Summary
PROJECT SUMMARY
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Use of Biomass and Ammonia fuel discounted due to spatial constraints and emissions concerns.
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Use of Ground Source Heat Pump discounted due to spatial constraints.
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Hydrogen delivery via truck found logistically not feasible due to the large number of deliveries required, as well as emissions concerns with transport emissions.
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Hydrogen delivery via grid desirable in future when available.
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Scenario 1- 3 X 3MW Water Source Heat Pumps from the river Clyde.
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Scenario 2- 1 Electrolyser produces sufficient hydrogen to meet the demand of the system for CHP and 3 Boilers.
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Scenario 3- 2 x 3MW water source heat pumps from the river Clyde and 1 electrolyser producing hydrogen to fuel CHP alone, negating the need for boilers.
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Scenario 2 offers the fastest payback period of 4 years if oxygen is sold to create a revenue of income.
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Scenario 1 offers the greatest potential in carbon emission savings, equating to 14.6 tCO2e- per year in the event of a switch from natural gas CHP system to WSHP system.
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Scenario 3 is the most technically viable option, at this stage, with current technology as it negates the need for 8MW hydrogen fuelled boilers, which do not currently exist. Current technology shows only a pilot 1MW hydrogen boiler in use in the UK.
Conclusion
All three Scenarios provide viable and adequate options to decarbonise the heat supply to the Strathclyde University campus DH Network, each scenario providing a low carbon pathway, only dependant on the carbon intensity of the electrical grid.
Scenario 1 provides a very low carbon solution, the downfalls of the WSHP system are the associated costs and more importantly, losses for the first 15 years of operation. Such losses leave the scenario undesirable. However, It is also important to consider that these costs may be reduced in the future, with developments of WSHP technology and investment from low carbon energy transition funds.
Scenario 2 shows the most income generation potential with the sales of the oxygen by-product from electrolysis, and resultantly a low payback period of 4 - 5 years. In the future, where hydrogen may possibly be delivered via the grid this is seen as desirable due to ease of delivery. However, sourcing hydrogen from the grid may cause increases in operational costs. As Hydrogen technology develops, large hydrogen fuelled boilers are expected to emerge, resulting in this scenario becoming technically viable.
The development of Scenario 3, negating the need for large hydrogen boilers provides a pathway that is technically viable for implementation now, disregarding dependency on technology developments. The connected capacity of the third scenario has the chance to grow with future connections to the DH Network moving into Phase 3. With room for an additional purpose-built hydrogen CHP within the energy centre, and the capacity for additional electrolysers to meet increased demands the potential for growth of connections is very high. Demand reduction measures within buildings may also create a surplus in the capacity of the system.
The need for district heat will not be ceased due to passive house standards within buildings, there are many buildings within Glasgow city centre, such as City Chambers or the hospital -both proposed Phase 3 connections- will struggle to be retrofitted to the standard of passive house and thus still requiring high levels of heating. Where passive house retrofits of residential, or more compliant commercial buildings do create large decreases in demand, this creates a surplus of capacity; giving potential for additional connections to the DH Network, creating an innovative energy hub within the city of Glasgow.
Recommendation
From our analysis and taking into consideration technology currently available in the market, scenario 3 which is the hybrid system would be the most feasible to implement at the moment. Despite its high capital cost, it brings a consistent profit into the university and is capable of paying for itself in under 8 years. With the consistent advances in research into hydrogen technology, scenario 2 would also offer benefits to the university and the environment once the technology becomes available, and at a lower cost when compared to scenario 3. The water source heat pump has not been recommended due to financial unreliability from the high losses seen for the first 15 years.
It is important to note that the recommendation for the scenario may change and evolve over time, as the implementation of such low carbon projects has to move hand in hand with improvements to the national electricity grid, and the potentials of hydrogen in the Future. The consideration of the impact on the wider grid must be considered for the strain on the electrical grid, with a future move within both the heat and transport sectors to electrification; will there be an adequate supply of electricity?
Similarly, the growth of a hydrogen economy and Industry may pose the question wherein the case of grid delivery, is the DH network the greatest use of Hydrogen available within the UK? In cases where the answer is no, this may be mitigated by the generation onsite, as suggested in this project. However again, this relates back to the intensity of the electricity grid.
It is a delicate and ever-changing balance to predict the future in low carbon infrastructure, in 10 years' time the situation will be vastly different from how it currently stands, and the technology selection should reflect that. It is out of scope to produce a prediction of such events however, it is recommended that such predictions are imperative for future work.
Further future work suggested can be found here