Nid yw’r dudalen hon wedi’i chyfieithu eto.
Economic Impact Model, version 1
retired The workbook exactly as published on 24 March 2026, with the cells that carry the error or a retired claim outlined. Download the unaltered original (SHA-256 4f5d58036d3743c9caf5021228f2b8a16287fce3ae8de023b5f3521b4b1641f6).
What was wrong. One formula, 'Investment & Returns'!B6, divides methane energy by 1,000 when million m³ × kWh/m³ is already GWh. The sheet showed 0.2 where 183.3 GWh was meant, and everything downstream (capacity, capital, electricity revenue, bond interest, maintenance, construction jobs) was 1,000 times too small. The same slip is in the Phased Works Investment revenue column. Separately, the model reached its capital cost two ways that disagree by a factor of 28. The changelog entry.
Solid red outline: a cell whose number is wrong; it shows what it should be with only the units fixed. Dashed outline: a claim we have retired. The values are computed by the same tested code that reproduces this workbook to nine decimal places.
| THE TRIPLE FLIP | ||||||
| How waste becomes wealth: every cost becomes income | ||||||
| This sheet models what Wales currently PAYS for the status quo, and shows how | ||||||
| every cost line flips to zero or to positive income when waste is treated as a resource. | ||||||
| All figures are annual (£m/year) at full programme build-out. Blue cells are editable assumptions. | ||||||
| CORE ASSUMPTIONS | ||||||
| Welsh working-age population | 1,500,000 | Source: ONS / Welsh Gov | ||||
| Currently unemployed | 65,000 | Source: Welsh Gov APS ~4.5% rate | ||||
| Welsh GDP / GVA (£m) | £78,000 | Source: ONS Regional GVA 2023 | ||||
| Average annual benefit cost per unemployed person (£) | £12,500 | Est: UC standard + housing element average | ||||
| Average salary in programme (blended, £) | £33,000 | Est: blend of construction, operations, technical | ||||
| Effective tax + NI rate on employment (%) | 30.0% | Combined income tax + employee/employer NI | ||||
| Pension contribution rate (%) | 8.0% | |||||
| Economic multiplier (Type II) | 1.7 | |||||
| Jobs created (direct + multiplier, from Employment sheet) | 1,400 | Total permanent jobs with multiplier from main model | ||||
| FLIP 1: COSTS THAT BECOME ZERO — what Wales currently pays that it wouldn't | ||||||
| COST NOW (£m/yr) | COST AFTER (£m/yr) | SWING (£m/yr) | ||||
| Welsh Water energy bill (purchased from grid) | £46mThe £46m energy bill is a 2021 press figure. Welsh Water's 2024-25 accounts show a power cost of £93.8m (gross). | £10m | £36m | Residual £10m for grid-dependent sites. Source: Utility Week | ||
| Sludge disposal / management costs | £25m | £0m | £25m | Est: transport, treatment, landspreading currently. Becomes feedstock | ||
| Farm slurry compliance costs (across all suitable farms) | £30m | £0m | £30m | Est: storage, spreading restrictions, NVZ compliance. ~£13k/farm × 2,250 | ||
| Chemical fertiliser imports (replaced by digestate) | £35m | £5m | £30m | Est: Welsh farm fertiliser spend. Digestate replaces ~85%. Source: AHDB / Defra | ||
| Unemployment benefits (for jobs created) | £10m | £0m | £10m | Calculated: jobs created ÷ multiplier × benefit cost (direct jobs only) | ||
| Ofwat fines & penalties (annualised recent trend) | £8m'£40m fine in 2024 ÷ 5 years': the 2024 case ended in a £1 penalty and a £39.4m redress package. | £0m | £8m | £40m fine in 2024 ÷ 5 years. Better performance = fewer penalties | ||
| Pollution-related health costs (bathing water illness) | £5m | £0m | £5m | Est: NHS Wales costs from sewage-related illness. Conservative | ||
| Environmental monitoring & remediation (NRW) | £4m | £1m | £3m | Est: NRW enforcement, monitoring, incident response for sewage/slurry | ||
| TOTAL FLIP 1: COSTS ELIMINATED (£m/yr) | £147m | |||||
| FLIP 2: ZERO BECOMES INCOME — new revenue that doesn't currently exist | ||||||
| NOW (£m/yr) | NEW INCOME (£m/yr) | SWING (£m/yr) | ||||
| Electricity generation from sludge AAD | £0m | £0m£0.0084m → should be £8.36m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | £0m | From Investment & Returns sheet | ||
| Biomethane grid injection revenue | £0m | £15m | £15m | Est: biomethane sales to grid from gas-to-grid hub sites | ||
| Farm AD energy sales to grid | £0m | £51m | £51m | From Employment & GDP sheet | ||
| Digestate sales as certified fertiliser | £0m | £2m | £2m | From Investment & Returns sheet | ||
