Overheating in homes

This post was written by BSRIA's Saryu Vatal

This post was written by Saryu Vatal, Senior Consultant of BSRIA’s Sustainable Construction Group

BSRIA’s Residential Network organised an event on the 22nd of July focussing on the issue of overheating in homes with an excellent line up of speakers. Nicola O’Connor started the day summarising an extensive research project by the Zero Carbon Hub that brought together input from government, industry and academic experts to understand the challenges around tackling the risk of overheating in homes (http://www.zerocarbonhub.org/current-projects/tackling-overheating-buildings). Chris Yates from Johnson and Starley made an appraisal of the assumptions and requirements within the Building Regulations and associated guidance as well as the implications for mechanical ventilation system manufacturers. Neil Witney from DECC explained the challenges around defining and regulating of overheating within homes, current policies and mechanisms that may be introduced in the future in response to the growing body of evidence highlighting the issue. Paul Ciniglio from First Wessex shared the organisation’s findings from several research projects and experience from their own developments, which resonated with issues highlighted by members of the audience. Bill Gething of Sustainability + Architecture and professor at the University of West England brought into perspective how changes in the way homes have been designed and built over the recent years has led to a shift in the performance of homes. James Ford, partner at Hoare Lea discussed some key considerations for designers to address the issue at early stages, to help minimise risk and dependence on active cooling solutions.

Extent of overheating

Evidence indicates that up to 20% of homes in England may already be overheating. Areas where additional risks have been highlighted include:

  • Common areas in apartment blocks, especially where community heating is installed – these areas are not assessed using SAP as they are outside the dwelling envelope. In reality, being unoccupied spaces these are often not modelled for their thermal performance (and energy use) at all. Community heating is being incorporated in an increasing number of projects and the supply network remains live even in the summer to meet the domestic hot water demand. Ensuring that the specification and installation of insulation for the distribution pipework is adequate is becoming increasingly important as buildings are made more airtight. Often stairwells and circulation areas have a high proportion of glazing and, with recent improvements in the general standard of construction and materials, tend to retain a large proportion of the heat gains. It is now important to incorporate a ventilation strategy for these spaces so that the accumulated heat can escape.
  • Urban areas – the average temperatures in city centres can be more than 4°C higher than rural areas. Flats are more common to city centres and these are often close to sources of noise and air pollution and have limited, if any, potential for cross ventilation. All these factors can combine to limit the effectiveness of natural ventilation in addressing the build-up of heat and not just in the summer. Building designs that incorporate large proportions of glazing in their facades, such as penthouses, if not carefully designed, can require air change rates that are unrealistic to achieve, using natural or mechanical ventilation systems.

Need for a definition

A number of sources and definitions are being referred to currently when evaluating for the risk of overheating in homes. These include CIBSE’s Environmental Design Guide A (2006) which sets standards for comfort, although it is not mandatory to use this to demonstrate compliance with the Building Regulations. Dynamic modelling through tools such as TAS and IES offer the opportunity of making a more comprehensive evaluation than SAP, but this option is skill, time and cost intensive. Building Regulations do not relate to limiting overheating for thermal comfort, just limiting the use of fuel and power for air-conditioning. The minimum evaluation for demonstrating compliance with Criterion 3 of Approved Document Part L of the Building Regulations needs to be carried out using SAP. While SAP is not intended to be a design tool, it is accepted that it is the default tool the industry uses widely.

Research projects have highlighted that dwellings can demonstrate a risk of overheating when evaluated against the CIBSE standard but not when modelled in SAP. Surveys from the Zero Carbon Hub study showed that nearly 60% of the housing providers surveyed had checks in place to assess the risk of overheating. However, only 30% of these housing providers explicitly included the requirement for considering the risk of overheating as part of their employees’ requirements to architects and designers. This suggests a missed opportunity for the issue to be addressed early on in the process, when cost and energy efficient measures may be effectively incorporated.

There are several challenges around the definition of conditions under which overheating can be said to occur as several factors contribute to this, including but not limited to air and radiant temperatures, humidity, air velocity, level of activity the adaptability of the individual. There are several checks that can be built into the design process which can help identify the risk at an early stage and allow for a method for mitigating these to be set up and followed through.

