Planning for the next forty years – Wardell Armstrong’s renewable energy assessment shows the way for Stoke-on-Trent City Council Latest News Article
Article added 7th September 2010
Planning for the next forty years – Wardell Armstrong’s renewable energy assessment shows the way for Stoke-on-Trent City Council
Sustainable development, fuel poverty and climate change are the key drivers in the development of both national and local policy[1] aimed at reducing energy consumption and carbon emissions. The Renewable Energy Planning Guidance Planning Policy Statement 22 affects local development frameworks – and these in turn require districts to put in place a renewable energy policy. Local authorities therefore face a continual drive to reduce CO2 emissions in their area as a whole, and on the buildings they own and operate – 10% by 2010 and 20% by 2020.
Similarly, the six-level building regulations code for new sustainable homes becomes progressively more demanding in the coming years – a 44% saving of CO2 over current levels by 2013, and 70% to 100% by 2016.
In common with other local authorities, Stoke-on-Trent City Council is therefore thinking and planning up to forty years ahead to meet such demanding CO2 emissions reduction targets.
To help understand the city’s potential for generating renewable energy, and to see how best to meet and exceed its share of carbon reduction, fuel poverty and renewable energy targets, the council called on engineering and environmental consultancy Wardell Armstrong to carry out a renewable energy assessment.
Stoke-on-Trent covers an area of around 93km², with 238,000 people living in
112,000 households. The assessment covered the council’s social housing stock of 19,367 dwellings, as well as its private housing stock and public buildings. Houses account for around two thirds of the council stock, with the remainder split roughly between bungalows and flats. Most council houses are at least thirty to forty years old with a large number built in, or before, the 1960s.
Private sector stock in the central core of the city consists mainly of older properties built pre-1919, with a significantly high proportion of fuel-poor households. There are also around 350 British Iron and Steel Federation houses with low insulation levels. The total annualised energy demands and associated CO2 emission levels for public buildings and council housing stock is 540,708 GWh pa, which equates to 601,894 tonnes of CO2 pa.
Savings in energy and emissions at the required level don’t come easily, and certainly can’t be achieved by fabric changes alone. Stoke-on-Trent City Council also had to factor in an anticipated additional energy demand due to a planned increase in housing.
The challenge facing Wardell Armstrong was therefore to carry out a detailed assessment which would inform policy development and provide an evidence base to help determine the most effective forms of renewable energy technologies to integrate into the existing housing stock. This would build on existing initiatives already put in place by the council, such as insulation programmes to improve energy efficiency of properties and reduce heating bills.
Tackling fuel poverty in the city was a key issue. The UK government set out in 2001 to eliminate fuel poverty (where more than 10% of household income is spent on fuel bills) by 2016 – and their estimate is that an extra 40,000 households become fuel poor for every 1% rise in energy prices. A survey in 2004 estimated that 16.5% (17,039) of all Stoke-on-Trent households (both private and social) within the city were fuel poor, and this level will undoubtedly have increased since then as the result of higher energy costs.
Wardell Armstrong’s approach to energy efficiency and the use of renewable energy within buildings includes a “three Bs” principle, as associate director John Carr explains: “The first is to be lean – minimise energy requirements. The second is to be green – maximise the feasible use of renewable energy and implement energy management. The third is to be clean – if you’re using fossil fuels, use those with the least carbon emissions.”
Renewable energy technologies bring countless advantages, according to John Carr – starting with significant reductions in fuel bills. “A system that provides all heating needs can completely eradicate the impact of fuel price fluctuations or rises. In social housing, tenants don’t have to pay directly for installation or upkeep if this is provided as part of the social housing package. Once installed, many options such as wind turbines, solar photovoltaic (PV), solar thermal and ground or air source heat pumps have minimal operational and maintenance cost. Many improve Standard Assessment Procedure (SAP) 2005 ratings as they have low or even no carbon emissions. They can also contribute to fuel poverty relief in “hard to treat” properties, where there is a lifespan of ten years or more left in the building.”
Combining extensive data on properties with a detailed assessment of energy demand and Geographic Information System (GIS) mapping to estimate future energy consumption and CO2 emissions, Wardell Armstrong looked for the most cost-effective ways for Stoke-on-Trent City Council to hit their CO2 targets.
Options included micro renewables such as wind turbines, biomass boilers, solar roofing panels for hot water, solar photovoltaic panels to convert sunlight to electricity, and ground source heat pumps. Macro renewables included larger wind turbines and biomass district heating combined heat and power (CHP) plants for tower blocks.
First, wind turbines. The review identified potential locations for four large wind turbines, 321 medium sized turbines and over 41,000 micro scale turbines suitable for installation on a residential council house property. The full deployment of these could deliver a total saving of 36,713 tonnes per annum in CO2 emissions.
Biomass also emerged as a strong contender, with enough woody material managed by the city council and available within the city’s boundary to supply four 500kWe biomass combined heat and power plants either as stand alone units or fitted into the city council’s flat housing stock and capable of delivering a saving of 6,780 tonnes per annum in CO2 emissions. A feasibility study was recommended to consider biomass
integration into the city’s stock of 1960s flat either as a boiler or CHP district heating system.
Solar thermal and solar photovoltaic energy were also identified as useful contributors. On the basis that 25% of the council’s 16,500 houses and bungalows have a south facing and unobstructed roof, a total of 4064 solar thermal and 4063 solar PV installations would give savings of 1,854 and 5,235 tonnes per annum in CO2 emissions respectively.
Finally, the study found that the council’s social housing stock had the potential both for ground and air source heat pumps – which are especially appropriate for new build housing. Ground source heat pumps take in heat through plastic pipes installed either in trenches or boreholes, and transfer it into a building through an underfloor piping system with a ducted air system or fan assisted radiators. Air source heat pumps use the same principles, but collect low-level heat from the ground instead of from the air. The study identified a potential total of 13,090 ground source and 19,440 air source heat pumps which would give savings of 75,922 and 89,424 tonnes per annum in CO2 emissions respectively.
The study found that in order to achieve carbon reduction, renewable energy and fuel poverty targets, the Council would need to adopt a two-pronged strategic approach to renewable deployment.
This will involve a mix of micro-generation technologies deployed across existing housing tenures to achieve the shorter 2010, 2015 and 2016 fuel poverty targets and the generation of 26% renewable energy by 2020.
In order to meet the longer term carbon reduction targets (80% by 2050), a mix of further micro-generation technology is needed, combined with large scale renewable deployments achievable in the new build sector and integrated into the planning process and regeneration aspirations of the city.
Based on the detailed menu of options and costs that Wardell Armstrong were able to supply, Stoke-on-Trent City Council’s area action plan for the coming decade is now taking shape. Iain Podmore, their Policy and Strategy Officer said: “Working together with Wardell Armstrong has helped to identify our current level of CO2 emissions for the city’s housing stock and identify the potential for deploying renewable energy technology across the city. We now feel that we are in a strong position to work with local businesses, and private and social housing sectors to deploy renewable energy technologies. We feel confident that we will make a real difference in the city over the next ten years.”
[1] The Energy White Paper 2007 sets out intended requirements for a 20% reduction in CO2 emissions and generation of 10% of UK energy requirements through renewables by 2010, greater reliability of energy supply, a move away from dependence upon fossil fuels, and affordability of home heating. The White Paper and Climate Change Act 2008 also include long term goals such as the generation of 26% renewable energy by 2020, and an 80% reduction in CO2 by 2050. The West Midlands Climate Change Action Plan published in December 2007 set the regional renewable target as 5% of electricity consumption by 2010.