| Gate fees from accepting third-party organic waste | £0m | £8m | £8m | Est: food waste, trade effluent gate fees at hub AD plants | ||
| Carbon credits / GGSS / green certificates | £0m | £10m | £10m | Est: Green Gas Support Scheme + voluntary carbon market | ||
| Tourism uplift from cleaner bathing waters | £0m | £50m | £50m | Est: 2% of ~£2.5bn coastal tourism. Conservative — clean Blue Flag beaches | ||
| Tax & NI receipts from new employment | £0m | £8m | £8m | Calculated: direct jobs × salary × tax rate | ||
| Pension fund contributions from new employment | £0m | £2m | £2m | Calculated: direct jobs × salary × pension rate | ||
| TOTAL FLIP 2: NEW INCOME CREATED (£m/yr) | £146m | |||||
| FLIP 3: INCOME BECOMES GROWTH — the multiplier effect | ||||||
| Direct wages circulating in Welsh economy (£m/yr) | £27m | |||||
| Supply chain spend retained in Wales (£m/yr) | £128m | WW capex (60% local) annualised + farm AD (80% local) | ||||
| Local consumer spending from new wages (£m/yr) | £19m | Est: 70% of wages spent locally (rent, food, services) | ||||
| VAT generated from local spending (£m/yr) | £4m | |||||
| Secondary jobs from local spending (est.) | 577 | Each £33k of local spend supports roughly one further job | ||||
| THE TOTAL ANNUAL VALUE SWING | ||||||
| Costs eliminated (Flip 1) | £147m | |||||
| New income created (Flip 2) | £146m | |||||
| TOTAL ANNUAL VALUE SWING (£m/yr) | £294m | |||||
| As % of Welsh GDP | 0.38% | |||||
| WHY THIS IS LIKE DISCOVERING A RESOURCE | ||||||
| Unlike oil, gas, or minerals: | ||||||
| • The feedstock replenishes every day — 3.1m people and 1.1m cattle produce it continuously | ||||||
| • It never depletes — population and livestock are permanent | ||||||
| • Extracting it CLEANS the environment instead of polluting it | ||||||
| • Wales already owns 100% of the resource — no extraction licences, no foreign ownership | ||||||
| • The 'extraction infrastructure' (treatment works, farms) largely exists already | ||||||
| • No subsidy is required — the resource pays for its own processing'No subsidy is required': wrong. See the changelog. | ||||||
| Current status: Wales is PAYING to flush this resource into its own seas and rivers. | ||||||
| THE EMPLOYMENT HEADLINE | ||||||
| Currently unemployed in Wales | 65,000 | |||||
| Total jobs created by programme (direct + multiplier) | 1,400 | |||||
| As % of currently unemployed | 2.2% | |||||
| Each employed person shifts from COSTING the state to CONTRIBUTING | ||||||
| Per-person annual swing: benefit saved + tax gained (£) | £22,400 | Benefits no longer paid + tax/NI now received = double swing per person | ||||
| "Wales is sitting on a resource that replenishes every day, cleans the environment when extracted,Quotation: 'creates thousands of permanent jobs … needs no subsidy … There is no cost to acting.' Not supported. | ||||||
| creates thousands of permanent jobs, generates energy and fertiliser, needs no subsidy, and is currently | ||||||
| being flushed into the sea at public expense. There is no cost to acting. There is only the cost of not acting." | ||||||
| WASTE AS RESOURCE | |||
| Economic Impact Model for Comprehensive Sludge-to-Energy Investment by Dŵr Cymru Welsh Water | |||
| THE PROPOSITION | |||
| Welsh Water could pay every household 25p a week, create hundreds of'25p a week': unsupported. See 'Investment & Returns'!B28. | |||
| permanent skilled Welsh jobs, clean up your seas and rivers, and boost'hundreds of permanent skilled Welsh jobs': the 300 plant jobs behind this were an unsourced assumption. | |||
| Welsh GDP — simply by turning sewage into energy. No subsidy required.'No subsidy required': Welsh Water's own sludge energy earned £6.6m in subsidies in 2025-26, and this model counts subsidy income. | |||
| THE PRECEDENT | |||
| Northumbrian Water processes 100% of its sewage sludge through advanced anaerobic digestion. | |||
| It has the lowest combined water and sewerage bills in England, is rated by Ofwat as the mostOfwat did not rate Northumbrian 'most efficient'. The 32% is Northumbrian's own analysis of Ofwat's 2019 models. | |||
| efficient bioresources company in the sector, and its investment programme creates 3,000 jobs/year.'3,000 jobs/year' is a company projection for its whole £2.6bn programme, not for digestion. | |||
| KEY ASSUMPTIONS | |||
| This model is built on the following core assumptions. All are editable on the Assumptions sheet. | |||
| Welsh Water serves | 3,100,000 | people across 838 treatment works | |
