# Greenhill power station

Greenhill power station supplied electricity to the town of Oldham, England and the surrounding area from 1921 to 1960. It replaced the older Rhodes Bank generating station and was superseded by Chadderton B power station. Greenhill power station was owned and operated by Oldham Corporation until the nationalisation of the British electricity supply industry in 1948. The power station was built over the period 1921–24 and was decommissioned in 1960.

## History

In 1890 Oldham Corporation applied for a Provisional Order under the Electric Lighting Acts to generate and supply electricity to the town. This was granted by the Board of Trade and was confirmed by Parliament through the Electric Lighting Orders Confirmation (No. 3) Act 1890 (54 & 55 Vict. c. clxxxviii). The power station was built in Gas Street at Rhodes Bank (53°32'24"N 2°06'22"W) and first supplied electricity on 20 March 1894.
Following the First World War the demand for electricity was outpacing the available supply. Oldham Corporation built Greenhill power station adjacent to the railway in Churchill Street East (53°32'21"N 2°06'12"W). Greenhill station was first commissioned in 1921 with further generating sets commissioned in 1923 and 1924. In addition Oldham Corporation built another electricity generating station at Slacks Valley known as Chadderton power station which was first commissioned in November 1929.

## Equipment specification
### Rhodes Bank plant 1898

The original plant at Rhodes Bank power station comprised Willans engines and Charlesworth Hall and Siemens dynamos. To maintain supplies at times of peak demand Crompton-Howell and EPS accumulators were provided. Electricity supplies commenced on 20 March 1894. In 1898 the generating capacity was 657 kW and the maximum load was 413 kW. By 1898 9,330 yards (8,530 m) of electricity mains had been laid.

### Greenhill plant 1923

In 1923 the generating plant at Greenhill power station comprised:
* Coal-fired boilers producing up to 383,500 lb/h (48.3 kg/s) of steam. Coal was delivered to the power station via a dedicated railway siding. Steam was supplied to:
* Generators:
** 1 × 2,000 kW steam turbo-alternator
** 2 × 3,000 kW steam turbo-alternators
** 2 × 6,000 kW steam turbo-alternators
These machines gave a total output of 20,000 kW of alternating current.
A variety of electricity supplies were available to consumers:
* 3-phase, 50 Hz AC at 400 and 230 Volts
* Direct current 420 and 210 Volts
* Direct current Traction supply 500 Volts

### Greenhill plant 1954–1958

In 1954 the plant at Greenhill power station comprised:
* Boilers:
** 3 × 25,000 lb/h (3.15 kg/s) Babcock & Wilcox boilers with chain grate stokers
** 2 × 15,000 lb/h (1.9 kg/s) Babcock & Wilcox boilers with chain grate stokers
** 4 × 10,000 lb/h (1.26 kg/s) Babcock & Wilcox boilers with chain grate stokers
The boilers had a total evaporative capacity of 145,000 lb/h (18.3 kg/s), steam conditions were 200 psi and 650 °F (13.8 bar, 343 °C), which was supplied to:
* Turbo-alternators:
** 2 × 6.6 MW Metropolitan-Vickers turbo-alternators, generating at 6.6 kV
** 1 × 4 MW Metropolitan-Vickers turbo-alternator, generating at 6.6 kV
The installed capacity was 17.2 MW with an output capacity of 10 MW.
There were also:
* 2 × 500 kW GEC motor generators
* 1 × 1.25 MW Westinghouse rotary convertor
* 3 × 1.5 MW Westinghouse rotary convertors
Condenser cooling water was cooled in five Premier chimney type cooling towers with a capacity of 1.36 million gallons per hour (1.7 m$^3$/s).

## Operations
### Rhodes Bank operations 1898

In 1898 and there were 213 customers supplied with a total of 305,859 kWh of electricity plus 16,444 kWh for public lighting. The sale of electricity provided revenue of £5,862 for Oldham Corporation against a generating cost of £1,486.