Contributing factors
The energy efficiency of homes in the UK has improved significantly in terms of reduction of space heating loads. This has come about in new homes through Approved Document Part L 1A of the Building Regulations and in existing homes through schemes such as the Green Deal. Homes are now less leaky and better insulated to keep warmth in but attention and emphasis is needed on measures to facilitate the expelling excess heat adequately when temperatures rise.

Homes are expected to provide comfortable conditions for occupants all year round and through a range of different occupancy patterns, which may in reality be considerably different to the standard assumptions made in modelling tools like SAP. It is possible that if modelling for thermal comfort is carried out assuming worst case assumptions for occupant density, external conditions and hours of occupancy, many homes would require mechanical cooling. There are, however a number of common sense measures that can be applied to ensure the impact of key contributing factors are minimised. These include controlling solar gains from south and west facing glazing and making provisions for adequate, secure ventilation especially when thermal mass has been incorporated in the structure.
The current extent of overheating in homes must be seen in the context of the anticipated changes in climate. With external temperatures expected to rise with an increased frequency of extreme weather conditions, homes built today must be fit for purpose for warmer summers.

Mechanical cooling?
There has been a rise reported in the installation of mechanical cooling systems in homes in the UK, more noticeably so in the south. While this may be an expected feature in high end homes, the cost of running these systems can be prohibitive, or at least perceived as so, for households where minimising expenditure on energy and fuel is a priority.
There is potential to develop low carbon mechanical cooling systems such as reversible heat pumps. The large scale uptake of these can however have some serious implications for energy supply and the capacity of the grid to accommodate a draw in peak summer months.

Way forward
In addition to affecting comfort, exposure to high temperatures over prolonged periods can have a significant impact on the health and well-being of residents. It is critical therefore to agree on a set of parameters that can help define overheating in homes and this should be carried out with input from bodies such as Public Health England.
Until a definition and modelling strategy is developed, designers and housing providers can refer to several good practice guides and research studies that help embed a common sense approach to design. There is significant potential to mitigate the risk of overheating in homes if early stage design decisions are taken with due consideration for the issue. The limitations of mechanical ventilation systems to help achieve comfort in homes must be acknowledged so that the final burden of an ill-considered design does not rest with the occupants.

References and further reading
http://www.zerocarbonhub.org/sites/default/files/resources/reports/ZCH-OverheatingInHomes-TheBigPicture-01.1.pdf
Design for Climate Change, Bill Gething and Katie Puckett, RIBA Publishing Feb 2013
http://www.arcc-network.org.uk/wordpress/wp-content/D4FC/01_Design-for-Future-Climate-Bill-Gething-report.pdf
http://www.zerocarbonhub.org/sites/default/files/resources/reports/Understanding_Overheating-Where_to_Start_NF44.pdf

To find out more about our Residential Network and to download the presentations from this meeting check out BSRIA’s Network pages.  To find out more about all of BSRIA’s networks contact tracey.tilbry@bsria.co.uk.

Global BEMS Market set to Approach $7 billion by 2020

This blog was written by BSRIA's Henry Lawson

This blog was written by BSRIA’s Henry Lawson

If I could point to a market which is already worth some $3.5 billion, or 3 billion Euros, and which is growing globally at well over 10% per annum, at a time when growth in building automation is a fraction of that, I suspect that many investors and industrialists would bite my hand off. This is the industry that we explore in BSRIA’s newly updated report BEMS Opportunities.

Even Europe, which currently accounts for almost half the current Building Energy Management Systems (BEMS) market, is growing at around 10%, while North America has been growing faster, and the rest of the world substantially faster still.

BSRIA forecasts that the global BEMS market will almost double, to more than $6.8 billion by the year 2020. This impressive growth is set to occur in spite of numerous obstacles and uncertainties. This is partly because the factors driving this growth differ from one region to another.

In Western Europe, gas prices almost doubled between 2005 and 2013, while at the same time major economies like Germany became increasingly dependent on import of gas from politically sensitive countries like Russia and the Gulf states, raising the spectre of uncertain supplies.

While the rise in electricity prices has been less dramatic, Germany faces the huge task of fulfilling its commitment to

henry dec2shut down all nuclear power generation by 2022, and the UK faces similar challenges as its ageing, coal-consuming and CO2-spewing power stations reach the ends of their lives, with the ghost of Christmas back-outs rising like a Dickensian spectre to haunt the business and political worlds.

