Renewable Energy

Why Heat Pumps

In little more than 100 years humanity has burned a large percentage of the oil, gas and coal reserves that took so many millions of years to form. In the process of burning we have released billions of tonnes of carbon, in the form of CO2, into the atmosphere and oceans – resulting in climate change. There is no doubt that climate change is happening, is caused by human burning of fossil fuels and is rapidly worsening. In short, we must stop ‘burning stuff’.

Climate change can be, in part, addressed by the take-up of electrical heating and cooling technologies i.e. heat pumps to replace fossil-fuel boilers. Our particular area of specialization is with ground source heat pumps (GSHP), sometimes referred-to as GSHC if cooling is also involved.

GSHP systems use renewable heat present in soil and rock formations together with electrical energy to provide buildings of any size with heating, cooling and hot water. Although the UK’s electricity supply is partly provided by gas power stations, this proportion is falling.  The ‘carbon intensity’ of electrical power supply is today much lower than just a few years ago due to greater use of renewables, the scrapping of coal power stations and continued use of nuclear power (which does not emit carbon). At present GSHPs are a low-carbon heating/cooling technology. Within 20 – 25 years, the UK’s electricity supply will become ‘zero-CO2,’ and so all electrical heat pump technologies will become zero-carbon systems. Add to this the very long-life of a GSHP system*, and lower running costs** compared to oil, direct electric and LPG heating systems and the mass uptake of GSHP technologies seems like a ‘no-brainer’.

In short, by taking up RE alternatives the trend of rising CO2 can be managed and reduced.

By incorporating RE technologies into your business or home you will reduce CO2 emissions and running costs compared to oil and gas. Because RE is produced on-site, this leads to increased independence and security of supply and greater energy price stability.

  • * GSHP are highly reliable and long-lived systems. Closed loop pipework in trenches or boreholes will last for 100 years or more and are considered as heating infrastructure in the same way as gas pipelines and power cables have been for many years.
  • ** Running costs for GSHP systems are similar to mains gas boilers, but very much cheaper than LPG, oil or direct electric heating.

renewable energy

Current renewable schemes and policies

Over the last 30 years or more, the UK has found itself in a privileged position with a plentiful supply of home-produced oil and gas as well as an excellent distribution system. Over 80% of homes and businesses are connected to (cheap) mains gas. However, this is now changing as we are no longer self-sufficient and as a consequence, are open to political and market volatility. Furthermore, the ‘spark gap’ (the difference in cost between electricity cost and gas cost. Electricity unit cost is too high in comparison to gas, this situation is to be addressed by this government.

  • The renewable heat incentive (RHI) will come to an end in March 2022 for domestic installations and March 2021 for non-domestic (although tariff guarantees to extend this are still available).
  • Homeowners, including landlords, can, from October 2020, apply for a Green Homes Grant of up to £5,000 to pay part of the cost of energy saving measures like insulation, or heat pump installation.
  • The Department for Business, Energy and Industrial Strategy (BEIS) has recently launched the Public Sector Decarbonisation Scheme (referred to as the Grant Scheme) which will be delivered by Salix.  The Grant Scheme will offer £1bn of grant funding for capital energy efficiency and heat decarbonisation projects within public sector non-domestic buildings.

The future of incentives for larger, commercial systems is not yet clear. However, we believe GSHP technology is easily capable of standing on its own without incentive in terms of capability to provide heating and/or cooling, running costs and longevity. PROVIDED planning laws make it very clear that the widespread use of gas boilers must cease, immediately.


An excellent summary of the Hydrogen or electrical heating debate was issued by David Cebon – 28 September 2020:

A frequently proposed way to heat buildings in a low carbon future is the use of hydrogen to power hot water boilers or electricity to power heat pumps. There are two ways to make hydrogen: these are known as ‘green’ (using electrolysis) and ‘blue’ (using steam methane reformation). This article compares the various options on the basis of energy efficiency, carbon emissions, infrastructure requirements and technology readiness.

The key conclusions are:

  1. Heat pumps are far more efficient than green hydrogen for heating buildings. The ‘wind-to-heat’ energy consumption of heat pumps is 1/6 that of green hydrogen, for delivery of the same amount of heat. Therefore the energy generation costs for heat pumps are 1/6 of those for green hydrogen.
  2. As a consequence of the inefficiency of the green hydrogen route, it would require an inordinate amount of renewable electricity to heat the UK’s buildings: approximately 40 times the current installed capacity of offshore wind. The heat pump route would require significantly less additional renewable electricity.
  3. The blue hydrogen route for heating buildings would require a 25% increase in the amount of natural gas imported into the UK, taking the imports to 60% of national consumption. This would be detrimental to the balance of trade and energy security.
  4. Neither the green hydrogen nor the blue hydrogen route is ‘clean’. Both generate substantial carbon emissions. In 2020, the green hydrogen route emits 50% more carbon than burning natural gas in a condensing boiler.
  5. Blue hydrogen will always generate significant ‘fugitive’ CO2emissions, that escape into the atmosphere. Consequently, use of blue hydrogen for heating would prevent the UK government from meeting its legal commitments for ‘Net Zero’ emissions by 2050.
  6. Heat pumps generate 1/4 of the emissions of a natural gas boiler in 2020 and this will reduce significantly with time as the electricity grid becomes cleaner. They are the most effective way to reduce carbon emissions from heating. Heat pumps are available off-the-shelf, now.
  7. It is unlikely that the infrastructure needed for blue or green hydrogen could be built in time for 2040.
  8. Government policy should promote the of use of heat pumps for heating new and retrofitted buildings, and should reject hydrogen as an option for heating.

