Thursday, 26 June 2014

Non-domestic RHI - small biomass tariff reduced

Ofgem has announced that the small biomass tariff will be reduced by 5% from July 1st 2014.

This is in response to increasing uptake in the sub 200 kW category as well as higher than anticipated levels of eligible heat being submitted in meter readings.

This degression of the small biomass category follows the annual inflation increase that took place on April 1st.  This saw the tariff increase from 8.6 p/kWh (Tier 1) and 2.2 p/kWh (Tier 2) to 8.8 and 2.3 p/kWh, respectively.

The 5% reduction from July 1st will mean that the tariff falls again to 8.4 and 2.2 p/kWh (which is similar to the levels seen in 2012).

The latest uptake figures clearly indicate that whilst the RHI overall is operating within it budgets, uptake of the small biomass category has accelerated.

Meanwhile, uptake of the medium tariff remains strong but is currently operating below budget forecasts.

Activity in the large biomass tariff category is far lower than the other categories.  However, there are clearly a number of schemes at pre-application stage (green column) and these may start to have greater impact on budgets over the next 24 months.

Overall biomass heating remains the clear 'winner' in the non-domestic RHI.  The majority of the available budget (and installed capacity) is currently allocated to biomass technologies and activity in the other RHI-eligible technologies remains relatively modest. 

Tuesday, 17 June 2014

New report assesses alternative tree species to Ash

We have been closely following Ash dieback over the last two years and have spoken to many woodland managers and stakeholders about the impact of the disease.

One of the most frequently asked questions relates to how woodlands will adapt to the disease, and in particular which tree species will make effective replacements.

Until recently our response to this question was fairly limited and was based on a few species such as small leaved lime.

It is therefore very timely that Natural England has released a new report that may help guide practitioners in the selection of alternative tree species that are ecologically similar to Ash.

The report (Assessing and addressing the impacts of ash dieback on UK woodlands and trees of conservation importance) examines the ecological function of 11 tree species considered most likely to replace ash across the UK. 

It also provides a range of case studies showing how existing management plans may be adapted to conserve ash-associated biodiversity should significant ash dieback occur.

In this post we have attempted to summarise the main findings of the report to assist with the dissemination of the findings.  If proactive management action is being considered we recommend reading the report in full.

The eleven tree species looked at were:

The ecological similarity of these alternative to Ash was assessed by considering three main factors:
  • their ecological functioning
  • the number of ash-associated species they support
  • their traits
Ideally any alternative tree should be similar to ash in all of these characteristics.

Ecological functioning

Ash lies at an extreme of the ecological range of native tree species in the UK. It produces nutrient-rich highly degradable litter that does not form a deep litter layer and which maintains a high soil pH.

For ecological functioning the  11 alternative species were assessed in terms of leaf litter decomposition rates, litter quality (chemical and physical properties), nutrient cycling and succession rates.

A change from ash to a tree species with very different ecosystem functioning (e.g. oak or beech) will result in changes in the characteristics of the woodland: slower nutrient cycling, increased carbon storage and changes in the ground flora species present.

Ash-associated species

Around 1,000 species are known to 'use' Ash trees and tree species native to the UK support more ash-associated species than non-native tree species.

Native oak species were found to support the greatest number of ash-associated birds, invertebrate, lichen and mammal species.  

Elm, hazel, oak, aspen and sycamore were found to support the greatest number of the ash-associated species that are most vulnerable to ash-dieback. However elm remains susceptible to Dutch elm disease and is therefore not widely suitable as an alternative to ash.

Traits of alternative tree species

The traits of trees such as tree height, bark pH and fruit type indicate, in part, the type of habitat created by a tree species and the resources available to species that use the tree. Ideally the traits of any alternative tree should be as similar as possible to ash.

Of the native tree species assessed elm had the most traits the same as ash followed by silver birch and rowan.


The study found that the alternative tree species that support the greatest number of ash-associated species are very dissimilar to ash when assessed by traits and ecological function. 