This, and increasingly aggressive environmental targets, at national and EU level, mean that even a Europe which has been in or near recession for more than five years continues to invest in energy efficiency. At the same time, there are signs that organisations at all levels are beginning to understand the full potential of BEMS to save money while meeting obligations and improving the brand.

In North America, the pressure of energy prices has been less relentless, especially since fracking of shale gas has got underway. The movement towards environmental regulation has also been patchier – often varying at local and state level, and has faced more opposition. At the same time, the proportion of energy consumed by office buildings has been rising inexorably at a time when energy used in such areas as transport, industry and homes has been either stable or falling, placing office buildings firmly in the sights of those wishing to make savings. North America also benefits from the plethora of firms developing innovative energy management solutions in both the USA and Canada.

In the rest of the world the picture is extremely varied, from developed countries like Japan and Australia with widespread adoption of BEMS, to major emerging economies like China, where energy has hitherto been seen as rather less of a problem but where the pollution associated with fossil fuels is becoming more pressing.

This growth presents huge business opportunities but also as many gauntlets thrown down. The mainstream building automation suppliers are all active, unsurprisingly, given that the two are so genetically interlinked that building automation was originally widely referred to as building energy management. They can offer the benefit of relatively easy integration of energy management into the building’s wider functioning.

Against this, as virtually every device, appliance and component of a building becomes capable of generating and communicating data, the advent of big building data has opened huge opportunities both to enterprise data and IT suppliers and to an army of smaller newer suppliers of advanced analytics, allowing building managers to predict and pre-empt problems that degrade a building’s energy performance.

Some of these new entrants will fall by the wayside, especially given the level of overlap between many of the offerings, others will be ripe for take-over, but a few are likely to emerge as major disruptive players. In our report we identify the leaders and challengers, along with the niche players and some of the most likely acquisitions. As always, there is an implicit conflict between the move towards integration on the one hand and the desire for innovation on the other, and we look at some of the standards that are emerging to address this.

The prize is most likely to go to companies that can combine innovation in new technologies, and understanding of how a building’s occupants interact with the building, with a deep-seated understanding of how buildings function. This report should help to shine a light on who will be left holding a torch for others to follow if and when the lights really do threaten to go out.

This is the industry that we explore in BSRIA’s newly updated report BEMS Opportunities.

Best & Worst Practices Please!

Julia Evans, BSRIA Chief Executive

Julia Evans, BSRIA Chief Executive

BSRIA recently held a workshop on behalf of DECC identifying priorities to promote low carbon heating and cooling in non-domestic buildings as part of the development of its low carbon heat strategy.  Attendees were drawn from both the Young Engineers and Energy and Sustainability BSRIA networks.  Personal thanks to AECOM’s Ant Wilson for chairing the event.

It was a busy day.  It recognised that both new and existing buildings have a pivotal role in reducing greenhouse gas emissions, and by 2050 one of the key requirements will continue to be how we provide heating and cooling.

BSRIA’s Peter Tse and Ian Orme both gave excellent presentations which drew on both good and poor practices identified from more than 50 independently assessed case studies.  These, I felt, answered the questions “what does good practice look like”, as well as “what are the consequences when its not followed”.

The workshop session resulted in many suggestions as to priorities for the future.  There were a couple which caught my eye.

In response to the suggestion that one of the priorities for DECC should be identifying independently assessed best practice and developing exemplars of new technologies, a number of delegates felt that instances of “bad practice” were even more helpful.  It seemed to me that a priority for at least a part of the audience was to know what to avoid doing.  Perhaps this reflects the industry’s receptiveness to messages about risk, and that we often learn most when we make mistakes.  The emphasis on “independent assessment” also resonated.  Many have become sceptical about instances of self-identified “best practice”, and BSRIA’s independent guidance on what works, and what does not, is there to assist the industry do things better.

Another of the workshop themes was on “skills shortages”.  After many years of recession, construction companies have euphemistically “right sized”, and this means that we have lost a lot of great talent from the industry.  Now that there are green shoots of recovery in construction, there is already talk of an exacerbated “skills gap”.  This gap makes it even more challenging for the industry to deliver buildings which meet the needs of their occupiers and where innovation is required to help tackle climate change, and meet the UK’s commitment to “zero carbon” and “very low energy” buildings. This reminded me of another of BSRIA’s strengths – training provision.

