Our aim is to provide you with useful information about our company that we hope will encourage development of similar schemes throughout the UK.
Shetland Heat Energy and Power Ltd has been serving district heating to both domestic and non domestic properties in Lerwick since 1998. Hot water is pumped around Lerwick through underground insulated pipes and enters properties through a heat exchanger, supplying their heating and hot water needs. The heat used in the scheme is generated at a Waste to Energy Incinerator located on the outskirts of Lerwick. The incinerator at the Energy Recovery Plant burns domestic and commercial waste from Shetland, Orkney and from the offshore oil industry, reducing the amount of waste going to landfill. Up to June 2009 there was a total of 1002 connections and 961 of these are receiving heat.
As the number of customers is increasing, the requirement for a further energy source is essential. In 2006 a hot water storage tank was installed to store excess heat during off-peak periods and provide heat during peak loads. This allowed for the equivalent of a further 500 properties to be connected without the need for a further heat source. Another 6.5 MW boiler was installed in 2008 to give a total back up capacity of 15 MW based at the Peak Load Boiler Station. Using customers former boilers as additional back-ups, there is a further 6 MW of boiler capacity spread around Lerwick.
Benefits to the Economy
For the customer, district heating is nearly 100% efficient. The customer only takes heat when they require it. Hot water storage tanks are not required. Radiators come on only when the temperature falls below set levels. The response is instant. As dark clouds pass over Lerwick preventing sunlight warming houses we can see an increase in demand within a short period of time.
One of the biggest surprises we found when connecting large customers was how small a peak demand they required compared with the oil fired facilities that were previously provided. The over provision was enormous. A factor of three was quite common but there has been worse. Even though oversized heat exchangers have often been installed, based on the original provision, these are a mere fraction in costs and space compared with oil boilers.
From an economic view point the district heating scheme contributes a significant role in the Shetland economy:-
About £1,000,000 per annum of the income from sales stays in Shetland rather than paying for oil which would go straight out of the economy. In addition the customers are saving between £300,000 and £1,000,000 depending on the price of oil.
We are playing an important part in reducing fuel poverty at a time when, in the UK, more are falling into it as a result of rising prices. Just as importantly, local businesses are cushioned from the fuel price uncertainty helping to provide some stability. For services such as local government and the Health Board this is equally important where budgets are under pressure.
New large buildings such as the museum and high school will have massive capital savings on plant facilities. The area required for a heat exchanger can be less than 20% than that for boilers and there is no need for storage tanks and flue.
Large users are also finding they have significant reductions in maintenance over conventional boilers. Also, administration is no longer required for ordering and monitoring fuel.
Up until recently we were creating around £700,000 of civil engineering works a year of which around 75% was local input with the remainder being materials.
Housing being converted to wet radiator systems are generating over £300,000 of plumbing works of which much of the cost will be local labour input.
The district heating scheme directly employs six people. It out sources most of its maintenance works to the private sector.
The Energy Recovery Plant also plays an important economic role in addition to its environmental benefits:
* Creating about twenty direct jobs
* Reducing landfill tax which is rising significantly each year
The scheme has reached capacity until another heat source can be developed. Options currently being examined include:-
(a) Wind power with a large thermal storage tank
(b) Waste heat from the proposed new power station
(d) Waste Oils
(e) Heat pumps
(a) is looking like the most promising short term answer but will not allow the scheme to expand. It could allow consolidation where mains have been already laid.
Expansion will be possible if (b) happens.
The scheme has proved popular and we have many applications for connections.
James Watt Award
William Spence, Plant Manager and Neville Martin, District Heating Manager have been awarded the James Watt Medal for a paper they have written on the Energy Recovery Plant and Lerwick District Heating Scheme.
The medal is awarded annually by the Institute of Civil Engineers and celebrates excellence within technical writing. It is named after the Scottish mechanical engineer and inventor who died in 1819 and is awarded for papers that have substantial mechanical engineering content.
The Energy Recovery Plant has been operating successfully in Shetland for 12 years, burning domestic, commercial and industrial waste from Shetland, Orkney and Offshore to produce heat for approximately 50% of the buildings in Lerwick. Hot water generated by the plant is purchased by Shetland Heat Energy and Power Ltd and distributed around the town via insulated pipes.
“There are very few district heating schemes in the UK” said Neville Martin, “so we were glad to have the opportunity to write about the way things work in Lerwick and to show it as an effective method of waste management.
“Nobody writes about these kinds of things, they tend to concentrate on more glamorous large scale engineering projects, so it has been good to get the professional recognition of this award. Hopefully this will encourage other local authorities to consider energy from waste as a sustainable and clean way to generate power and heat in the future.”
Telephone: 01595 697111
Fax: 01595 745150
Shetland Heat Energy and Power Ltd
Marina Business Park