| Welsh Water's annual energy bill is approximately | £46m | ||
| Current energy self-generation is approximately | 23.0% | of needs (target was 35% by 2025) | |
| Estimated total sludge production | 67,890 tDS/yr | tonnes dry solids per year | |
| Capital cost per kWe installed | £4,500 | (industry range £2,500–£7,000; mid-point used) | |
| Bond interest rate | 4.5% | (long-duration utility infrastructure bond) | |
| Local supply chain spend target | 60.0% | (matching Northumbrian Water's 60p per £1 commitment) | |
| Economic multiplier (Type II) | 1.7 | (ONS UK construction range 1.5–2.0; sensitivity shown) | |
| Construction jobs per £1m capital spend | 12 | (UK construction industry average) | |
| Plant operational life | 35 years | (standard AD plant lifespan) | |
| KEY OUTPUTS | |||
| Total investment (Welsh Water + farm AD, £m) | £2,290m | £940m | over 10 years (avg £m/yr on Investment sheet) |
| Net annual benefit at full capacity | £17.6m/yr£17.58m → should be £23.90m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | ||
| Net benefit per household per year | £13£13.04 → should be £17.73 with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. The '25p a week' figure. | — that's 25p a week back to each household | |
| 1,360 | 3,814 | per year during build phase (WW + farm + engineering) | |
| 1,400 | 1,326 | for the 35-year life of the plants (all roles, with multiplier) | |
| £509m/yr | £156m/yr | capital programme + ongoing revenue + wages + tourism | |
| 0.65% | 0.20% | ||
| 50% of sludge fully processed within | 4 years | ||
| All 838 works connected to hub network within | 10 years | ||
| THIS WORKBOOK CONTAINS | |||
| 1. Front Page | This page — headline figures and core assumptions | ||
| 2. Executive Summary | All key outputs on one page | ||
| 3. Phased Works Investment | Year-by-year build plan for all 838 treatment works | ||
| 4. Assumptions | All editable inputs with sources — change any number and the model updates | ||
| 5. Investment & Returns | Energy generation potential, revenue, costs, net benefit | ||
| 6. Employment & GDP Impact | Jobs, wages, tax, pension contributions, farm-scale AD | ||
| 7. Northumbrian Comparison | Side-by-side: Northumbrian Water vs Welsh Water current vs proposed | ||
| 8. Sensitivity & GDP | Multiplier range analysis, full value chain trace, GDP % calculation | ||
| IMPORTANT NOTE | |||
| This model illustrates the scale of opportunity using publicly available data and standard industry parameters. | |||
| It is not a detailed feasibility study. All assumptions are transparently stated and editable. A full engineering | |||
| feasibility study commissioned by Welsh Water would refine these figures — but the order of magnitude is sound. | |||
| March 2026 |
| EXECUTIVE SUMMARY: KEY FIGURES | ||
| THE INVESTMENT (all 838 treatment works) | ||
| Total Welsh Water AD capital required (£m) | 940.5 | |
| Tier 1: 15 major hub sites (£m) | 375.0 | |
| Tier 2: 40 regional hubs (£m) | 320.0 | |
| Tier 3: 120 spoke sites (£m) | 96.0 | |
| Tier 4: 663 rural micro works (£m) | 99.5 | |
| Transport fleet & logistics (£m) | 50.0 | |
| Average annual spend over 10-year programme (£m) | 94.0 | |
| Additional: Farm-scale AD investment (£m) | 1,350.0 | |
| COMBINED TOTAL INVESTMENT (£m) | 2,290.5 | |
| THE RETURN (annual, at full build-out) | ||
| Electricity revenue from sludge processing (£m/year) | 0.0£0.0070m → should be £7.01m with the units fixed and nothing else changed. Copies 'Phased Works Investment'!L11. | |
| Avoided energy purchases - savings (£m/year) | 24.8 | |
| Digestate/fertiliser revenue (£m/year) | 2.4 | |
| TOTAL ANNUAL REVENUE/SAVINGS (£m/year) | 27.2£27.18m → should be £34.18m with the units fixed and nothing else changed. Total revenue and savings. Includes £24.8m of 'avoided energy purchases' that probably overlaps with the electricity income. | |
| Net annual benefit after costs (£m/year) | 17.6£17.58m → should be £23.90m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |
| Farm energy revenue + fertiliser savings (£m/year) | 67.5 | |
| THE JOBS | ||
| Peak construction jobs (direct, all programmes) | 800 | |
| Peak total jobs with multiplier (construction) | 1,360 | |
| Total permanent direct jobs (all roles) | 824 | |
| Permanent transport/logistics jobs | 80 | |
| Total permanent jobs with multiplier | 1,400 | |
| THE GDP IMPACT | ||
| Total infrastructure investment in Wales (£m) | 1,914.3 | |