BSRIA's 2014/15 Training Brochure

BSRIA’s 2014/15 Training Brochure

Finally there was an astute observation that our recent quest for low carbon buildings has meant that we have worried less about the efficient use of energy, with the net outcome that we can end up with an EPC A rating for carbon design, but a DEC G rating for energy in use.  The move to policies that move us to buildings which are both zero carbon and nearly zero energy use will hopefully remedy this, although I suspect this particular journey may contain further unintended consequences before we reach that goal.

The workshop identified many requirements if we are to create environmentally conscious buildings that meet user needs, and importantly maintain these elements over the life of the building.

BSRIA’s mission remains to “make buildings better”.  As part of my role, I’m listening to our members and the industry what they expect from BSRIA.  I’d like to extend this offer to you, so if you have ideas about BSRIA’s future role, please send them to me: Julia.evans@bsria.co.uk.

To learn more about the BSRIA workshop you can download all the presentations from our website. 

The hidden menace of corrosion in heating and cooling systems

Written by Reginald Brown, Senior Consultant at BSRIA

Written by Reginald Brown, Senior Consultant at BSRIA

Most buildings services engineers will have come across a heating or cooling system that has not received water treatment and still appears to function perfectly and another that has apparently been treated but experienced serious corrosion related failures. Why should one be vulnerable and the other not? The answer is that most common metals are subject to corrosion but the rate of corrosion and risk of failure depends on a variety of factors including the chemical and microbiological environment, temperature, flow rate and not least the thickness of the metal.

In many respects water is the ideal heat transfer medium for building services. It has a reasonably high specific heat, is liquid over a convenient temperature range and is non-flammable, non-toxic and freely available. The downside is that water is an electrolyte that facilitates corrosion in metallic pipework and components. One might think that the obvious solution is to use plastic pipework but this can actually increase the risk of corrosion of the corrodible components that remain.In a steel pipework system, the dissolved oxygen in the system water will rapidly be used up as it reacts with the large area of corrodible surface but the loss of metal thickness should be insignificant. In a plastic pipework system there are few corrodible components so oxygen concentration will remain higher for longer and the corrodible materials will continue to corrode at a high rate. This means that almost all water based heating and cooling systems should have some form of water treatment to control corrosion, and it may be even more important in plastic pipework systems.

The usual construction programme for large building projects involves installation and pressure testing of pipework followed by pre-commission cleaning and commissioning several months later. During the gap between pressure testing and pre-commission cleaning the system may be both stagnant and still contaminated with manufacturing and construction residues. This is an ideal environment for the development of biofilm and corrosion.

In traditional steel pipe systems (using BS 1387:1985 or BS EN 10255:2004 medium or heavy grade pipe) this is not too much of a problem. The relatively thick pipe (at least 3.2 mm for 1 inch nominal bore and larger) can tolerate the initial corrosion due to the oxygen in the fill water and biofilm development during subsequent stagnation conditions. Provided the pre-commissioning cleaning is carried out effectively, ideally with a biocide wash prior to chemical cleaning, there should be minimal impact on the lifetime of the system.

Thin wall steel pipes and steel panel radiators may not be so fortunate. The thickness of 25 mm nominal bore thin wall carbon steel pipe is only 1.5 mm while a typical steel panel radiator is only 1.3 mm thick. If the initial corrosion was spread uniformly across the metal surface it would not be problem but what tends to happen is that small patches of the surface become anodic relative to their surroundings and are preferentially corroded leading to rapid localised pitting. If dissolved oxygen levels persist or are replenished due air ingress, continuing additions of fresh water or permeation through non-metallic materials then the pitting can progress to perforation. Components that should last 25 years can be perforated in a few months. This is one of the most frequent types of corrosion failure reported to BSRIA and can result in expensive remedial works even before the building is occupied.

Water treatment chemicals work by inhibiting the corrosion process, either by coating the surface of the metal (anodic inhibitors) or otherwise blocking the corrosion reactions (cathodic inhibitors). However, inhibitors are not the solution to poor closed system design or operational deficiencies and certainly won’t work to best effect in a dirty system i.e. one with a high level of suspended solids and/or biological contamination. Also, the system operation must allow the inhibitors and other water treatment chemical to be maintained at an effective concentration and circulated throughout the year.

