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South Dakota: Find which cost can actually change
Start with EIA: natural gas volume, heat content and energy units. The table below links this decision to the represented gas companies in South Dakota. It does not establish service or supplier availability for every account.
Use five separate checks
Check the billed class; reconcile readings and corrections; identify supply versus delivery; count recurring account fees; and update the consumption forecast for operational changes. Keep each proposed action tied to the charge it can affect.
Avoid counting a reduction twice
Model an equipment project at the revised gas volume before comparing supplier offers. A fixed monthly charge remains even when therms fall. Keep equipment investment, supply cost and retained utility costs in separate budget lines.
South Dakota utility application
| Gas service company | Cost component to investigate | Primary reference |
|---|---|---|
| NorthWestern Energy | Sales gas-cost component versus transport, balancing and supplier costs | Official program / tariff |
| Montana-Dakota Utilities | Purchased-gas adjustment under sales versus transportation and retained gas obligations | Official program / tariff |
| MidAmerican Energy | Sales gas-cost component versus transport, balancing and supplier costs | Official program / tariff |
| Watertown Municipal Utilities | Local gas rate and any gas-cost adjustment | Official program / tariff |
NorthWestern Energy: the program detail behind this decision
The South Dakota PUC lists distinct commercial sales and transportation schedules by gas company. NorthWestern lists Rate 87 transportation; MidAmerican lists monthly-metered transportation and transportation of customer-owned gas. These require their own qualification and agreements, rather than statewide small-business open enrollment. Sd Current Tariffs.
Apply the evidence to an account file
For this account, investigate Sales gas-cost component versus transport, balancing and supplier costs. If the proposed action changes only the supply component, retain the other components when calculating the total bill effect.
Worked check: price and volume are different effects
Assume purely hypothetical comparable commodity use falls from 10,000 to 9,000 therms while its price rises from $0.80 to $0.85 per therm. Commodity cost changes from $8,000 to $7,650. At the original price, lower volume explains negative $800; the price change on actual use adds $450. The net difference is negative $350. Fixed charges, delivery, taxes and other costs are excluded. It would be incorrect to report that entire $350 as a supplier-price saving.
Turn the review into a calculation
Compare constant supply rates and fees. Enter documented assumptions in matching energy units. Keep any charge outside both supply offers separate; the result does not establish eligibility or an available quote.
Read the South Dakota utility guide for the wider service-company distinctions. Convert billed gas units using the bill’s heat-content factor when moving from volume to energy.
Sources and review notes
- EIA: natural gas volume, heat content and energy units
- South Dakota PUC natural gas tariffs
- Mdu Tariffs
- Sd Utility Directory
Reviewed October 16, 2026. Program information can change. Confirm the effective utility tariff, supplier availability and written offer before proceeding. Examples and planning tools are educational; they are not executable quotes or verified customer results.