| Total annual GDP impact at steady state (£m/yr) | 509.1 | |
| As % of Welsh GDP | 0.65% | |
| THE CUSTOMER BENEFIT | ||
| Net benefit per household per year (£) | £13 | |
| Cleaner bathing waters | Yes'Cleaner bathing waters: Yes': not shown. Sludge digestion does not change overflow spills or treated-effluent bacteria. | |
| Reduced sewage discharges | Yes'Reduced sewage discharges: Yes': not shown. See the changelog. | |
| Welsh jobs created | Yes | |
| Dividends leaving Wales | None | |
| THE TIMELINE | ||
| 50% of sludge processed at full AAD | By year 4 | |
| All major and regional hubs operational | By year 6 | |
| 100% of works connected to hub network | By year 10 | |
| NOTE: All figures are estimates based on publicly available data and stated assumptions. | ||
| Assumptions can be adjusted on the Assumptions sheet. All calculations update automatically. | ||
| This model illustrates the scale of opportunity. A detailed feasibility study would refine these figures. |
| WASTE AS RESOURCE: ECONOMIC IMPACT MODEL | |||
| Assumptions & Input Parameters | |||
| Blue cells with yellow background are editable assumptions. All other values are calculated. | Sources | ||
| WELSH WATER BASELINE | |||
| Population served | 3,100,000 | Source: Welsh Water corporate website, 2024 | |
| Number of treatment works | 838 | Source: Welsh Water corporate website | |
| Annual energy bill (£m) | £46 | Source: Utility Week, June 2021 | |
| Current energy self-generation (%) | 23.0% | Source: Welsh Water Journey to Zero, 2020-21 | |
| Annual revenue (£m) | £928 | Source: Moody's credit opinion, Dec 2024 | |
| Current employees | 3,500 | Source: Wikipedia / Welsh Water | |
| SLUDGE & ENERGY PARAMETERS | |||
| Sludge production (g dry solids/person/day) | 60 | Source: Ofwat standard (60g BOD/PE/day)'60g BOD/PE/day' is a pollution-load definition, not a sludge dry-solids rate. Welsh Water's own reported sludge (2025-26: 70,500 tDS) is a better guide. | |
| Estimated total sludge (tonnes dry solids/year) | 67,890 | Calculated: population × sludge rate × 365 days | |
| Biogas yield (m³/tonne dry solids - AAD) | 450 | Source: Industry typical for thermal hydrolysis AAD | |
| Methane content of biogas (%) | 60.0% | Source: Industry standard 55-65% | |
| Energy content of methane (kWh/m³) | 10 | Source: Physics constant | |
| CHP electrical efficiency (%) | 38.0% | Source: Typical CHP engine efficiency | |
| Biomethane grid injection price (p/kWh) | 6.5 | Source: Approximate UK biomethane price 2024-25 | |
| Electricity export price (p/kWh) | 12.0 | Source: Approximate UK wholesale + ROC/RGGO | |
| Digestate fertiliser value (£/tonne dry solids) | £35 | Source: Assured Biosolids - £60m/yr for UK ÷ ~1.7m tDS | |
| CAPITAL INVESTMENT PARAMETERS | |||
| Capital cost per kWe installed (£) | £4,500 | Source: edie.net £2,500-7,000/kWe range, mid-point | |
| Programme duration (years) | 10 | ||
| Plant operational life (years) | 35 | ||
| Bond interest rate (%) | 4.5% | Source: Approximate long-duration utility bond rate | |
| Maintenance cost (% of capex/year) | 1.5% | Source: edie.net 1-2% range | |
| % already invested (current capacity) | 15.0% | Estimate: ~15% based on current 23% self-gen vs potential | |
| EMPLOYMENT & ECONOMIC MULTIPLIERS | |||
| Construction jobs per £1m capital spend | 12 | Source: UK construction industry average | |
| Permanent operational jobs per major AD plant | 15 | Source: Industry estimate for hub-scale AAD | |
| Number of hub AD plants to be built | 20 | Estimate: centralised model like Northumbrian | |
| Local supply chain spend (%) | 60.0% | Source: Northumbrian Water commits 60p in every £1 | |
| Economic multiplier (Type II) | 1.7 | Source: ONS UK construction multiplier approx 1.5-2.0 | |
| Average salary - construction (£) | £35,000 | Source: ONS median construction salary Wales 2024 | |
| Average salary - plant operations (£) | £32,000 | Source: Estimate for skilled plant operators Wales | |
| Income tax + NI rate (effective %) | 30.0% | Estimate: combined employee + employer NI + income tax | |
| Pension contribution rate (%) | 8.0% | Source: UK auto-enrolment employer minimum + employee | |
| FARM-SCALE AD PARAMETERS | |||
| Number of Welsh farms | 24,677 | Source: Welsh Gov June 2020 Survey — 24,677 holdings | |
| Dairy farms (primary AD candidates) | 1,750 | Source: Welsh Gov — ~1,469 dairy + some larger beef. Rounded up | |
