RHI makes some commercial solar hot water systems very attractive
Posted by Gabriel Wondrausch on 21 May 2012 at 9:39 am
Solar thermal was by far the most cost effective renewable energy technology on the market a few years ago. Since the government support schemes have been introduced, first for renewable electricity generating systems via the feed-in tariff and now through the renewable heat incentive (RHI) for non-domestic heat generating technologies, the question is, does solar thermal still stack up?
The short answer is that, in the right situation, it certainly does!
Getting the site right...
The first important thing to remember is that solar thermal systems are site specific. They are only suitable where there is a heat or hot water demand. Unlike solar PV, if there is no on-site demand then there is nowhere for the energy to go and you will not get any benefit from the system. The bigger the demand, the bigger the potential benefits from a solar thermal system.
Phase one of the RHI (for non-domestic properties) requires the use of heat metering to determine the amount of energy units generated and where the energy is used. Ensuring systems are designed and working efficiently will be key to ensuring a good return on investment and a long lifespan. If you can get the site and the design of a system correct, then the potential returns can be very attractive.
Typical sites that could benefit from a solar thermal system would include sports clubs, swimming pools, care homes, hospitals, dairy farms and or camp sites.
Getting the installation right....
The second thing to ensure is that the system is installed by a fully competent and Microgeneration Certification Scheme (MCS) accredited installer. Solar thermal systems can be relatively complicated and simply won’t work unless they have been designed correctly. I have seen far too many badly installed systems, many of which haven’t worked since they were installed.
For example, a typical dairy farm...
Most dairy farms have a high hot water demand and use electricity as their main source of fuel, making them particularly suitable for a large scale solar thermal system.
⋅ System size = 21m² (8 x flat plate solar thermal panels, 1 x 1,000ltr buffer store)
⋅ Approximate cost = £10,000 + VAT
For a typical dairy farm, the payback calculations for solar thermal system would look something like this...RHI Payback Calculations:
Figures given are per year, and (in brackets) over 20 year lifetime of RHI:
Estimated energy generation: 6,858.1 kWh* (137,162 kWh*)
Estimated income from the RHI @ current rate of 8.9p per unit, index linked: £610.37 (£12,207.42)
Estimated minimum savings on electricity bill (likely to rise as energy costs rise): £960.13 (£19,202.60)Income + savings: £1,570.50 (£31,410.00) Estimated payback time = 6.4 years
* Calculated using Polysun simulation software
Solar thermal systems are naturally well suited to the British climate. They work well in cloudy conditions as well as sunny conditions, and are up to 95% efficient, making them one of the most efficient technologies available.They have been somewhat overlooked in recent years having been overtaken by other more glamorous technologies. However, with the introduction of the non-domestic RHI they are once again stepping back into the limelight.
If you have a question about anything in the above blog, please ask it in the comments section below.
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