Standard Bundled Units (SBU)

Rough's official capacity is 30,300 GWh (100bcf, 2.82 bcm) of space, 455 GWh/day of deliverability/withdrawal rights and about 160 GWh/day (variable depending on the fullness of the reservoir) of injection rights.

The capacity is sold as SBUs in the above ratio, each SBU comprising a 67 day duration service as follows:

Customers generally use Rough in a seasonal fashion, injecting gas in the summer when prices are low and withdrawing during periods and days when prices are favourable. Typical flow profiles from Rough are shown below.

Rough’s flexibility enables customers to vary their use at short notice to take advantage of attractive spot prices and arbitrage versus forward markets. The forward Quarter 1 (January to March) minus summer difference normally gives the best indicator of Rough’s capacity value.

S Store is our original storage product, consisting of SBUs as described above. Download our S Store Within-Day and our S Store Day-Ahead information sheets.

View Indicative prices for SBUs

Rough Storage Flows – June 2006 to July 2007

CSL adopt pricing policies based on the current forward Summer/Q1 spreads and are an entirely market-based product. We provide offers on request for SBUs on at least a fixed-price and "Q1 minus summer, indexed" basis. The "indexed" prices allow the customer to hedge their capacity purchase progressively through the index-fixing period and to purchase capacity for future years and pay the ‘market rate’ for capacity at that time. Our standard indexing period is during Q1 of the preceding storage year; we calculate the average “Q1-summer” during this period and negotiate a multiplier.

• Download Example Terms for Indexed SBUs PDF (33K)

The basis by which Centrica companies may purchase capacity from CSL is contained within the Undertakings PDF (131K). Ultimately 85% of our SBUs will be available to Third Party companies with 20% of all capacity being offered for sale on annual contracts.