| Beef/sheep farms suitable for community AD | 500 | Estimate: larger beef farms that could cluster into community AD schemes | |
| Total farms with AD potential | 2,250 | Source: Farmers Weekly 275kWe for 250-cow unit | |
| Average farm-scale AD capital cost (£) | £1,200,000 | Source: Farmers Weekly / NNFCC — £1.2m for 250-cow dairy unit | |
| Average farm AD electrical output (kWe) | 200 | Source: Conservative — range 100-500kWe depending on herd size | |
| Farm AD uptake rate over 15 years (%) | 50.0% | Assumption: 50% of suitable farms with coordinated support programme | |
| Jobs per farm AD installation (construction) | 8 | Estimate: 6-12 months construction per unit, 8 person-years equivalent | |
| Permanent jobs per 10 farm AD plants (maintenance/operations) | 3 | Estimate: shared technicians serving clusters of farm plants | |
| Fertiliser cost saving per farm (£/year) | £15,000 | Estimate: digestate replaces £10-20k/yr chemical fertiliser per dairy farm | |
| Average farm energy income (£/year per AD plant) | £45,000 | Estimate: 200kWe × 8,000hrs × 85% × £0.12/kWh ≈ £163k revenue minus costs | |
| DEEPER ECONOMIC PARAMETERS | |||
| Welsh GDP / GVA (£m, 2023) | £78,000 | Source: ONS Regional GVA 2023 | |
| Tourism revenue for Welsh coast (£m/year est.) | £2,500 | Source: Visit Wales — coastal tourism estimate | |
| Est. tourism uplift from cleaner bathing waters (%) | 2.0% | Conservative estimate: 2% uplift in coastal tourism from water quality improvement | |
| Digestate supply chain jobs per 100 farms | 5 | Haulage, spreading, testing, compliance — per 100 farm AD plants | |
| Engineering/consultancy jobs for programme | 200 | Estimate: design engineers, project managers, environmental consultants | |
| Monitoring/environmental science jobs | 50 | Water quality monitoring, compliance, NRW interface |
| PHASED INVESTMENT: ALL 838 TREATMENT WORKS | |||||||||||||
| Modelled on Northumbrian Water's hub-and-spoke approach: centralised AAD at major sites, sludge transport from smaller works | |||||||||||||
| WORKS CLASSIFICATION BY SIZE | |||||||||||||
| Category | Number of works | Population served | % of total load | Sludge (tDS/yr) | Treatment approach | Capex per works (£m) | Total capex (£m) | Jobs per works (perm) | Total perm jobs | Annual energy output (GWh) | Annual revenue (£m) | Build phase | Notes |
| Tier 1: Major hubs (>50k PE) | 15 | 1,800,000 | 58.1% | 39,420 | Full AAD + gas-to-grid | 25.0 | 375.0 | 20 | 300 | 40.4 | 0.0£0.0049m → should be £4.85m with the units fixed and nothing else changed. A second ×1,000 slip: GWh × 1,000 × p/kWh ÷ 100 ÷ 1,000,000 should be GWh × 1,000,000 × p/kWh ÷ 100 ÷ 1,000,000. | Years 1-4 | Cardiff, Swansea, Newport, Wrexham etc. Upgrade existing + new build |
| Tier 2: Regional hubs (10k-50k PE) | 40 | 800,000 | 25.8% | 17,520 | AAD + CHP | 8.0 | 320.0 | 8 | 320 | 18.0 | 0.0£0.0022m → should be £2.16m with the units fixed and nothing else changed. Same slip as L6. | Years 2-6 | Market towns, larger coastal towns. New AAD builds |
| Tier 3: Spoke sites (2k-10k PE) | 120 | 400,000 | 12.9% | 8,760 | Sludge holding + transport to hub | 0.8 | 96.0 | 0 | [object Object] | Processed at hubs | Included in hub revenue | Years 3-7 | Sludge thickening, holding tanks, tanker loading. Processed at Tier 1/2 hubs |
| Tier 4: Rural micro works (<2k PE) | 663 | 100,000 | 3.2% | 2,190 | Periodic tankering to nearest hub | 0.2 | 99.5 | 0 | [object Object] | Processed at hubs | Included in hub revenue | Years 5-10 | Tanker collection infrastructure. Many already tankered. Minimal new capex |
| Sludge transport fleet & logistics | Tankers, vehicles, depots | 0.0 | 50.0 | 0 | 80 | Estimated: 80 drivers/logistics staff. £50m fleet + depot investment | |||||||
| TOTALS | 838 | 3,100,000 | 100.0% | 67,890 | 940.5 | 700 | 58.4 | 0.0£0.0070m → should be £7.01m with the units fixed and nothing else changed. Same slip as L6. | |||||
| VERIFICATION | |||||||||||||
| Total works count check | 838 | Should equal 838 | |||||||||||
| Total population check | 3,100,000 | Should equal ~3,100,000 | |||||||||||
| PHASED ANNUAL CAPITAL SPEND (£m) | |||||||||||||
| Category | Year 1 | Year 2 | Year 3 | Year 4 | Year 5 | Year 6 | Year 7 | Year 8 | Year 9 | Year 10 | Total | ||
| Tier 1: Major hubs | 93.8 | 93.8 | 93.8 | 93.8 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 375.0 | ||
| Tier 2: Regional hubs | 0.0 | 64.0 | 64.0 | 64.0 | 64.0 | 64.0 | 0.0 | 0.0 | 0.0 | 0.0 | 320.0 | ||