  • Oak supports 640 of the 955 ash-associated species and beech supports 505 ash associated species.
  • However, in terms of ecological function, oak and beech have much slower rates of leaf litter decomposition and nutrient cycling than ash and their canopies cast a much darker shade which will influence the ground flora species.
  • Alder is similar to ash with respect to ecological function (leaf decomposition rates, litter quality and nutrient cycling) but supports fewer ash-associated species (389 out of 955)
As such the method that is most suitable to assess how similar the alternative tree species are to ash will depend on the objectives at the site, for example maintaining ash associated species or maintaining the woodland character and ecological function.

Management scenarios

Six management scenarios that could be applied to woods infected with ash-dieback were considered over two time periods (1-10 years and 50-100 years). The scenarios were:
  1. Non-intervention – stands are allowed to develop naturally with no interventions.
  2. No felling with natural regeneration promoted – no felling but otherwise stands initially managed for natural regeneration.
  3. Felling – all ash trees and coppice removed in one operation with, if necessary, additional trees of other species cut to make the operation more viable.
  4. Felling and replanting – all ash trees and coppice removed in one operation with, if necessary, additional trees of other species cut to make the operation more viable. Then active management to replant with alternative tree and shrub species.
  5. Thinning – regular operations to thin stands by removing diseased and dead trees or coppicing ash, with, if necessary, additional trees of other species cut to make the operation more viable.
  6. Felling with natural regeneration promoted – all ash trees and coppice removed in one operation with, if necessary, additional trees of other species cut to make the operation more viable. Then active management initially to achieve natural regeneration in the stand, with subsequent management to develop overstorey species.
In the short term (1-10 years) more ash-associated species were supported under scenario (5) ‘thinning’ than scenario (6) ‘felling with natural regeneration promoted’.

In the long-term (50-100 years) there was little difference between scenarios (5) and (6) in their impact on obligate and highly associated ash species with of these species predicted to decline in abundance or be at risk of extinction. 

However, the confidence level of these assessments is only low to medium suggesting that the actual impact on ash-associated species is currently only partially understood.

For species 'partially associated' the assessment is somewhat brighter:
  • Species partially associated with ash are generally predicted to decline initially following the onset of ash dieback but after 50-100 years the majority of partially associated species are predicted to be unchanged in abundance compared to current population levels due to an increase in the abundance of other tree species which they utilise.
Overall there is a clear difference in the response of highly associated species, which are predicted to either decline or go extinct and the majority of partially associated species which are predicted to remain unchanged in abundance after 50-100 years.


When woodland managers are considering which alternative tree/shrub species to regenerate or plant in order to mitigate the impacts of ash-dieback on biodiversity, the number of ash-associated species supported is only one factor to consider. 

Woodland managers should also think about other information provided in this report such as the impact alternative trees might have on ecosystem function and factors which will influence the occurrence of ash-associated species in the woodland, such as: woodland structure, food availability, the size, shape and number of holes in trees for roosting bats and hole nesting birds, interactions between species, and changes in woodland ground flora composition.

Ash dieback is just one of several diseases and other potential drivers of change within woodlands within the UK. Other tree diseases and drivers such as grazing, pollution and climate change will also need to be taken into account. 

Management for biodiversity will usually be considered together with the other objectives of woodland management including timber production, amenity, flood prevention and carbon sequestration.

Monday, 2 June 2014

Training voucher scheme to help cross-skill heating engineers to renewable heating systems

The Department for Energy and Climate Change (DECC) has announced a £650,000 fund aimed at expanding the skill set of domestic heating engineers to include the installation and maintenance of renewable heating systems. 

Many of the people installing renewable heat technologies today come from the heating and plumbing sectors and most of the experience is related to oil, gas and LPG systems.

Whilst most conventional renewable technologies are based on familiar electrical, mechanical and hydraulic principles, renewable technologies bring with them a range of additional technical considerations that may not have been encountered during conventional oil, gas or LPG projects.  

Biomass heating, for example, is a proven and reliable technology, but a lack of installation experience can lead to technical difficulties, additional costs and sub-optimal performance.  For example, poorly designed fuel stores can lead to fuel degradation and high fuel delivery costs.

Giving consumers and installers reliable information is an important part of helping them make decisions about their heating system. With the launch of the domestic Renewable Heat Incentive it is important to ensure that consumers have a range of installers to consult, and that these installers are trained to the very latest standards.