Overall Conclusions

The push towards use of hydrogen for heating is misguided. Burning hydrogen is very inefficient compared with the alternatives. Consequently hydrogen is wasteful of renewable electricity and would substantially increase the amount of natural gas used in the country. The carbon emissions caused by burning blue or green hydrogen are significantly higher than those of heat pumps. It is unlikely that the infrastructure needed for a hydrogen economy could be built by 2040.

Hydrogen is a fundamentally poor choice for heating buildings. It should not be on the agenda. A far better strategy is to convert the country’s heating systems to heat pumps. This should be government policy.

Renewable Energy Services

Carbon Zero Consulting’s major area of expertise is in Ground Source Heating and Cooling GSHC. However, we are also very knowledgeable and experienced in other areas of renewable heat and power.
  1. Renewable technology appraisal

As independent consultants, our first service is to provide you with a detailed, pragmatic appraisal of your options for renewable heat and power. Carbon Zero Consulting will advise you of technologies that suit your circumstance – and those that do not. All buildings and clients are different in their characteristics and requirements and so every situation should be considered in its own light – without preconception.

  1. Heat loss assessments

Understanding the heat loss characteristics of your building is key to successful renewable energy design. It is pointless installing a low temperature heat pump system in an unsuitable building unless changes are made to the building fabric. Our associates have the skills to analyse heat loss (and gain) for buildings of all sizes and types. This might be achieved through calculation or detailed room by room modelling. The output is used to specify renewable heat technologies capable of maintaining required room temperature – at the right price.

For smaller renewable energy schemes, heat loss calculations are essential for compliance with the Micro generation Certification Scheme (MCS) and required in order to receive Renewable Heat Incentive payments (RHI will close for domestic systems in March 2022).

If you are confused or have queries regarding MCS, the RHI or the Green Homes Grant then please give us a call and we will be happy to guide you through the various procedures – and help you on the road to replacing your existing gas or oil with a suitable renewable heating alternative.

3 Ground Source – Horizontal, Borehole or Open Loop?

Our involvement often starts with an initial chat on the telephone. We are happy to talk through options and pros & cons of available renewable heat technologies. We don’t charge for a chat! Our first formal design stage is a domestic or commercial ‘Georeport‘.

Typically a Georeport will be a ‘desk-top’ assessment of geology, potential for open loop, drilling risks and rock thermal properties (for closed loop). We use initial building heating and cooling requirements to provide a first pass design of the number, depth and specification of boreholes or trenches needed to ensure sustainable ground heat exchange capacity for your building.

At this stage we can also provide budget project costs. Our Georeport often accompanies other tender documentation to obtain formal quotes from drilling contractors or system installers, as well as advice on reliable contractors in your area.

Once decisions have been made to proceed with a particular GSHC design, we provide thermal response testing, soil testing and other services to back-up detailed borehole design and system modelling expertise required to ensure the ground source system matches the building’s long-term heating and cooling characteristics

  1. Thermal Response Testing and Soil Thermal Conductivity surveys

See specific sections of our website for further detail – Thermal Response Testing and Soil Thermal Conductivity.

Case Study: a typical project

A recent project that brought the skills of the Carbon Zero Consulting team together is our work for the Nottinghamshire Police HQ.

We provided an appraisal of options to replace their large oil boilers (over 1.4MW) with green biomass technology. Although the underlying geology was suited to the specification of a ground source heating scheme, we concluded that the building fabric and heat emitters could not be economically refurbished to allow the use of low temperature heat pump technology. Biomass boilers have been specified and we have successfully managed the process from heat loss modelling, boiler system specification, a tender process and installation. Solar thermal panels are also being considered to provide renewable hot water for a new shower block to be constructed at the HQ site.

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Other Renewable Sectors

Carbon Zero Consulting are leading specialists in the fields of GSHP technology viability and design and alternative water supply. Unlike some – we don’t pretend to know everything about all other renewable technologies! However, we have experience of, and are able to provide good engineering advice on, the potential for combining renewable heating with solar technologies.

We also provide advice, feasibility assessment and regulatory compliance support for smaller wind power and hydro-electric projects and specialised input to deep-geothermal assessment.