| Tier 3: Spoke infrastructure | 0.0 | 0.0 | 19.2 | 19.2 | 19.2 | 19.2 | 19.2 | 0.0 | 0.0 | 0.0 | 96.0 | ||
| Tier 4: Rural micro works | 0.0 | 0.0 | 0.0 | 0.0 | 16.6 | 16.6 | 16.6 | 16.6 | 16.6 | 16.6 | 99.5 | ||
| Transport fleet & logistics | 0.0 | 10.0 | 10.0 | 10.0 | 10.0 | 10.0 | 0.0 | 0.0 | 0.0 | 0.0 | 50.0 | ||
| TOTAL ANNUAL SPEND (£m) | 93.8 | 167.8 | 187.0 | 187.0 | 109.8 | 109.8 | 35.8 | 16.6 | 16.6 | 16.6 | 940.5 | ||
| CONSTRUCTION JOBS BY YEAR (direct) | |||||||||||||
| Year 1 | Year 2 | Year 3 | Year 4 | Year 5 | Year 6 | Year 7 | Year 8 | Year 9 | Year 10 | ||||
| Construction jobs (12 per £1m) | 1,125 | 2,013 | 2,243 | 2,243 | 1,317 | 1,317 | 429 | 199 | 199 | 199 | |||
| With economic multiplier (×1.7) | 1,913 | 3,422 | 3,814 | 3,814 | 2,239 | 2,239 | 730 | 338 | 338 | 338 | |||
| CUMULATIVE ENERGY CAPACITY COMING ONLINE | |||||||||||||
| Year 1 | Year 2 | Year 3 | Year 4 | Year 5 | Year 6 | Year 7 | Year 8 | Year 9 | Year 10 | ||||
| Tier 1 hubs online (cumulative) | 4 | 8 | 11 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | |||
| Tier 2 hubs online (cumulative) | 0 | 8 | 16 | 24 | 32 | 40 | 40 | 40 | 40 | 40 | |||
| % of total sludge processed at full AAD | 15.5% | 36.1% | 52.9% | 73.5% | 78.7% | 83.9% | 83.9% | 83.9% | 83.9% | 83.9% | |||
| Cumulative energy generated (GWh/yr) | 9.0 | 21.1 | 30.9 | 43.0 | 46.0 | 49.0 | 49.0 | 49.0 | 49.0 | 49.0 | |||
| Cumulative revenue (£m/yr) | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | 0.0Cumulative electricity revenue: the same ×1,000 slip as column L, every year. | |||
| KEY MESSAGES FOR CAMPAIGN | |||||||||||||
| 1. Total investment required to bring all 838 works into full sludge processing: | £940m | ||||||||||||
| 2. This is spread over 10 years, averaging per year: | £94m | ||||||||||||
| 3. Peak year construction jobs (with multiplier): | 3,814 | ||||||||||||
| 4. Permanent operational jobs created: | 700 | ||||||||||||
| 5. Annual energy revenue at full build-out: | £0m | ||||||||||||
| 6. 50% of sludge processed within: | ~4 years | ||||||||||||
| All assumptions are editable on the Assumptions sheet. The tier classification is an estimate based on typical UK water industry size distributions. | |||||||||||||
| Actual works-level data is published by Welsh Water in their bioresources market information and could refine this model significantly. |
| INVESTMENT PROGRAMME & ENERGY RETURNS | |||||||||||
| ENERGY GENERATION POTENTIAL (at full build-out) | |||||||||||
| Total biogas production (million m³/year) | 30.6 | ||||||||||
| Methane production (million m³/year) | 18.3 | ||||||||||
| Total energy content (GWh/year) | 0.20.1833 GWh → should be 183.3 GWh with the units fixed and nothing else changed. The error. '=B5*Assumptions!B18/1000': million m³ × kWh/m³ is already GWh, so dividing by 1,000 gives terawatt-hours labelled as GWh. | ||||||||||
| Electrical generation potential (GWh/year) | 0.10.0697 GWh → should be 69.66 GWh with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | ||||||||||
| Installed electrical capacity needed (MWe) | 0.00.0088 MWe → should be 8.83 MWe with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | Assuming 90% availability | |||||||||
| CAPITAL INVESTMENT REQUIRED | |||||||||||
| New capacity needed (MWe) | 0.00.0075 MWe → should be 7.51 MWe with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | ||||||||||
| Total capital investment (£m) | 0.0£0.0338m → should be £33.79m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. Also: this per-kWe capital (£34m once fixed) is 28 times smaller than the £940m in 'Phased Works Investment'!H11; the model used both. | ||||||||||
| Annual investment over programme (£m/year) | 0.0£0.0034m → should be £3.38m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | ||||||||||
| ANNUAL REVENUE AT FULL CAPACITY | |||||||||||
| Electricity revenue (£m/year) | 0.0£0.0084m → should be £8.36m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | ||||||||||
| Avoided energy purchase savings (£m/year) | 24.8 | Estimate: 70% of currently purchased energy could be offset | |||||||||
| Digestate/fertiliser revenue (£m/year) | 2.4 | ||||||||||
| TOTAL ANNUAL REVENUE/SAVINGS (£m/year) | 27.2£27.18m → should be £35.53m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | ||||||||||
| ANNUAL COSTS AT FULL CAPACITY | |||||||||||
| Bond interest payments (£m/year) | 0.0£0.0015m → should be £1.52m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. Interest is on the £34m per-kWe capital, not the £940m shown elsewhere; on £940m it is £42m a year. | ||||||||||