In summary, the factors necessary to avoid pitting corrosion of steel components in closed systems are:

  1. Minimise the delay between first fill and pre-commission cleaning.
  2. Carry out effective pre-commission cleaning of the pipework system.
  3. Establish, monitor and maintain effective water treatment and water quality as soon as possible in the life of the system.
  4. Circulate water throughout the system on a daily basis to avoid stagnation.
  5. Avoid ingress of oxygen from inadequate pressurisation or excessive fresh water additions.
What happens in the first few weeks of the system can prevent pipe corrosion like this over the next 25 years

What happens in the first few weeks of the system can prevent pipe corrosion like this over the next 25 years

What happens in the first few weeks of the life of the system will influence its fate over the next 25 years. You can’t easily see what is going on inside a pipe but get it wrong and you could be looking at major remedial works in a tenth of that time.

A detailed discussion of corrosion and the use of inhibitors and other chemicals is contained in BSRIA BG50 Water Treatment for Closed Heating and Cooling Systems. Pre-commissioning cleaning is described in BSRIA BG29 Pre-commission cleaning of pipework systems. Guidance on the monitoring of water quality in closed systems is contained in these documents and BS 8552 Sampling and monitoring of water from building services closed systems – Code of practice.

BSRIA also runs a Pre-commission cleaning of pipework systems training course and provides independent failure investigations for all types of building plant and systems including pipweork corrosion.

This article was first published in Modern Building Services.

Is this the Real Answer for Cheap Green Energy?

Ever since the first serious concerns were raised about man-made climate change a generation ago the world has been caught on the horns of a dilemma. The choice has too often seemed to be between securing the kind of short-term economic growth which the developed world expects and the developing world desperately needs  on the one hand, and paying more now in order to secure the future of our world on the other.

It is small wonder that green energy solutions are still seen as something of a luxury accessory, perhaps affordable in times of prosperity, but pushed into the background at times of world recession, when achieving growth and combatting fuel poverty becomes an even bigger concern.

But could it be that a large part of the answer is beneath our feet, or that at least it might be: an answer that could have a huge impact on the UK as it already has had in similar countries. For once I am not  talking about fracking, but about something that has been around for a century, though the technology continues to evolve in exciting ways.

The heat network rests on the fundamentally simple idea of producing heat (or cooling) centrally, in the most efficient and environmentally friendly way, and then distributing this through highly insulated underground piping, to homes, offices, hospitals, factories and anywhere else that needs it. Often this simply taps into heat that would otherwise be pumped wastefully straight into the atmosphere.

Different measures could radically affect the growth of Heat Networks in the UK

Different measures could radically affect the growth of Heat Networks in the UK

 Such networks not only distribute heat but can store it, for hours or potentially  months, ironing out the wild and often unpredictable fluctuations in both and supply and demand and making it much more practicable to use ‘green’ power sources, such as wind or photovoltaic that are inherently unreliable, not to mention biofuels. Even where gas is still used there is scope for greater efficiencies, especially where the opportunity is taken to use generated combined heat and power (CHP)

 So why is it that this technology accounts for only about 1% of the UK’s current heating needs while in Denmark, with an only slightly colder climate, the figure is over 60%. In fact most European countries already make much greater use of this resource than the UK does, as do countries as diverse as China, Japan and the USA.

In fact the benefits of district energy are already recognised by many UK hospitals, universities and industrial plants and office complexes, frequently powered by CHP systems which offer added security of supply. So why has the residential sector been so slow up until now?

Part of the answer lies in how the UK population lives: predominantly in individual houses which are more expensive to connect, and in most cases owner occupied or privately rented, making it much harder to convert individual householders to heat networks. The relatively low rate of house building in recent decades hasn’t helped either. Gas prices that are low by international standards have also reduced incentives to innovate in this direction.

However the last few years have seen a sea-change, with far more new homes tapping into heat networks, especially new flats, spurred on partly by enhanced incentives from government and encouragement from local planners, but also by a growing Energy Services industry that is prepared to make substantial investments in order to make a long term return.

Here at BSRIA we have recognised this trend, and so decided that a fresh look at the UK district energy market was needed. The result is a report which examines the market, the main players and what has drawn them into the market. It also considers the main positive drivers along with the biggest barriers to future development, and what can be learned from experience outside of the UK.

Our research indicates that the UK District Energy market is already worth over £400 million annually (including capital investment), and that it is growing at the fastest rate in its history, so that we expect it to exceed £500 million by

This blog was written by BSRIA's Henry Lawson

This blog was written by BSRIA’s Henry Lawson

2015).

