The OK for AD? Overcoming planning barriers to the growth of anaerobic digestion.
Principal Consultant at ADAS http://www.adas.co.uk
Post date: Friday, 24th February 2012
Traditionally, gaining planning permission was a fairly simple process whereby the planning officer visited the proposed site to discuss the options available. An application would then be submitted, which in many cases required some simple drawings, a letter and a short wait before permission was granted.
The process is much more complex today and the following points illustrate the key changes and how to cope with the evolving process.
The new way
Planning officers are very reluctant to visit sites nowadays until a formal request has been made for consultation and it is important to note that the visit may incur a charge.
Prior consultation is widely encouraged and in most cases it is also advisable to have a scoping and screening assessment. A screening report will determine whether an environmental impact assessment (EIA) is required for the proposed site and a response is usually received within seven weeks.
The scoping report will detail what environmental information the council will need to consider when deciding upon the AD application. Some planners will choose to look at the site, the proximity of houses, suitability of roads etc and give an informed response detailing the relevant information to supply. Often, completing the necessary assessments can incur high costs so it is therefore imperative to decide what level of detail to include from assessment and what can be covered with a basic statement.
It is reasonable for planning officers to require specific information to demonstrate that an AD plant will not affect the quality of life of surrounding residents and that its development is a worthwhile project.
Below is a list of the common assessment areas in a planning application, along with advice on how to approach each in the most cost-effective way.
In the majority of cases, a landscape assessment is obligatory to show what the development will look like when complete and what will be done to mitigate any impact. The only time a landscape assessment is not required is if the site is naturally screened by the council. The main issues to review include the height and colour of the tanks. If possible, try to get an opinion on a preferred colour from the planners at the outset and consider using low level of partially underground tanks, however when considering the latter option, bear in mind the potential objections due to leaking and pollution issues.
The average AD plant takes in around 10,000 tonnes of material, which equates to around 750 vehicles. Initially this sounds excessive however the key is to break this down into expected daily trips for the planning proposal, which once reduced is a much more manageable and less invasive six trips per day.
It is also worth highlighting that depending on the type of AD plant, the farm may already be using vehicles to remove slurry which, if planning was approved, would no longer need to be transported anywhere.
All AD plants consist of a sealed tank so there should therefore be no issues with odour. It must be accepted, however, that if methane is exhausted during engine servicing then it is possible it may be detectable to neighbours nearby.
Most odour problems are caused by open stores of feedstock or uncovered digestate stores, bringing material to site immediately before use can solve this problem but is sometimes impractical. An alternate option is to store material in an enclosed building, which through the use of extractor fans and bio filters will reduce odour emissions; however this can create additional costs.
Other odour and air quality issues may arise, especially for applications where residential housing is close by.
In many cases surveys will need to be carried out by a qualified ecologist to determine the possible impacts on the environment of bats, badgers and newts. The survey itself is not too difficult or costly, but the mitigation measures can be. In extreme cases additional surveys will be required and then detailed mitigation strategies drawn up, if possible it is preferable to move the site slightly if it means avoiding things like badger setts. It is also a fair assumption that any development will protect flora and fauna.
Many AD plants are in the countryside where background noise is at a very low level, especially at night. Herein lies the problem in that noise impact is judged based on how many decibels it is above background noise. If background noise is low then even low level noise may be deemed unacceptable. It is difficult when applying for planning when engines are expected to run 24 hours a day, but acoustic enclosures and noise barriers can be particularly effective.
This concern mainly refers to what you put in the AD (feedstock), what comes out (digestate) and how it is handled, and treated. The main concerns in this area are associated with potential leaks and pollution, as alluded to earlier.
To reduce the risk of this there are a variety of measures, including; bunding, effluent tanks for drainage or roofs to prevent rainwater falling on silage clamps or feedstock stores plus safeguards for storing and spreading digestate. Bear in mind that some materials may be stored elsewhere such as in the field and moved to the site immediately before use.
Trees are an asset to many sites as they provide screening. Beware however, that councils are very keen to protect existing trees from damage during site works. In essence an application must prove that during site development nothing will enter the root protection zone of the trees causing them to die at a future date.
It is a statutory requirement that all sites with a development area of greater than 1ha need a flood risk assessment. This seems a good idea in principle, but many sites are simply unlikely to flood. The Environment Agency flood risk maps will give an indication, but may not be completely accurate.
Sustainable urban drainage
It is now compulsory to provide accurate details of where all the water from the proposed site will go from roofs and hard standing areas, if it is a potential problem it will also be necessary to submit any mitigation strategies to deal with any issues. In general this assessment is combined with flood risk but the Environment Agency will no longer accept a simple statement on this matter as they have done in the past.
For an AD site, ideally the proposed site should be 1km away from any houses, close to a dual carriageway, situated on arable land and screened by trees. In reality, land with this criterion is rarely found and the best strategy is often to work with what you have and submit a solid planning application following the above advice.