An Bord Pleanála (ABP) recently requested further information from Sustainable Bioenergy Limited on their proposed development of a Biogas plant in Gort, Co. Galway. The ABP requested focused on the water requirements to run this facility, where this water would be sourced from, and how these numbers were calculated. The water requirement, as stated within the application, is 120,000,000 litres per year (120,000 m3).
The ABP request…
“Please provide a breakdown of the water/liquor supply sources to be utilized at the proposed development with the associated calculations which confirm the availability of water/liquor capacity to meet the statement requirement of 120,000 cubic metres of liquor per annum as outlined in the application documentation (Appendix 7.2 – Stormwater Report – of Volume 3 of the Environmental Impact Assessment. “
An Bord Pleanála, Further Information request
Sustainable Bioenergy Limited (via Halston) responded to on 3rd June 2022. Here we delve a little deeper into the numbers from the original application.
Let’s start at the beginning….the Gort water supply
For the last five months Gort has endured a boil water notice. Thankfully we are at the end of this long and drawn out process now and ‘normal’ service has resumed. A clean water supply is a precious commodity most of us fail to recognise until we have to sit up and pay attention. Aside from the inconvenience to most, the affect hit the more vulnerable members of our community the hardest. The underlying issue here is that the towns water supply is in a precarious position; ‘highly sensitive’ and in ‘severe crisis’, not my words, but those used in recent Dail[1] discussions about the Gort water supply.
The Gort water supply is currently close to maximum capacity and even a modest increase in demand will require significant improvements to the network. To give an understanding of capacity sensitivity, according to the Irish Water Capacity Register, in dry summers the Gort Water supply is barely able to keep up with demand. The total capacityofthe current Gort water supply is 1,440 m3 /day and the summer of 2019 saw a daily usage of 1,407 m3/day. This doesn’t leave much of a margin before things become critical.
Water requirements for the proposed Gort Biogas plant
Starting up a biogas plant requires feedstock and water to create a Liquor to start the Anaerobic Digestion Process. The amount of water required is dependent on the type of feedstock used and the amount dry-matter content (DMC) it contains. The water requirement calculations shown in Table 1 are based on a median 7% dilution rate, whereas actual ranges are from 5%-8%.
Table 1. Sustainable Bioenergy Limited proposed feedstock material, tonnage and water requirements for dilution.
| Feedstock | Annual Tonnage | Dry Matter Content (DMC) | DMC (Tonnes) | Water Content (m3) | Water Required for Dilution to 7% (m3) |
| Grass Silage | 54,000 | 28% | 15,120 | 38,880 | 162,000 |
| Cattle Slurry | 22,500 | 11% | 2,475 | 20,025 | 12,857 |
| Agri-Food Residues | 13,500 | 12% | 1,620 | 11,880 | 9,643 |
| Total | 90,000 | 19,215 | 70,785 | 184,500 |
Water requirements to meet the minimum (8%) and maximum (5%) ranges are shown in Table 2.
Table 2. Water dilution range, potential dilution requirements
| DMC of digestate in digesters | Water Required to Dilute Feedstock (m3 per annum) |
| 5% | 294,300 |
| 6% | 230,250 |
| 7% | 184,500 |
| 8% | 150,188 |
Rain glorious rain
Sustainable Bioenergy Limited state in the EIAR that they will source all of their water requirements for the digesters from rainwater. A standard connection to the Gort water supply is included to meet building supply needs (offices, toilets, etc). Based on their own information (supplied via Halston), the plant will source most of their feedstock material from Grass Silage. This will see peak water demand during the driest months of the year.
Worth stating again…. Peak demand period for rainwater will be during the summer months when we have the least rain. The numbers provided by do not take into account the seasonality of rainfall and assume it rains equally each month of the year, throughout the year!
Whichever way you cut it once again the number simply don’t add up.
As defined in the EIAR, and taking into consideration the proposed Biogas plant feedstock inputs, process and digestate outputs there will be a significant shortfall in water supply for the plant. There is a significant lack of detail applicant’s response when it comes to water supply and demand and this simply isn’t good enough.
ABP Request for additional information…are things clearer now?
The simple answer is no. Ample opportunity was provided to address the information requested by ABP. However, all the remains is uncertainty.
“Please provide a breakdown of the water/liquor supply sources to be utilized at the proposed development with the associated calculations which confirm the availability of water/liquor capacity to meet the statement requirement of 120,000 cubic metres of liquor per annum as outlined in the application documentation
Table 3. Water demand requirements included in the original EIAR submission and if clarification has been provided in the response to ABP.
| Water Demand | Figures Supplied? | Demand calculation clarified? |
|---|---|---|
| Office (kitchen toilet) for 20 people & Laboratory + 20+ truck drivers | No, but potentially part of connection to the Gort mains supply | No |
| Washing of facility and trucks | No, but potentially part of connection to the Gort mains supply | No |
| Production start-up Seeding | No, but potentially part of connection to the Gort mains supply | No |
| Fire Water | Yes | Yes |
| Anaerobic Digestion process | Yes – 120,000 m3 | No |
| Maintenance (annual shutdown and cleaning) | No | No |
Given ambiguities in the EIAR submitted in the original application, ABP were correct in questioning the numbers provided and how they were calculated. In response to the information request, we have presented our review of their submission and have highlighted the errors and miscalculations in the EIAR, while providing empirical data on current demands on the Gort water supply, highlighting the precarious state of the Gort water supply.
We can only hope that ABP will uphold the decision of Galway County Council to refuse planning permission. South Galway already has one environmental planning disaster with the Derrybrien Windfarm and the prospect of another is unthinkable. If this plant goes ahead, you may well be reminded of this bad decision every time you go to turn on the tap. Let’s not let the well run dry!
[1] https://galwaybayfm.ie/galway-bay-fm-news-desk/dail-hears-deep-disrespect-shown-to-gort-over-boil-water-notice-saga/
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Gort Biogas Concerns 