The overview takes in different possible initatives on the part of national, and local government, as well as the EU, which could speed up development or hinder it, and at the key changes in technology which are likely to make a difference in future.

If you want to know how big this market is likely to be in two or five years’ time and what the prospects are for the future, then this should be an indispensible read.

To find out more about the report or to purchase it contact our Worldwide Market Intelligence team on 01344 465610 or wmi@bsria.co.uk

When will the lights go out?

In the UK and some other countries the maximum demand on our supply network is perilously close to the supply capacity. In the UK we have a total supply capacity of 80 Gigawatts, and only around 67GW is available at any one time according to OFGEM director-general Alistair Buchanan. The maximum demand last winter was 60.5GW and the peak summer demand isn’t much less. It would only take a prolonged cold spell or a power station failure to drop the supply capacity below our maximum demand.

What this means in practice to an individual customer is that there is an increased risk of outages or voltage dips. It has been predicted that this could be a one in twelve chance of losing power in a year for any customer by 2015 and an increasing risk until either the supply capacity is increased or demand is cut. In the UK we are closing our coal fired power stations, decommissioning our old nuclear stations and not building new capacity fast enough to replace them. Read more about this in The Spectator.

Last week OFGEM published electricity supply and demand forecasts, showing that spare capacity has fallen as more gas-fired plants have been mothballed. It reiterated warnings that even if blackouts are avoided, power prices will rise steeply.  With the UK generation capacity margin likely to drop to 2% by 2015 the competition for supplies is likely to push prices up by 20%. Read more in The Telegraph.

Graph taken from Bill Wright's presentation given at BSRIA Workshop

Graph taken from Bill Wright’s presentation given at BSRIA Workshop

The profile of generation capacity over the next ten years is affected by political decisions such as closure of coal-fired power stations, extending the life of old nuclear stations, availability of imported gas, introduction of fracking for shale gas and planning permission for renewable energy.

Businesses need to prepare for the increased risk to protect their business continuity. At a recent BSRIA workshop, business leaders talked about how they could respond to the risks and the knock-on effects of power outages.

There are two main approaches:

  • reducing demand, including demand side management
  • adapting to a less reliable power supply with standby power.

But the effects of power outage on security of supplies, transport and even public order and crime need to be considered.  The process of planning for outages and continuity of power is part of a more general process of Business Continuity Management, for which there is a British Standard Code of Practice, BS25999.  This Standard covers all the threats to business continuity, but with the risk of power loss to a business and its supply chain and the effects of power loss on staff, customers and the public there may be a need to re-assess the risks and amend the business continuity plan.

OFGEM are hosting a Working Group to develop solutions to network capacity problems using the Low Carbon Networks Fund.  Their recent seminar presented the results of commercial and domestic demonstration projects.  The domestic demand peaks at nearly double the daytime demand between 4pm and 8pm on weekdays.  The early part of this peak coincides with the last hour of the working day so commercial demand is also high.  Various approaches to demand management are being trialled in different areas of the UK including incentives and variable pricing.

There are incentives for customers agreeing to cut their demand when local supply nears capacity.  These are set up locally with different priorities, such as the Thames Valley Vision which utilises Automated Demand Response and Business Consumer Consortia along with energy storage to reduce peak demands and avoid the need for supply network reinforcement.

In summary, the UK electricity supply network is expected to become less reliable and this will affect consumers as soon as 2015.  If consumers don’t do something they are likely to be hit by power cuts more often.  Solutions include planning for power failures, checking the reliability of standby systems, negotiating demand reduction facilities or permanently reducing demand.

BSRIA is keen to work with building operators, manufacturers, network operators, consultants and anyone involved in power continuity management.

District heating is on the move

Last November at the BSRIA Briefing, I shared my thoughts about how CHP and Energy Supply Contracting models can possibly contribute to building a low carbon community. CHP is a low carbon technology but is only suitable for a larger scale site with a good base load to have better efficiency. ESCOs using the Energy Supply Contracting model can avoid a client’s upfront cost on implementation. However, no matter how good the solution and technology is, capital is always the barrier. Recently, I came across two pieces of news that I would like to share with you. It looks to me things are now moving.

First, the Scottish government announced in March a new £2.5 million District Heating Loan Fund. Registered social authorities, SMEs and ESCOs can apply for funding. The fund will offer loans of up to £400,000 to support low carbon and renewable district heating in Scotland.