| Maintenance costs (£m/year) | 0.0£0.0005m → should be £0.5069m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | ||||||||||
| Operational staff costs (£m/year) | 9.6 | ||||||||||
| TOTAL ANNUAL COSTS (£m/year) | 9.6£9.60m → should be £11.63m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | ||||||||||
| NET ANNUAL BENEFIT (£m/year) | 17.6£17.58m → should be £23.90m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. Even corrected, it leaves out financing the £940m programme: at 4.5% that is £42m a year in interest alone. | ||||||||||
| Net benefit per household per year (£) | £13£13.04 → should be £17.73 with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. This was the '25p a week' figure; it is not supported (see the changelog). | Assuming average 2.3 persons per household |
| EMPLOYMENT & GDP IMPACT FOR WALES | ||||
| CONSTRUCTION PHASE EMPLOYMENT (during 10-year build) | ||||
| Annual capital spend in Wales (£m) | 0.0£0.0020m → should be £2.03m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |||
| Direct construction jobs per year | 00.0243 jobs → should be 24.33 jobs with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |||
| Total jobs supported (with multiplier) | 00.0414 jobs → should be 41.36 jobs with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |||
| Annual construction wage bill (£m) | 0.0£0.0009m → should be £0.8516m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |||
| Tax & NI revenue from construction (£m/year) | 0.0£0.0003m → should be £0.2555m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |||
| PERMANENT OPERATIONAL EMPLOYMENT | ||||
| Direct permanent plant jobs | 300 | |||
| Total permanent jobs (with multiplier) | 510 | |||
| Annual permanent wage bill (£m) | 9.6 | |||
| Annual tax & NI from operations (£m/year) | 2.9 | |||
| Annual pension contributions (£m/year) | 0.8 | |||
| FARM-SCALE AD EMPLOYMENT | ||||
| Total farms with AD potential | 2,250 | |||
| Farms adopting AD (over 15 years) | 1,125 | |||
| Total farm AD capital investment (£m) | 1,350.0 | |||
| Annual farm AD investment (£m/year over 15 yrs) | 90.0 | |||
| Farm AD construction jobs (total person-years) | 9,000 | |||
| Farm AD construction jobs per year (over 15 yrs) | 600 | |||
| Farm AD permanent maintenance/operations jobs | 338 | 85% capacity factor for farm AD | ||
| Farm energy revenue (£m/year at full build) | 50.6 | |||
| Farm fertiliser cost savings (£m/year) | 16.9 | |||
| Direct Welsh Water capital spend in Wales (£m over programme) | 0.0£0.0203m → should be £20.28m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |||
| TOTAL PROGRAMME — ALL EMPLOYMENT | 1,350.0 | |||
| Welsh Water construction jobs/year | 0 | |||
| Farm AD construction jobs/year | 600 | |||
| Engineering & consultancy jobs | 200 | Source: ONS Regional GVA, Wales 2023 | ||
| TOTAL DIRECT CONSTRUCTION PHASE JOBS/YEAR | 800800.0 jobs → should be 824.3 jobs with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | Spread over 15 years for combined programme | ||
| WITH MULTIPLIER (×1.7) | 1,3601,360 jobs → should be 1,401 jobs with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |||
| WIDER FISCAL BENEFITS (annual, at steady state) | ||||
| Welsh Water plant operation jobs | 300 | |||
| Welsh Water transport/logistics jobs | 80 | |||
| Farm AD maintenance/operations jobs | 338 | Estimate: £12k/year benefit saving per job filled | ||
| Digestate supply chain jobs | 56 | |||
| Environmental monitoring jobs | 50 | |||
| TOTAL DIRECT PERMANENT JOBS | 824 | |||
| WITH MULTIPLIER (×1.7) | 1,400 | |||
| COMPREHENSIVE GDP IMPACT | ||||
| Welsh Water capital in Wales (£m) | 564.3 | |||
| Farm AD capital (£m) | 1,350.0 | |||
| Total direct capital in Welsh economy (£m) | 1,914.3 | |||
| Annual ongoing revenue retained in Wales (£m/yr) | 94.7 | WW energy + farm energy + farm fertiliser savings | ||
| Tourism uplift from cleaner waters (£m/yr) | 50.0 | |||
| Permanent annual wages in Welsh economy (£m/yr) | 27.2 | Blended average salary ~£33k across all permanent roles | ||
| GDP impact of capital (with multiplier, £m) | 3,254.3 | |||
| GDP impact annualised (over 15yr programme, £m/yr) | 217.0 | |||
| Ongoing annual GDP contribution (revenue + wages, £m/yr) | 292.2 | |||
| TOTAL ANNUAL GDP IMPACT AT STEADY STATE (£m/yr) | 509.1 | |||
| AS % OF WELSH GDP | 0.65% |
| COMPARISON: NORTHUMBRIAN WATER vs WELSH WATER | |||
