- Energy Saving
- Heat Pumps
- Electricity Generation
What is next for renewable heat?
On 12 December, GrowSave hosted an event exploring the future of renewable heat in horticulture. This was similar to the event held in Evesham in May (videos of which are available on the website) but focused on recent changes to the Renewable Heat Incentive (RHI) scheme and what this means going forward. GrowSave consultants were joined by speakers from CMW Horticulture, EBTech, IPT and Priva.
Delegates heard about heat pump systems (air, ground and water source) and how these can be used effectively to heat glasshouses or polytunnels despite the relatively low temperature heat output from a heat pump, typically around 55°C; Matthew Evans, from IPT, told of projects that had achieved space heating at 30+°C. RHI for ground and water source heat pumps remains attractive and can go a long way to offsetting high investment costs, with paybacks of six or seven years not unrealistic.
Biomass boilers remain a viable option, despite changes to the RHI scheme. In fact, large boilers (>1MW) are more viable than ever, thanks to one set of tariffs for all boiler sizes and an increase in the number of eligible operating hours. Jon Swain, of GrowSave, highlighted the importance of compliance with Ofgem’s regulations when claiming RHI. Eligible systems will receive payments for 20 years following accreditation, although the scheme is currently set to end in March 2021. Tighter control over what is considered an eligible heat use is also likely to come into force, expected early in 2018.
Matt Blood, of EBTech solutions, provided a good insight into the practicalities of installing greenhouse and polytunnel specific heating systems so that they can be arranged and managed appropriately. Whether you choose plastic or steel pipes or warm air heating, systems are often choices that are site-specific and a one size fits all approach is rarely appropriate.
In addition to heating, delegates also heard about the manipulation of irrigation patterns for crop improvement. By monitoring crop conditions and irrigating the plant when required, production can be increased with the more efficient use of water and fertilizers.
Good control can be achieved through the use of a computer system, which manages the building blocks of the heating system as units, rather than individual controlled items using their own programmes. Nick Field, CMW technical sales manager, has extensive experience in setting up good control systems and presented some simple approaches that could be implemented to manage greenhouse heating efficiently.
The key take-home messages from the event were:
- The RHI scheme is set to continue until 2021
- Tariffs set to encourage large biomass boilers (>1MW)
- RHI tariffs for ground/water source heat pumps remain attractive
- A heat store is an essential part of any heating system and should be sized appropriately
- A well set-up environmental control system will reduce energy consumption
Here are the presentations from the event which you can download: