Fossil Fuel Free BuildingsPosted by karen in Front, News, on February 13, 2012
We often have people contact us who are interested in taking their home or commercial building “off the grid.” Taking a building completely off the grid can be difficult and expensive. A more realistic target is a “net-zero” building. This type of building is still connected to the grid but produces as much power as it uses. Generally most of that power is produced by solar energy systems. A net-zero building would supplement the solar power with grid power during the winter when the solar resource is limited. And during the summer excess solar energy could be added to the utility grid and the building owner can receive credit for that power.
Net-zero buildings can still be expensive. For those with a more limited budget but who still want to reduce their energy footprint, another target to consider is the “Fossil Fuel Free” building. This is a more realistic target where the building only uses energy that does not produce greenhouse gas emissions. It also reduces the need for expansion of oil production and transport which are currently hot topics in our region.
The first step in achieving this target is to reduce the heating load on the building. When building a new home one might want to consider the passiv-haus standard. Existing buildings would upgrade their envelope to achieve better air tightness and insulation. Then rather than use natural gas to heat the building, heat pumps can be employed. Heat pumps use electricity, but are 3-4 times more efficient than regular resistive electrical heaters. The heat pumps could be air-source, water-source or ground-source (geo-exchange). Ideally, these would be combined with a heat-recovery ventilation system.
The second application that often uses natural gas is domestic hot water. Consumption here could be reduced in half by using a solar hot water system. The remaining heating load can be handled efficiently using heat pumps or an on-demand electric heater.
With natural gas eliminated from the building, the goal becomes making the electrical consumption fossil fuel free. In BC, 85-90% of our electricity is generated from renewable sources. To offset the electricity that is generated by fossil fuels, the building owner need only offset about 10-15% of their electrical consumption with a solar photovoltaic system.
VREC can install both photovoltaic and solar hot water systems to help you towards a goal of being fossil fuel free. We also work with partners that can upgrade your building envelope and install heat pump systems.