Aug 10, 2021
Much of the discussion surrounding district heating projects naturally gravitates towards the adoption of heat pumps and other heat network infrastructure that allows for incredibly efficient heating in urban areas.
This is perhaps expected, as the government is planning for a 20-fold increase in heat pump installations over the next seven years.
However, the other part of the equation is generating the heat itself, and for that, a huge range of options have been proposed, from the conventional to the geographically specific.
Combined Heat And Power
Most power plants, particularly those that rely on coal, natural gas, nuclear power or biomass, generate considerable amounts of heat as a byproduct. This heat was previously wasted, funnelled away from the turbines via large cooling towers and left to heat up the sky.
Combined Heat and Power (CHP) plants get around this by channelling the heat by-product into a district heating system. It is a very economic system and energy-efficient in some respects but does also emit carbon dioxide as a result of the power generation process.
Geothermal
There are underwater reservoirs of water that are naturally very hot, such as the hot springs in Bath. This water could be distributed to nearby buildings as a heat source and is a historically proven way to do so.
However, other alternatives exist for cities that are not close to geothermal sources. Closed mines are often effective sources of heat and the potential for former mining sites as heat sources are currently being explored.
Solar Panels
Solar panels can be used to generate electricity as well as heat, and so in some areas (particularly in Germany and Denmark), solar heat is used to generate power over particularly hot summers and store it over the winter.
Aug 10, 2021
A modification to the proposed Clean Heat Grant could offer £7000 to incentivise homeowners to replace gas boilers with energy-efficient and eco-friendly alternatives.
The proposal, having been consulted upon earlier in the year, is set to come into force next April and could help to connect homes to district heating projects and heat networks and replace the reliance on individual boilers.
The proposal is predicated on the idea that heat pumps, which cost an average of £10,000 for individual homeowners, would halve in price over the next two years, which would considerably reduce the price of a heat pump.
The initial consultation proposed a £4,000 grant, which would reduce the price of the heat pump to £1,000, which is lower than the price of many boilers.
The logic behind the price reduction is scale; the ten-point green industrial revolution plan called for 600,000 heat pumps to be installed per year compared to the 30,000 that are currently installed each year.
This would increase the economy of scale and in theory reduce prices, which along with grants and other incentives could make district heating a desirable option for many homes.
Heat pumps qualify for Renewable Heat Incentive payments, the Clean Heat Grant could considerably shrink the cost of installation, and reduce energy bills considerably, particularly when built into an energy-efficient home.
Other proposed options include the adoption of hydrogen boilers, biomass boilers and solar power, which could be used to generate electricity for heating or absorb heat directly and form part of a more conventional heating system or heat network.
Aug 6, 2021
District heating has reentered the conversation as a low-carbon, low-cost heat solution for large groups of people.
These heat networks take heat from a central source, often as a waste byproduct of manufacturing, power generation or waste destruction, and channel it through a series of insulated pipes into a group of different buildings, with heat pumps allowing for cold and hot air to be transmitted on request.
Whilst the concept is simple and dates back to the Roman Empire, its scalability and adaptability makes it far more effective for heating homes than an individual boiler in each home, especially if you take advantage of heat sources that already exist.
The most common example that has been explored is the combined heat-and-energy plant, where a power plant that would have heat as a waste byproduct instead distributes it to homes that need it.
Whilst this, and natural geothermal sites such as those in places like Bath are well known, there are other district heat sources that are not as well known but could be a major part of the heat network ecosystem in the future.
Here are some examples of unique district heating sources.
Flooded Coal Mines
Whilst much of the UK’s historic coal mining industry has long been closed, the mines themselves may have the potential to provide affordable low-carbon heat.
The UK Coal Authority published a report in December 2020 that suggested that flooded mines would have heated water thanks to geothermal processes underground, which would be between 12 and 20 degrees Celcius.
This temperature is only just under the optimum temperature for central heating systems and low carbon heat pumps would work to efficiently heat the water the rest of the way.
The temperatures that were challenging to miners decades ago would help to provide a sustainable source of heat and energy long beyond the mine’s viability for coal.
Nuclear Reactors
Nuclear power produces huge amounts of energy but as a consequence also generates intense levels of heat, requiring huge cooling towers to remain viable. This heat is wasted when it could be potentially be used in district heating schemes.
The government has opened a consultation to demonstrate the potential in using advanced nuclear power stations to help decarbonised heavy industry and pave the way for net-zero carbon.
District Heating
Computer systems generate large amounts of heat, and server rooms have utilised increasingly creative means to keep large racks of computers cool to avoid malfunctioning systems and a potentially catastrophic loss of data or access.
However, a potential solution may be taking advantage of district heating systems by utilising waste heat from server farms and using this heat as part of heat network systems.
A study undertaken in Finland suggested that not only could it save energy for heat generation but could also save up to 7 per cent for the business managing the server farm.
Given that the past year has seen an increasing number of people use remote access servers and systems rather than work in offices, this could be an increasingly viable method of gathering and distributing heat in cities.