Second, Leicester City Council is going to extend the current district heating network across the City of Leicester. The Council signed a 25-year contract with an ESCO to maintain and operate the plant. The ESCO will be responsible for part of the capital investment and there is additional funding from the Community Energy Saving Programme (CESP). It is predicted that the project will help the Council to reduce at least 10% of their carbon footprint.

It seems funding is coming and district heating is on the move. Are you aware of this move?

As an aside I noticed National Grid runs a program called Short Term Operating Reserve (STOR). Under this scheme, National Grid buys electricity power from privately owned generating facilities. The need for STOR is because at certain times of the day, the National Grid needs reserve power in the form of either generation or demand reduction to be able to deal with actual demand being greater than forecasted demand.

The question is, how will STOR influence large scale CHP in the future?…

Making CHP ‘do-able’

Front view of a CHP unit

The Government’s set a target for the UK to generate 15.5 GWe from combined heat and power (CHP) by 2020. Today, only 5.5 GWe is generated from CHP. So, how do we deal with this target shortfall in CHP?

The planning department has, in recent years, relaxed their policy on approving CHP plant projects. On the other hand, they try to insist on new building design incorporating CHP.  Of course, nobody likes to be coerced like this. But what is more important is that arguably this approach is not effective. For example, design engineers sometimes find it difficult to justify using CHP instead of the traditional boiler. It is seen to be too costly to build the CHP where the return on carbon reduction will be so little.

There is nothing inherently wrong with CHP, but rather in how we apply it. This large kit, even with better efficiency, is not suitable for a building-by-building application. We need to think at a community scale. It works perfectly well in district heating, or even a small community with several buildings. The key is to have more buildings where the load profile requires a constant energy demand.

CHP is more costly than traditional boilers. When it comes in a larger scale, the capital investment will probably be rejected by your finance director. But, does that really have to be the end of the story?

A happy ending with Energy Supply Contracting?

Perhaps, if you haven’t already done so, you should consider Energy Supply Contracting (which is also called Contract Energy Management in the UK). The service providers (ESCOs) provide low carbon energy to the clients, and the advantage of this business model is that it can allow the end user to enjoy low carbon energy without any upfront cost.

More thoughts on this particular model to follow – but what do you think? Can you tell me about any good or bad experiences with this?

Look at carbon, not energy

We urgently need a clear strategy for decarbonising the grid…and here’s why.


by thinkpanama, creative commons, flickr

The world is still awash with energy.

Peak oil may have passed but peak coal has not. Nor has peak gas, and nuclear and renewables are now a rising trend.  In other words, the problem is not a shortage of energy it is too much carbon.

The trouble is, at the moment it’s hard to find a quick and easy way of taking carbon out of the primary fuel mix. So, the focus is on reducing loads, getting more out of each unit of carbon fuel, and using so-called renewables to substitute for fossil fuel.

We’re too used to having energy on tap, generated and piped from a distance. Community scale services challenge this view of life (we’ll be debating this at our briefing). Low-carbon communities attempt to use waste in order to distribute relatively low-grade heat rather than high-grade energy.

This heat is ‘free’ insofar as it recovers energy from electrical generation, household waste, or from geothermal sources. Of course, nothing is actually free. Pipe work, pumping, capital costs and so forth means that fixed costs can exceed the notional cost of the primary fuel burned to generate distributed heat.

Because of high capital costs and the long lifetime of systems (like water mains), financial planning for low-carbon communities needs to take the long view.

We  don’t know what the carbon advantage of such systems will be in the future. If there is a significant and quick (economically speaking) rise in zero carbon wind and marine generation, and carbon sequestration in coal fired plants becomes the norm, then the carbon intensity of the grid will reduce to the point where the advantage of community based systems is lost.  In short the carbon arguments for community heating systems depend crucially on the speed of decarbonisation of the grid.

This is a community-scale heating dilemma. We should have invested in CHP/DH a couple of decades ago when we had access to North sea gas – instead we face the prospect of digging up the roads yet again and forcing householders to abandon their cherished boilers. But, without a guaranteed connected load and the effective displacement of high carbon intensity grid supply it will be difficult to make community scale heating financially attractive to a commercial investor.

So, we should focus on decarbonising the grid or develop heat-sharing technologies through low-carbon communities?  These are mega questions and need a national strategy where government must lead the way. What will be the role of the building services engineer and construction teams in planning and delivery whole-community solutions?

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