Electric Currents

Energy Use In a 'One Tonne Life'

Aug 17, 2011

The Lindell family is your average Swedish family of four, each producing about 7 tons of CO2 annually, then they tried living the 'One Tonne Life.'

Lindell family with their A-hus solar home and Volvo C30 electric car.

Volvo Cars, A-hus and Vattenfall, the Swedish energy company collaborated this past winter on the One Tonne Life project, the goal of which was to demonstrate what life at one ton of carbon dioxide per person might be like. The Lindell family of four moved into the A-hus designed solar home, and traded their two gasoline cars for a Volvo C30 Electric. They also gave up a skiing vacation in Switzerland for one in Sweden; and also changed their eating patterns, in the process cutting their per person emission to 1.6 tons by the time the experiment wrapped up earlier this summer.

EV World communicated with both A-hus and Vattenfall to better understand the family's actual energy use and the contribution its solar thermal and photovoltaic panels made. The shortfall, indicated in the table below, was made up by low-and-no CO2 sources like hydroelectric and nuclear power, as explained by Vattenfall's Lars Ejeklint in his response to our inquiries.

Energy Profile of the One Tonne Life

The “One Tonne Life” house has (triple-layer walls with exceptional) high insulation capability and minimal air leakage as well as low energy windows and doors

The sealed design is an important factor behind low energy consumption. It is important that the plastic foil in the construction keeps the entire climate shell sealed.

The classic wind-catcher in the entry hall has double doors so the heat inside does not disappear every time the door is opened. This creates a comfortable climate inside the house and the energy consumption becomes lower.

The problem with this type of house is not that it gets cold indoors in the winter, but that it gets hot in the summer. That is why the frames have been designed so it only let in the sun light when the sun is low on the horizon during the winter months. 

The house is equipped with both solar collectors and solar cells.

The solar collectors on the roof of the carport has an angle of 30 degrees so that the panels can capture more energy from the sun when it is lower on the horizon during the spring, autumn and winter and produce a lot of hot water and heat when the house needs it.

Accumulator tanks of 300+300 litres installed in the laundry provide hot water and the little heating that is needed.

When the sun is not shining and the accumulator tanks have no solar power stored, the house gets renewable energy from Vattenfall.

The solar cells on the roof and the south-facing facade generate energy that is used to power facilities such as supplementary heating, ventilation, the fridge-freezer and so on. Surplus production is used to recharge the family’s electrically powered Volvo. Any electricity that is not consumed by the family is fed into the national grid

In order to ensure that the occupants get a supply of fresh air of the right quality in this well-insulated house, air turnover is handled by a ventilation unit that sucks out poor-quality air from the bathroom/toilets, the laundry room and the kitchen, while at the same time replacing it with fresh, tempered air in the bedrooms, living room and other public areas.

About 80 percent of the heat in the spent air is recycled and used to heat the income air

The building’s needs of are met by the incoming air, the occupants’ body heat and heat-generating household apparatus such as white goods and kitchen appliances. On the bottom floor, under-floor heating provides additional heat when it’s necessary cold days.

During the project, the Lindells reduced emissions from their home and energy consumption by 60 percent. The single most important contributory factor was their new “One Tonne Life” home, which is not only an exceptionally energy-efficient house but also a producer of heating and electricity.

Before the project, the family purchased about 29,000 kWh of electricity a year in there old house. (The average houses in Sweden consume 26.200 kWh. 15.000 kWh is used to heat the building. 5.000 kWh is used fore producing hot water. The rest, 6.200 kWh, is used to power facilities such as the fridge-freezer, TV, lighting and so on.)

During the project this dropped to just 6000 kWh, a reduction of about 80 percent. What is more, on sunny days the house generated a surplus of electricity corresponding to about 1500 kWh a year, supplied to the mains grid for use by other customers. Emissions from construction of the house correspond to about 400 kg of CO2 per person per year. Maintenance-related emissions must be added to this.

The sun panel produce total about 5000 kWh in the Stockholm area.1500 kWh of these is sold.

Halfway through the project the family started buying electricity from hydropower. This meant that emissions from electricity dropped considerably since previously, part of their power came from coal-fired stations. As of May the family have started to sell more home-generated electricity to the mains grid than they have needed to buy to run their home.

The emission of CO2 in Sweden are extremely low because almost half of the production are are produced in water power plants. Nuclear plants produce also produce almost half of the production. A couple of % is produced by wind power and fossil.

Since the family only lived in the house in six month we have to calculate how much energy the house will consume during a year.


kWh/year

Needs of energy


Hotwater and heating

8063

Electricity for household equipment for instance lighting, freezer, computer, dishwasher

5600

In total

13700



Energy production


Energy from the solar panel and the solar cell

6350



Needs of energy – Energy production

7350



Surplus production of electricity

1500



Net need for purchased electricity

~ 6000

We have no battery installed. The surplus production of electricity is sold to Vattenfall. The production during a sunny day is higher then the needs.

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