### Greenhill operations 1921–23

The operating data for the period 1921–23 was:
Greenhill power station operating data 1921–23 :
| Electricity Use | Units | Year | Year | Year |
| Electricity Use | Units | 1921 | 1922 | 1923 |
| Lighting and domestic | MWh | 2,879 | 3,162 | 3,823 |
| Public lighting | MWh | 83 | 90 | 166 |
| Traction | MWh | 4,225 | 4,669 | 4,943 |
| Power | MWh | 11,153 | 14,325 | 20,901 |
| Total use | MWh | 18,340 | 22,246 | 29,832 |
| Load and connected load |||||
| Maximum load | kW | 10,996 | 14,187 | 16,260 |
| Total connections | kW | 16,555 | 19,985 | 21,387 |
| Load factor | Per cent | 24.3 | 22.0 | 25.7 |
| Financial |||||
| Revenue from sales of current | £ | – | 166,875 | 29,833 |
| Surplus of revenue over expenses | £ | – | 52,271 | 94,597 |
Under the terms of the Electricity (Supply) Act 1926 (16 & 17 Geo. 5 c. 51) the Central Electricity Board (CEB) was established in 1926. The CEB identified high efficiency ‘selected’ power stations that would supply electricity most effectively; Greenhill was designated a selected station. The CEB also constructed the national grid (1927–33) to connect power stations within a region. Oldham Greenhill became part of one of the three grid rings in Lancashire. This local ring connected Oldham, Manchester, Tame Valley and Stockport.

### Greenhill operations 1946

Greenhill power station operating data for 1946 is given below, data for Chadderton power station is shown for comparison:
Greenhill and Chadderton power station operating data, 1946 :
| Station | Load factor per cent | Max output load MW | Electricity supplied GWh | Thermal efficiency per cent |
| Greenhill | 27.8 | 21,040 | 23.119 | 12.02 |
| Chadderton | 32.0 | 39,959 | 97,910 | 17.14 |

### Nationalisation

The British electricity supply industry was nationalised in 1948 under the provisions of the Electricity Act 1947 (10 & 11 Geo. 6 c. 54). The Oldham electricity undertaking was abolished, ownership of Greenhill power station was vested in the British Electricity Authority, and subsequently the Central Electricity Authority and the Central Electricity Generating Board (CEGB). At the same time the electricity distribution and sales responsibilities of the Oldham electricity undertaking were transferred to the North Western Electricity Board (NORWEB).

### Greenhill operations 1954–58

Operating data for the period 1954–58 was:
Greenhill power station operating data, 1954–58 :
| Year | Running hours | Max output capacity MW | Electricity supplied GWh | Thermal efficiency per cent |
| 1954 | 2729 | 15 | 21.818 | 11.19 |
| 1955 | 2594 | 15 | 18.566 | 11.13 |
| 1956 | 1977 | 15 | 15.874 | 11.528 |
| 1957 | 2533 | 10 | 16.424 | 11.074 |
| 1958 | 2295 | 10 | 12.327 | 10.809 |

### Oldham electricity supply district

The Oldham electricity supply district, covered an area of 29 square miles (75 square kilometres) and included the County Borough of Oldham, the borough of Middleton, and the districts of Chadderton, Crompton, Lees, and Royton. It served a population of 215,800 (1958). The number of consumers and electricity sold was:
| Year | 1956 | 1957 | 1958 |
| Number of consumers | 80,348 | 82,001 | 83,476 |
| Electricity sold MWh | 287,017 | 313,355 | 340,341 |
In 1958 the number of units sold to categories of consumers was:
| Type of consumer | No. of consumers | Electricity sold MWh |
| Residential | 74,909 | 92,706 |
| Shops, offices, etc. | 4,139 | 23,306 |
| Combined premises | 3,086 | 10,407 |
| Factories | 1,116 | 209,539 |
| Farms | 220 | 1,109 |
| Public lighting | 6 | 3,274 |
| Total | 83,476 | 340,341 |
There were 747 miles (1,202 km) of high voltage mains in the district comprising 728 miles (1,172 km) of underground mains and 19 miles (31 km) of overhead cables.

### Closure

Greenhill power station was decommissioned in 1960. The buildings were subsequently demolished although a working substation remains on the site.