Developing economic well-being and preserving a healthy environment are not opposed forces but do, on the contrary, have a primary relationship and require a similar way of thinking: maximizing the efficiency of a product over its life cycle will minimize its total financial cost as well as the total environmental impact over its life cycle.

Evaluating Environmental Performance in Low-Carbon Energy Systems

Sergio Ferreira | Leonardo Energy

The case studies below were developed to substantiate this Life-Cycle-Thinking by delivering high-level messages supporting decision making on the sustainable energy arena.

Developed by PE International using the capabilities of the GaBi Software embedded into the Ecodesign Toolbox 3, the case studies provide results for several realistic (future and present) situations in regard to different scenarios and boundary conditions for energy systems.

The aim is to define a common denominator that can be used as a starting point for further developments and discussions. To complement the decision-making landscape, future scenarios are also modeled – not as a straight jacket, but as a means to assess the influence of various trends or decisions.

The full paper "Evaluating Environmental Performance in Low-Carbon Energy Systems" is available at

Case 1 - Environmental impact of the electricity mix

Case study 1 was constructed with the intention of assessing how the choice of power grid mix influences the environmental impact of producing electricity. Electric power can be produced from various renewable and non-renewable resources, and the technologies to harvest renewable resources are gaining momentum, together with the global pressure to increase their contribution to energy provision.

In the EU, targets have been set for 2020 to generate 20% of the total energy demand from renewable resources. National schemes have been set up to reach this overall goal, stricter for the more advanced and economically stable nations and laxer for the more economically disadvantaged ones. Although the target is very demanding, the potential benefits are likely to compensate for the efforts within a short time. In this theoretical exercise, the environmental impact of the current grid mix is assessed against potential future scenarios of electricity production in 2020, 2030 and under conditions of zero carbon emissions. The baseline for the comparison is the provision of 1kWh of electric power.

Full Case Study PDF

Case 2 - Low-Energy House heating system

In this case study, the analysis targets a comparison between heating systems in a low-energy house. The definition of a low-energy house can be found in the Glossary.

Heating systems today are still largely fossil fuel-based, although electric heating systems are also gaining ground. Considerable debate surrounds the use of electric heaters versus efficient (~100%) gas heaters. While gas is the cleanest of fossil fuels with regards to emissions, and the heat gain is also very high, electric power has the potential to improve its emission profile by the incorporation of more and more renewable resources. Today, however, electric power is both inefficient (a single unit of usable energy produces 2 units of losses) and still largely dependent on fossil fuels.

In this case study, the Best Available Technology of both heating systems will be compared, namely gas condensing boilers and heat pumps. The efficiency of gas condensing boilers lies in their capacity to capture the latent heat of water vapour produced through the burning process that would otherwise (in older designs) escape through the vent. On the other hand, the heat pump utilises the thermal energy in air or groundwater to pump heat into the house, and while the pumping itself requires energy, the produced thermal energy (heat) is four times higher than the electricity consumed by the equipment.

In addition to comparing different heating technologies, the case study also endeavours to assess them using different future grid mixes. Current scenarios refer to the use of the latest GaBi power grid mix dataset for EU-25 countries. Therefore the analysis not only compares the best available technologies today, but also looks at how the relationship may change in circumstances where electric power provision will derive increasingly from renewable resources. While it may seem unfair to show potential improvement for only one of the technologies under scrutiny, it is indeed only realistic to expect an increase in renewable energy sources in the grid mix, while there is little to no room left for improvement in gas-based heating systems. The basis for comparison is the provision of heating for the life cycle of the same low-energy house.

Full Case Study PDF

Case 3 - Low Energy House vs Passive House

Low Energy and so-called Passive Houses (LEH and PH, respectively) represent innovative design and technologies implemented in favour of energy efficiency. Compared to a standard house, both of these housing types have increased window surface area facing south, increased insulation on both walls and windows, sand-lime brick replacing the traditional bricks. The general description of the housing types is provided in the Glossary, while the list of parameters defining the houses in the model is provided in Supplement A.

The difference between LEH and PH is mostly a question of degree of efficiency: insulation is better in the PH and therefore the total heat demand of the same-sized house is much reduced. To match this high level of efficiency, an electric heat pump is the desirable choice, while in the LEH the best available fossil fuel-based heater, i.e. the gas condensing boiler, is implemented.

