently be acceptable under building regulations, BREEAM or code for sustainable homes as a form of renewable energy to fulfill a requirement relating to renewable energy generation as it is viewed as merely accounting for the same grid renewables element in a different way)
• wind turbines – renewable source
• photovoltaics – renewable source

Regional energy strategies provide a useful mechanism for exploring the role of different technologies across a region. The suitability of different forms for particular locations and needs can be particularly important in steering the strategy. This should closely inform the evidence base for the Local Development Framework.

Some planning authorities, such as the Greater London Authority, require consideration of low carbon systems for developments over a threshold size. These would include any of the combined heat and power (CHP) or communal heat pump-based systems, which necessarily involve district heating and/or cooling pipework networks.

The EU 2020 renewable energy targets are met by providing renewable heat as much as by renewable electricity. As heat is much cheaper to produce (and free in the case of waste heat) there will be a significant incentive to increase the uptake to meet the binding targets in the most cost efficient way. This suggests that technologies such as CHP will be increasingly popular. It will be particularly important that waste heat is primarily used to serve existing buildings and industry to tackle the major challenge of retrofitting.

Research commissioned by the Communities and Local Government department as part of the introduction of the Code for Sustainable Homes investigated the differing costs of low carbon and renewable technologies. This analysis shows that the costs of achieving the higher code levels can vary quite substantially as a result of dwelling type, development type and site characteristics. The choice of energy technology was found to be central in the range of costs. Lowest costs were typically seen for those developments where there is potential to use site-wide carbon saving technologies (for example CHP systems). These are typically sites with relatively high numbers and densities of development.

Priority: develop a low carbon and renewable energy portfolio
Tags: energy, regions and subregions, cities and towns, neighbourhoods, buildings and spaces