maintenance costs, and, in some cases, losses and savings on both sides. For a power plant, the electricity production will decrease by changing to CHP, and income is lost. Savings can, for example, be investments both in new and existing equipment and costs for cooling heat away in power plants (cooling towers), data centres, wastewater treatment plants, supermarkets, industrial plants, etc. For some categories of industries, like food factories, the input energy is used for both cooling and heat production. By reusing the heat energy from cooling production, these types of factories can often reduce both the energy demand and, thereby, the available waste heat. The investigation must first focus on using the waste heat for internal purposes. The heat source investigation should result in a calculated average waste heat production cost, including cost and saving on investments, O&M, other losses, and savings, but before a profit, calculated for the number of years selected for the first contract period and taking into account the risks regarding delivery. This price is often called the “marginal delivery price” or “cost-based price”. The heat source investigation and average waste heat production cost should be based on the possible heat temperature without including energy-using equipment to increase heat temperature. How to increase temperature, if necessary, should be a part of negotiations. Heat network price investigations Like the investigation done by the heat source, the district heating network company should also make a price investigation. The heat network price investigation should include all operation and maintenance costs (O&M costs) for
input to an industrial plant can be a good starting point for initial discussions. When understanding energy input, the two partners get an idea about potential delivery. Experiences made by other similar industries can often help in understating temperature and the amount of waste heat available. Regarding possible heat delivery compared to heat demand and capacity need, the heat source and demand often do not fit perfectly. The heat network then often needs to be enlarged before delivery can be feasible, and delivery may be postponed until the heat network size fits or the contract has to take this into account, making it even more complex. After the initial collection of information, both partners need to evaluate the risks before it is decided to carry on. If risks and investments are high for one partner, they must be addressed in the following negotiations. Heat source price investigation A heat source investigation can be complex, and often, it can be a good idea for the heat network company and heat source owner, in cooperation, to find a specialist with knowledge about the industrial processes and district heating systems to investigate on behalf of both partners. Industrial plants do not want to spend much on investigations as it is not their primary business. Often, the district heating company or government, through subsidies, can finance the investigations. Some of the first investigation steps, though, can be done before a specialist is hired as it is pretty easy to determine the grade of the heat source and to understand the expected lifetime of the industrial plant or the production line from where the waste heat can be utilised.
Besides temperature and possibly delivery profile, the investigation needs to explore investments, operating costs,
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