In Case Study 2, the gas condensing heater was compared to the heat pump inside the LEH. In the present case study, the comparison is between the two houses with their standard heating system, i.e. gas condensing boiler for LEH and heat pump for PH. In addition to comparing different heating technologies, the case study also endeavours to assess them using different grid mixes.

Full Case Study PDF

Case 4 - Primary Energy vs Global Warming

In previous case studies, the best available fossil fuel-based heating system was compared with the best available electric heating system. A relatively outdated technology of heaters, however, may in the future prove to imply the environmentally cleaner solution. Night storage (or accumulation) heaters are electric appliances that produce and store heat overnight when electricity from the grid is cheaper due to a situation of more available provision than demand, and release it throughout the day.

Although intended more as an economical incentive for customers, the long-term environmental consequences are worth considering and revisiting.

On the one hand, using night time electricity may redistribute the power demand over day slightly better resulting in so-called peak-shaving, or a decrease in the peak-time energy demand. This effect is very difficult to quantify though and is therefore purely speculative.

On the other hand, future power grid mixes may contain sufficiently high shares of renewable resources that make it possible to (partially) shut down the fossil-fuel based plants overnight. While electricity is still consumed, and the losses through the grid are considerable (~65%), the benefits in terms of emissions can become significant, and shall be investigated with this case study.

Full Case Study PDF

Case 5 - Investing 1 million Euros into higher efficiency motors or wind turbines

In case studies 1-4, considerations of energy use were purely environmental. Decision-making processes, however, need to factor in economics as this may change rankings entirely: if a limited amount of money has to be spent, cheaper solutions may be implemented numerous times and thus the multiple uses of smaller changes may even outperform a single grandiose scheme. To assess the economic aspects of electricity use, a simple yet powerful exercise will be conducted in this chapter.

One million Euros can be invested a million ways, but two of them were chosen for this purpose: (1) a wind-power turbine that will allow electric power generation with almost no carbon dioxide emissions, and (2) an electric motor with a high efficiency construction. While the one creates practically emission-free power, the other reduces the electricity consumed. The question investigated here is: which one prevails when environmental gains are factored in with their costs?

Full Case Study PDF

Case 6 - Building new houses (1 million Euros financing different energy efficiency levels)

In case studies 3-4 the environmental benefits of a Low-Energy House (LEH) were compared to a Passive House (PH) both equipped with the best available technology to suit the house type.

In this case study, the environmental comparison was complemented with an economic assessment of the decision alternatives. This case study can be thought of as a cost-benefit analysis of building a new house with different environmental and economic costs and benefits.

Basically, the study aims at analysing the sustainability one can buy investing 1 million Euros in different concepts. Three alternatives for improvement are considered, using a Standard house as the baseline (see definition in the Glossary and parameter settings in the Appendix). The LEH with gas condensing heater represents one option, the PH with heat pump another, while the PH with night storage heater a third one.

The environmental benefits of the first two options have been discussed before on Case Study 3 and will only be referred to here. The storage heater benefits have been discussed in the context of a LEH in Case Study 4, and so this scenario is expected to show improvement compared to that one. The night storage heater (NSH) scenario will also be investigated using the future grid mix of 2030 with a night tariff system in place.

Full Case Study PDF

Case 7 - Renovating standard houses (1 million Euros financing different energy efficiency levels)

In Case Study 6, the investment costs and environmental payoffs of newly built houses were compared. In this case study, the renovation options of a standard house (see Glossary and parameter settings in Appendix) will be compared both in terms of the environmental benefits obtainable with the investment of 1 million Euros in each case.

Two alternatives are considered: in scenario (1) the standard house will simply be equipped with a gas condensing heater, the Best Available Technology among fossil fuel-based heating systems; in scenario (2) the standard house will be renovated with additional insulation and equipped with gas condensing heater.

While one option represents a very economical but short-sighted approach, the alternative represents a financially more burdensome, yet far-sighted approach. The question addressed here is whether the lower investment costs can compensate for the higher consumption in the use phase of the standard house versus the newly insulated house.

Full Case Study PDF

Leonardo ENERGY aims to contribute to the sustainable energy community. To help understand your perception of the initiative and improve it in the long-term, we are conducting a short survey.

We are seeking input from visitors who have been with us a long time and also that of new visitors who have recently discovered us.

Your contribution would be greatly appreciated.

The Leonardo ENERGY Team


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