| Metric | Northumbrian Water | Welsh Water (current) | Welsh Water (proposed) |
| Sludge processed by AAD (%) | 100% | ~15-20%'~15-20%': Welsh Water's audited tables show 98.2% (2025-26) and 98.5% (2024-25). | 100% |
| Energy self-sufficiency | Approaching 100% at major works | ~23% | 70%+ potential |
| Biomethane to grid | Yes - 5,000 homes equivalent | 1 site (Five Fords) | Multiple hub sites |
| Ofwat bioresources efficiency | Frontier company (+32%)'Frontier company (+32%)': Northumbrian's own analysis of 2019 models, not an Ofwat statement. | Below average | Target: frontier |
| Combined bills ranking (England) | Lowest | N/A (Wales) | Target: lowest possible |
| Ownership model | Private (KKR etc.) | Not-for-profit (Glas Cymru) | Not-for-profit (Glas Cymru) |
| Dividends paid | Yes - to shareholders | None | None |
| Investment stays local | 60p per £1 local commitment | Not stated | Target: 60p+ per £1 |
| Net zero target | 2027 | 2040 | Accelerate to 2030-35 |
| Jobs from current programme | 3,000/year'3,000/year': a company projection for its whole programme. | Not stated at this scale | See Employment sheet |
| SENSITIVITY ANALYSIS & GDP IMPACT | ||||
| GDP IMPACT — HEADLINE FIGURES | ||||
| Welsh GDP (GVA, approx 2023) | £78,000m | Source: ONS Regional GVA, Wales | ||
| Total Welsh Water infrastructure investment (£m) | 940.5 | |||
| Total farm-scale AD investment (£m) | 1,350.0 | |||
| Combined investment (£m) | 2,290.5 | |||
| Local spend proportion (%) | 60.0% | |||
| Investment retained in Wales (£m) | 1,374.3 | |||
| MULTIPLIER SENSITIVITY ANALYSIS | ||||
| Conservative (1.5) | Central (1.7) | Rural Wales (2.0) | Notes | |
| GDP impact of total investment (£m) | 2,061.4 | 2,336.3 | 2,748.5 | Total economic activity generated |
| GDP impact annualised over 15 years (£m/yr) | 137.4 | 155.8 | 183.2 | Combined WW + farm programme over 15 years |
| AS % OF WELSH GDP (annualised) | 0.18% | 0.20% | 0.23% | |
| Peak year construction jobs (direct) | 2,243 | 2,243 | 2,243 | Direct jobs same; multiplier affects total |
| Peak year total jobs supported | 3,365 | 3,814 | 4,487 | |
| Permanent operational jobs (direct) | 780 | 780 | 780 | |
| Permanent total jobs supported | 1,170 | 1,326 | 1,560 | |
| VALUE CHAIN — WHERE THE MONEY GOES | ||||
| ROUND 1: Direct investment | Construction, equipment, installation | |||
| Capital spend retained in Wales (£m) | 1,374.3 | |||
| ROUND 2: Supply chain (indirect) | Concrete, steel, pipe, electrical, engineering consultants | |||
| Estimated Welsh supply chain value (£m) | 481.0 | Est: 35% of local spend goes to Welsh suppliers of suppliers | ||
| ROUND 3: Wage spend (induced) | Workers spend locally: shops, housing, services | |||
| Total construction wages over programme (£m) | 0.0£0.0085m → should be £8.52m with the units fixed and nothing else changed. Depends on 'Investment & Returns'!B6, which divides by 1,000 where it should not. | |||
| Permanent annual wage bill (£m/year) | 9.6 | |||
| ROUND 4: Fiscal return | Tax, NI, reduced benefits, business rates, VAT | |||
| Annual tax & NI from all jobs (£m/year) | 50.0 | |||
| Annual pension contributions (£m/year) | 0.8 | |||
| ROUND 5: Secondary economic effects | These are real but harder to quantify precisely | |||
| Lower customer bills → more disposable income | £13 | |||
| Farm supplementary income (£m/year at full build) | 337.5 | |||
| Tourism benefit from cleaner beaches | Not quantified | Significant but requires specific coastal tourism study | ||
| Fisheries/shellfish improvement | Not quantified | |||
| ROUND 6: Avoided costs | ||||
| Ofwat fines avoided (recent: £40m penalty)'recent: £40m penalty': a £1 penalty and a £39.4m redress package. | Not quantified | Welsh Water fined £40m in 2024. Future fines likely without investment'Welsh Water fined £40m in 2024': see above. | ||
| Environmental remediation avoided | Not quantified | |||
| Public health costs avoided | Not quantified | |||
| THE HEADLINE | ||||
| Boost to Welsh GDP (annualised, central estimate) | £156m | |||
| As percentage of Welsh GDP | 0.20% | |||
| Net benefit per household per year | £13 | |||
| Or to put it another way: | ||||
| "Welsh Water could pay every household 25p a week, create hundreds of permanent Welsh jobs, and clean up your swimming water — just by turning waste into energy. No subsidy. No dividends leaving Wales. Why isn't this happening?"Quotation: 'No subsidy. No dividends leaving Wales.' The subsidy statement is wrong. |