The two main areas of support are as follows:

Short course vouchers for existing heating installers

  • The short course vouchers are aimed at existing plumbing and heating engineers in order to encourage them to undertake training in renewable heating technologies.
  • This part of the scheme will deliver vouchers worth 75% of the cost of the training and assessment, up to a maximum of £500 per voucher (including VAT).
  • A maximum of ten vouchers per company will be available. To be eligible the company must be a small to medium-sized enterprise (SME).

Vouchers will be available for:

  • Solar thermal
  • Heat pumps (both air source and ground source)
  • Biomass
  • For solar thermal and heat pump training courses to be eligible, the training must include a QCF assessment that leads to a qualification that is accredited by an awarding organisation. 

Apprenticeship support vouchers

  • The apprenticeship support scheme will support those nearing the end of their plumbing/heating apprenticeship to become skilled with one or more renewable technologies.
  • The apprenticeship support vouchers are worth up to £2,500(including VAT).
  • A maximum of ten vouchers per company will be available. To be eligible the company must be a small to medium-sized enterprise (SME).
  • If an apprentice has already chosen to take the “renewable technology” pathway, they can apply to extend the number of technologies within that pathway and use the funding to support that training.
  • If an apprentice has already selected a non-renewable pathway such as oil or gas, they can still apply and use the funding to take one or more of the QCF units in the renewable technology pathway.

Eligible training includes:

  • Understand the fundamental principles and requirements of environmental technology systems
  • Solar thermal (installation & service and maintenance)
  • Heat pump (installation & service and maintenance)
  • Biomass [solid fuel] (installation & service and maintenance)
  • In addition applications can be made from apprentices to support them in other ways, such as the provision of learning materials and, if required, assistance to enable them to access work types that they may require to complete their apprenticeship programme.

Full details can be found here.

Green heat technologies more affordable with RHI upgrade

The Department for Energy and Climate Change (DECC) has announced changes to the non-domestic (commercial) Renewable Heat Incentive (RHI).

The main changes are as follows:
  • Increased financial support for:
    • renewable CHP
    • large biomass boilers (over 1MW)
    • deep geothermal
    • ground source heat pumps
    • solar-thermal
    • biogas combustion
  • New technologies added:
    • air-water heat pumps
    • commercial and industrial energy from waste

  • An evolved approach to budget management:
    • Improved market intelligence has been used to inform growth rates across the range of renewable heating technologies supported
The updated tariff table is shown below.

These changes are the result of co-operation between industry and Government, and have been welcomed by the Renewable Energy Association (REA) and affiliated trade bodies.

"The RHI is now a truly world-leading renewable energy policy," said the REA's chief executive Dr Nina Skorupska. "Almost all renewable heat applications are now supported under the scheme, offering businesses greater choice than ever before on how to sustainably meet their heating needs.”

The Solar Trades Association provided evidence to Government in support of increasing the 'value for money cap' for renewable energy support programmes, which has enabled support for solar water heating to increase to 10p/kWh (from 9.2 pence/kWh).

Stuart Elmes, chair of the STA Solar Thermal Working Group, said: 

"The extra support for solar heating means that the economics will now stack up for more projects. More swimming pools, sports centres, food factories and hospitals will now be able to afford year-round heating from the sun."

We have also proposed that future improvements should include front-loading RHI payments for solar into the first seven years, as with the domestic scheme, to help businesses get over payback hurdles."

Support for large biomass heat has doubled (to 2p/kWh), but this technology sub-sector still draws the lowest fixed level of subsidy of any low carbon technology.

The newly formed Wood Heat Association (WHA) announced its affiliation to the REA last week. Speaking of these changes to the RHI, the WHA's interim chairman Julian Morgan-Jones said: 

"Under the previous cost-control mechanisms, wood heat was being unnecessarily constrained in order to preserve head room in the budget for heat pumps that was clearly not going to be used. The revised cost control mechanisms more closely match real world deployment and will ensure that wood heat can maximise its contribution to cost-effective emissions savings and renewable energy targets."

The RHI counts towards the UK's 2020 renewable energy target and helps reduce the UK's dependence on polluting fossil fuels. The above changes came into effect on May 28th 2014.

Full details can be found here.