The Issues With Energy

Today there are a myriad of energy issues, domestic and commercial, personal and global, causing stress, degrees of hurt and concern to all at various levels. Globally, the present economic situation and that of the last few years has removed any feeling of confidence, especially as it seems every news bulletin and newspaper headline only serves to increase the uncertainty.

Behind the economics, energy has become the biggest business in the world. with an explosion of doubts, experts, legislation, new terminology and a general ignorance about the security of supply and many other related topics.

In recent times, increasing attention on the issue of energy security has bred a number of concerns, including fears about peak oil and reliance on potentially unsavoury and unstable foreign sources of energy. The rising energy needs of rapidly developing countries, such as China and India, and their highly criticised efficiencies, worries many.

At home, the energy sector has changed drastically over the last decade. We consume more energy than ever, and energy prices have become more volatile than before. Global oil consumption has increased by more than 20% since 1994, while oil and gas prices have nearly doubled in the EU over the past two years. The threat of climate change is driving the greater need for global reductions in greenhouse gas emissions.

For the construction industry, many of those involved struggle to keep up to speed with the ever-increasing changes in legislation and regulations derived from Europe. There are many new terms and synonyms that stress and stretch the levels of understanding. European terms such as ‘eco-building’ or ‘green building’ which are used to describe homes and buildings, along with the terms low energy house, zero carbon house, passive house, highperformance house, zero energy house, energy positive house, three-litre house and many more.

Variations not only exist regarding the terms selected, but also what energy use is included in the classifications. Ideally, the lowest performance requirements should take into account all types of energy use demanded for space heating and cooling, domestic hot water, air conditioning and overall electrical consumption.

The main area of disquiet for the industry would be Passive House standards and the Code for Sustainable Homes, with a level of debate as to what both are, and at what point do they become relevant. There is a trail of misinformation and the need for a decisive lead and informed guidance on all the standards and the impending changes. Without this, the industry will struggle to quickly come to terms with modern building techniques.

The key movers will be the Code for Sustainable Homes, BREEAM and Passive House.

Passive House (PassivHaus) refers to a standardised category of low energy building where thermal comfort can be achieved without a need for a conventional heating system. Passive house design typically utilises passive solar gain, glazing with U-values around 0.75 W/(m2K), airtight building envelope with Mechanical Heat Recovery Ventilation and devoid of thermal bridging. The annual demand for space heating is designed @15 kWh/(m2a), roughly 80% less overall energy, with the total primary energy use being 120kWh/m2 p.a.

Zero carbon houses – the zero carbon house/zero energy house is designenhanced so that the remaining energy needs of a ranked passive house are entirely offset with carbon free, renewable sources. A house with zero net energy consumption can be, in certain conditions, self-sufficient from grid supply. This will be the only design-led type of dwelling that will meet building regulations by 2016 if current UK government regulated changes are maintained. This major move in standards creates the biggest sea change in standards of build for the industry designers and builders.

The pending energy and building statutory variations that are driving change are causing the construction industry and designers real problems. For example, the difference between Passive House design standards – energy rating per square metre of floor area – and the Code for Sustainable Homes (CSH), which is purely an environmental assessment method, is causing many issues. Typically a Passive House can achieve a rating equivalent to code level 4 – 5 relating to the code for sustainable homes rating scheme. It would be wrong to attempt to issue a code (CSH) rating using passive house methodology. The CSH has nine key areas that the overall assessment is based on:

Energy/CO2

Health and Well-Being

Water

Pollution

Materials

Waste

Site Management

Ecology

Surface Water Run-Off

To fully understand the importance of this method, the ‘energy’ assessment on its own equates to a maximum of 36.4% points overall in the points awarded – the other 63.6% is accredited in the other eight categories.

The Code for Sustainable Homes proposed graduated UK implementation and minimum requirements over time (some have already been brought forward): 2010 level 3 (25% better than November 2006 regulations), 2013 level 4 (44% better than previous regulations and almost Passive House standards) 2016 level 5 (zero carbon for heating and lighting, Passive House standard) 2016 level 6 (zero carbon for all uses and appliances) Both assessment methods have different objectives – the CSH targets a wider set of nine environmental criteria, while PH primarily covers the energy required for space heating.

They are both seen as mutually beneficial to addressing improved energy use, but can’t be used together. A comparison of both assessment methods would be like an appraisal of a Mini and a Rolls Royce. Both are excellent cars and very reliable, but there is no direct comparison! Passive house has a beneficial application in that it can be applied to the residential sector, as well as commercial, industrial and public sector buildings. Across Europe, it would be difficult to set a single assessment method, given the varying climatic, cultural and regulatory conditions. It is therefore difficult to define exactly the concept of low energy buildings for the entire European Union. National assessment methodologies and standards contrast so that ‘low energy’ developments in any one country may not meet standards in another.

BREEAM is an environmental assessment method and rating system for industrial and commercial buildings and large housing developments. BREEAM, like the CSH, uses nine criteria areas for the overall environmental assessment. Other major areas of concern are build costs, the choice of materials to build with, and how best to meet regulation changes, based on purely environmental aspects. Initial passive and zero carbon projects have reflected noticeable increased construction costs, as improved insulation techniques, thermal bridging reduction, improved glazing methods and mechanical heat recovery ventilation systems became key systems and drove up costs.

The issue of building houses that are thoroughly sealed and moisture-proofed is extremely difficult but very important. This means that the construction personnel require more time to design and complete the projects in an era of quality-driven standards. Modern Passive Homes are technically complex by their very nature and require high standards of application to maintain integrity. Therefore it’s important that builders addressing these modern build techniques understand the need for highly skilled and well trained personnel in all trade areas. Without a build sequence and dedicated build programme, the likelihood of a breach in the airtight membranes during construction could lead to major structural issues at a later date. If such situations were allowed to happen, then the costs to repair or replace structural elements could be considerable. The control of humidity levels in these building types is crucial for health and well-being – and more importantly for building integrity, especially in the case of wooden structures.

The use of mechanical heat exchangers for ventilation air change will become a life-saving device in times of increased occupational use. Filters will need to be maintained to ensure health issues are adequately addressed, with a minimum requirement of cleaning or changing them at least once a year. The growth and use of renewable technologies has increased at a steady rate for the past decade and they will be integral part of the solution for achieving zero carbon building standards. Appropriate design and installation of renewable technologies has long been an area of great concern for many who paid for their install, only to be let down by poor design or installation. Simply using a named technology in any circumstance, without proper understanding of the reasoning behind the choice and the overall performance criteria for any system, cannot be allowed to happen. All renewable systems should be designed with full consideration for the geographical location and orientation, available natural resources, the building type, its occupation, lifestyle, usage patterns and control methods. Only then will the technology have the capability of maximising returns in energy savings. Clearly there are major hurdles ahead for the industry, where the use of energy is concerned!