Development projects often attract controversy. The issues are rarely clear cut, or matters of right or wrong, but of conflicting goods. People who approve of a policy in principle often object when it impinges on their neighbourhood.
The plan for a large biodigester plant at Deal Farm, Bressingham, near Diss, is an example. For its advocates it will reduce global warming, converting agricultural waste into clean gas, liquid CO2 and fertiliser. For its opponents it will generate unmanageable levels of traffic, encourage unsustainable agricultural practices and cause environmental damage. They also believe that the developers have tried to bypass proper planning regulation by repeatedly changing the plans.
What is a biodigester?
A biodigester plant puts organic material and waste (feedstock) into an enclosed tank (anaerobic digester) where the material breaks down to produce gases. The “biogas” is used to produce low carbon energy, and carbon dioxide is filtered out for industrial uses. The remaining “digestate” forms a nutrient rich material which be used to replace chemical fertilisers.
The feedstock can be any organic material. Small biodigesters usually burn the biogas for heating or to generate electricity on site. Larger plants, like the one at Deal Farm, combine the gas with imported propane and feed it into the national grid.
This is not new. In the UK there are currently over 600 biodigester plants. Unlike wind and solar, the process provides a steady supply of power. In East Anglia we already have more than 45 installations, 12 of which feed gas into the national grid.
The government wants to encourage this
Because biodigesters can contribute to reducing our carbon output, the government subsidises such plants .
When government develops a scheme to incentivise a change like reducing carbon emissions, it creates rules to ensure that public money is used to achieve the planned purpose. However, rules often have unintended consequences, because they fail to recognise important factors, or leave loopholes to allow “subsidy farming” (where the developer makes money from the subsidy without actually contributing to the objectives of the scheme).
In 2018, the National Audit Office (NAO) reviewed the operation of the RHI (which covers a variety of technologies in addition to biodigesters). The NAO concluded that the scale of environmental benefits depended very heavily on government assumptions, that may be overly optimistic
So the balance of costs and benefits is not simple.
How green is a biodigester?
The case for a biodigester is strongest when it makes use of waste which might otherwise be left to rot, contaminating the environment with release of methane and pollution of groundwater and rivers. The benefits are greatest where transport is minimised, by using feedstock generated locally, piping gas into the grid, and using the digestate in the local area.
The benefits are less clear if a biodigester uses purpose grown crops. Feedstock crops use land which might otherwise be used to grow food. These require fossil fuels for planting, harvesting and transport. They also typically require heavy use of artificial fertilisers, which are produced by very carbon intensive processes, and contaminate water courses. This is particularly true of maize, the crop which is most productive in biodigesters. but which provides poor ground cover, allowing rain to erode soils and deplete nutrients.
As the scale increases, so do the problems. Finding a reliable consistent supply of feedstock can result in a farm having to grow crops simply to keep up with the demands of the digester. Because the calorific value of the biogas is lower than mains gas, it has to be mixed with imported propane. So in addition to vehicles delivering feedstock, and removing digestate, there are tankers delivering propane.
So where does Deal Farm fit?
Deal Farm is a large arable farm, located in open country in South Norfolk, about 5 kilometres North West of Diss.
The first planning application for a biodigester on the site was approved in 2013. Since then, several changes have been agreed in response to technical issues and changes in government policy. The current approval was given in 2015, with little opposition.
Development of the site, and its future operation, is in the hands of Biowatt Ltd, a company specialising in anaerobic digester systems. Funding issues have caused delays, but in 2021, funding was agreed from Storengy UK, a UK subsidiary of the French renewable energy company Engie. Storengy identified technical problems with the design, and some possible improvements, including the addition of carbon capture equipment. In September 2021 they submitted a “minor amendment” (Section 73a) proposal to South Norfolk District Council. They claimed that these changes would improve efficiency and safety without changing the overall size of the plant.
This time, however, there was significant public protest and the Local Authority intervened. Construction work, which was already advanced, was paused. In December, the developers submitted a proposal to revise the plan to South Broadland District Council.
The latest plan is for the biodigester to produce enough gas for 4,000 homes, 7,000 tons of liquid CO2, and 19,000 tonnes of digestate a year. This would require 3,439 vehicle movements (which Biowatt claim is less than the traffic currently used to dispose of the farm waste which the digester is to consume). The previous planning approval limits those movements to within 5 kilometres of the site, and the plans show the location of local feedstock sources.
There is debate about how significant the changes are. Protesters believe that there has been a substantial increase in the scale of the plant, with a corresponding increase in traffic on the narrow local roads, and construction work will probably have increased concerns about traffic. They also believe that there has been a deliberate strategy to bypass proper planning processes, by proceeding rapidly with the work, to get it completed before the changes in the government subsidy regime, and presenting the Local Authority with a fait accompli. This has led locally to a lack of confidence that the site will be managed safely and in accordance with the planning requirements.
There would seem to be three possible outcomes from the current Deal Farm situation.
The developers are right, and the revised plan will prove to be an efficient way of converting farm waste into low carbon energy, fertiliser and liquid CO2, contributing to Britain’s carbon reduction targets, and improving the environment. That would be a win for the world, for the developer and for the farmer.
Alternatively, as some protesters argue, the project may satisfy the requirements of the government’s subsidy scheme without actually achieving the underlying goals. This would be a win for the investors, but a potential loss for the public purse.
Finally, the project may fail all tests, and be rejected by the local authority. The protesters would see that as a win. However, work is well advanced, and the developers might choose to appeal, which could involve South Norfolk District Council in an expensive legal process.
There are still many uncertainties in the equation. If there is adequate feedstock and demand for digestate locally, there may be real environmental benefits. The further away the plant needs to go to find feedstock, and to distribute digestate, the higher the cost in fossil fuels. If it proves necessary to grow crops to feed the plant, again the costs rise.
We shall see how far the revised information allays the anxieties of objectors. However designed, biodigesters do generate traffic. Badly managed, there can be environmental risks. But this is a potential contribution to the global heating crisis which threatens us all.
Where are we now?
The proposal to amend the plans was submitted to South Norfolk District Council at the end of December. At the same time, the developers launched a dedicated website, which describes the history, technology and planning process. It also provides contact details to allow members of the public to raise issues directly with the developers.
The Bressingham Parish Council have called a public meeting on the evening of 10 January to discuss the situation.
Although work is well advanced, the protesters hope that the new application will be rejected. William Hudson, one of the campaigners, commented:
“I am amazed at the number of very well-informed people who have come forward from all of the communities. I am equally amazed and impressed at how the council have listened. We will continue to inform and help South Norfolk Council through the planning process even though the final decision will rest with the council.”
The planning authority will now have to judge all these questions. As with many planning decisions, the most difficult question may be how to balance conflicting interests.
As we struggle with the challenge of global heating, there will be more battles of this sort. We must hope that developers will become better at engaging the local community, and that our planning systems are up to resolving the disputes.