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UK Renewable Heat Incentive Flawed

There are some very serious issues regarding renewable thermal energy in UK and Germany that have not been told. At present both governments are excluding solar air heating in favour of their own technologies and industries which produce solar water heating panels. In Canada last year, solar air heating systems out sold all other solar thermal systems and yet, solar air technology is not accepted as a renewable energy technology in Germany and in the UK Renewable Heat Incentive dated March 2011. These governments are depriving their citizens of improved solar heating technologies.

The UK Dept of Energy & Climate Change has introduced a Renewable Heat Incentive and it has a major flaw in that it excludes solar air heating and especially transpired solar collectors.

Below are a few sections from the RHI report with comments on them in italics.

The Government will take a phased approach to implementing the RHI. Initially, in the first phase, long-term tariff support will be targeted at the big emitters in the non-domestic sector. This sector, which covers everything from large-scale industrial heating to small business and community heating projects, will provide the vast majority of the renewable heat needed to meet our targets and represents the most cost-effective way of increasing the level of renewable heat. The Government therefore wants to provide support now in order to kick-start take-up in this sector.
These buildings are heated with air and heating water first to heat air is not cost effective.

Page 10 – The first phase of RHI tariffs will only support the non-domestic sectors. These sectors represent the most cost-effective way of delivering renewable heat, which will help us meet our renewables targets and reduce carbon emissions. We therefore want to introduce support now so installations can start being built.
Excluding solar air heating and transpired collectors contradicts this statement.

P 34 – Technologies supported
We will only provide incentives for technologies which are in commercial use in the UK.
SolarWall is in commercial use in UK and likely has more square metres of collectors in use for heating industrial buildings than solar water collectors – see http://www.CAGroup.ltd.uk

P 37 – Solar thermal
Solar thermal technologies collect heat from the sun onto a collector which transfers the heat energy to a working liquid. This liquid can then be used directly to provide hot water within a building, or an exchanger can transfer the heat from the working liquid to the water.
Solar thermal panels (liquid filled flat plate or evacuated tube solar collectors) will be eligible for support.
Air panels are not eligible even though air in buildings can be solar heated directly and not via expensive solar water panels and heat exchangers.
Government is picking winners and losers as they are supporting only expensive solar technologies and excluding lower cost solar air systems

P 40 – Direct air heating
Technologies which deliver renewable heat directly through hot/warm air will not be supported in the RHI from the outset. This means technologies such as ground or water source to air heat pumps; biomass kilns; furnaces; ovens and air heaters will not be able to claim the RHI. We will, however, look at whether and how these technologies could be included in the RHI from 2012.
There are a number of reasons for not including these technologies from the start of the scheme, which are primarily practical. Our methodology is to meter the heat generated and pay the RHI on that basis, however, there are practical difficulties with metering direct air heating, rather than water and steam. Furthermore, there is insufficient evidence of the costs of these technologies on which to base the RHI tariffs.
Conserval is monitoring solar air systems around the world and other governments (USA, Canada, France etc) are able to monitor solar air systems.

P 42 – Technologies and fuels excluded from the scheme
Transpired solar thermal panels
A small number of stakeholders have argued that direct air heating or transpired solar panels should be supported under the RHI. These technologies will not be included as they are not counted as a renewable technology under the RED.
How can solar heating of air not be a renewable technology?
This is the most damming statement for the Minister and if left as is, and it will certainly come back to haunt him. SolarWall is the most cost effective solar thermal technology for heating buildings currently available and it is being manufactured and sold in UK and in many other countries.

By John Hollick, CEO
Conserval Engineering Inc, SolarWall


  1. I would agree with some of the analysis here but I don’t believe it will be enough for any one company to rely on their own in-house monitoring for performance validation or for predictive sizing.

    As you are an international company, I would recommend further co-operation with the international software simulation companies in Europe such as Valentin Energie Software that I am involved with. I would welcome if Conserval products were listed in their database if only to allow fair comparison. They’ll have a booth at Intersolar in Munich should you wish to make first contact there.

    In the case of the UK minister blaming the ‘RED’, that needs closer inspection as I can only find reference to not counting passive solar gains to avoid potential double-counting. That said, we do need an algorithm to separate the heat flow from inside the building back into a façade-mounted air collector and then it is easier to validate the ‘renewable’ contribution.

    I have approached your UK distributor in the past to promote co-operation the UK technical committees but got no headway. If Conserval already works with one of the solar ISO committees, then please let me know which so as to set up any UK committee liaisons.

  2. Hello Chris,

    Thank-you for your comment….see response from Conserval below:

    We encourage prospective clients to go one step further and use an independently managed and verified predictive energy tool such as RETScreen Feasibility Analysis software. RETScreen was developed by a core team at Canmet ENERGY located in Varennes (Canada) in collaboration with a number of other government and multilateral organisations, and with technical support from a large network of experts from industry, government and academia around the world.

    Conserval provided input into the new ISO9806 standard through Natural Resources Canada. The working group was TC180. This new standard provides the basis for testing solar thermal collectors including air collectors such as SolarWall. The testing measures include elements such as building heat loss recapture. The empirical data is them embedded into RETScreen in order to estimate energy performance of a collector under site specific conditions. RETScreen predictions for SolarWall have been vetted through 3rd party monitoring of field installations.

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